Why is the last part(transmit) of the Feynman learning technique optional? I read some articles about The Feynman Learning Technique but I don't know why the fourth part, transmit, is optional?
From my perspective, the implementation part should be more important because the practice and theory breed feedback that can be used to optimize the theory.

From your source:

If you really want to be sure of your understanding, run it past someone (ideally someone who knows little of the subject). The ultimate test of your knowledge is your capacity to convey it to another. You can read out directly what you’ve written. You can present the material like a lecture. You can ask your friends for a few minutes of their time while you’re buying them dinner. You can volunteer as a guest speaker in your child’s classroom or your parents’ retirement residence. All that really matters is that you attempt to transmit the material to at least one person who isn’t that familiar with it.

This step being "optional" in this particular write up (it isn't noted as such everywhere) is just a practical matter; the author does not want you to be discouraged and feel the technique cannot be applied when you don't have someone else to teach to or don't feel comfortable doing this. It's suggesting that it's ideal to spread what you've learned as a final check on your knowledge, with some ideas here of how to accomplish that, but failing to do so doesn't make the other steps useless, it just makes it slightly incomplete.


What was her/his name again.....ahh got it! You all know the situation described in the title. You forgot something and start to search your memory and then after quite a while it jumps right in front of you, out of nowhere.

My questions are:

What happens in the brain during that moment of awareness?
Is it different from when we know something right away, since the subconscious mind is working for quite a while to produce the answer?
Is it possible to measure this moment and was it done already?

You'll want to look up literature on the "Tip of the Tongue" (TOT) phenomenon.  It's been studied since the 60s I believe and can be experimentally reproduced.


How is the g-factor of intelligence calculated? I am currently reading Dr. Richard Haier's book The Neuroscience of Intelligence and I am a little confused about the g-factor. Note that I have no education in psychology outside of general ed courses at university.

I have two questions regarding the g-factor.  What confuses me is for one, he does not go into technical detail about how the g-factor is calculated.

He does include this illustration:

Here we see that 15 mental tests are taken in groups of 3, where each group is correlated to a certain factor. So tests 1-3 are for reasoning, 4-6 for spatial ability, and so on.  These factors then correlate to the g-factor.

I am wondering what is the methodology used to find the correlations between the tests and factors/factors and the g-factor? For example, I don't quite understand how they measure the correlation between the test and the factor given that the factor is abstract (ie. reasoning). I hope what I am asking makes sense. I am not asking how to perform linear regression or calculate Pearson's r.

My second question is about the statement in the book:

"Different mental abilities are not independent. They are all related to each other and the correlations among mental tests are always positive.... It strongly implies that all the factors derived from individual tests have something in common, and this common factor is called the general factor of intelligence."

Wouldn't this imply that all of the factors are multicollinear and make it difficult to distinguish which factors are most significant?

PCA or EFA: A standard approach to calculating a g factor would be to use principal components analysis (PCA) or exploratory factor analysis (EFA). Basically, you administer a broad battery of cognitive ability measures. Then you use these tests as variables in a PCA or EFA. This will partition the variance in the tests into a set of uncorrelated factors. The first factor will be the factor that explains the most variance in the tests. It is this first factor that represents "g". Typically, each test will "load" (or correlate) with this first factor, some tests more than others. The first factor will capture something that is common across most or all of the tests. I.e., it is g, for general factor, that measures cognitive ability.

An empirical finding is that almost all tests of specific cognitive abilities correlate with the general factor. And typically, the loadings are fairly substantial. I.e., the first factor is quite substantial relative to second and subsequent factors.

Confirmatory factor analysis: It seems that what you present is a confirmatory factor analysis. This is a variant on exploratory factor analysis. Basically, you specify which observed variables load on latent factors and all other possible loadings are constrained to zero. More specifically, this is a higher-order confirmatory factor analysis (CFA). It is higher-order because, there are two-levels of latent factors. I.e., tests load on domain-specific latent factors (e.g., reasoning, spatial ability), and these domain specific latent factors load on g.

The CFA estimation procedures will find the parameter estimates that best model the data (i.e., the covariance/correlation structure of the tests).

So in this case, we see that all the tests load fairly well on their domains (i.e., > .70) and all the domains load on g (> .65), although reasoning and spatial ability load a little stronger.

In general, multivariate statistics training in psychology (typically presented at postgraduate level and sometimes latter undergraduate-level) will cover these statistical techniques. Here's Bill Revelle's notes that cover some psyhometric theory: http://www.personality-project.org/r/book/

Wouldn't this imply that all of the factors are multicollinear and make it difficult to distinguish which factors are most significant?
That's why researchers often focus more on g (i.e., the general factor). But yes, you are in a sense correct. Of course, you can still do multiple regression and such with correlated predictors; you can then look at things like semi-partial correlations to look at the unique prediction of any one domain.


What are the pros and cons of the hot sauce paradigm to measure aggression? The hot sauce paradigm is a way to measure aggressive behavior in the lab. Participants are asked to give a portion of hot sauce to another person (who they know hates hot sauce) and who will have to eat it all, ostensibly as part of a taste test.

What are the pros and cons of the hot sauce paradigm?

The hot sauce paradigm was reviewed as part of a paper discussing laboratory measures of aggression. They argued that the hot sauce paradigm's main advantages are that it is very economical, easily quantifiable, less likely than other methods to be interpreted competitively, and that it has ecological validity (Ritter and Eslea, 2005).

Given the prevalence of its use, there appears to be a surprisingly limited amount of validation studies for the hot sauce paradigm. Adachi and Willoughby (2011) reported the following in a more tangential discussion of aggression measures.

  Lieberman et al. [1999] found that scores on [the hot sauce] paradigm were positively related to both trait and physical aggression scores on the Buss and Perry (1992) Aggression Questionnaire, supporting the convergent validity of the Hot Sauce Paradigm, although to date no study has measured its association with aggressive behavior outside the lab.

Ayduk, Gyurak and Luerssen (2008) suggested that one threat to the hot sauce paradigm's validity comes from rejection sensitivity (RS): "a processing disposition to anxiously expect, readily perceive and overreact to rejection." They reported that failing to control for RS could influence the results in a hot-sauce paradigm, but that statistical control was sufficient to guard against it.

The Ritter and Eslea (2005) review also provides an extensive and general critique of the hot sauce paradigm and other classic aggression measures, but this is not readily summarized. The potential problems raised by the review relate to mediating variables, social cognition, affect, questions of overt/covert aggression, among others. Overall, the biggest weakness of the method appears to be the apparent inability to conclusively rule out the influence of mediators and moderators.

References

Adachi, P. J., & Willoughby, T. (2011). The effect of video game competition and violence on aggressive behavior: Which characteristic has the greatest influence?. Psychology of Violence, 1(4), 259.
Ayduk, Ö., Gyurak, A., & Luerssen, A. (2008). Individual differences in the rejection–aggression link in the hot sauce paradigm: The case of rejection sensitivity. Journal of experimental social psychology, 44(3), 775-782.
Buss, A. H., & Perry, M. (1992). The aggression questionnaire. Journal of Personality and Social Psychology, 63, 452– 459.
Lieberman, J. D., Soloman, S., Greenberg, J., & McGregor, H. A. (1999). A hot new way to measure aggression: Hot sauce allocation. Aggressive Behavior, 25, 331–348.
Ritter, D., & Eslea, M. (2005). Hot sauce, toy guns, and graffiti: A critical account of current laboratory aggression paradigms. Aggressive Behavior, 31(5), 407-419.


Why would someone state that "self-esteem doesn't exist"? In the video "Self-esteem Doesn't Exist, the author Jordan Peterson clearly seems to argue he doesn't believe in self-esteem, given the title of the talk. However, I do not notice him mentioning anything in relation to this and therefore I do not understand what he means exactly (maybe because I am not an English speaker).

Could you clarify why exactly he claims self-esteem does not exist, or what he is referring to?

In the video, he states:

  What is self-esteem? It is a word (actually it is two words). It is sort of something you think you might have or not have. But, that's a figure of speech. That's not an empirical phenomenon.

Thus, by stating "self-esteem does not exist", he is implying it cannot be empirically observed, i.e., it is not something that can be observed reliably and systematically.

From there on out, he starts arguing why this is so. Some key points:

Reported self-esteem measures are pretty appalling.
You can already model the concept of self-esteem with the Big 5. I presume he is implying here the concept is superfluous and implications of 'low or high self-esteem' are modeled better using Big 5.
The introduction of the concept has lead to undesirable consequence of advocating for self-esteem. But, there is no reason to believe that increasing your self-esteem is a good idea. "It is not at haste that you should have a good opinion of yourself in every bloody situation."

He continues to give examples for these points, e.g., "self-esteem might become disconnected from the actual accomplishment", but I believe this is outside of scope what you are asking for here.


Terminology: why do psychologists use "positive" and "negative"? In a lot of places in psychology - for example in operant conditioning and in describing symptoms of psychological disorders - various things are described as "positive" and "negative". Positive rewards/punishments or positive symptoms are things that are added or given to an individual, whereas negative rewards/punishments or symptoms are things that are taken away or that disappear.

This terminology seems confusing - both the word "positive" and the word "negative" have other connotations in areas that psychology is concerned with, for example in describing mood. Using this particular terminology for things like the symptoms of psychological disorders, instead of less ambiguous words with more direct meanings like "additive" or "subtractive", seems confusing. Is there a particular reason why the words "positive" and "negative" continue to be used in a scientific sense over such less ambiguous alternatives?

They are used in conditioning because those terms were originally used by Skinner, and after some shuffling around ("negative reinforcement" used to be used to describe what is now called "punishment" or more specifically "positive punishment") became standard terms. Dinsmoor (2004) covers a bit of the history and cites the relevant source literature.

For the positive and negative symptoms of schizophrenia, that goes back earlier, to Bleuler who was also the first person to use the term "schizophrenia" in 1908 to describe the disease known by that name today. The 1908 use of schizophrenia was at a conference, but there are also published books and articles by him later that use the terms, I've included a reference to one from 1912 below.

