Origin of group-level statistics in psychology and cognitive neuroscience In experimental psychology and cognitive neuroscience today, with the exception of a few specific subdisciplines, the consensus seems to be that an experimental study has to be performed on a group of subjects which are considered as a sample from an underlying population. Statistics is then applied in such a way as to allow an inference on properties of the distribution in that population of a certain psychological function or feature, most often the population mean.

My question is: When was this consensus established, with which reasoning, and on whose initiative?

In my experience, current textbooks on statistics in psychology discuss the statistical procedures in great detail, but contain only a few cursory remarks on the psychological (not statistical) motivation of these procedures. They do not discuss why a cognitive scientist should be interested in a population-average reaction time, a population-average event-related potential etc. – instead of e.g. effects that are present in every single individual in the population, or a specific sub-population. Or maybe I'm just looking at the wrong books?

What you are actually asking about is the debate surrounding the question:

Can psychological quantities be measured?

Up until about 1800 psychological questions where discussed by philosophers. A separate psychological discipline did not yet exist. Answers to questions relating to perception, emotion and cognition where attempted on the basis of religious beliefs, philosophical tradition and unsystematic observation and introspection.

Over the course of the eighteenth century, the body-mind dualism was slowly being resolved, which allowed first physiologists and then physicists over the course of the nineteens century to begin to apply their methodology of experimenting with plants and animals and mathematical principles, as they had been developed within the natural sciences, to psychological questions. In the middle of the nineteenth century, the first psychological institutes were founded, the first by Wundt (in Leipzig, Germany), and the discipline of psychology came into existence.

Looking at the history of psychology, you will realize that while psychological questions are as old as humanity, the academic discipline of psychology came into existence when scholars began to measure, i.e. quantify, the psyche. This was in accordance with the rise of the natural sciences during the Enlightenment and their dominance over our whole worldview (almost?) until today.

In his classice monography, Psychometric Methods (1936), J. P. Guilford writes:

  The progress and maturity of a science are often judged by the extent to which it has succeeded in the use of mathematics. The “psychometric methods” are procedures for psychological measurement. Measurement means the description of data in terms of numbers and this, in turn, means taking advantage of the many benefits that operations with and mathematical thinking provide.

Thus, while psychological questions have traditionally been considered in the humanities and arts, the academic discipline of psychology has been created and finds its home within the natural sciences and shares their basic approach of quantitative measurement and statistical analysis. Philosophical and artistic "psychology" have continued to exist parallel to institutionalized academic psychology and have given rise to psychoanalysis (Freud), humanistic psychology (Rogers) or critical psychology (Holzkamp), among others.

The principles and standards of psychological experimentation and statistical analysis as we know them today where not discovered instantaneously but developed and refined until the middle of the twentieth century. In 1936 Guilford found that the natural sciences lacked a common theory of measurement:

  Measurement in the physical sciences has come so naturally that in that connection little thought has had to be given to what measurement really is. There are some physical scientists who maintain that what is called measurement in psychology is not measurement at all. It is true that the term measurement is sometimes defined in such a way that it does not apply to most of the operations in psychology commonly known as measurement. Definition of an abstract term such as measurement is an arbitrary matter, however, and psychologists will either define it to cover what they are doing under that concept or they will invent a new term for what they are doing with numbers and arithmetical operations. Fortunately, measurement can be defined sufficiently broadly to include the operations known as psychological measurement.

Four years before this statement, in 1932, the British Association for the Advancement of Science had established a committee of scientists that should consider the problem of measurement in the empricial disciplines. The committee was especially asked to resolve the question, whether a measurement of sensation was possible. The answer to this question would decide wether psychology was a natural science coequal to physics or chemistry. Psychologist S. S. Stevens (1946) writes about the committee's discussions:

  For seven years a committee of the British Association for the Advancement of Science debated the problem of measurement. Appointed in 1932 to represent Section A (Mathematical and Physical Sciences) and Section J (Psychology), the committee was instructed to consider and report upon the possibility of “quantitative estimates of sensory events” — meaning simply: Is it possible to measure human sensation? Deliberation led only to disagreement, mainly about what is meant by the term measurement. An interim report in 1938 found one member complaining that his colleagues “came out by that same door as they went in,” and in order to have another try at agreement, the committee begged to be continued for another year. For its final report (1940) the committee chose a common bone for its contentions, directing its arguments at a concrete example of a sensory scale. This was the Sone scale of loudness (S.S. Stevens and H. Davis, Hearing. New York: Wiley, 1938), which purports to measure the subjective magnitude of an auditory sensation against a scale having the formal properties of other basic scales, such as those used to measure length and weight. Again the 19 members of the committee came out by the routes they entered, and their views ranged widely between two extremes. One member submitted “that any law purporting to express a quantitative relation between sensation intensity and stimulus intensity is not merely false but is in fact meaningless unless and until a meaning can be given to the concept of addition as applied to sensations.”

So, while the committee could not agree on the question wether sensation can be measured, they made it clear that an empirical equivalent to arithmetic addition would constitute measurement. This refers to the foundation of the measurement of physical quantities by Hermann von Helmholtz (1887) and defined axiomatically by Hölder (1901).

I don't want to go into the details of this argument, because it goes beyond the scope of this question. In short, Helmholtz sought to base measurement on the empirical comparison of so-called "extensive quantities", for example physical length or mass. He correlated arithmetic addition to physical combination (e.g. lineal apposition of staves to measure lengths) and the equality of two numbers to a method of "physical comparison", for example the comparison of weights on a beam balance).

How these principles of extensive measurment can be applied in psychology, and if it should, has been heavily debated, and different "test theories" have been developed, such as classical test theory, latent trait theory, or the theory of knowledge spaces. Foundational texts for a representational theory of measurement are those by Krantz, Luce, Suppes, and Tversky (1971, 1989, 1990) and Robers (1979), if you are interested in this aspect. All books feature some general introduction but require mathematical understanding to follow.

This requirement of a broad and deep understanding of mathematics is the reason why all psychology looks the same to you.

Most currently publishing psychologists have only a superficial understanding of methodology. Gigerenzer, Krauss and Vitouch (2004) explain some of the methodological shortcomings and mistakes:

  One of us once had a student who ran an experiment for his thesis. Let us call him Pogo. Pogo had an experimental group and a control group and found that the means of both groups were exactly the same. He believed it would be unscientific to simply state this result; he was anxious to do a significance test. The result of the test was that the two means did not differ significantly, which Pogo reported in his thesis.

  In 1962, Jacob Cohen reported that the experiments published in a major psychology journal had, on average, only a 50 : 50 chance of detecting a medium-sized effect if there was one. That is, the statistical power was as low as 50%. This result was widely cited, but did it change researchers’ practice? Sedlmeier and Gigerenzer (1989) checked the studies in the same journal, 24 years later, a time period that should allow for change. Yet only 2 out of 64 researchers mentioned power, and it was never estimated. Unnoticed, the average power had decreased (researchers now used alpha adjustment, which shrinks power). Thus, if there had been an effect of a medium size, the researchers would have had a better chance of finding it by throwing a coin rather than conducting their experiments. When we checked the years 2000 to 2002, with some 220 empirical articles, we finally found 9 researchers who computed the power of their tests. Forty years after Cohen, there is a first sign of change.

  Editors of major journals such as A. W. Melton (1962) made null hypothesis testing a neces- sary condition for the acceptance of papers and made small p-values the hallmark of excellent experimentation. The Skinnerians found themselves forced to start a new journal, the Journal of the Experimental Analysis of Behavior, to publish their kind of experiments (Skinner, 1984, p. 138). Similarly, one reason for launching the Journal of Mathematical Psychology was to escape the edi- tors’ pressure to routinely perform null hypothesis testing. One of its founders, R. D. Luce (1988), called this practice a “wrongheaded view about what constituted scientific progress” and “mind- less hypothesis testing in lieu of doing good research: measuring effects, constructing substantive theories of some depth, and developing probability models and statistical procedures suited to these theories” (p. 582).

  The student, the researchers, and the editors had engaged in a statistical ritual rather than sta- tistical thinking. Pogo believed that one always ought to perform a null hypothesis test, without exception. The researchers did not notice how small their statistical power was, nor did they seem to care: Power is not part of the null ritual that dominates experimental psychology.

The articel runs on and explains what the p-value can and cannot do (read it, if you are a psychologist). I only quoted the beginning in length to show you that a methodologically savvy minority among psychologists believes that the majority of scholars publishing in their discipline does not know what they do. They follow a "ritual" of blindly applying the same methods to all problems, thus hampering the progress of the discipline and reducing the value of their findings.

Nevertheless, while widely ignored, progress has been made (see my brief remarks about different theories of measurement above).

If you want to learn more about the development of psychology as a natural science, grab any book on the history of psychology from a nearby university library. Make sure you pick one that starts at least in the nineteenth century, but for a better understanding it is necessary to look back until Leibnitz and his contemporaries.

If you want to learn more about measurement in psychology, books such as Joel Michell's Measurement in Psychology: A Critical History of a Methodological Concept provide a good introduction. I have not read any of those books and cannot recommend one. My own knowledge (and the summary given here) stems from a couse in psychometrics I took while studying psychology.

To summarize, academic psychology uses experimentation and statistical analysis because it is a natural science and adheres to the basic principles that define these disciplines. The belief that the universe is probabilistic (and events are distributed and these distributions can be described through arithmetic means and such) rules most of the natural sciences today and is not unique to psychology.

Beyond this unifying foundation, the different fields of psychology have quite different goals and methods. For example, general psychology (including the psychology of perception) is not interested in the distribution of a trait (such as intelligence) across a population, but in understanding, for example, the principles that govern learning in all individuals.

It is not true that experiments have to be performed on a group of subjects. In the psychology of perception, for example, which does not deal with interspecies differences but with the basic principles of human psychology, it is common to use only one single subject, because it is assumed that certain aspects of perception, such as trichromatic vision, are the same in all members of the population and can be investigated in any (healthy) individual. But of course this one test subject has to perform multiple trials, which are then analysed statistically.

