What causes emotions? I have absolutely no knowledge of psychology. But I am wondering what causes emotions in human? Emotions such as happiness, sadness, love, hate etc. Is there some sort of hormones responsible for this? How does brain understands this?

Let's break this down into two terms: affect and emotion.

Affect

Affect corresponds to two dimensions that underlie emotional experience: valence and arousal.

Valence - feelings of pleasantness and unpleasantness
Arousal - feelings of activation (e.g., alert, energized) and deactivation (e.g., de-energized, sleepy)

So what are the sources of these two basic sensory dimensions?

One answer is... immunologic, metabolic, and autonomic changes in the body, whose sensory input flows up and is processed by primary interoceptive cortex (posterior insula) (Barrett & Simmons, 2015).  Think of the body as a source of sensory input, just like any other modality (visual, auditory, etc.).

Additionally, there are top-down predictions descending from agranular interoceptive cortex, which are actually responsible for most of our interoceptive sensations (i.e., conscious affect).  That is, most of your affective feelings are produced by top-down predictions about input from the body rather than bodily input itself.  Weird!

Another part of the answer is... endogenous opioid and cannabinoid signals in certain "hotspots" of the brain (e.g., nucleus accumbens, ventral pallidum), which are thought to mediate pleasure (Berridge & Kringelbach, 2013).

But in general... this is still being figured out.

Emotion

The answer to this part depends on your theory, about which I'll be very brief.

Basic emotion theorists (e.g., Ekman & Cordaro, 2011) argue that emotions correspond to discrete, circumscribed parts of your brain (e.g., the amygdala and fear, the insula and disgust).  We have "affect programs," that when activated, produce a discrete emotion (fear, anger, etc.).

Constructionists (e.g., Lindquist et al., 2013) argue that emotions are essentially interpretations of your affect (valence and arousal) in a given context.  So "fear" is just a concept that you deploy in certain situations (e.g., when you feel negative, highly aroused, and are running from a bear). On this view, emotions emerge from interactions among distributed brain networks that are involved in more basic psychological processes (e.g., exteroception, interoception, conceptualization, language).

The meta-analytic evidence seems to favor the latter view, but there's still a buttload of work to be done on this end.

As far as controlling emotions--well, that's an entirely different question.  But see James Gross for more info.


Does transparency have its own visual channel? Referring to (for example) Visual Thinking for Design, the book discusses various low-level processing channels in the brain. Colour and orientation are two examples.

I wonder if transparency is another such channel; and if it isn't, how exactly transparency manifests itself within the brain.

One interesting way to study transparency is by looking at cases where we perceive transparency even though there isn't any objective transparency.

Take this illusion from Adelson (2000) as an example.

In the both panels the diamonds have the same physical brightness (pixel value on the monitor), but our perception of the diamonds on the right is warped by the seemingly-transparent dark stripe that covers the diamonds on the top. Thus, even low-level image features like brightness are perceptually warped by the way our brain perceives the structure of the image.

There are a large number of papers on mathematical models of illusory transparency perception. A starting point might be Anderson (1997) and the references within. But, the general message from this research is that we sometimes perceive transparency as the result of imposing some kind of higher-order structure to make sense of the image.


Death caused by "Failure to Thrive" (FTT) This question, whilst to a degree can be seen as "common sense" in some respects, has puzzled me in other ways.
Looking at the situations where Failure to Thrive (FTT) can cause death, even the Wikipedia article for it mentions mental issues as an endogenous cause, while there can also be one or more of both endogenous and exogenous causes.
I am intrigued by the mental issues for FTT deaths. What kind of mental issues, other than the obvious such as anorexia, can cause death due to FTT.
I am particularly interested in the cases where babies die due to FTT even though they have been fed, such as in orphanages.
Looking at a situation in Romania, I remember news reports during the dictatorship of Nicolae Ceaușescu, where there were large numbers of young children under 5 dying in orphanages due to FTT. I cannot find any reference to this online, however there is an APA report (Weir, 2014) which mentions institutional neglect causing developmental delays.
As well as developmental delays, can  neglect through lack of emotional care be the cause of death through FTT? If so, how does the death occur even if nutritional needs are met?
References
Weir, K. (2014). The lasting impact of neglect. Monitor on Psychology 45(6), 36. Retrieved from: https://www.apa.org/monitor/2014/06/neglect

The reason for failure to thrive other than insufficient nutrition, can be suppressed growth hormone secretion due to emotional neglect. In the following example, both the emotional neglect and insufficient nutrition were combined, though:

Psychosocially stunted growth masked as growth hormone deficiency, (Klinische Pediatrie, 1999):

  Short stature is a common reason for presenting a child to the
  pediatrician. Emotional deprivation may cause short stature and may
  simulate growth hormone deficiency. Diagnosis of emotional
  deprivation as the cause of growth retardation is difficult and
  misdiagnosed frequently despite of suspicious clinical signs. We
  report on 2 patients with growth retardation because of emotional
  deprivation. At the age of 5 years both children had a severe growth
  hormone deficiency. They received therapy with growth hormone and
  showed an increase of growth velocity to > or = 8 cm in the first year
  of treatment. But in the third year of treatment both patients showed
  a diminished response to the growth hormone therapy. During the period
  of observation the features of emotional deprivation became obvious
  through the extreme behavioural abnormalities. Both children showed
  disturbances in their social behaviour, and striking disorders
  concerning eating and digestion. The families of these children had
  severe social problems; alcoholism, low income and rejection of the
  child were risk factors. Removal from the current environment led to
  a characteristic increase of the growth velocity. Growth hormone
  deficiency was spontaneously reversible, so that treatment with growth
  hormone was terminated. The social environment and the psychical
  prosperity are essential growth factors in childhood and adolescence.
  The common features and risk factors of emotional deprivation are
  described. Spontaneous catch-up growth after removal from the
  current environment distinguishes this form of short stature from the
  other organic growth disorders.