It isn't all that uncommon for scientific terms to differ from their lay usage; language is also mutable, so even carefully chosen terminology can drift away from the meaning in broader society. I'm not suggesting that is what happened in this case, but I just want to emphasize that it is typically more important to use terms consistently in science. Changing terminology that has been used for a long time is difficult, potentially confusing, and makes it harder to connect older literature to newer work.

Ashok, A. H., Baugh, J., & Yeragani, V. K. (2012). Paul Eugen Bleuler and the origin of the term schizophrenia (SCHIZOPRENIEGRUPPE). Indian journal of psychiatry, 54(1), 95. Available from: http://www.indianjpsychiatry.org/text.asp?2012/54/1/95/94660

Bleuler, E., & White, W. A. (1912). The theory of schizophrenic negativism. Journal of Nervous and Mental Disease, 39(1), 50-57, 133-139, 195-202, 274-279. doi: 10.1097/00005053-191201000-00009

Dinsmoor, J. A. (2004). The etymology of basic concepts in the experimental analysis of behavior. Journal of the Experimental Analysis of Behavior, 82(3), 311-316. doi: 10.1901/jeab.2004.82-311 pdf: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1285013/pdf/15693525.pdf


What is the effect of Social Proof on Conversion Rate? I'm wondering to what extent Social Proof helps the Conversion Rate of websites and marketing.

Specifically I'm wondering what effect Social Proof would have on Conversion Rate for a sample task in an online context. Lots of marketing material espouses it's effectiveness but I would like academic research on the matter.

There's some basic research I've found that shows yes, people do things their friends do (such as some of the studies referenced in the Wikipedia article) but this is not specific to new methods of Social PRoof.

What quantitative research has been done in regards to social proof effects website conversion with modern Social Proof techniques like Facebook likes and Amazon customer reviews?

This is a partial answer, but there are a number of academic studies on this topic.  The findings of the Berkeley article "Long Tail or Steep Tail?
A Field Investigation into How Online Popularity Information Affects the
Distribution of Customer Choices" (Tucker and Zhang, 2007) suggest that

  evidence of a complementary effect, where
  the steep tail indicates new interest in the most popular vendors from outside, with
  negligible cannibalization of interest for less popular vendors. The ndings suggest
  that popularity information can serve as a powerful marketing tool that facilitates
  product category growth. They also explain the prevalence of rm practices to highlight
  bestsellers.

where 'long tail' refers to customers buying low-volume products and 'steep tail' refers to the flocking to popular products.

A couple of key conclusions from that study:

  We find strong evidence for a steep tail effect, where customers are more likely to click
  on the most popular vendors when the popularity information is publicized and made salient
  through ranking the vendors on the page by popularity.

and that there was little negative effects to less popular product sales

  If a steep tail effect exists, and if it complements the long tail, websites such
  as Google.com and Digg.com can increase overall number of clicks at little cost to the less
  popular listings.

A caveat of sorts is stated in the article "On the Depth and Dynamics of Online
Search Behavior" (Johnson et al. 2004) in that their study showed a bit of 'consumer inertia', in that their study

  show that the amount of online search is actually quite limited.


Labeling and discrimination I recently saw a video (unfortunately can't remember where), where someone claimed that the use of labels to identify social groups produced or increased prejudice. So the labels of nationality, ethnicity, religion, sexual orientation, etc. influence the perception of such groups by others, and result in segregation and discrimination rather than a desired effect of acceptance or unification.

I believe the context is described as "identity politics", where social groups label themselves, or are labeled, in an attempt to promote awareness of their social status / plight / cause, etc.  My impression was that the labels promote an "us vs. them" mindset, potentially by reinforcing differences rather than shared traits. (Tribalism?)

Does this theory regarding the 'negative' consequences of the use of labels have a name?

Are there studies demonstrating such behavior?

I found the term "labels" used in the context of symbolic interactionism, but the articles I've found so far seem to describe that as the tendency of a person to act in a way that conforms to the label (e.g. a person labeled as "deviant" will adopt behavior to meet the definition of the term).  I'm interested in how the self-adoption of a label by a group may produce a negative perception or separation / isolation of the group, such as producing discrimination that might not otherwise occur.

UPDATE: I saw this discussion of ingroup / outgroup behavior, which sounds relevant. Are labels one mechanism by which ingroup / outgroup associations developed?  Is the discrimination a reliable / consistent result of identifying people as outgroup?

What is the primary mechanism behind nationalism, sports-team-ism, product-ism etc.?

It seems like ingroup-outgroup stereotyping / bias / discrimination is the concept I'm looking for.  This article seems to sum it up well.

https://www.psychologytoday.com/blog/fulfillment-any-age/201012/in-groups-out-groups-and-the-psychology-crowds


Comprehensive list of cognitive techniques in CBT I'm not a cognitive science student, but I'm interested in CBT (Cognitive Behavior Therapy) and I'm using it to overcome some of the problems I have.

However, I have difficulty in finding resources online for it. AMAIK CBT has a list of cognitive errors, which I prefer to call dysfunctional mental sceneries. You can simply Google for common cognitive errors and you end up with like 20 good results.

To overcome those errors, people are encouraged to use some techniques like reality testing for example. But I can't find a good comprehensive list of techniques used in CBT. Here are the links to sites I've found:

http://cognitivetechniques.com/what-is-cognitive-behavioral-therapy-cbt/
http://www.calmclinic.com/anxiety/treatment/cognitive-techniques
http://brownbackmason.com/articles/5-common-techniques-of-the-cognitive-behavioral-therapist

However they barely provide more than 5 techniques. In comparison to the lists of cognitive errors, it seems that there are not enough cognitive techniques proposed by cognitive psychologists. I've heard somewhere that we have more than 100 cognitive techniques, and I can't find more than 5 on the Internet.

Is it that I've misunderstood techniques part of CBT? Or is it that techniques are not free to be published online? Can anyone clarify me here, or show me a comprehensive list of cognitive techniques?

You might want to check out http://www.anxietyonline.org.au/ . It's free for the eTherapy version and is funded by the Australian federal government.

A colleague of mine gave a presentation and it looks really good. From the website:

  Anxiety Online is a comprehensive online mental health service
  offering information, assessment, online diagnosis and treatment
  programs ("eTherapy") for the anxiety disorders:-

Once you have gone through the the fairly long diagnostic process, you get access to a range of eTherapy resources. In particular, you can use it to learn more about CBT. It has exercises and videos.


How does oxygen deprivation affect neural activity? It is increasingly common for someone to regain a heartbeat after a cardiac arrest. During the time that the person is without a heartbeat, and so without circulation, the brain is deprived of oxygen.
Why are there long-term consequences to temporary deprivation of oxygen?
I understand that the short-term effect of loss of oxygen to the brain is to make it impossible for the cell to maintain the gradients of ions needed to initiate action potentials. As long as the cells don't die, or not too many die, why is there often long-term neurologic damage after a heart attack.
My question differs to the question of what happens during a stroke. During a stroke the deprivation is longer and more focussed.

A stroke results in impaired blood flow. A lack of blood supply to the brain results in prolonged cortical hypoxia, cells die. Neuronal cells have a relatively high background metabolism, for example because of their reliance on ion pumping that costs energy. A lack of oxygen can kill a cell and therefore deplete the brain of thousands and thousands of neurons after a serious stroke. Depletion of certain areas of the brain of cells will reduce the output to other areas, and decrease the input to that area. Moreover, epileptic foci may appear, resulting in epileptic discharges in the brain, referred to as post-stroke seizures.

Upon recovery, gross rearrangements may occur in the brain, alongside gross changes in cellular activities throughout the affected areas, due to the brain's plasticity.

Having said that, if the oxygen depletion is short, I don't see any reason why there should be gross changes in neuronal behavior after recovery.


What are the main differences between the FreeSurfer volumetric approach and the statistical parametric mapping from SPM? In modern research of brain volume and function there are two main players. FreeSurfer which is free of cost and open source and the older, but more frequently used, statistical parametric mapping that itself is also opensourced but is typically used within Matlab, which is closed source.

What should I have in mind while deciding which one to pick for my research?

Freesurfer is great for mapping cortical thickness using anatomical MRI data, while SPM can be used to compare two populations, voxel-by-voxel. This is useful for PET imaging. For example you can see where in the brain amyloid uptake occurs in alzheimer's patients, vs healthy controls.

Our lab uses Freesurfer to process functional MRI data, so I don't have any experience using SPM for this. I will say though that probably the main difference is that many of the Freesurfer processes are simple via command line in UNIX, while SPM has a easy-to-use graphical interface.

SPM however also has command line functionality, so if you are comfortable with that, you might want to explore that. The bottom line is that you will just have to experiment with both programs to find what works for you. Methodologically, both tools should give you the same results, so it's really just a matter of preference, and depends on what you are studying.


Why do some days feel fast and others feel slow? As per the title, why is it some days it just feels like a day can go so fast, yet other days can feel slow? Every day has the same amount of hours, minutes and seconds after all. What is the actual science behind our state of mind when we feel like this?

Several factors are proven to affect our experience of time. Those that differ from one day to the next include:

Biochemistry affects our perception of time.

  Stimulants produce overestimates of time duration, whereas depressants and anesthetics produce underestimates of time duration.
  http://en.wikipedia.org/wiki/Time_perception

Fear affects our perception of time:

  Hammond points to a study in which people with arachnophobia were asked to look at spiders — the very object of their intense fear — for 45 seconds and they overestimated the elapsed time. The same pattern was observed in novice skydivers, who estimated the duration of their peers’ falls as short, whereas their own, from the same altitude, were deemed longer

  When a person is scared, a brain area called the amygdala becomes more active, laying down an extra set of memories that go along with those normally taken care of by other parts of the brain.