Statistical analysis and the application of mathematics to reality itself goes back to ancient times. Bakker (2003) finds predecessors of contemporary statistical concepts as far back as ancient Indian texts:

  In an ancient Indian story, Rtuparna estimated the number of leaves and fruit on two great branches of a spreading tree (Hacking 1975). He estimated the number on the basis of one single twig, which he multiplied by the estimated number of twigs on the branches and found a number, which after a night of counting turned out to be very close to the real number.

Aristotle, in the Nichomachean Ethics calculated the mean as "a point equally distant from either extreme", and this was developed further by Ticho Brahe and others until Legendre introduced the least squares method, that we use today, in 1805.

If you want to know about the history of statistics, that is beyond the scope of this site.

The answer to your question in detail:

Why group level statistics?

Because there is no other way of measurement. As a physicist you know that every measurement is a sample from a population. If, for example, you measure weight, each measurement of the same weight will be different, if your scale is sensitive enough. You will then calculate the distribution and its characteristics (mean, slope, range etc.) to describe that distribution. If you do only one measurement, then that is because the differences are negligible for your purpose (e.g. human body weight) or measurement is too expensive and time consuming.
Since when group level statistics?

The ancient Indian example shows that group level statistics has been done since the dawn of time: a representative sample of leaves where drawn from a tree to understand the whole population of leaves. Of course that Indian "mathematician's" estimations where primitive, since the relevant mathematics hadn't been invented yet. The arithmetic mean was defined as late as 1805. But the basic idea and principles are identical to ours: estimate the properties of a population from a representative sample.
Why group level statistics in psychology?

The reason is not a psychological but a methodological one, and it is given in the quote by Guilford: It is the dominating belief of our culture that a true science must employ mathematics. So as soon as psychology was created as a separate scientific discipline, it had to use statistics. Otherwise it would have remained an area of speculation, in the eyes of the scientific community.
Since when did psychology employ group level statistics?

Building on the groundbreaking work of Ernst Heinrich Weber, Gustav Fechner defined the absolute threshold as the statistical mean of all threshold values in the method of limits in his work Elemente der Psychophysik (1860). Fechner also developed the notion of the median (in 1878).

But my answer describes that the use of mathematical methods in psychology was not so much a singular event that affected the rest of the science like an explosion, but a gradual process that happened as psychology was slowly detached from philosophy and grew into a natural science from around 1800 to around 1950, when the process was largely finished (with Stevens' publication).

And again, you must understand that the theory of measurement – and even statistics itself! – was in development in all of the natural sciences at the same time. For example, the arithmetic mean was defined in 1805, Legendre published the least squares method in the same year, and Gauss defined the normal distribution and maximum-likelihood estimation in 1809. This ongoing development was why the British committee on measurement was set up in 1932: because no satisfying theory of measurement had been created until then!
Why the popularity of the mean?

Because most psychologists don't understand statistics well enough to do more than that.
Why population average instead of effects that are present in every single individual in the population, or a specific sub-population?

You obviously did not read a lot of psychological texts. The field of general psychology focusses on effects that are present in every single individual and often does experiments of one proband. Only the field of differential psychology explores the distribution of traits among the population. Other fields look at sub-populations (e.g. children or old people, psychiatric patients, workers of a certain occupation, and so on).

In the history of psychology, the first studies (all through the 1800s) explored general psychology: perception, cognitition, memory. Beginning around 1900, differential psychology began first with the measurement of intelligence, and then the study of medical psychology in psychiatric patients. Around the First World War occupational psychology began to study work behaviour and pedagogical psychology began to apply the findings to the training of future workers and soldiers. Workers and soldiers are groups, so there is also an economic and political reason for group-focussed psychology. Advertising and Human Resources are still today the largest areas of psychology beside clinical psychology, which partially explains the continuing focus on population based studies.

Finally, of course there are scholars that employ a more refined statistics and do not focus on the mean so much, and there are scholars that believe there are aspects of human psychology that are not covered by a statistical approach. If you are interested in them, go deeper into psychology or create your own alternative methodology that represents what you believe about the human psyche.

All of this is of course my personal opinion. I am no historian of psychology and do not have the overview to judge the correctness of my interpretation. I used the small sample of publications that my professor for methodology provided and that I hope is representative. From this sample, I estimated the history of psychology, and my estimation may, of course, be wrong.

Sources:

Bakker, A. (2003). The early history of average values and implications for education. Journal of Statistics Education, 11(1), 17-26.
Fechner, G. Th. (1860). Elemente der Psychophysik [Elements of Psychophysics]. Leipzig: Breitkopf und Härtel.
Gigerenzer, G., Krauss, S., & Vitouch, O. (2004). The null ritual. The Sage book of quantitative methodology for the social sciences, 391-408.
Guilford, J. P. (1936). Psychometric Methods. New York: McGraw-Hill.
Helmholtz, H. (1887). Zählen und Messen erkenntnistheoretisch betrachtet. In Philosophische Aufsätze Eduard Zeller zu seinem fünfzigjährigen Doctor-Jubiläum gewidmet. Leipzig: Fues.
Hölder, O. (1901). Die Axiome der Quantität und die Lehre vom Mass". Berichte über die Verhandlungen der Koeniglich Sächsischen Gesellschaft der Wissenschaften zu Leipzig, Mathematisch-Physikaliche Klasse, 53, 1–46.
Krantz, D.H., Luce, R.D., Suppes, P. & Tversky, A. (1971). Foundation of measurement. Vol. I. Additive and polynomial representations. New York: Academic Press.
Luce, R.D., Krantz, D.H., Suppes, P. & Tversky, A. (1990). Foundation of measurement. Vol. III. Representation, axiomatization, and invariance. New York: Academic Press.
Roberts, F.S. (1979). Measurement theory with applications to decisionmaking, utility, and the social sciences. Reading: Addison-Wesley.
Stevens, S. S. (1946). On the theory of scales of measurement. Science, 103, 667-680.
Suppes, P., Krantz, D.H., Luce, R.D. & Tversky, A. (1989). Foundation of measurement. Vol. II. Geometrical, threshold, and probabilistic representations. New York: Academic Press.


Why don't the Big 5 personality traits have more neutral names? Lots of different areas of study appropriate common-language terms as jargon words with a specific meaning in the context of that particular field, but the names of the Big 5 personality traits have always bothered me. They appear to be rather prejudicial.

For example, scoring high on Agreeableness sounds like it should be a good thing to an uninformed person. But from a psychological perspective, highly agreeable people often allow themselves to be taken advantage of, and tend to be emotional doormats.

Openness is another one that is confusing. Nobody wants to believe they are closed-minded. But in reality, a person who scores low in Openness is consistent, cautious, and deliberate in their actions, which is not a bad thing at all in many circumstances.

Language has a tendency to bias our thinking in certain ways, and one would think this would be more of a problem in psychology than in other sciences.  Other sciences either borrow obscure words from other languages or they make up new ones to avoid terms that are culturally or linguistically loaded.

Since there is a growing body of evidence that the Big 5 are more innate than learned, and since each dimension is a scale on which either extreme is considered a bad thing, it would seem to me that we'd want to use less partisan names for those traits.

Why aren't the descriptors more neutral in tone?

Well, in a recent debate whether Big Five is... ahem... sexist, this was mentioned, which pertains your question:

  There’s another flaw when it comes to taking Big Five personality tests online. The online versions of the Big Five traits inform people of negative character traits, without explaining that the positivity or negativity of all characteristics is shaped by context.

  Costa believes that the Big Five’s willingness to point out negative traits makes the test more accurate: Myers-Briggs avoids “anything that could be negative. And that’s a great big marketing thing,” he says. But each potentially negative Big Five character trait is informed by the situation. “They’re only negative in certain contexts,” he says.

  For example, Costa explains, agreeable people are great for a blind date, but tend to be overly dependent. Disagreeable people, meanwhile, aren’t good at smoothing over arguments. But they’re also less likely to obediently follow immoral orders—such as those demonstrated by the Milgram experiment, wherein participants are asked to administer increasingly intense electric shocks to a victim. (The longer IPIP-NEO test briefly acknowledged the importance of context, noting, “agreeableness is not useful in situations that require tough or absolute objective decisions,” but the Big Five Inventory website offered no such explanations.)

For more context, Paul Costa is one the original authors of NEO-PI, one of the main instruments that shaped Big Five testing.

So, according to him, avoiding negativity either explicit (or the complementary/implicit one) in the design wasn't a goal because it hindered accuracy. I guess that doesn't completely answer the question about naming of the dimensions, but it's probably informative. (Do note that one of the Big 5 dimensions has a rather negative name--neuroticism.)

Costa's point about commercial tests' negativity-avoidance seems to apply to DISC as well.

The factor-naming issue itself was covered in detail in a 1992 paper of McCrae and John (which has very high number of citations for a psychology paper):

  The consensus that five-factorists see among themselves may be puzzling to outsiders because the "disagreement among analysts as to factor titles" that Tupes and Christal noted still plagues the field (John,
  1990b). Factor names reflect historical accidents, conceptual positions,
  and the entrenchment that comes from a published body of literature
  and from published instruments. There are two prominent systems for
  naming the factors, one derived from the lexical tradition and one from
  the questionnaire tradition.

  Many writers take Norman's (1963) annunciation of an "adequate
  taxonomy of personality attributes" derived from Cattell's reduction of
  natural language trait terms as the formal beginning of the FFM, and
  the factor numbers and names Norman chose—I: Extraversion or Surgency; II: Agreeableness; III: Conscientiousness; IV: Emotional Stability;
  and V: Culture—are often used. Peabody and Goldberg (1989)
  have noted that the order in which these factors emerged roughly parallels
  their representation among English language trait terms in the
  dictionary: Many more words can be found to describe aspects of Factors
  I through III than of Factors IV and V. The factor numbers, I to V,
  are thus meaningful designations. Roman numerals also have the advantage
  of being theoretically neutral; they seem to stand above the fray
  of disputed factor interpretations.