  "In this way, frightening events are associated with richer and denser memories," Eagleman explained. "And the more memory you have of an event, the longer you believe it took."
  http://www.brainpickings.org/2013/07/15/time-warped-claudia-hammond/
  http://www.livescience.com/2117-time-slow-emergencies.html
  http://en.wikipedia.org/wiki/Time_perception

Our attention affects our perception of time:

  Wearden et al. (2014) administered a questionnaire which asked about passage of time in different drug and emotional states, and generally found that situations associated with “distraction” from time were associated with faster passage of time, in accord with the idea that “attention to time” is an important determinant of time judgements.
  http://www.mind-and-brain.de/postdoctoral-program/scientific-events/archive/time/

Having fun(or not):

  When this was tested by Kellaris (1992), they found that when listeners enjoyed the music more, time seemed to slow down.

  Or—prepare yourself for a 180 degree about-face—it could all be the other way around. Perhaps you’re having fun when time flies. In other words, we assume we’ve been enjoying ourselves when we notice that time has passed quickly.

  There’s evidence for this in a recent experiment by Sackett et al. (2010). Participants doing a boring task were tricked into thinking it had lasted half as long as it really had. They thought it was more enjoyable than those who had been doing exactly the same task but who hadn’t been tricked about how much time had passed.

Being tired:

  When we’re tired, though, our perception of time goes awry and we find it more difficult to distinguish between short spaces of time. This fact can be used to measure whether people are too tired to fly a plane, drive a truck or be a doctor. Indeed just such simple hand-held devices that quickly assess your tiredness are already being developed (Eagleman, 2009).
  http://www.spring.org.uk/2011/06/10-ways-our-minds-warp-time.php

Emotional self-regulation:

  The effort of trying to either suppress or enhance our emotional reactions seems to change our perception of time. Psychologists have found that when people are trying to regulate their emotions, time seems to drag on.

  Vohs and Schmeichel (2003) had participants watch an 11 minute clip from the film Terms of Endearment. Some participants were asked to remain emotionally neutral while watching the clip and others were told to act naturally. Those who tried to suppress their emotions estimated the clip had lasted longer than it really had.
  http://www.spring.org.uk/2011/06/10-ways-our-minds-warp-time.php

Body temperature:

  Experiments have found that when body temperature is raised our perception of time speeds up (Wearden & Pento-Voak, 1995). Conversely when we are cooled down, our sense of time also slows down.
  http://www.spring.org.uk/2011/06/10-ways-our-minds-warp-time.php


How strong is the correlation between selfies and narcissism? We have concluded that posting selfies is correlated with narcissism, but how strong is the correlation?

Reference: Correlation between selfie and Narcissism

Table 1  of Fox and Rooney (2015) report this correlation between selfies posted on social networks and narcissim to be r = .19 in a sample of 800 U.S. men, (mean age = 29, SD = 6.5). I.e., the observed correlation was small in a general sense. But in the broader domain of personality-behaviour correlations, .19 is fairly moderate.

  Participants’ selfie posting behavior was assessed with one item
  inquiring how many pictures they had taken of themselves and posted on
  SNSs in the past week (M = 0.56, SD = 2.33; min = 0, max = 30).

Fox, J., & Rooney, M. C. (2015). The Dark Triad and trait self-objectification as predictors of men’s use and self-presentation behaviors on social networking sites. Personality & Individual Differences, 76, 161-165. doi: 10.1016/j.paid.2014.12.017


Why are so many people arachnophobes (afraid of spiders)? Why are so many people arachnophobes (have an extreme fear of spiders)?

Humans are most comfortable with those things that resemble themselves, both in terms of physical features and mentality. A dog, for example, may have an extra set of legs and a tail, but does not differ all that significantly from humans or other mammals—we can similarly see ourselves in the behavior and apparent emotions they exhibit.

Arachnids, on the other hand, are several orders of magnitude more alien. Beyond the gross physical dissimilarities, it is impossible to attribute anything resembling human emotion or motivation to them. Add to that their penchant for appearing unexpected in dark places and their inherently predatory nature, the very idea of spiders triggers in many people a primordial dread.


How is "mislabeling" cognitive distortion different from "labeling"? David Burns in his book Feeling Good describes "labeling and mislabeling" cognitive distortions:

  Personal labeling means creating a completely negative self-image based on your errors. It is an extreme form of overgeneralization. The philosophy behind it is "The measure of a man is the mistakes he makes." There is a good chance you are involved in a personal labeling whenever you describe your mistakes with sentences beginning with "I'm a..." For example, when you miss your putt on the eighteenth hole, you might say, "I'm a born loser" instead of "I goofed up on my putt." Similarly, when the stock you invested in goes down instead of up, you might think, "I'm a failure" instead of "I made a mistake."

  Labeling yourself is not only self-defeating, it is irrational. Your self cannot be equated with any one thing you do. Your life is a complex and ever-changing flow of thoughts, emotions, and actions. To put it another way, you are more like a river than a statue. Stop trying to define yourself with negative labels—they are overly simplistic and wrong. Would you think of yourself exclusively as an "eater" just because you eat, or a "breather" just because you breathe? This is nonsense, but such nonsense becomes painful when you label yourself out of a sense of your own inadequacies.

  When you label other people, you will invariably generate hostility. A common example is the boss who sees his occasionally irritable secretary as "an uncooperative bitch." Because of this label, he resents her and jumps at every chance to criticize her. She, in turn, labels him an "insensitive chauvinist" and complains about him at every opportunity. So, around and around they go at each other's throats, focusing on every weakness or imperfection as proof of the other's worthlessness.

  Mislabeling involves describing an event with words that are inaccurate and emotionally heavily loaded. For example, a woman on a diet ate a dish of ice cream and thought, "How disgusting and repulsive of me. I'm a pig." These thoughts made her so upset she ate the whole quart of ice cream!

But labeling and mislabeling seem equivalent. I see no difference between, "She's irritated by me, therefore she's an uncooperative bitch," and, "I ate a dish, therefore I'm a pig". How does David Burns differentiate between these cognitive distortions? How do other cognitive therapists differentiate?

It seems that in this case David Burns describes Labeling as an overgeneralization, not necessarily a misattribution. As in his example, a breather does breathe, it is just not the only aspect of the breather.

Mislabeling in this example is an inaccurate label, not an overgeneralization but qualitatively false, and "emotionally heavily loaded".

This explanation would fit with regular English semantics for the words, so it seems to make sense. I would not qualify the terms Labeling and Mislabeling as rigidly defined per this text though.


Does the Sapir-Whorf hypothesis apply to artificial (specifically programming) languages? As a computer programmer, I have an intuition that the idea "language influences thought" is very relevant to programmers and programming languages.

Is there any research that examines whether artificial languages influence thought?
How can such a theory be expressed as a testable hypothesis?

Firstly realize that Sapir-Whorf was proven wrong in the strong sense, but is accepted in the weak sense.  I don't think there's really any doubt now that learning new symbols and languages, or just enhancing your vocabulary in one language, influences thought.  Many mathematicians are especially proud of how accurately proofs communicate, and having gained this accuracy, the mind comes to expect it more and loathe ambiguities.  You see this happen with a lot of people in quantitative disciplines.

There doesn't seem to be a lot of research, but you're not the first to think of it.  Many programmers before have too (see wiki's references):

http://en.wikipedia.org/wiki/Linguistic_relativity#Linguistic_relativity_and_artificial_languages

Of course, none of them were neuroscientists or psychologists.  To test for causality would be difficult to control for (you'd have to provide a mechanism and we're only just about getting there at the neural systems level).  On the other hand, I'm sure you would find a correlation between programmers and certain kinds of behavioral and cognitive traits very easily.

In the end though, I don't really think there's any doubt among neuroscientists or psychologists; it's just a matter of finding the neural mechanism.  Language has been a pain in that regard.


Binocular rivalry in animals? Are there any experiments on binocular rivalry in animals? (In humans, brain responses to Rubin's vase are for example well studied.)

Yes! Binocular rivalry has been studied in monkeys (Logothetis & Schall, 1990; Lehky & Maunsell, 1996)
and extensively in cats (Fries, Roelfsema, Engel, König, & Singer, 1997; Sengpiel, Blakemore, & Harrad, 1995; Sengpiel, Blakemore, Kind, & Harrad, 1994; Sengpiel, Bonhoeffer, Freeman, & Blakemore, 2001; Varela & Singer, 1987; Moore, Spear, Kim, & Xue, 1992; Tong, Guido, Tumosa, Spear, & Heidenreich, 1992),  to say the least. This is all the further I got into a literature search today, but I'm sure there's much more out there.

References
- Fries, P., Roelfsema, P. R., Engel, A. K., König, P., & Singer, W. (1997). Synchronization of oscillatory responses in visual cortex correlates with perception in interocular rivalry. Proceedings of the National Academy of Sciences, 94(23), 12699–12704. Retrieved from http://www.pnas.org/content/94/23/12699.full.
- Lehky, S. R., & Maunsell, J. H. (1996). No binocular rivalry in the LGN of alert macaque monkeys. Vision Research, 36(9), 1225–1234. Retrieved from ScienceDirect.
- Logothetis, N. K., & Schall, J. D. (1990). Binocular motion rivalry in macaque monkeys: Eye dominance and tracking eye movements. Vision Research, 30(10), 1409–1419. Retrieved from http://www.psy.vanderbilt.edu/faculty/schall/pdfs/binmoriv.pdf.
- Moore, R. J., Spear, P. D., Kim, C. B., & Xue, J. T. (1992). Binocular processing in the cat's dorsal lateral geniculate nucleus III. Spatial frequency, orientation, and direction sensitivity of nondominant-eye influences. Experimental Brain Research, 89(3), 588–598.
- Sengpiel, F., Blakemore, C., & Harrad, R. (1995). Interocular suppression in the primary visual cortex: A possible neural basis of binocular rivalry. Vision Research, 35(2), 179–195. Retrieved from ScienceDirect.
- Sengpiel, F., Blakemore, C., Kind, P. C., & Harrad, R. (1994). Interocular suppression in the visual cortex of strabismic cats. The Journal of Neuroscience, 14(11), 6855–6871. Retrieved from http://www.jneurosci.org/content/14/11/6855.full.pdf.
- Sengpiel, F., Bonhoeffer, T., Freeman, T. C., & Blakemore, C. (2001). On the relationship between interocular suppression in the primary visual cortex and binocular rivalry. Brain and Mind, 2(1), 39–54.
- Tong, L., Guido, W., Tumosa, N., Spear, P. D., & Heidenreich, S. (1992). Binocular interactions in the cat's dorsal lateral geniculate nucleus, II: Effects on dominant-eye spatial-frequency and contrast processing. Visual Neuroscience, 8(06), 557–566.
- Varela, F. J., & Singer, W. (1987). Neuronal dynamics in the visual corticothalamic pathway revealed through binocular rivalry. Experimental Brain Research, 66(1), 10–20.