  The second tradition that led to the modern FFM comes from the
  analysis of questionnaires, and particularly from the work of H. J.
  Eysenck, who identified Extraversion (E) and Neuroticism (N) as major
  components of psychological tests. (It was Wiggins, 1968, who dubbed
  these the "Big Two," setting the stage for Goldberg's 1981 designation
  of the FFM as the "Big Five.") Costa and McCrae (1980) added
  a dimension they called Openness to Experience (O), and later (1985,
  1989) created scales to measure Agreeableness (A) and Conscientiousness
  (C). A number of publications (e.g., Borkenau & Ostendorf, 1990;
  Funder & Colvin, 1988; Tellegen & Waller, in press; Wiggins & Pincus,
  1989; Zuckerman, Bernieri, Koestner, & Rosenthal, 1989) have
  adopted this nomenclature. Note that N corresponds to low Emotional
  Stability, —IV, and O is a variant of Norman's Factor V.

  If the advantage of the Norman numbers is their theoretical neutrality,
  the disadvantage is their low mnemonic value. Initials, originally popularized
  by H. J. Eysenck, are easier to interpret, and they may be less
  theoretically laden than full names. To those for whom Neuroticism
  connotes psychiatric disorder, negative affectivity (Watson & Clark,
  1984) or simply nervousness may seem more apt; all can be characterized
  by N. Likewise, E can also stand for energy or enthusiasm (cf.
  Watson & Clark, in press); O for originality; A for affiliation (Leary,
  1957) or affection (Brand, 1984), and C for constraint (Tellegen, 1982)
  or control (Krug & Johns, 1986).

So yes, if the spelled-out names really bother interpretation-wise, an alternative is to use just the first letter designator (and/or numbers, but the latter seems a less popular approach). I did see recent papers do the former (use just the letters) although mainly in tables for compactness.

And in excruciating detail as to level of consensus on the naming of each factor (which seems to be roughly N > E ~ A ~ C > O), the same paper continues:

  The problem of what to call the factors is not merely a matter of convention.
  The labels refiect conceptualizations, and five-factor advocates
  differ in the details of their views on the factors, and thus in their
  preferred names. [...]

  There is probably the least controversy about the definition of N. N
  represents individual differences in the tendency to experience distress,
  and in the cognitive and behavioral styles that follow from this tendency.
  High N scorers experience chronic negative affects (Watson &
  Clark, 1984) and are prone to the development of a variety of psychiatric
  disorders (Zonderman, Stone, & Costa, 1989). The recurrent
  nervous tension, depression, frustration, guilt, and self-consciousness
  that such individuals feel is often associated with irrational thinking,
  low self-esteem, poor control of impulses and cravings, somatic complaints,
  and ineffective coping (McCrae & Costa, 1987). Individuals
  low in N are not necessarily high in positive mental health, however
  that may be defined—they are simply calm, relaxed, even-tempered,
  unflappable.

  Despite the long and common use of the term Extraversion, there is
  less consensus about E. Most of the differences can be traced to the
  fact that E and A together define the Interpersonal Circumplex, around
  which interpersonal terms are spaced almost evenly. The traditional
  axes of the circumplex are Dominance (or Status) and Affiliation (or
  Love; Wiggins, 1979), and the major dispute about E (Norman's Factor
  1) concerns its alignment with these axes. Goldberg (1990), guided
  by his analyses of English language trait terms, and Wiggins (in press),
  guided by the interpersonal tradition, identify this factor with Dominance.
  McCrae and Costa (1989c) argue that E is best seen as located
  midway between Dominance and Warmth (although perhaps a bit closer
  to Dominance). This position, which Peabody and Goldberg (1989)
  designate as I', is close to the location of such traditional questionnaire
  measures of E as H. J. Eysenck and S. B. G. Eysenck's (1975) E scale
  and the EI scale of the MBTI.

  The advantage ofthe I' position is that it aligns the factor more closely
  with its noninterpersonal aspects, particularly positive emotionality. As
  Watson and Clark describe in their contribution to this issue, the tendencies
  to experience positive and negative emotions are not opposites, but
  orthogonal dimensions that define an affective plane. People who are
  cheerful, enthusiastic, optimistic, and energetic are not necessarily low
  in anxiety or depression—that depends on their level of N. But cheerful
  people consistently tend to be dominant, talkative, sociable, and warm,
  and Watson and Clark (in press) argue that positive emotionality should
  be seen as the core of E. This somewhat unorthodox view is probably
  a useful corrective to the narrowly interpersonal interpretation of E as
  sociability.

  E is distinguished by its breadth of content. In their review, Watson
  and Clark (in press) identified seven components of E: venturesomeness,
  affiliation, positive affectivity, energy, ascendance, and ambition.
  As Table 1 shows, Costa and McCrae's view of E is similarly broad,
  although they would divide affiliation into warmth and gregariousness
  and assign ambition to C." The fact that such a wide variety of interpersonal,
  affective, and temperamental variables covary probably accounts
  for the fact that this factor is so well represented in English language
  adjectives and so often described by personality theorists.
  The lexical literature suggests that individuals low in E can be described
  as quiet, reserved, retiring, shy, silent, and withdrawn (John,
  1990a), and Q-sort correlates point to emotional blandness and overcontrol
  of impulses as additional attributes. Nowhere in this description
  is introspectiveness seen: Low E must be distinguished from Guilford's
  (1977) Thinking Introversion (which is more closely related to O and
  C). The confusion between social and thinking introversions is perpetuated
  in the MBTI, where both kinds of traits are attributed to individuals
  classified as Introverts. In fact, the MBTI EI scale is a relatively pure
  measure of low E (McCrae & Costa, 1989a).

  The label Agreeableness has been almost universally used for Norman's
  Factor II, but as Digman (1990) noted, "Agreeableness . . .
  seems tepid for a dimension that appears to involve the more humane
  aspects of humanity—characteristics such as altruism, nurturance, caring,
  and emotional support at the one end of the dimension, and hos
  tility, indifference to others, self-centeredness, spitefulness, and jealousy
  at the other" (pp. 422-424). Digman and Takemoto-Chock (1981)
  offered "Friendly Compliance versus Hostile Noncompliance" as an
  alternative descriptor for the factor, and Graziano and Eisenberg (in
  press) adopted the contrast "Agreeableness versus Antagonism."
  Because A must be orthogonal to E, the location—and thus the interpretation—
  of A depends to some extent on one's view of E. Again,
  Goldberg and Wiggins see this factor as Love or Warmth; Costa et al.
  (1991) note a cluster of attributes that blend Warmth and Submission,
  including trust, modesty, and compliance.

  Like A, C is a highly evaluated dimension; indeed, A and C are
  the classic dimensions of character, describing "good" versus "evil"
  and "strong-willed" versus "weak-willed" individuals. Perhaps it was
  these moral overtones that often led scientific psychologists to ignore
  these factors, but in fact, both represent objectively observable dimensions
  of individual differences. Some people are thorough, neat, wellorganized,
  diligent, and achievement-oriented, whereas others are not,
  and self-reports of these characteristics can be validated by peer or
  spouse ratings (McCrae & Costa, 1987).

  A number of different conceptions of C have been offered. Tellegen's
  (1982) Constraint and Hogan's (1986) Prudence reflect an inhibitive
  view of C as a dimension that holds impulsive behavior in check.
  Digman and Takemoto-Chock's (1981) Will to Achieve represents a
  proactive view of C as a dimension that organizes and directs behavior.
  The term Conscientiousness combines both aspects, because it can
  mean either governed by conscience or diligent and thorough. Empirically,
  both kinds of traits seem to covary.

  The greatest controversy concerns O, and the root ofthe controversy
  is the disparity between natural language and questionnaire studies.
  Studies of trait adjectives in English (Goldberg, 1990; John, 1990a)
  and German (Ostendorf, 1990) typically show a factor defined by such
  items as intelligent, imaginative, and perceptive, and researchers from
  Fiske (1949) to Hogan (1986) and Digman (1990) have identified this
  factor as some form of Intellect. However, many traits related to O
  are not represented among English trait adjectives—there is, for example,
  no single English word that means "sensitive to art and beauty"
  (McCrae, 1990). Researchers using questionnaires have typically found
  a much broader factor that includes, in addition to creativity and intellectual
  interests, differentiated emotions, aesthetic sensitivity, need for
  variety, and unconventional values. This broader concept can be traced
  to Rogers (1961), Rokeach (1960), and Coan (1974); McCrae and Costa
  (in press) have argued that O is seen structurally in the depth, scope,
  and permeability of consciousness, and motivationally in the need for
  variety and experience. Ideas, of course, form an important aspect of
  consciousness, but fantasies, feelings, sensations, and values are also
  experiences to which individuals can be more or less open.
  Several discussions of the relative merits of these two conceptions
  have been offered (Digman, 1990; John, 1990a; McCrae & Costa,
  1985b, in press; Peabody & Goldberg, 1989). One point that should
  be emphasized is that neither Openness nor Intellect is equivalent to
  measured intelligence; O is a dimension of personality, not intellectual
  ability, and many people score high in O without having a correspondingly
  high IQ.

  A recent study illustrates the empirical basis for broadening the conception
  of this factor beyond Intellect. John (1989a) examined ACL
  and CQS data from expert raters at the Institute of Personality Assessment
  and Research. Based on a review of the literature, a panel of
  judges selected 112 prototype items from the ACL to mark the five dimensions.
  Many of the terms selected to represent O were consistent
  with either an Intellect or an Openness interpretation, including wide
  interests, imaginative, original, curious, and artistic. But because the
  literature emphasized the Intellect interpretation, judges also included
  such terms as wise, logical, and foresighted. When observer ratings on
  the 112 items were factored for a sample of 280 ratees, the five-factor
  model was clearly recovered, but wise, logical, and foresighted were
  not among the clear definers of the Intellect/Openness factor (Table 1
  lists the six highest-loading adjectives). Empirical analyses shifted the
  factor from a clear Intellect to a mixed Intellect/Openness factor.
  When ACL factor scores were correlated with CQS ratings by the
  same experts, the significant correlates (|r | > .40) showed the full range
  of traits associated with Openness. Individuals rated low on the factor
  were described by "judges in conventional terms," "favors conservative
  values," and "represses anxiety;" those rated high were described by
  "high degree of intellectual capacity," "enjoys aesthetic impressions,"
  "has wide interests," and "unusual, unconventional thought." As seen
  in this list, O includes aspects of intellect, but is considerably broader
  in scope.