What are the purported mechanisms of eidetic memory and why is it comorbid with autism? Eidetic memory, often called "photographic" or "flashbulb" memory, is often associated with amazing feats of recall.  Is the mechanism behind this phenomenon an aberration of the visualization of a scene or the way that such visual information is encoded into long-term memory?

We often associate such accurate recall with those that exhibit savantism.  Kim Peek, the model for the character in Rain Man, is not autistic, but according to an overview article (actual reference pdf here), 50% of savants are autistic.  Is there any neurophysiological or anatomical reason why this might be true?

From my very brief skim of the field, it seems like the consensus is that savants have access to the kind of low-level information processing which non-savants do not. I'll summarize one such theory in some detail, since it's the one that I've happened to read. But I'm not an expert in this field and this is just one of the theories, the rest of which I haven't studied. I'll provide some pointers to the other theories at the end.

Snyder (2009) speculates that "savants have privileged access to lower level, less-processed information, before it is packaged into holistic concepts and meaningful labels". This is something that everyone would in principle have the potential for: savants are accessing information that is present in everyone's brain, but not normally available for introspection. As some supporting evidence for this idea, Snyder notes that savant-like abilities can sometimes be artificially induced in healthy individuals by inhibiting a part of the brain, and that savant abilities are known to appear spontaneously and suddenly in childhood or as a result of brain injuries. Once acquired, savant abilities typically do not improve by training.

  I have argued that the extraordinary skills of savants are latent in us all and that they can be induced artificially owing to the inhibiting influence of low-frequency rTMS, that is, by turning off part of the brain, not by exciting it. My hypothesis is that savant skills are facilitated by privileged access to raw, less-processed sensory information, information that exists in all brains but is inaccessible owing to top-down inhibition. Thus, autistic savants tend to see a more literal, less filtered view of the world. Their ‘skill’ or performance does not depend on active learning, but simply on an effortless ‘reading off’ of this less-processed information.

Snyder does not explicitly draw the connection between this and memory, but I would infer the connection to be as follows. Non-savants mostly consciously process information that has been packaged into holistic, high-level concepts, and it is these high-level concepts that are stored into memory. When we try to recall something that happened, we cannot recall specific details, because they were never stored into memory in the first place. Savants think more in terms of low-level details, so that's also what gets stored in memory.

As for the autism connection, Snyder proposes that a lack of high-level concept formation and seeing things mainly in terms of low-level detail is what autism essentially is. High-level concepts allow us to order the world and understand it, and autists are lacking in those kinds of concepts.

So why are all autists not savants? There are many varieties and degrees of autism, and it is conceivable that a lack of high-level concept formation could be caused by many different things. Some of those things could also cause more widespread damage to other systems. Snyder's suggestion is that autist savants represent autism in its "purest" form, uncontaminated by other disorders. (And why are all savants not autists? Presumably because they have access to both low-level and high-level concepts.)

How well-supported is this theory? Writing in the same issue as Snyder, Happé & Frith (2009) note that Snyder's hypothesis is "controversial", but note that a lot of other theorists also propose explanations which seem to imply some sort of focus on low-level processing:

  Several authors in this issue offer hypotheses for why autism should be associated with talent, with remarkable consensus that the ability to process local information plays a key role. Happé & Vital (2009) suggest that detail-focused attention and memory predispose to the development of talent, both in the general population and in autism. Baron-Cohen et al. (2009) suggest that superior sensory acuity across modalities underlies such detail focus, which in turn fosters the tendency to explore and master closed systems (e.g. the calendar). With the enhanced perceptual functioning theory, Mottron et al. (2009) propose that locally orientated processing and, specifically, detection of patterns in the environment, underlies the high incidence of savant skills in autism. Plaisted Grant & Davis (2009) also emphasize the qualitative differences in perceptual and cognitive processing in ASD, and make tentative links to underlying neural systems. These very different theorists share the view that an ability to attend to and process featural information plays an important part in predisposing to special skills of a savant sort. This view is upheld, for example, in a detailed case study of a prodigious mnemonist and calculator with Asperger syndrome and synaesthesia who shows a preference for local processing and an unusual pattern of brain activation while remembering digits (Bor et al. 2007).

Likewise, Neumann et al. (2010):

  One way to approach the question of how savants achieve their
  astonishing abilities is to investigate their brain activity during
  savant skills demonstration. Most theoretical accounts act on the
  assumption that some lower-level (perceptual) information processing
  mechanisms are enhanced in contrast to [41,7], or at the
  cost of higher-level operations [65,20,56,16]. Thus, single aspects
  of perception or lower-level information processing are preferentially
  processed or accessed resulting in a local or early processing
  bias that is benefiting for the development of savant skills. This is
  associated with an enhanced memory trace for these features [41].
  Treffert [61], assuming different brain mechanisms, postulated a
  model that implies compensatory right-hemispheric functioning
  after left-hemisphere damage and reliance upon lower-level procedural
  memory due to damage of higher-level memory.

So at least some version of this theory seems to be right. See the references below if you want to look more into the other theories.

References

Happé, F. & Frith, U. (2009) The beautiful otherness of the autistic mind. Philos Trans R Soc Lond B Biol Sci 364(1522):1345-1350. http://rstb.royalsocietypublishing.org/content/364/1522/1345.full

Neumann N, et al. The mind of the mnemonists: An MEG and neuropsychological study of autistic memory savants. Behav Brain Res (2010). http://ki.se/content/1/c6/10/06/19/Neumann_2010_BBR%5B1%5D.pdf

Snyder A. (2009) Explaining and inducing savant skills: privileged access to lower
level, less-processed information. Philos Trans R Soc Lond B Biol Sci 364(1522):1399–405. http://rstb.royalsocietypublishing.org/content/364/1522/1399.long

References cited in the quote from Happé & Frith:

Baron-Cohen S., Ashwin E., Ashwin C., Tavassoli T., Chakrabarti B. (2009) Talent in autism: hyper-systemizing, hyper-attention to detail and sensory hypersensitivity. Phil. Trans. R. Soc. B. 364, 1377–1383. doi:10.1098/rstb.2008.0337.

Bor D., Billington J., Baron-Cohen S. (2007) Savant memory for digits in a case of synaesthesia and Asperger syndrome is related to hyperactivity in the lateral prefrontal cortex. Neurocase. 13, 311–319. doi:10.1080/13554790701844945.

Happé F., Vital P. (2009) What aspects of autism predispose to talent?. Phil. Trans. R. Soc. B. 364, 1369–1375. doi:10.1098/rstb.2008.0332.

Mottron L., Dawson M., Soulières I. (2009) Enhanced perception in savant syndrome: patterns, structure and creativity. Phil. Trans. R. Soc. B. 364, 1385–1391. doi:10.1098/rstb.2008.0333.

Plaisted Grant K., Davis G. (2009) Perception and apperception in autism: rejecting the inverse assumption. Phil. Trans. R. Soc. B. 364, 1393–1398. doi:10.1098/rstb.2009.0001.

References cited in the quote from Neumann et al.:

[7] Bölte S, Hubl D, Dierks T, Holtmann M, Poustka F. An fMRI-study of locally oriented
perception in autism: altered early visual processing of the block design
test. J Neural Transm 2008;115(3):545–52.

[20] Happé F. Understanding assets and deficits in autism: why success is more
interesting than failure. Psychologist 1999;12:540–6.

[56] Snyder AW, Mitchell DJ. Is integer arithmetic fundamental to mental processing?:
the mind’s secret arithmetic. Proc Biol Sci 1999;266(1419):587–92.

[41] Mottron L, Dawson M, Soulieres I, Hubert B, Burack J. Enhanced perceptual
functioning in autism: an update, and eight principles of autistic perception. J
Autism Dev Disord 2006;36(1):27–43.

[61] Treffert DA. Extraordinary people. Lincoln, NE: iUniverse, Inc.; 2006.

[65] Waterhouse L. Speculations on the neuroanatomical substrate of special talents.
In: Obler LK, Fein D, editors. The exceptional brain.NewYork: The Guilford
Press; 1988. p. 493–512.


How do responses to Likert type response scales vary across countries and cultures? I gave an answer here on stats.stackexchange.com about how to analyse ordinal items, such as those on Likert type response scales (e.g., Strongly disagree to Strongly agree).
Someone asked whether there were differences between countries and cultures in how respondents use such scales. I remember reading research about this many years ago. I can remember something about certain countries preferring extreme responses. Such differences naturally have implications for cross-cultural comparisons of levels of like life satisfaction, personality, and presumably any self-report measure that uses such response scales.

Questions

How does use of Likert type response scales vary across countries and cultures?
What explains any such differences?
How are differences in response style differentiated from differences in levels of the underlying construct?

Culture reference effects

Heine et al (2002) discuss how people in different cultures often answer questions relative to a reference group in their own culture. Thus, for example, if a culture is  more collectivistic in general, measured cultural differences may less when people within a culture answer test items  relative to their own cultural reference group.

To quote the abstract:

  Social comparison theory maintains that people think about themselves
  compared with similar others. Those in one culture, then, compare
  themselves with different others and standards than do those in
  another culture, thus potentially confounding cross-cultural
  comparisons. A pilot study and Study 1 demonstrated the problematic
  nature of this reference-group effect: Whereas cultural experts agreed
  that East Asians are more collectivistic than North Americans,
  cross-cultural comparisons of trait and attitude measures failed to
  reveal such a pattern. Study 2 found that manipulating reference
  groups enhanced the expected cultural differences, and Study 3
  revealed that people from different cultural backgrounds within the
  same country exhibited larger differences than did people from
  different countries. Crosscultural comparisons using subjective Likert
  scales are compromised because of different reference groups. Possible
  solutions are discussed.