What is obvious from all this is that many researchers have gone to great lengths to put interpretive names to the factors. You can argue that that is a bad thing, but then I'm not here to argue the counterpoint, but to show it happened.

There are however some researchers which have argued that [counter]point, on the basis that interpretive naming can lead to further testable hypotheses as to the underlying mechanisms for the factors:

  Whatever
  the inadequacies of the natural language for
  scientific systematics, broad dimensions inferred
  from folk usage are not a bad place
  to start a taxonomy. Even in the biological
  taxonomy of animals, “the technical system
  evolved from the vernacular” (Simpson,
  1961, pp. 12–13).

  Obviously, a system that initially derives
  from the natural language does not need to
  reify such terms indefinitely. Indeed, several of
  the dimensions included among the Big Five,
  most notably Extraversion and Neuroticism,
  have been the target of various physiological
  and mechanistic explanations (e.g., Canli et
  al., 2001; see also L. A. Clark, 2005). In research
  on emotion regulatory processes, the
  links between the Big Five, the chronic use
  of particular regulatory strategies, and their
  emotional and social consequences are being
  articulated (John & Gross, 2007). Similarly,
  the conceptual explication of Extraversion
  and Neuroticism as persistent dispositions
  toward thinking and behaving in ways that
  foster, respectively, positive and negative affective
  experiences (e.g., Tellegen, 1985; see
  also Clark & Watson, Chapter 9, this volume)
  promises to connect the Big Five with
  individual differences in affective functioning,
  which, in turn, may be studied in more tightly
  controlled laboratory settings (see Gross,
  Chapter 28, this volume). At this point, the
  Big Five differentiate domains of individual
  differences that have similar surface manifestations—
  just like the early animal taxonomy
  that was transformed by better accounts of
  evolutionary processes and by the advent of
  new tools, such as molecular genetics. Likewise,
  the structures and processes underlying
  these personality trait domains are now
  beginning to be explicated. Explanatory and mechanistic terms will likely change the definition
  and assessment of the Big Five dimensions
  as we know them today.


Is the concept of "employee engagement" flawed? In theory, improving business performance by improving engagement makes sense. Yet surveys suggest that since 1991, the workforce is about 30% engaged, 40% disengaged and the remaining 30% actively disengaged, as widely reported by Gallup. http://www.gallup.com/services/178517/state-global-workplace.aspx

Billions are being spent for no result, despite the considerable benefits the engaged enjoy, and the disbenefits suffered by the others. It seems that engaged people are so both at home and work, likewise the disengaged. Neither group seem able to turn it on or off.

Does the failure to improve aggregate employee engagement levels suggest that the concept of employee engagement is flawed?

A few points:

Cut-offs are somewhat arbitrary. Engagement is typically measured using a mulit-item scale. It will generate a scaled response. E.g., there might be 10 items each measured on a 1 to 5 scale. Presumably, Gallup adopts an approach of carving up that scale into categories of engagement. I think they use 12 items from the Gallup Q12; they might be the items listed in Harter et al (2002). Anyway, the main point is that employees will get a score from 1 to 5. If an employee gets a mean of 3.9 on a 1 to 5 scale do we say that they are engaged or neither engaged nor disengaged. If you define 3 as the cutoff for being engaged, then more workers will appear engaged than if you make 4 the cutoff.
I'm not saying that the cutoff is completely arbitrary. Presumably you could ask managers about what set of responses imply engagement. I had a read of some Gallup material (see here) and I could not find a specification of how these categories are operationalised other than they were based on the 12 items. My main point is that a consulting company could readily choose cutoffs to present a more positive or pessimistic picture of engagement in the workplace if they were so motivated. Furthermore, the choice of items will also influence the means you obtain. If you choose more extreme items, then you'll get lower means (e.g., mean agreement will be lower on items like "I absolutely love my work" than on "I like my job").
Self-report measures of engagement correlate extremely highly with job satisfaction. Thus, the entire literature about job satisfaction is relevant. I agree that the construct of engagement has greater linkages with motivation and commitment. However, the survey responses you get pick up on largely the same variance as obtained when measuring job satisfaction.
Job satisfaction is influenced by personality (Judge et al 2002). So there is a degree of stability that is driven by underlying individual differences. That said, just because group-level means may have remained stable over the years, individuals will change over time in their job satisfaction.
Job satisfaction is related to expectations, and expectations can change over time (e.g., https://en.wikipedia.org/wiki/Expectancy_theory). So for example, if workplaces implement flexible work practices or other initiatives to increase motivation and engagement, then this will be begin to form an expectation. And the absence of these expectations will lead to lower satisfaction. A parallel line of research examining life satisfaction often shows that mean life satisfaction is often around 7.5 out of 10 and that it does not change much over the years as economic conditions have improved. The idea is that there is a homeostatic process related to expectation management and so on that leads to fairly stable scores (Cummins et al 2003).

Despite all of the above, organisations should still invest in increasing the motivation, satisfaction, and commitment of their staff. Employee opinion surveys also serve a range of useful purposes for organisations. In particular, the provide a more data-driven approach to tracking and understanding the satisfaction-levels of their workplace. Furthermore, there are a range of interventions and strategies that are important for managing engagement, which in turn should influence productivity and retention.

References

Harter, J. K., Schmidt, F. L., & Hayes, T. L. (2002). Business-unit-level relationship between employee satisfaction, employee engagement, and business outcomes: a meta-analysis. Journal of applied psychology, 87(2), 268.
Cummins, R. A., Eckersley, R., Pallant, J., Van Vugt, J., & Misajon, R. (2003). Developing a national index of subjective wellbeing: The Australian Unity Wellbeing Index. Social indicators research, 64(2), 159-190.
Judge, T. A., Heller, D., & Mount, M. K. (2002). Five-factor model of personality and job satisfaction: a meta-analysis. Journal of applied psychology, 87(3), 530.


What is the difference between an Atlas and a Parcellation? I come from a computer science background and am just starting out in the area of analyzing brain imaging data (fMRI predominantly) and while going through some of the literature, I am kind of confused about the difference between a brain atlas and a brain parcellation?

Are the two used interchangeably? Does one correspond to anatomical units and the other to functional units?

[This is an older post, but...]  A brain atlas is going to, typically, be a set of images or volume that is labeled anatomically or functionally.  Typically one would take a single volume of data and register or align it to the atlas (or vice-versa).

Parcellation is a way of segmenting sub-regions of a particular region of the brain. (What a "region" is or "sub-region" might be a bit up for debate).

One could do image registration / alignment of an MRI data volume to an atlas (that is parcellated or segmented) and then the parcellation can be applied to the MRI data volume.


How does the Forgetting curve change after repeated exposure to the same item we would like to memorise? There has been a long debate going on on the actual form of the Forgetting curve, but my question will be about its change when we review a previously memorised fact - Unfortunately, I couldn't seem to find too much information (or perhaps I used wrong terms) on this topic.

Maybe the most up-to-date and least divisive research paper on the topic of the actual form of the Forgetting curve would be Averell, L., & Heathcote, A. (2011). The form of the forgetting curve and the fate of memories. Journal of Mathematical Psychology, which I have seen referenced here multiple times. According to it the shape of the curve is best described as
$$R(t) = a + (1-a)*b*(1+t)^{-β}$$
which would yield $1$ at $t=0$ if the encoding happened without a problem (which we assume did). My concrete question would be that how the three parameter change after repeated exposure to the fact (where we assume that at this specific $t_r$ the retention increases to $1$ again). I think it is fair to assume that it is going to be yet another curve describable with a Power function starting at $t_r$ which should have a higher asymptote as the original function.

A picture (although not scientific nor correct in terms of the actual form) illustrating my question has been already posted here at How are these review-forgetting curve calculated?, although for different purposes than mine.

Currently, I am working on various demonstration graphs of various spacing effect algorithms.  From the research it seems like two of the parameters exist to constrain the outputted values...

  The parameters a and b are also assumed bounded between zero and one,
  and hence R(t) is similarly bounded, which must necessarily be the
  case as R(t) is a probability. Enforcing this bound is important as
  otherwise data fits can be inflated (see Navarro, Pitt, & Myung, 2004,
  for further discussion).

I think Ebbinghaus' original function R(t) = e ^ -(t/s) (see this thread) can more easily explain things.  t is time and s is the strength of the memory.  After every review, s increases.
If you plot this out, you see that if you increase s, the forgetting curve function flattens out.


What happens psychologically to a Robinson Crusoe? In 2000 film Cast Away Tom Hanks's hero is stranded on an uninhabited island, Robinson Crusoe style, and after a while starts talking to a volleyball. And I thought: what would actually happen to a person with total social isolation (not necessarily stranded on an island)? How would their cognitive functions, behavior, mental health, skills change? There are many variables that might influence the changes happening to a person.

Time: when each psychological change starts to appear?
Age: how would children, teenagers, adults and elderly differ?
Socialization: what if the person simply has less social interactions? (e.g. prison, remote living)
Pre-existing mental issues: how would depression, schizophrenia, personality disorders or any other disorder influence the change during isolation?
Any other variable?