Cultural differences in response tendencies

Lee et al (2002) summarised some of the empirical literature on cross-cultural differences in use of response scales:

  Only a few researchers have addressed the issue of cultural
  differences in rating scales empiri- cally. Wong, Tam, Fung, and Wan
  (1993) found no difference in the way Chinese participants in Hong
  Kong responded to an odd versus an even number of response choices.
  Johnson (1981) found no difference in how readers of Horizons USA who
  resided in Great Britain, Italy, the Philippines, and Venezuela
  responded to bipolar scales. Stening and Everett (1984) found that
  Japanese managers responding in Japanese were more likely to choose
  the midpoint than were American or British managers responding in
  English. Chen, Lee, and Stevenson (1995) found the same effect for
  Japanese and to a lesser extent for Taiwanese in a sample comparing
  11th-grade students in Japan, Taiwan, Canada, and, in the United
  States, Minneapolis. Iwata, Saito, and Roberts (1994) and Iwata,
  Roberts, and Kawa- kami (1995) reported that junior high school
  students in Japan and the United States responded similarly on
  negative items but that Japanese were less likely to endorse positive
  items.

When reviewing the literature on cross-cultural differences in response style Hamamura et al (2008) stated that:

  Compared to North Americans of European-heritage, higher levels of
  extreme responding have been observed in African–Americans (Bachman &
  O’Malley, 1984) and Latino Americans (Hui & Triandis, 1989). In
  contrast, East Asians seem to show more moderacy than samples of
  European-heritage (Chen, Lee, & Stevenson, 1995)

References

Bachman, J. G., & O’Malley, P. M. (1984). Yea-saying, nay-saying, and going to extremes: Black–white diﬀerences in
response styles. Public Opinion Quarterly, 48, 491–509.
Chen, C., Lee, S. Y., & Stevenson, H. W. (1995). Response style and cross-cultural comparisons of rating scales among
East Asian and North American students. Psychological Science, 6, 170–175.
Hamamura, T., Heine, S.J. & Paulhus, D.L. (2008). Cultural differences in response styles: The role of dialectical thinking. Personality and Individual Differences, 44, 932-942.
Heine, S.J. and Lehman, D.R. and Peng, K. and Greenholtz, J. (2002). What's wrong with cross-cultural comparisons of subjective Likert scales?: The reference-group effect. Journal of personality and social psychology, 82, 903, PDF
Hui, C. H., & Triandis, H. C. (1989). Eﬀects of culture and response format on extreme response style. Journal of CrossCultural Psychology, 20, 296–309.
Iwata, N., Roberts, C.R., & Kawakami, N. (1995).
Japan–U.S. comparison of responses to depression
scale items among adult workers. Psychiatry Research, 58, 237–245.
Iwata, N., Saito, K., & Roberts, R.E. (1994). Responses
to a self-administered depression scale among
younger adolescents in Japan. Psychiatry Research,
53, 275–287.
Johnson, J.D. (1981). Effects of the order of presentation of evaluative dimensions for bipolar scales in
four societies. Journal of Social Psychology, 113,
21–27.
Lee, J.W. and Jones, P.S. and Mineyama, Y. and Zhang, X.E. (2002). Cultural differences in responses to a Likert scale. Research in nursing & health, 25, 295-306.
Stening, B.W., & Everett, J.E. (1984). Response styles
in a cross-cultural managerial study. Journal of
Social Psychology, 122, 151–156.
Wong, C.S., Tam, K.C., Fung, M.Y., & Wan, K. (1993).
Differences between odd and even number of
response scale: Some empirical evidence. Chinese
Journal of Psychology, 35, 75–86.


What are the minimal requirements for successful gamification? I am very interested in the concept of Gamification, the idea (used here on Stack Exchange) that by making mundane tasks into a game, you can elicit desired behavior from users of software. (For example, by giving people arbitrary reputation points, you encourage them to help the best answers rise to the top...)

Wikipedia says that some of the techniques used for gamification include:

  achievement "badges"
  achievement levels
  "leader boards"
  a progress bar or other visual meter to indicate how close people are to completing a task a company is trying to encourage, such as completing a social networking profile or earning a frequent shopper loyalty award.[7]
  virtual currency
  systems for awarding, redeeming, trading, gifting, and otherwise exchanging points
  challenges between users
  embedding small casual games within other activities.[2]

I'd like to see what studies actually say about gamification. If I wanted to start a new website which used gamificiation to entice users to participate, which techniques are the most efficient? Do some techniques work better than others? Do you need multiple rewards (E.G. reputation and badges)?

What do studies show are the minimum requirements for successful gamification?

In short, I'd say the minimum requirement is to understand which behaviours you are influencing and why.

Before you consider which game techniques to use, consider the 'story' of the product/service.

Each story includes:

Actor/s. Who are your targets?
These actors are motivated by something. This is what your game should leverage.
There is a goal. What are you/the actor trying to achieve. Help them progress towards the goal. Motivational factors / game techniques should encourage behaviours that move towards this goal and discourage behaviours that move away from it.
The actor begins in a context. Understanding the context gives you clues to opportunities and constraints.
The actor progresses through a journey (or arc). Mapping this journey helps you know when to employ certain techniques.
An outcome is achieved. This is the most critical part of course.

Draw this out in a path. Include the diversions, obstacles etc. Identify the main path as well as the little loops of activity that contribute.

Tip: If this isn't clear consider well known kid's stories. They are all shaped by this familiar pattern.

The techniques you list above and ones you will see elsewhere are valid. However by considering the story you will understand when to use certain techniques and how they should be approached.


How synapses are hold in place if they're not phisically attached? When two neurons connect to form a synapse, between the pre-synaptic and post-synaptic cells some space is found (synaptic cleft). How does this keep in position if there is no physical connection between the two?

There is a physical connection.

Synapses are held together by adhesion molecules, like cadherins and neuroligins/neurexins.

Missler, M., Südhof, T. C., & Biederer, T. (2012). Synaptic cell adhesion. Cold Spring Harbor perspectives in biology, 4(4), a005694.


Is there a diagnostic term for a person who impulsively keeps secrets? Almost like an addiction, similar to the way a pyromaniac feels about fire or burning...  I don't know if there's even a word for this, seeing as it's not a common experience, but if there is, it would probably end with "maniac"?

Wikipedia has a list of impulse control disorders described in the DSM.

As can be seen from the list, many "official" names of impulsive disorders do not end in mania - eg, pathological gambling, sexual compulsion, compulsive buying, and the one most closely related to what is described in the question: Pathological lying.  And if it doesn't fit in the latter category, then:

  Disorders characterized by impulsivity that were not categorized
  elsewhere in the DSM-IV-TR were also included in the category
  "Impulse-control disorders not elsewhere classified".


Do subjects with a missing cerebellum have a superior ability to verbalize motion sequences? Since the function of the cerebellum in patients with cerebellar hypoplasia needs to be taken over by other brain components such as the motor cortex, and since the cortex is the source of language, is it easier for these patients to verbalize their movements, i.e. are all their movements voluntary? Or does the brain stem rather replace the cerebellum's function?

I think that this question is hard to answer because there is little known about the cerebellum, and few instances of people who have been born without one. There are only 10 known cases of complete cerebellar agenesis, which can hardly be considered a sample size.

Broadly speaking, the cerebellum can be seen a 'fine tuning' device in the brain. It does not initiate movement, but rather allows movement to be fine-tuned and coordinated by receiving input from sensory systems in the spinal cord. This 'fine tuning' can apply to other areas, such as behavior, affect, and social expectations, as well as speech difficulty (often in the form of slurred speech). However, it is not well known how the cerebellum affects cognitive functions.

The 'output source' for the cerebellum is its Purkinje cells. But since Purkinje cells are found in high quantities within the cerebellum itself, they are unlikely to be of much use if the patient has no cerebellum to begin with. Therefore, it is not clear how the brain could 'replace' cerebellar function. I think that muscle memory and conscious developmental strategies are the only methods to overcome setbacks from cerebellar agenesis, and after reading a few case studies, common anecdote seemed to confirm this.

Given this information, and given the lack of evidence in any of the observed ten cases, I would conclude that it is likely that patients with a missing cerebellum do not have any sort of extraordinary ability elsewhere in the brain -- much less related to their own deficit. However, this cannot be confirmed without more case studies of cerebellar agenesis.


Why people choose "boring" colors for new cars? I've been interested in this question for a few years, sorry if this is not the right place to ask it.

As I've been driving around the US for the last few years, I noticed that some community parking lots "lack color" - the vehicles can be defined as colorless - they are white, black, various shades of gray or beige. Yet I've seen several new car catalogs and see that most cars come in several colors.

I was surprised to see this "lack of color" again and again, so I googled it, and found that the trend is not just in America, but worldwide:

2009 Top 10 world car colors

This is interesting, because I've never ever heard of white, silver or black being called people's favorite color. Most search results point to "blue" being the favorite color (at least in the United States) for English search results.

This begs the question: Why do people go for boring/conservate exterior car colors, like white or silver when buying a new car, instead of choosing their favorite color?

Here are my wild guesses, and it would be great to debunk them:

Is this due to conformity, resale value, or an attempt to stand out
less on a highway?
Is this because a car is big enough to be seen with rods in the eye?
Or do people see their cars as just another "appliance", like a
toaster, microwave or a fridge, and pick a color similar to what they
see in their kitchen?

I appreciate your input!

PS. This article is especially interesting, because it predicts orange/brown becoming the "new color" of expensive cars, while most color psychology results I've seen list people naming orange as "cheap" color, and advise to avoid it.

America's favorite car colors for 2012 are ... boring

Mainly, because they're too noticeable.