I have skimmed this paper about solitary confinement and the consequences seem disastrous

"The paradigmatic psychiatric disturbance was an agitated
confusional state which, in more severe cases, had the characteristics
of a florid delirium, characterized by severe confusional, paranoid,
and hallucinatory features, and also by intense agitation and random,
impulsive, often self-directed violence. Such disturbances were often observed in individuals who had no prior history of any mental
illness. In addition, solitary confinement often resulted in severe
exacerbation of a previously existing mental condition. Even among
inmates who did not develop overt psychiatric illness as a result of
solitary confinement, such confinement almost inevitably imposed
significant psychological pain during the period of isolated
confinement and often significantly impaired the inmate’s capacity to
adapt successfully to the broader prison environment. "

A statement from the US supreme court regarding the matter (in the same paper)

"[E]xperience [with the penitentiary system of solitary
confinement] demonstrated that there were serious objections
to it. A considerable number of the prisoners fell, after even a
short confinement, into a semi-fatuous condition, from which it
was next to impossible to arouse them, and others became
violently insane; others, still, committed suicide; while those
who stood the ordeal better were not generally reformed, and
in most cases did not recover sufficient mental activity to be of
any subsequent service to the community."

http://openscholarship.wustl.edu/cgi/viewcontent.cgi?article=1362&context=law_journal_law_policy&sei-redir=1&referer=https%3A%2F%2Fscholar.google.ch%2Fscholar%3Fhl%3Den%26q%3Dsolitary%2Bconfinement%26btnG%3D%26as_sdt%3D1%252C5%26as_sdtp%3D#search=%22solitary%20confinement%22


Is homosexuality a psychological illness or a natural disposition of a person's sexual orientation? Homosexuals are oft criticized for their sexuality to which they would say they are just not attracted to the member of the opposite sex and that it's the other way round.

So, is this attraction to member's of the same-sex a (by-birth) psychological illness (that could be treated), a natural disposition, or just voluntary choice?

Or maybe something else?

Freud (1905) believed that every human was innately bisexual, and that monosexuality (i.e. hetero- or homosexuality) is a result of internal and external influences during psychological maturation.

Currently, the question of a biological, e.g. genetic or uterine, cause of non-heterosexual sexual orientation is still a subject of research and has not yet led to any conclusive results. Until that question has been answered with some level of certainy, we simply do not know whether homosexuality is a natural variety of sexuality or a deviation from an inborn disposition through influences after birth. (Wikipedia summarizes the research well: http://en.wikipedia.org/wiki/Biology_and_sexual_orientation)

What you must differentiate is homosexual behavior, which can appear in heterosexual individuals such as experimenting adolescents or prisoners, and homosexuality, which is a preference for same-sex partners, which might not show up in behavior at all. Historically, many homosexuals led heterosexual lives, marrying, mating with and procreating with opposite-sex partners, despite a contrary sexual preference.

Freud, S. (1905). Drei Abhandlungen zur Sexualtheorie. Leipzig: Deuticke.


What is the minimum spatial IQ needed to solve the rubik's cube? Solving the rubki's cube is bona fide spatial IQ challenge.
Has there been studies done on the minimum spatial IQ score needed to solve it?
EDIT:
By solve, I mean to discover the algorithm by oneself.

I don't think it's a matter of IQ, really. Here's why: The Rubik's cube can be solved easily following a simple algorithm. Anyone can follow this step-by-step process mindlessly and solve a Rubik's cube. Remembering the algorithm is a different thing altogether, maybe that depends on a person's IQ (does memory depend on IQ?) There are many bots that can solve the Rubik's cube in a matter of seconds, just following this algorithm. So, it actually doesn't need much IQ I guess, but considering that the algorithm generally starts from the step after one side (usually black/white/yellow) is completed, a person should have enough IQ to be able to solve one face of the cube and remember the steps, so I am guessing that the IQ measure would be around the room temperature in Celsius scale!


How large is a neurotransmitter? Max and min sizes? What size(s) are neurotransmitters? What is their size relative to the synaptic cleft? Relatively speaking,  can we tell how far they must travel to cross the gap? Twice their own length? More?

I reallize this calls for gross oversimplification, and there are bound to be infinite variations, but I am building a conceptual model to understand relationship between the neurotransmitters and their respective "milieux".

From the textbook Neuroscience. 2nd edition:

Neuropeptides are relatively large transmitter molecules composed of 3 to 36 amino acids
Individual amino acids, such as glutamate and GABA, as well as the transmitters acetylcholine, serotonin, and histamine, are much smaller than neuropeptides and have therefore come to be called small-molecule neurotransmitters

Large proteins are around 10nm, because the amino acids wrap around each other.
This means that a good estimate of the size of neurotransmitters would be from around 0.5 to 5 nanometers.
Typical synaptic cleft distance is around 20 nanometers


What's the explanation of this optical illusion where many coloured arcs radiate from a central point? I saw the image below on facebook. At first, I thought it's a GIF animation since it doesn't appear static but it turned out to be a static JPEG image and the apparent motion is caused by the brain. So why does my brain trick me into believing that there's something moving? Does the brain have a purpose to do this optical illusion?

This is a type of illusory motion (or motion illusion) called the Enigma Illusion.

The cause of motion illusion in general is not well understood, but research suggests that there may be slightly different reasons for the different types of motion illusions.

A common theory is that particularly high-contrast colours are perceived separately in the retina (perhaps turning photoreceptor cells on takes a slightly different amount of time than turning them off), and as a result, the signals from the retina arrive at the visual cortex at slightly different times, causing the illusion of motion.  Comparison of brain activity using fMRI between actually moving and apparently moving images shows similar activity in the visual cortex, supporting the assertion that the illusion is caused at the retina rather than at the visual cortex.

In the particular case of the Enigma Illusion:

  When the eye movements, called microsaccades, were suppressed, test
  subjects reported that the Enigma illusion — an illustration that
  seems to flicker and turn — remained stationary.

That is, small, rapid, unconscious eye movements are also involved in creating the illusion.

Here is a nice collection of different illusory motion images: http://brainden.com/eye-illusions.htm

The reason for optical illusions such as this one is a side-effect of the way the brain processes typical visual information efficiently, at the expense of handling unusual situations incorrectly.


When we all fall asleep, where do we go? I was thinking about dreams from a psychoanalytic perspective. I want to know about falling asleep. What is everybody's destination on that bed? Is it the future past or our imagination?

In short, it depends on the dream. Sometimes dreams can play out a past event with or without truth, sometimes they can project a possible present and future. Sometimes they can play out a fantasy you may have and have no bearing on reality at all.
Whilst I am a defender of Freudian and Neo-Freudian psychology, please be aware that this covers areas of psychology considered by some here to be pseudoscientific

Sigmund Freud’s The Interpretation of Dreams was one of the most important books of the 20th century.
First published in 1900, it provides a groundbreaking theory of dreams and an innovative method for interpreting them that captivates readers to this day (Freud Museum of London)

Sigmund Freud said:

The interpretation of dreams is the royal road to a knowledge of the unconscious activities of the mind.

For this reason, there are many books and websites purporting to be an accurate way of interpreting your dreams. Some believe that interpreting dreams can be a way of working out what you will do or should do. Freud himself said these books are not to be followed.
The main thing to take to mind is that dreams cannot be relied upon to accurately recall or predict anything.

Dream interpretation was an important "technique" in psychotherapy. However, after over a hundred years of research, there is still no scientific consensus on the meaning of dreams, or even if they mean anything at all! Dream interpretation is currently patent quackery. (RationalWiki)

To call dream interpretation "quackery" would signify that dream interpretation is seen as a means of therapy.  Whilst there is no scientific consensus on the accuracy of dream interpretation, and therefore it is pseudoscience; it is not a form of therapy and never was.  It is a tool, which whilst possibly inaccurate, can give an indication as to possible areas of concern when exploring with your client where problems lie.
Take for example the Freudian case of "Wolf Man" Sergei Pankejeff.

Pankejeff sought treatment for depression in 1910 after his sister and father committed suicide. Freud fixated on a dream about wolves (hence the "Wolf Man" moniker) Pankejeff reported and spun a strange tale from this (RationalWiki)

Freud

interpreted [the dream] in minute detail to represent a disguised memory of the patient, at age one and a half, observing his parents engaging in “coitus a tergo [from behind], three times repeated.” (Esterson, 2003)

Without knowing the full details of the dream and the conversation between Sergei and Freud, we cannot determine how he came to this idea, however, this is a possible interpretation according to Freud.
References
Esterson, A. (2003) Freud's Theories of Repression and Memory. Scientific Review of Mental Health Practice 2(2)
http://www.srmhp.org/0202/review-01.html


Does sleep = consciousness, unconsciousness or something else? Among the various definitions of the word consciousness is awareness, with wakefulness a general synonym.

If someone hits you over the head, knocking you unconsciousness (though still alive), then you're said to be unconscious. But are you also considered to be unconscious when you're sleeping?

One of the key differences (for me) is that a sleeping person can typically react to an alarm clock, whereas a person who has been rendered unconscious through an injury is effectively dead to the world.

If sleep is NOT a form of unconsciousness, what is it? Is a sleeping person still conscious, or is there another term to describe it?

The dictionary definition  of "unconscious" is to not be capable of conscious thought, ie, be asleep and unaware. Technically, you are unconscious when you are asleep.

When you get knocked out ie. a concussion, it is thought that the forces from the injury disrupt the normal cellular activities in the reticular activating system located in the areas impacted and that this disruption produces the loss of consciousness.

Terminology wise, I believe this would be considered a temporary coma. (The definition of a coma is: a state of unconsciousness in which a person: cannot be awakened; fails to respond normally to painful stimuli, light, or sound; lacks a normal wake-sleep cycle; and does not initiate voluntary actions.)


How to map EEG time-series and visualize meditative states frequencies? I came across this research article "Case Study of Ecstatic Meditation: fMRI and EEG Evidence of Self-Stimulating a Reward System" about the brainwaves when a Yogi went into a meditative level.

I know that we have 5 types of brainwaves:

Gamma 40Hz~
Beta 14-40Hz
Alpha 7.5-14Hz
Theta 4-7.5Hz
Delta 0.5-4Hz

As for Meditative Stages, we have 8 stages:

Material

Jhana 1
Jhana 2
Jhana 3
Jhana 4

Immaterial

Jhana 5 / Arupa Jhana 1
Jhana 6 / Arupa Jhana 2
Jhana 7 / Arupa Jhana 3
Jhana 8 / Arupa Jhana 4

As for what I've read on the paper, they could only start from Jhana 2 as "Jhana 1 was not practiced because the associated head movements would induce excessive artifact". Until Jhana 5 as there is some problem with Jhana 6-8 because the "fMRI recording then ended due to scanner memory limitations (421 volume maximum)".

How can I transform each meditative states [time-series data] into brainwaves frequencies?

Thank you for your interesting question!

Generally, there are three types of methods to process your EEG time-series data:

Time domain methods (e.g., regression, statistical analysis on your EEG time-series data, etc.)
Frequency domain methods (e.g., Fourier Transform)
Time-frequency domain methods (e.g., Short-Time Fourier Transform, Wavelet Transform, Gabor Transform, etc.) Wikipedia

You may use time-frequency methods to categorize or classify those states, if you will. It is very simple. Time-frequency methods transform your [1-D] time-series EEG data into a new [2-D] domain that you can see both time and frequency information.

[1-D] Frequency domain methods only return frequency information of your [1-D] EEG time signals, which means that your [1-D] time data will be lost in exchange for having [1-D] frequency data.

[1-D] Time domain methods only return [1-D] time analysis of your EEG signals, which also cannot help you to capture the frequency information.

May I suggest you to use Continuous Wavelet Transform or Discrete Wavelet Transform to do this job?

There are many tools/languages that might help you to do so: MatLab, Python, and such. If you might have a programmer around you, s/he can probably help you in a few hours or a day to pass your [1-D] EEG time data through one of these [2-D] time-frequency methods and visualize the outputs.


Are men subject to optimism bias when it comes to assessing their sexual/romantic appeal? Intuitively, I imagine that men are strongly subject to optimism bias when dating, and in particular facing rejection. (ie. not believing that she's really not attracted to him).

My question is:

How well studied is this? What methods of study do they use?
How prevalent is it amongst men? (Are all men subject it it?)
How strong is the bias? By how much do men overvalue their attractiveness?
How does this compare with women?

Short answer: Yes, but not really...

Self-enhancement:

Self-enhancement (sometimes referred to as positive illusions) refers to a general preference for positive self-views (in men and women alike).  It includes several common strategies, such as: The "above average effect" (aka illusory superiority), self-serving bias, and optimism bias.  Optimism bias however refers to perceived risk, whereas this question is about illusory superiority:

  ... a cognitive bias whereby individuals overestimate their own
  qualities and abilities, relative to others. This is evident in a
  variety of areas including intelligence, performance on tasks or
  tests, and the possession of desirable characteristics or personality
  traits.

Self-esteem is a particularly dicey subject matter - it seems to refer to a conglomerate of fairly independent / mildly correlated factors.  So when we examine say, self-perceived sexual attractiveness (sex appeal), the results are different from a variety of other similar sounding - but independent - constructs such as self-perceived physical attractiveness, sexual self-schema, self-valuation, sexual self-esteem, sexual satisfaction, sexual performance, body image, self-image, etc...

Therefore, to keep the scope of this question manageable, I'll focus on gender differences in illusory superiority with respect to sexual attractiveness, though as will be discussed, physical attractiveness will come into play as well.

Research methodology:

Self-esteem factors such as perceived sexual attractiveness are measured using surveys / self-reporting.  For sexual attractiveness in particular, there doesn't appear to be a well-established scale in common use, so researchers tend to develop questionnaires as needed for their particular studies.  Furthermore, there is evidence that many confounding factors exist that cannot be easily controlled for, such as societal changes.  So unfortunately, some questions of validity and reproducibility of the results exist, as is common in many facets of social psychology and personality research.

Another issue is the extricability of sexual attractiveness from physical attractiveness.  Studies have shown that these are in fact two different constructs.  However, different scales used by different researchers emphasize physical attractiveness in sexual attractiveness measures to different degrees, making the separation difficult.

As suggested in the question, self-enhancement is known in general to increase when under threat - Wikipedia says:

  This motive becomes especially prominent in situations of threat,
  failure or blows to one's self-esteem.

and:

  Positive illusions are a form of self-deception or self-enhancement
  that feel good, maintain self-esteem or stave off discomfort at least
  in the short term.

To manipulate self-esteem in the lab, subjects can be presented with a comparison point (contrast), such as a photo or video of someone else that may be highly attractive, or unattractive.  An ego-threatening contrast may affect self-enhancement differently from an unthreatening scenario.

Summary of results:

As expected, both men and women report a "better-than-average" bias for sexual attractiveness - ie, the average rating compared to others is higher than average.  The bias is slightly greater for men than women on some scales, and not significantly different on others, eg:

  ... on the dimensions of Sexual Attractiveness, Sexual Restraint, and
  Sexual Orientation ... no significant sex differences [were] found.

Here is an example where women actually rated themselves higher than men:

  ... we found that males rate themselves higher on explicitly sexual
  dimensions (e.g., sexually responsive, experienced) and females
  perceive themselves to be more romantic and sexually attractive.

It would be good to see a meta-analysis of such studies to get a better idea of the overall effect, but the bottom line is that it's not clear - it may depend on the particular scale used, or any number of other confounding factors.

Some examples of such factors: Black men rate themselves higher than white men, but women do not; men and women base their ratings on physical traits to different degrees; self-esteem affects females differently from males; and effects vary in cultures where physical attractiveness is more or less emphasized.  That is, it appears that gender differences vary based on societal changes, such as before and after the feminist movement, differences in idealized representations in the media, cultural changes in messages such as "black is beautiful", etc.  And gender differences also vary depending on the incorporation of physical attractiveness.

Physical attractiveness:

In the 1980's and 90's, there was a flurry of research on self-perceived body image and physical attractiveness related to increased diagnosis of anorexia/bulemia, so much more is known about these measures.  In line with suggested epidemiology for anorexia, that is most associated with young women, body image is typically lower in females than males, and females are more often subject to a "lower-than-average" effect, while males more often rate their physical attractiveness as better than average.

As before, there are many confounding factors, including some of the same ones to do with skin colour, cultural context, different physical traits, and self-esteem.  Nonetheless, the effect suggested in the question is perhaps more pronounced for physical attractiveness than sexual attractiveness / romantic appeal.  And since self-perceived physical attractiveness often constitutes an important component of sexual attractiveness, then some of the differences in results may depend on how heavily a particular study incorporates physical attractiveness into their own measure of sexual attractiveness, and how important physical attractiveness is as a component of sexual attractiveness for the particular group studied.  With this factor removed, and limiting findings to modern Western culture, it may turn out that men and women do not differ in self-enhancement of sex appeal, or even that women do so to a greater degree.


Perfectionism, and approval addiction: how are these two generated from a trauma? Depression and anxiety most of the time stem from a past trauma, but it is actually not the events, but the thoughts that create the symptoms of depression and anxiety.

Out of those thoughts, perfectionism and approval addiction are prominent, and I, myself, am an example of it. So how does a traumatic event tend to generate the cognition of perfectionism and approval addiction, or does it even tend to generate it or is it, itself a result of it(depression and anxiety)?

I want to say that this kind of issue is environmental. Behaviours of perfectionism are developed because of certain factors that may stem from early childhood (as in how the parents treat the child). If self esteem is measured based on the standards that the authority sets, but the child cannot reach them, they may come to know themselves as inadequate. Freud talks about this in his theory of psychoanalysis and in the psychodynamic theory.

I don't think it's specifically one case of trauma, but a series of evaluations that causes the development of low self esteem.

Before the child has a complete theory of mind he may not seperate himself from his environment and in turn mirror or internalize the negative image of how his parents treat him.
Some evidence suggests that perception becomes more global with age (which may reflect the development of a pragmatic perceptive system that allows faster identification of objects in the environment. ) (Akshoomoff et al., 1995).

Its possible that this global perceptive system may become tied to negative emotional trauma. Which makes negative behaviours more easily developable.
Predictions of outcomes of events have also been tied to perception, as perception as been shown to be constructive (in the sense that it builds on itself from past experiences, even emotional ones)  (Sinke,  et al., 2012)

Individuals who experience abuse may unconsciously recall the outcomes of that abuse during similar situations, causing distress.

Also, some Self theorists may also see the traumatic experiences as negatively affecting the sense of self. Approval addiction may be seen as an act taken to strengthen self identity, as the authority figure did not properly bolster the self esteem during development, so the individual may try to compensate for that by seeking approval.

Reference

Developmental trends in visuospatial analysis and planning: I. Copying a complex figure. Akshoomoff, Natacha A.; Stiles, Joan
Neuropsychology, Vol 9(3), Jul 1995, 364-377

Sinke, Charlotte B. A. et al. “The Constructive Nature of Affective Vision: Seeing Fearful Scenes Activates Extrastriate Body Area.” PLoS ONE 7.6 (2012): e38118. Web.


How can you gamify the recruitment of new employees? We recently had a user on our site ask if they could add game mechanics to their employee recruitment. To be honest, I'm having a little trouble finding solutions for this. I'd really appreciate any insight you guys might have.

I guess my first question is, who would you incentivize for this, and how? Are there any case studies that cover a scenario like this?

I would try to work on stimulating rejected candidates to become referrals.

Every candidate who has been rejected is already quite well into what the job is all about. S/he should be very good at explaining the job requirements. (The pitfall of the majority of job ads, IMHO is that they bitterly fail at explaining what the job is about.)

At the same time rejected candidates must be likely to know colleagues good for that job. And it is in their self-interest to promote those colleagues, because they would have less competition for all the other vacancies.


Does every human brain have the same shape? Apart from the general structure (6 layer cortex, same areas, etc.) does every brain have the exact same number and arrangement of sulci, gyri, etc?
Do these elements have the same shape?