You don't really see houses in electric green, pink, or yellow. No one wants to stand out in a crowd or be the sore thumb.

Here: http://www.usnews.com/news/articles/2012/10/12/survey-americans-pretty-much-the-whole-world-prefers-boring-colored-cars

I'll post more sources when I can.


What is the field that studies community responses to incentives? Having recently read Freakonomics I was particularly interested by the idea of the responses of a community to incentives - as an example, the tale of a school which tried to introduce a financial penalty for picking up children late, which inadvertently had the opposite effect, as it nullified the previously existing (but largely invisible) social penalty.

Is there a general theory for this kind of interaction of incentives with community? If so, what is its name, and where could I read more about it? I'm interested in books and papers on a variety of levels, from popular accounts (à la Freakonomics) to textbooks to research papers.

There is a specific field of economics that deals with the process of changing people's responses through incentives: Behavioural Economics.

  study the effects of social, cognitive and emotional factors on the
  economic decisions of individuals and institutions and the
  consequences for market prices, returns and the resource allocation.

A recent issue of The Economist covers some of the current approaches used by governments to change individual behaviour:

  Behavioural economists have found that all sorts of psychological or
  neurological biases cause people to make choices that seem contrary to
  their best interests. The idea of nudging is based on research that
  shows it is possible to steer people towards better decisions by
  presenting choices in different ways.

Some of the approaches, for instance used by the British Behavioural Insights Team, are merely ways of changing a message:

  The Nudge Unit has been running dozens of experiments and the early
  results have been promising*. In one trial, a letter sent to
  non-payers of vehicle taxes was changed to use plainer English, along
  the line of “pay your tax or lose your car”. In some cases the letter
  was further personalised by including a photo of the car in question.
  The rewritten letter alone doubled the number of people paying the
  tax; the rewrite with the photo tripled it.

It's become a very fruitful area of research so would recommend taking your interest further.


Why ADHD instead of ADD? / Why predominantly hyperactive-impulsive instead of predominantly-impulsive? The types of Attention deficit hyperactivity disorder are:

predominantly inattentive
predominantly hyperactive-impulsive
combined

Not sure I understand. People with ADHD are hyperactive because of the H in ADHD. So what's the point of the word "hyperactive" being in both "predominantly hyperactive-impulsive" and "Attention deficit hyperactivity disorder" ? Why not just say predominantly impulsive or attention deficit disorder?

Edit to justify this question not being a duplicate:

I think one of the terms unnecessarily uses the word "hyperactive":

ADHD
predominantly hyperactive-impulsive

Why do we use hyperactive twice? Why not

ADD has 3 types: predominantly inattentive, predominantly hyperactive-impulsive, combined

or

ADHD has 3 types: predominantly inattentive, predominantly impulsive, combined?

ADHD used to be called just ADD in DSM-III (released in 1980), with the subtypes ADD/H (ADD with hyperactivity) and ADD/WO (ADD without hyperactivity). However, by 1987 when DSM-III-R was published, it turned out there was not enough empirical evidence to support the multidimensional view of ADD from DSM-III, so DSM-III-R adopted a unidimensional view, which was reflected in the name change to ADHD. This change was not without criticism, and it turned out that the criticism was well founded, because by the time DSM-IV came about (it was published in 1994), enough empirical evidence had accumulated for the multidimensional view, however the dimension space was refined into inattention and hyperactivity-impulsivity, and allowed for a combined type as well. From empirical research it turned out that the DSM-III diagnoses of ADD/WO and ADD/H correspond fairly closely with
the DSM-IV diagnoses of ADHD predominantly inattentive type and combined type, respectively (cf. Morgan et al.)

Now for the terminology, the proper name howadays is attention-deficit/hyperactivity disorder (i.e. with the slash), which correctly reflects the equal importance of the two dimensions (from DSM-IV and 5) in the name. If you want to be really nitpicky, the proper, unambiguous abbreviation of this name should be something like {AD/H/AD+H}D or ADD/HD/AD+HD, though of course nobody writes it like that for reasons of parsimony.

If you propose to say that "ADD has 3 types: predominantly inattentive [...]" you're still semantically repeating inattentive which means attention deficit, so I don't get the parsimony you propose at 1 as it asymmetrical, i.e. you're still repeating something in the first subtype from the title name even though you avoid it for the 2nd subtype.

As for proposal 2 "ADHD has 3 types: predominantly inattentive, predominantly impulsive", you're now calling the hyperactive-impulsive just impulsive. This is more a matter of how do you want to call the hyperactivity-impulsivity subtype. There is probably not enough empirical evidence to to have 3 dimensions (inattention, hyperactivity and impulsivity) for ADHD, nevertheless DSM-IV distinguished between the latter two for reasons not entirely clear to me, but which I suspect are a matter of calling a spade a spade:

  Hyperactivity: (a) often fidgets with hands or feet or squirms in seat
  (b) often leaves seat in classroom or in other situations in which remaining seated is expected
  (c) often runs about or climbs excessively in situations in which it is inappropriate (in adolescents or adults, may be limited to subjective feelings of restlessness)
  (d) often has difficulty playing or engaging in leisure activities quietly
  (e) is often “on the go” or often acts as if “driven by a motor”
  (f) often talks excessively

  Impulsivity: (g) often blurts out answers before questions have been completed
  (h) often has difficulty awaiting turn
  (i) often interrupts or intrudes on others (e.g., butts into conversations or games)

For diagnostic purposes these two are combined, i.e you need 6 of any of these for hyperactive-impulsive diagnosis. Nevertheless it seems somewhat awkward to say that someone who has difficulty awaiting his/her turn is hyperactive rather than impulsive. There may be more history behind this sub-subheading split without diagnostic consequences; the DSM is designed by a committee so there may have been more to it, but I wasn't able to find out. What seems obvious is that lifting hyperactive rather than impulsive to the disorder name is appropriate given that most criteria for the subtype are of the hyperactive kind. Calling it "attention-deficit/hyperactive-impulsive disorder" seems really a mouthful.

It turns out there's at least one 2005 paper that partially agrees with your criticism though:

  Not only is “ADHD without hyperactivity” (ADHD of the predominantly inattentive type) an awkward locution, but it also tries to squeeze ADD into a box in which it does not belong. The term ADHD should be reserved for when hyperactivity is present (as the term implies), regardless of whether inattention is also present.

As it's evident in the above, abbreviations don't capture alternatives. So ADHD is hard to read as {AD|H}D. Nevertheless the DSM-5 committees were not convinced and the name remained what it is. Although some changes were made to the ADHD diagnosis the DSM-5:

  The retention of the ADHD symptom domains and 18 core symptoms likely reflects a judgment that the DSM-IV definition of ADHD has largely withstood the test of time.

However

  The change in nomenclature from “subtypes” in DSM-IV to “presentations” in DSM-5 reflects increasing evidence that symptoms are often fluid within individuals across their lifespan rather than stable traits. DSM-IV ADHD subtypes change across development due to the heterotypic continuity of symptom trajectories over time. For example, since inattention is relatively stable across development while hyperactivity/impulsivity often wane with age, many children diagnosed with ADHD, Combined eventually transition to ADHD, Predominantly Inattentive [...]. The “presentation” terminology better reflects that the symptom profile represents the person’s current symptomatology, which may change over time. The “type” terminology implied more stable, trait-like characteristics.


What causes systematic under- or over-estimation of general knowledge quantities? What psychological theories predict whether individuals will underestimate or overestimate when responding to particular kinds of general knowledge quantity questions?

For instance, I have seen an unpublished study in which people were asked to guess the weight of the fuel in a certain space shuttle, and almost everyone wildly underestimated the weight. Then in another question they were asked to guess the weight of the horse which won the last Kentucky Derby and the responses were distributed fairly evenly around the truth. Why is this?

I think that the heuristics and biases literature must be relevant here, but I haven't found any citations that allow me to make predictions which are sufficiently specific.

One theory that may explain this is is Kahneman and Tversky's anchoring heuristic.

If you ask how much fuel the space shuttle needs, most people don't have the proper background knowledge to answer this accurately. Instead, they'll rely on a piece of information they do know--e.g., how much fuel a car needs--and adjust from there. Responses will be biased towards the anchor. Since a car requires very little fuel in comparison (~12 gallons), people will tend to underestimate the true response (~500,000 gallons).

If you first told them: The cruise ship The Norwegian Dream holds roughly 350,000 gallons of fuel, and then asked how much fuel weight the space shuttle needs, their answers will likely be closer to the truth. (Though there is the confounding variable of size-- larger vessels need more fuel, but even small vessels will need a lot of fuel to launch into space).

When it comes to horses, people have more accurate anchors-- such as a human, or an elephant-- and will tend to make more accurate judgments.

Although there are certainly more cues that people use to make size judgments, a complete theory must take into account one's background knowledge. Thus, even the anchoring heuristic   is limited in that we must know what people are likely to use as an anchor for any given question.


What are the main sensory features of earliest memories of childhood? I understand that experiences are compound in nature and take inputs from multiple senses. But when I ask people to describe the sense associated with their earliest memories I get answers that vary. For some its visual, others auditory yet others tactile.

I would like to know more about the specific aspect of first memories that help me understand the reason for this varied response.

I found a study by Mullen (1994) which discusses the empirical literature on earliest childhood memories (see also the wikipedia article on childhood amensia).

Here are a few interesting quotes:

  The average age of earliest memory is consistently found to be in the vicinity of 3.5 years.

Mullen mentions theories for the amnesia prior to this point focussing particularly on the role of language development and training provided by parents in how to socially construct accessible memories.

Mullen distinguishes between types of memories which in some sense pertains to your question about senses:

  White and Pillemer (1979) suggest that there may be a dual system of
  autobiographical memory in which one aspect is a verbally accessible
  store of interconnected narratives organized with respect to a time
  frame and the other aspect is an unorganized collection of fragments
  of images, behaviors and emotions.

In study 3, Mullen (1994) examined the content of earliest reported memories.
Here is a table summarising content features of these memories:

Thus, it appears that most of these memories reflect an event in some sense.