No, not at all--or not necessarily; different sulci & gyri may be different shapes--this is one of the reasons why individual brains are transformed or normalized into standard space in group analysis of MRI data (see here for a good basic explanation of how & why this is done). In some cases canonical landmarks may be missing entirely--famously, an autopsy showed Albert Einstein to have quite anomalous anatomy in the area of the frontal operculum or Sylvian fissure.


Psychology of brand names Marketers use the fact that different letters are associated with different mental images and emotions when they create brand names.

Studies show that letters and their combinations produce different connotations in terms of size, shape, brightness and overall impression of an object. The letters <a> and <o> symbolize depth and size, while <i> evokes the mental image of something small. Among consonants, soft, voiced sounds such as <d>, <l>, <m>, <n>, <w> can be distinguised from hard, voiceless sound such as <f>, <k>, <r>, <t>, <p>. The soft consonants evoke associations of harmony, softness, gentleness and femininity, while the hard cononants are connected to hardness, dynamism, vigor, strength and masculinty.
(translated from http://comrecon.wordpress.com/2010/02/26/namen-sind-wegweiser-bei-konsumentscheidungen-naming-branding/)

On some other brand name blog I read that the letter <b> is associated with trustworthiness.
What are those studies, and what else has been found regarding the psychology of letters (graphemes) and sounds (phonemes)?

What you are looking for is usually considered within synesthesia, specifically auditory-visual synesthesia.

Usually these topics are developed in "commercial or industrial psychology" in a general way and more specifically by psychologists incorporated in marketing, these last studies are often not published, are made for the best initial orientation of the product with a line of consumers.

Here is a general book:
https://books.google.es/books?id=ESH7AAAAQBAJ&pg=PA812&lpg=PA812&dq=psychology+synesthesia&source=bl&ots=zC3KmJPT2h&sig=pGlZ9qPf1d14T7i96AL8OmMvVSo&hl=es&sa=X&ved=0ahUKEwjmnYvRyanVAhUNfFAKHbX-CV84ChDoAQhWMAY#v=onepage&q&f=false

It seems that what ultimately interests most is why (cerebrally) and what repercussions (especially in clinical) has this phenomenon.

You will not find it difficult to find end-of-grade papers, there are also theses.


Is talking to oneself loudly a very common sign of schizophrenia? Schizophrenia.com states that

  Replaying or rehearsing conversations out loud- i.e. talking to yourself [is a] (very common sign) [of schizophrenia].

Looking at the site it's not clear who edits it (or what their credentials are)... so is this claim supported by research, i.e. is talking to oneself loudly a very common sign of schizophrenia?

And is it so irrespective of the content of the talk? E.g. talking to "oneself" as if having a conversation with an imaginary person [different than oneself] seem somewhat different to me (and indicative of hallucinations) in contrast with clearly self-directed self-talk, e.g. as described in the first paragraph of a NYT article of someone wondering out loud in a supermarket. Or is it simply the case that so few people talk to themselves loudly so that the group (of loud self-talkers) is dominated by those who have schizophrenia? (About 75% of people with schizophrenia experience auditory hallucinations.)

I also found that

  Self-talk [and by this the article means loud] and behavior rituals were found to be common behavioral features in adults with Down syndrome, and in most instances, were not a sign of a psychiatric disorder.

But then the number of people with Down syndrome is only about 1/12 of those with schizophrenia.

Before I answer this question, I would like to point out that at the bottom of Schizophrenia.com is a disclaimer, and part of it says

  No health information on Schizophrenia.com, including information about herbal therapies and other dietary supplements, is regulated or evaluated by the Food and Drug Administration and therefore the information should not be used to diagnose, treat, cure, or prevent any disease without the supervision of a medical doctor.

If you look at their write-up on the DSM diagnostic criteria, it seems that they are taking about the diagnosis criterion of Disorganised Speech within the Diagnostics and Statistics Manual (DSM).

The bit after the brackets:

  these are also called "word salads". Ongoing disjointed or rambling monologues - in which a person seems to talking to himself/herself or imagined people or voices.

is their own annotation to what is in DSM-IV (American Psychiatric Association, 1994)

The key point is the bit where they say that the talking is "ongoing disjointed or rambling monologues".  Just talking to yourself is not necessarily disorganised speech.

WebMD describes disorganised speech in their schizophrenia page.

  They may act silly and giggle for no apparent reason. They often make up words and sentences that make no sense to other people. And they often don't show facial expressions.

  Examples of disorganized speech include:

  Making up words (neologisms). For example: "I'm going to the park to ride the wallywhoop."
  Rhyming words (clang speech). For example: "Deck the halls with boughs of holly, folly, polly, dolly, hello Dolly, want a lollipop?"
  Saying sentences that make no sense to other people (word salad). For example: "Give paper floor me school hop bus."
  Repeating exactly what someone else has said (echolalia).

Another point of note is that whether following DSM-IV or the latest edition — DSM-5 (American Psychiatric Association, 2013) — disorganised speech on its own is not enough to diagnose schizophrenia.  It would have to accompany at least one more item from Criteria A, plus there are also Critera B through to F to meet.

References

American Psychiatric Association, 1994. Diagnostic and Statistical Manual of Mental Disorders (Fourth Edition). Washington, DC: American Psychiatric Publishing.

American Psychiatric Association, 2013. Diagnostic and Statistical Manual of Mental Disorders (5th Edition). Washington, DC: American Psychiatric Publishing.


Why did humans evolve to be traumatizable? Why did humans evolve to be traumatizable, instead of being more resilient and treating trauma in a detached manner? Don't symptoms of trauma reduce a person's biological fitness? Is PTSD an adaptation, and if so, what is it an adaptation for? After all, the stress reaction and emotional imprinting appears to be designed rather than an accident.

There are a lot of assumptions you are making here. "Being traumatizable" isn't really a trait. We evolved a brain in a certain way, with an amygdala and hippocampus that work a certain way. Those components have been critical in our ability to form knowledge + interact socially with one another. Instances of malfunction in the face of trauma/PTSD are a side-effect of an imperfect biological system, BUT that doesn't render the whole system useless/detrimental in the evolutionary sense.
Secondly, you're assuming it does reduce biological fitness. I'm sure it makes it harder in indirect ways, but ultimately, PTSD symptoms actively mess with very few people's ability to have sex and pass on genes. PTSD does seem to have a strong, albeit complex genetic component. For as long as people with PTSD are reproducing (and most of them are) then there will be a genetic predisposition for developing PTSD in the gene pool.
Third, how is it designed? I am confused by this one. People have a tendency to wrongly assume that almost every trait is an adaptive trait. Maybe in this case it is and we just haven't found what the beneficial feature is BUT, it is highly more likely and logical that a) as stated above, it's just a by-product of another highly adaptive trait aka, our particular brain structure and function. They come in a 2-for-1 deal and as much as PTSD sucks or might reduce biological fitness, those are completely offset by the benefits and increase in fitness due to our brain circuitry.
OR b) it's a neutral variation that doesn't significantly increase or decrease our fitness, therefore is maintained in the population because it has no reason to be selected out. Another reminder that our own negative human experience of suffering through PTSD doesn't inherently mean much in the eyes of evolution, as long as we can reproduce.


This is the 2,000th question posted. Why do people care about big round number events more than the surrounding events? People seem to have a preference for celebrating "big round numbers", like the 2,000 post in the forum (although the 10,000 post would probably be more "special" - but not the 10,234 post, so it's not strictly a magnitude bias). There are lots of examples of this. Sports stats are another: baseball players celebrate 3,000 hits, 500 home runs, and 20 wins. Football players 1,000 yard seasons, and so on.

Why do we prefer marking events that are round numbers?

I might be wrong but it might have something associated with the numerical goals we acheive as children, young adults and grown up. For example, becoming 10 years of age is a sign of maturity, mainly due to the double digits it contains. This leads us (as children) to believe that we are that much closer to becoming adults. When people turn 40 or 50 they put a lot more pressure on them selves than they would have if that number was decreased a year or two. Maybe it's the obvious facts such as 50 is closer to 60 than 49 is?

Also, when we learn how to count, we don't necessarily stop at 3, or 7, 10 is usually the number that kids are first introduced to, and once they learn it get appraise from external figures.

Basically, our preffered simplicity for numbers may or may not reflect our own personal achievements during our childhood and other significant life experiences. I know for a fact that I wouldn't be as proud of running a 39.7K as I would have been for running a 40K, even though the difference is a tiny 0.3.

When we announce our achievements to others we say "I'm in the top 10 for my age in cross-country!", assuming we come 7th, top ten sounds like a greater acheivement, this is just me, others may have different opinions.

Growing up and being congratulated for our achievements by older family members and other adult figures for unspecified winnings might have an impact on our greater admiration of "rounded numbers". I'm not quite sure whether or not I explained my self very well but I hope you understand what I'm saying.


Why do people behave better when observed? Why does it seem that people behave like they are supposed to when they are being observed?

For example. If you place a fake security camera on an employee, they would behave better (or at least appear to).

Alternatively, when a system or workflow becomes transparent, it seems to me that people would make an extra effort to do better since they are more exposed.

Is there any particular identified effect, cognitive bias, or phenomenon that describes the reasons behind this change of behavior?

It sounds like rational behaviour (i.e., it is not a cognitive bias). Monitoring generally creates a closer link between behaviour and social consequences (either rewards or punishments).

A huge number of theories capture ideas about how the social context influences behaviour (e.g., social norms).

In the work context, you could look at ideas around maximal and typical performance.

That said, there is literature that looks at the pros and cons of monitoring on workplace performance. In particular, excessively fine grained monitoring can lead to increased stress, lower job satisfaction, turnover, etc. See for example Kinnie et al for a discussion.

References

Kinnie, N., Hutchinson, S., & Purcell, J. (2000). 'Fun and surveillance': the paradox of high commitment management in call centres. International Journal of Human Resource Management, 11(5), 967-985.


Could ketosis be therapeutic for ADHD based on the neuro-energetic theory of attention? I'm a complete neuroscience novice so please bear with me.

One of the more interesting theories of the etiology of ADHD that I've read posits that the disorder may be one of neuroenergetics - the result of insufficient and variable neuronal energy production due to insufficient "formation and supply of lactate" in astrocytes. As the theory goes, this impairs immediate response to cognitive demands due to a lack of sufficient ATP for "rapidly firing neurons," and also affects development of the brain by impairing myelination on longer time scales. Abstract here: http://www.ncbi.nlm.nih.gov/m/pubmed/16925830/

I'm quite interested in how ketosis can be therapeutic for neurological/cognitive issues in general, and how it might ameliorate ADHD symptoms in particular - there appears to be some experimental evidence (at least in rat models) that it might do the latter. There also appears to be experimental evidence that ketosis increases levels of lactate in the brain: http://www.ncbi.nlm.nih.gov/m/pubmed/11043913/

My question: if the theory proposed in the first link above is correct, would it be reasonable to think that a ketogenic diet might eliminate ADHD symptoms by addressing the lactate supply issue? Obviously the effects of years of impaired myelination would still be present, but could ketosis resolve the more immediate energy-supply issue and also possibly improve myelination going forward?

Whether or not there is truth to this theory, a ketogenic diet cannot 'eliminate ADHD symptoms'. ADHD is an impairment of executive functioning. Executive dysfunction is thought to be linked to a deficit in dopamine, as well as functional frontal lobe pathology. (1) There are certainly other theories as to what causes the disorder, and they are likely a byproduct of how broad a net the traditional ADHD 'symptoms list' seems to cast.

There is no doubt that lactate is important. Recent evidence may suggest that lactate is preferentially metabolized over glucose by neurons in the brain. (2) However, while low lactate levels might produce behavioral effects that imitate those of ADHD, there is no evidence to suggest that the disorder itself can be traced to lactate levels in the brain. One way that we can observe this is by measuring executive functioning ability and lactate levels in humans as the result of acute exercise, since exercise is observed to raise lactate levels. This study shows that:

  ...While acute exercise improved all aspects of executive functions in those without ADHD, acute exercise only improved inhibitory performance for those with ADHD.

Thus, it does not look like the cure you are looking for is found in ketosis, assuming that it is the lactate you are monitoring (and also assuming that a ketogenoc diet does not raise lactate levels by a hyperincreased amount relative to that generated through rigorous exercise). Furthermore, the Wikipedia page for ketosis cites several sources that suggest that a ketogenic diet may be unhealthy, and even fatal if done improperly (4). But that last bit exceeds the scope of your question, so I'll leave you to look into that if you so desire.

EDIT: Forgot to tackle the myelination issue, which seems to be a big part of your question, as well. Decreased myelination appears to lend itself toward addictive behaviors, and may worsen existing disorders through psychopathological means, but does not seem to cause the disorders themselves. An increase in myelination may help regulate symptoms, but cannot cure the sufferer of the disorder or eliminate the symptoms entirely, which seems to be what you are asking about. (5)
(6) A well-balanced diet that supports the strengthening of myelin (i.e. Omega 3) is often a method of regulation for ADHD sufferers, but is not the rule.


How to calculate absolute power for EEG from power spectra density? For example, I have power spectrum density calculated by pwelch

f = EEG.data;
f = f(2, :);
N = EEG.pnts;
Fs = EEG.srate;
NFFT = 2^nextpow2(N);
NOVERLAP = 0;
WINDOW = 512;
[spectra, freqs] = pwelch(x, WINDOW, NOVERLAP, NFFT,Fs);
deltaIdx = find(freqs>1 & freqs<4);
deltaPower = mean(spectra(deltaIdx));

The code comes from EEGLab, and can be found here: https://sccn.ucsd.edu/pipermail/eeglablist/2014/008043.html

How should I calculate absolute power from it? What's the relationship between absolute power and power spectrum density?

I had to do some searching to be able to answer this question. As a matter of fact, a similar questions was once asked on Signal Processing.

To make the explanation more laymen-like, I think the answer means the following:

With pwelch or an FFT analysis you can calculate the amplitude of sinusoids with particular frequencies (see this answer ).
These amplitudes squared, result in the absolute power within these specific frequencies. The resulting power per frequency is the power spectral density (PSD). In neuroscience, people do not often work with individual frequencies but work with frequency bands, such as the alpha band (8-14 Hz). This can be calculated by taking the average or the integral.

The absolute power (W), you referred to, is the power of the entire signal. It thus does not make a distinction between the different frequencies. This can be calculated, by summing the power of each frequency (i.e. taking the integral of the signal). By summing, you have the total amount of power within the signal.
The absolute power can be used to normalize the PSD, by dividing the PSD by the absolute power (as described in the answer on Signal Processing).

Average vs integral

It seems that it is possible to calculate either the average or the integral of a frequency band. But when would you take the integral and when would you take the average? The average is an easy way of calculating how high the power is in a specific frequency band. This way, it does not matter how large the range of a frequency band is. The alpha band average will not be more inflated then the delta band (0-4 Hz) because of a bigger range.

When you take the integral there will exist differences that are affected by the size of the frequency band, because you do not divide the sum by the amount of samples (i.e frequencies). However, it does allow you to normalize the PSD with the absolute power. Say, the integral of the alpha band results in 2W, the integral of the delta band results in 1W, and the absolute power of the entire spectrum equals 10W. Then we know that the alpha band plays a 20% part and the delta band a 10% part in the total signal. With mere averaging, this would not be possible because we 'neglect' the size of the range.

I think it depends on what exactly you are after. I haven't work with the absolute power and am not familiar with it's user. Perhaps it has something to do with comparisons between exp. conditions (within frequency-bands, i.e. alpha vs alpha) or within exp. conditions (between frequency bands). If an actual expert could elaborate on why one method is beneficial over the other, that would be great.


How does the brain know what to crave? I remember that at some point on House, M.D., one of the characters mentioned that her patient craved milk because it contained some chemical he/she needed. How does the brain figure out what chemicals it can get from what foods, and by extension what to crave? I know one craves very specific foods, but I eat a lot of foods per meal so I don't see how the body can connect something to its composition.

Check out this question on biology.stackexchange: Do omnivore mammals vary food preferences based on dietary needs?

The answers in that question mention that experiments on Rats and Birds determined that there's an internal chemosensor, the anterior piriform cortex (APC) within bird and rat brains that senses lack of Indispensible Amino Acids (IAA). Animals show aversion to foods that lack IAA in as short as 20-30 minutes.

There's another example listed that mentions that being sodium deficient makes animals like salt more. Their preference for salty taste increases.

I don't know if these findings apply to humans though.


What did Jung's patient find out? I'm reading Dreams by Carl Jung, and I couldn't understand a specific paragraph. Maybe I'm missing something so obvious that he didn't bother to write. It is the entry numbered 542:

What did the patient find out about his fiancee, i.e. what suspicion was "well founded" ?

Thanks !

Edit

Here is the plain text :

  On the basis of these conclusions and for the purpose of ascertaining
  the meaning of the dream. I have developed a procedure which I call
  “taking up the context.” This consists in making sure that every shade
  of meaning which each salient feature of the dream has for the dreamer
  is determined by the associations of the dreamer himself. I therefore
  proceed in the same way as I would in deciphering a difficult text.
  This method does not always produce an immediately understandable
  result; often the only thing that emerges, at first, is a hint that
  looks significant. To give an example: I was working once with a young
  man who mentioned in his anamnesis that he was happily engaged, and to
  a girl of "good" family. In his dreams she frequently appeared in very
  unflattering guise. The context showed that the dreamer’s unconscious
  connected the figure of his bride with all kinds of scandalous stories
  from quite another source-which was incomprehensible to him and
  naturally also to me. But, from the constant repetition of such
  combinations, I had to conclude that, despite his conscious
  resistance, there existed in him an unconscious tendency to show his
  bride in this ambiguous light. He told me that if such a thing were
  true it would be a catastrophe. His acute neurosis had set in a short
  time after his engagement. Although it was something he could not bear
  to think about, this suspicion of his bride seemed to me a point of
  such capital importance that I advised him to instigate some
  inquiries. These showed the suspicion to be well founded. and the
  shock of the unpleasant discovery did not kill the patient but, on the
  contrary, cured him of his neurosis and also of his bride. Thus,
  although the taking up of the context resulted in an “unthinkable"
  meaning and hence in an apparently nonsensical interpretation. it
  proved correct in the light of facts which were subsequently
  disclosed. This case is of exemplary simplicity, and it is superfluous
  to point out that only rarely do dreams have so simple a solution.

Jung does not tell us what his patient found.

He circumscribes the woman as appearing "in very unflattering guise" and "connected [...] with all kinds of scandalous stories". What kind of unfavourable scandal she was finally discovered to be involved in, Jung does not disclose. We can imagine anything from premarital sex to secretly working as a prostitute. What Jung's patient at the time of Jung's writing might have considered "scandalous" could well be seen as completely innocent and commonplace nowadays (e.g. premarital sex). Times change.

But the important aspect of this section is not what the woman did, but that the patient unconsciously had come to an insight that his conscious mind had not yet made, and that his unconscious informed him of this insight in his dreams.


Psychiatric name of disbelief disorder What psychiatric disorder would describe someone who doesn't believe anything presented to them (other than what they already know and are sure is true)?

P.S. Not to be distinguished by those that have a disorder because they are confused.

Thanks.

My research on your question has so far not showed any disorder that matches this description. Something we all suffer from, however, is confirmation bias. We interpret new information in the light of our current views and disregard information that don't match our existing beliefs. Research has shown that being confronted with convincing arguments for the opposite view might strengthen our belief in the one we already hold. You can read more about this in books like Mistakes Were Made But not By Me: https://en.wikipedia.org/wiki/Mistakes_Were_Made_(But_Not_by_Me)