Of course there are a bunch of methodological things going on here.
I imagine if you delve into the references or these related articles you will find out more on the topic.

Kihlstrom et al (1982) looks like it might be worth a read.

References

Mullen, M. K. (1994). Earliest recollections of childhood: A demographic analysis. Cognition, 52(1), 55-79.
Kihlstrom, J. F., & Harackiewicz, J. M. (1982). The earliest recollection: A new survey. Journal of Personality, 50(2), 134-148.


Analyzing control questions data for a survey I have an experimental study with a list of demographic and related questions and in order to identify data from participants that were potentially just answering the questions at random (to get through them more quickly I would assume), I've included two very similar 7-point likert scale questions at different points in the survey. My assumption would be that since the questions are reflective, the answers participants should give will be at least somewhat similar between the two questions (eg, it should be very unlikely that a participant answers 7 to one question yet 1 to the other).

I haven't yet collected the data, however I would like to have a method for determining which sets of data are suspicious (might be considered for exclusion in analysis) based on these control questions. One method might be to simply determine where the data fit on a Gaussian distribution. However, I think that the limited discriminating power of a 7-point scale would make this an improper test. My other idea was to do a cluster analysis on the data, looking for five groups: three along the line of correlation (between the questions), and two to examine unusually high/low and low/high values. I thought this could provide better suggestions for which data sets might be unusual since it wouldn't use somewhat arbitrary comparisons, it would only use the data given.

I'd really appreciate any suggestions for a better method, or improvements I could make as well as any comments toward more "standard" practices in this area, since I'm somewhat new to research.

You seem to be concerned with reliability, and more specifically internal reliability. Internal reliability is the degree to which different questions are measuring the same construct. This concept is used often in psychology and is usually measured using Cronbach's alpha. However, it is typically used to measure the reliability of a test, and not the reliability of an individual.

As Jeromy Anglim points out, I think it's important to consider the goal here. Using a two question Likert scale is probably not good enough to reliably detect outliers: What if the respondent checked all '4s' on a 7-point Likert scale? Reversing the scale would have no effect.

One alternative approach is to employ an instructional manipulation check (Oppenheimer et al., 2009). The gist of the technique is to trap participants into answering a question in a specific way that they could only have done by reading the instructions carefully. Here is an example from a survey administered by Facebook:

While this technique may throw out a few good participants, it will almost certainly raise the signal-to-noise ratio of your data by only including participants who followed instructions and read questions before answering.

Another tried and true technique is to use a computer-administered test and look at reaction times. You may be able to throw out a few responses (or whole participants) by simply looking for outliers in response time that are below the mean.

  Oppenheimer, D. M., Meyvis, T., & Davidenko, N. (2009). Instructional manipulation checks: Detecting satisficing to increase statistical power. Journal of Experimental Social Psychology, 45(4), 867-872.


Spurious attractors in Hopfield networks A classic "Hopfield network" is a type of artificial neural network in which the units are bi-stable and fully interconnected by symmetrically weighted connections. In 1982, Hopfield showed that such networks are characterized by an "energy function", under which stored memories correspond to local energy minima [1].

In a 1983 paper [2], Hopfield et al further showed that "spurious memories" (local energy minima that are created during training, in addition to the intended target patterns) can be suppressed by an "unlearning procedure", during which the network is repeatedly allowed to relax from random states, and the resulting states then "unlearned" by anti-Hebbian weight adjustments. The procedure affects spurious memories more than the desirable "learned memories", thus improving recall performance. However, the paper offers no explanation for why this should be so.

A 2004 paper by Robins and McCallum [3] demonstrates that spurious memories can be distinguished from learned ones because their "energy profiles" are different. Specifically, the ratio of lowest to highest energy contributions from individual units is significantly smaller in states corresponding to spurious memories than in states corresponding to learned memories. Again, the effect is not accounted for (except for a tentative partial explanation).

My questions are:

Is there a relationship between these two findings, i.e. does the lower "energy ratio" of spurious states explain their greater susceptibility to unlearning?
Have any explanations for either or both of these phenomena been put forward since the publication of the papers?
Are there other ways to suppress or detect spurious memories in the Hopfield family of neural networks?

[1] Hopfield, J. J. (1982). Neural networks and physical systems with emergent collective computational abilities. Proceedings of the National Academy of Sciences, 79(8), 2554 –2558.

[2] Hopfield, J. J., Feinstein, D. I., & Palmer, R. G. (1983). “Unlearning” has a stabilizing effect in collective memories. Nature, 304(5922), 158–159.

[3] Robins, A. V., & McCallum, S. J. R. (2004). A robust method for distinguishing between learned and spurious attractors. Neural Networks, 17(3), 313–326. doi:10.1016/j.neunet.2003.11.007

I think that your intuition about the lower "energy ratio" of spurious states explaining their greater susceptibility to unlearning might be correct.

In a Hopfield Network spurious states are activity patterns that have not been explicitly embedded in the synaptic matrix, but are nonetheless stable. They are in other words "unwanted" attractor states that, by virtue of a finite overlap with the "wanted" attractor states, come about as a local minimum in the energy function. The unlearning rule in Hopfield et al. (1983) consists in modifying the synaptic matrix so as to decrease the energy of the stable states in which the network dynamics settles down, be them spurious or embedded states. Because the spurious states have higher energy than the embedded states, they are more strongly affected by the unlearning step.

Now, why do spurious states have higher energy than the embedded attractor states? Well, this is actually not true in general, but it is the case in a regime where the Hopfield network doesn't exceed its loading capacity, that is when the number of learned patterns over number of units $p/N$ is lower than the critical capacity $\alpha_c\approx0.138$. In this regime, it is possible to estimate the overlap of the spurious states with the learned patterns, and show that is generally lower than $1$ (the overlap of the learned patterns with themselves). Because of how the Hebbian construction of the synaptic matrix in the Hopfield model, this overlaps are terms that appears in the energy function. The energy of a pattern is namely proportional to minus the square root of its overlap with the learned patterns. This means that the spurious patterns have higher energy than the learned ones.

In general this kind of naive considerations has to be supported by more rigorous arguments based on probability theory. These for instance point out that even for the regime below $\alpha_c$ the retrieved patterns are actually spurious states as soon as the number of embedded patterns $p$ exceeds above $\frac{N}{2\ln N}$. Such spurious states have however such a high overlap with the learned patterns ($0.97$) that they basically coincide with them.

This result and generalizations thereof for non-zero temperature (i.e. noise in the dynamics) and beyond critical capacity have been worked out in the following very technical paper:

Amit D.J, Gutfreund H and Sompolinsky H (1987) Statistical Mechanics of Neural Networks Near Saturation. Ann. Phys. (NY) 173, 30

and in the book:

Amit D.J, (1992) Modeling brain function: The world of attractor neural networks. Cambridge University Press, ISBN:9780521421249


Thinking Fast and Slow: Similarity of Linda problem and Dinnerware case While reading Daniel Kahneman's "Thinking, Fast and Slow" I've been stuck on the claim that Linda case and Dinnerware case have the same structure.

Linda problem:

  Linda is thirty-one years old, single, outspoken, and very bright. She
  majored  in  philosophy.  As  a  student,  she  was  deeply concerned
  with issues of discrimination and social justice, and also
  participated in antinuclear demonstrations."

  "Which alternative is more probable?

  Linda is a bank teller.
  Linda is a bank teller and is active in the feminist movement.

It is well-known that the majority of respondents chooses the second options (as most plausible, though the original question is about probability).

The Dinnerware case:

  Being presented two sets of dinnerware:

  Set A: 40 pieces / Set B: 24 pieces

  Dinner plates: 8, all in good condition / 8, all in good condition
   Soup/salad bowls: 8, all in good condition / 8, all in good
  condition  Dessert plates: 8, all in good condition / 8, all in
  good condition  Cups: 8, 2 of them broken / NONE  Saucers:
  8, 7 of them broken / NONE

It is known that respondents tend to select Set B, though it is more beneficial to select set A.

Here is the question:

The dinnerware case is explained via the notion of 'averaging'. That is, person's System 1 (Kahneman's terminology) performs some kind of averaging and goes to conclusion, that as Set B items are not broken and in average cost more, then the whole Set B shall be preferred.

  From the perspective of economic theory, this result is troubling: the
  economic value of a dinnerware set [...] is a sum-like variable." I.e.
  pure summation shall be performed where averaging and subsequent
  assessment is carried out.

Then,

  The Linda problem and the dinnerware problem have exactly the same
  structure (??).  Probability,  like  economic  value,  is  a
  sum-like  variable,  as illustrated by this example: probability
  (Linda is a teller) = probability (Linda is feminist teller)
  + probability (Linda is non-feminist teller)" "System 1 averages instead of adding, so when the non-feminist bank tellers are removed
  from the set, subjective  probability  increases.

Here is my difficulty: I do not see how the 'averaging' notion applies to the Linda problem. When I myself think about Linda question, I do not realize that try to average something, I just want to construct something that fits my stereotypes. Otherwise, when I think about dinnerware, I agree that subconsciously try to maximize the average price of item.

Question Restatement:

It seems that "have exactly the same structure" is actually a reference to whether the underlying syllogisms are similar - in both research designs.

Another assumption: Given the absence of a quote from Daniel Kahneman's, "Thinking, Fast and Slow" - the question seems to be hoping for answers that will make an inference as to the goal of the questions/research.  Otherwise, this would be moot as Kahneman probably explains in context.

Possible Answer - Identifying Bias when Rational Responses aren't Possible:

Both research designs exhibit the same challenge to BOTH a respondent, and a researcher -

  "What conclusions are they inclined to, (bias) - when it is impossible to respond reasonably?" (E.G., like be faced with a false dilemma logical fallacy).

The first tests Respondent's behavior; the second tests Researcher's behavior.

The Linda Problem - Measuring Respondents:

In the first case, the question speaks about a "philosopher", and an expectation that they would be "objective" in their role as a banker.  Regardless, a rationally minded respondent would immediately notices the absence of an obvious third answer, "None of the Above".  Obviously, "Probability cannot be inferred."

Note: Because respondents feel a generous inclination to "help" the researchers - only a very small number of respondents are likely to protest the validity of the test.

The Dinnerware Case - Measuring Researchers:

In the second case, the question is framed computationally, seeking a rational answer.   Regardless, a rationally minded researcher immediately notices the absence of an obvious third explanation, "Set Theory" ... Obviously, "Cups" rings "dissonant" and does not have as strong a connection as the others do.  So, the research design wrongfully disregards the primal valuation of "belonging" - which might have a higher valuation than "market value", and even "utility".

Note: Because researchers feel an obligation to make SOME inference - only a small portion might protest the validity of the test.

Conclusion:

In other-words, I feel that the similarity between the designs is not at all about "averaging" or "valuation" - but their similarity is due to the "dilemma" that both researchers AND respondents are faced with - when confronted with an irrationality:

How much does cognitive dissonance contribute to the even distribution of bias?  (The "Data" in the question suggests an inverse effect.)
And, if there is no even distribution of bias - when a rational answer cannot reasonably be provided, (given the logical errors of the circumstance) - then what biases do people tend towards? (The "Data" in the question suggests a universal bias towards "belonging, association", rather than rationality, personal values, etc.)

It would be very interesting to see the full implementation of this instrument - as it might inform political campaigns, (IMHO).

If the data from the two questions here is actually correct - then it might be consistent with what we observe in politics, (and relationships, etc).


How do certain frequencies of sound induce psychological states? As one example, a specific low frequency beyond our hearing perception can make people feel nauseous and even vomit.

I'm sure there are more documented studies surrounding the correlation of auditory induced states, but how and/or why does this occur?

Also, does this phenomenon happen to deaf people as well?

Auditory information is conveyed to the brain from the cochlea via the VIII cranial nerve (aka vestibulocochlear nerve). Under standard conditions the vestibular system gets activated when we move our heads. If we spin around rapidly this can obviously make us feel dizzy and nauseous. The vestibular system can also be activated do to other causes. For example, positional alcohol nystagmus (aka the drunk spins) occurs due to alcohol changing the densities of the endolymph and the cupula (part of the sensory organ in the semicircular canals). It turns out that low frequency pressure waves at high enough levels can activate the sensory cells in the vestibular system.

In some causes of deafness and hearing loss the vestibular system remains normal, or near normal. These individuals are therefore susceptible to these feelings. Other causes of deafness destroy the vestibular system making individuals immune to these feelings.


What is the role of (why )universal gas constant in Nernst equation? The Nernst equation is an equation that relates the the total voltage, i.e. the electromotive force, of the full cell at any point in time to the standard electrode potential, temperature, activity, and reaction quotient of the underlying reactions and species used. I have been wondering why Universal gas constant (R) is included in Nernst and Goldmann equations while describing the steady state of membrane potential?

As in the ideal gas law, the universal gas constant allows for calculation of amount of energy associated with a certain group of molecules (see https://en.wikipedia.org/wiki/Gas_constant).  As the Nernst equation compares the "osmotic pressure" to "electrical pressure", the universal gas constant is needed to convert amount of an ion on the two sides of a membrane ("osmotic concentrations") to the amount of energy associated with that concentration differential ("osmotic pressure").

Carefully looking at the units of all of the constituents of the equation can help clear things up.  R is in units of J / (mol * degree), and V is J/coulomb.  zF in the denominator gets you your coulombs.
In short, both the left and right sides of the equation are more or less measures of energy.  R converts amounts of ions to the energy associated with their osmotic pressure so that it can be compared with the electrical energy associated with their charge.


What is the state of the art research of the consciousness level for high-level cognitive activity? Everybody knows situations where activities requiring concentration and high level consciousness can over time become a "background" task.

For example:

you read a text aloud but think about other things
you drive a car but it just "happens" and you can listen to the news

Question: is it measurable to demonstrate how an activity "goes background" in the brain? What is the current state of research, or at least what are proper neuroscience terms to look for in this context?

One approach to this is to search for "habituation", "learned task", "concomitant task", "dual task" and "multiple task" studies, which may include cognitive and physical aspects (memory, reaction time and such). "Background tasks" are usually related to computers.


Why is it easier to see black text on a white background? I'm wondering why it's easier to see black text on a white background than it is to see white text on a black background. I say that it's harder based on life experience (Hate webpages with black backgrounds!) and not from any actual studies I know of that have been done. Nonetheless, I think most people will agree with me on this one.

My two general theories are:

For some reason it strains the eyes (not quite sure why that would be), and
We're just really used to it, so our brains have become wired specifically to process black text on white backgrounds

The short answer is that it is not necessarily easier to read black on white. Contrast is more important in lightness and colour, it just so happens that black and white is the highest contrast. So its no accident that most books are in black and white. There is a plethora of research on perceptual processing which is easily found on google scholar if you which to investigate this further.

Colour and Reading
In 1984 a study was conducted comparing 24 colour combinations of text and back ground, this was of course on an older monitor, but there wasn't any significant difference between individuals in there ability to detect text targets relative to colour different colour combinations. This included black and white. However research with colour contrast, has found that variations in contrast of colour rather than colour itself influence reading speeds, and errors in reading. Greater colour contrast between text and back ground is reported to enhance speed of reading and reducing errors. In addition improving speed of reading, high colour contrast has been found enhance retention of text based information when compared to lower colour contrasts.

fig 1. low colour contrast

fig 2. high colour contrast

In addition to colour, contrast in luminescence (lightness) between text and background also influences readability. According to Knoblach et al (2001) high contrasts in luminescence between background and text enhances reading speed to a greater degree than colour contrast, although colour contrast keeps reading speed high when luminescence is low. In other words greater differences in the lightness and the colour of text and background is optimum for reading ability. Industrial researchers have taken this further with a 2009 study by Hewlett Packard (HP) specifically stating that 30 units CIE lightness contrast is optimum for reading rates and reduced error, this is not the highest contrast, although still high. However high colour contract and luminescence contrast are not additive, as they are coded in the same way in the visual system. Essentially so as long one of the contrasts is high reading speed and errors should low, meaning you don't need to use back on white.

What I haven't discussed here the two systems which process light: the magnocellular and parvocellular systems. So yes we are hardwired to process colour differently from grayscale.

fig 3. Diagram of Visual system

note. Mi = Magnocelluar (grayscale, low resolution, movement) Pi = Parvocelluar (colour and high resolution)

The magnocellular visual pathway which is dominate for processing text, and uses gray scale (black to white). However dyslexics, like myself, appear to have a preference and adaption toward utilising the parvocellular visual pathway (colour processing). This is likely due to differences in visual processing using the magnocellular system between controls and dyslexics, which suggests that dyslexics do not process greyscale as well as non-dyslexics. However this isn't to say that you need to be dyslexic to prefer processing with the colour system than grayscale. THIS SECTION IS SPECULATION BASED ON NEURAL MECHANICS There is also the possibility that prolonged activation of the magnocelluar system, by reading, may fatigue the neurons or/and photoreceptors, consequently reducing ease of reading. Hence why e-readers tend to use grey backgrounds.

Summary

There is more stuff to add in about positive and negative contrasts, for instance there is little difference in reading ability for black on white in comparison to vice versa. Overall, however, there is little difference in reading performance so long as colour and luminescence contrasts are high, meaning that black on white (highest contrast in both) is not necessarily better. Some individuals have a preference for using colour over grey scale, which while activating different visual pathways is still coded similarly for contrast in the brain. The preference against black on white may be due to the fatiguing nature of over activation of neurons in the visual pathways, or other factors such as dyslexia.


Why we are more optimistic about ourselves and our peers and pessimistic about others? I watched a ted talk which is about optimism bias by Tali Sharot. It stated that we are more optimistic about ourselves and our peers and we are more passimistic about others.But, I can't find an apt explanation for it.I observed this behaviour in all humans at some extent.

What makes the difference? Is there any scientific explanation?

I'm going to take the evolutionary standpoint. Many of these reasons and explanations Tali Sharot already gave in her talk. You could also check out her books. I'm going to try to make the point I see in it clear.
First the basics of evolutionary advantages - traits in a species are favored by evolution if they make it likelier for us to survive and procreate. (those with unfavorable characteristics are less likely to survive in order to procreate!)
The genes we have are more likely to be passed on if we reach a mature age, find a partner and successfully rear our offspring.
This is the basic idea behind an evolutionary explanation.
As she says, optimism makes it more likely for us to reach for higher goals - and also for achieving them.
Hope and our happiness leads to better health, reduces stress and a longer life span and thus, it's more likely that we're going to pass on our genes.
Why not for others? We know that bad things happen and that the world is dangerous, but if we can convince ourselves that it happens to others, rather than us, we'll be happier.
Well, that's very basic evolutionary explanation.
Here's an article that goes into this:
https://www.brainpickings.org/2012/12/12/science-of-optimism-sharot/
Her full-length book: https://www.amazon.de/Optimism-Bias-wired-bright-English-ebook/dp/B005RZB6VU/ref=asap_bc?ie=UTF8


Why did DSM-5 and subsequently ICD-10 allow personality disorders to be diagnosed in children I was fine with the theory personality characteristics are so highly variable under the throes of adolescence that it is a practical impossibility, if not clinically inappropriate, to diagnose  such disorders until the age of 18. I'm aware that antisocial personality disorder hasn't changed.

Too many practitioners see a personality disorder diagnosis and turn off their brains to the likelihood of a mood, anxiety, or psychotic disorder.

Specifically, why is the new criteria considered better than the old criteria under DSM-3 and -4?

An article on the NCBI website states

  Many clinicians are reluctant to diagnose personality disorders (PDs) during youth, viewing paediatric personality deviations instead as reflective of given developmental stages. This is so despite evidence that certain youth are indeed at risk for the eventual development of PDs as adults. Unfortunately, late identification of these disorders prevents timely treatment and potentially increases morbidity.

There are also a fair few references to articles backing the idea up