Hopkins Medicine says that:

  Other factors that may lead to failure to thrive:

  Emotional deprivation as a result of parental withdrawal, rejection or
  hostility

and

  Problems with the endocrine system, such as thyroid hormone
  deficiency, growth hormone deficiency or other hormone deficiencies...

...some of which might be triggered by emotional neglect despite proper nutrition:

Failure to grow: lack of food or lack of love? (Professional Care of Mother and Child, 1994):

  One of the most important criteria for good health in childhood is
  normal growth. Taking regular accurate measurements of length and
  plotting them on a centile chart is essential to spot early signs of
  growth disorders. Be alert for a "zig-zag" pattern on the chart: it
  could indicate psychosocial dwarfism (see opposite). Length is
  more important than weight for identifying growth disorders. Lack of
  love, or an adverse emotional or social environment, can cause growth
  failure even in a child who is eating enough. Such children have a
  condition called psychosocial dwarfism, which is due to
  hypopituitarism (too little growth hormone secretion from the pituitary gland). This condition does not respond to growth hormone
  treatment. Once the child is placed in an alternative environment, eg
  a good foster home, the hypopituitarism is reversed and rapid
  "catch-up" growth takes place. It often emerges that such children
  have been physically, emotionally or sexually abused.

I'm not aware of any case in which psychological reasons alone in a properly fed child would result in death associated with failure to thrive. When it comes to failure to thrive in certain orphanges, I would not ascribe it solely to psychological reasons...


If babies were isolated, would they develop their own language? Let’s say that two or more babies/infants from the age of 0 were put in an environment without the affection of adults to teach them how to speak. Would the babies after 13 or so years develop their own language?

Let's assume that someone or something would take care of the babies, giving them food and water and so on, but never speak to them.

This question would require an experiment that cannot ethically be conducted, but it is interesting.

Wikipedia has an article on historical attempts at language deprivation experiments:

  An experiment allegedly carried out by Holy Roman Emperor Frederick II
  in the 13th century saw young infants raised without human interaction
  in an attempt to determine if there was a natural language ...
  "foster-mothers and nurses to suckle and bathe and wash the children,
  but in no ways to prattle or speak with them ... But he laboured in
  vain, for the children could not live without clappings of the hands,
  and gestures, and gladness of countenance, and blandishments." ...
  James IV of Scotland was said to have sent two children to be raised
  by a mute woman isolated on the island of Inchkeith, to determine if
  language was learned or innate. The children were reported to have
  spoken good Hebrew ...

While these experiments had the advantage of a lax ethical environment, they also had a major disadvantage of poor methodology, and the accuracy of their documentation is very questionable.

There are quite a few documented cases of feral children, but none that I'm aware of who were raised together so as to have had an opportunity to develop language.

The most compelling case for the innateness of language development that I'm aware of is the Nicaraguan sign language (ISN):

  ... a sign language that was largely spontaneously developed by deaf
  children in a number of schools in western Nicaragua in the 1970s and
  1980s. It is of particular interest to the linguists who study it,
  because it offers a unique opportunity to study what they believe to
  be the birth of a new language.

These children were in fact raised as normal children, but were language isolated, with no contact with other deaf children until school age.  Some variables not well controlled for here include that they were exposed to the concept of language, were aware that other people communicated with each other, and already had a proto-language (mimicas).  Nonetheless, they appeared to develop a proper structured language fairly quickly upon being introduced to each other, without any apparent support or encouragement from adults, who were entirely unfamiliar with any sign language.

There are similar examples of isolated sign-language development, such as ABSL and MVSL, but the problem with all of them is that the actual level of language isolation is not well controlled for, and hence not clear.


What is the correlation between grit and Big 5 conscientiousness? There's been quite a bit of talk about "grit", lately. And the first response of many was to ponder whether it is different from big 5 conscientiousness.

Thus, I was wondering what the correlation is between "grit" and Big 5 conscientiousness?

There is some discussion on Wikipedia

  A meta-analysis [by Crede et al] found that the grit was functionally a measure of conscientiousness

A study by Mayer and Skimmyhorn (2017) using two large military cadet samples (i.e., samples of approximately 1000 in each) obtained measures of Grit (12 item measure, Duckworth, et al 2007) and IPIP 20 item conscientiousness. They obtained correlations between conscientiousness and grit of .75 and .74 in the two samples. The reliability of conscientiousness was close around .90 for conscientiousness and .80 for grit. Thus, the correlations suggest that almost all of the meaningful individual differences are shared across the two scales.

References

Mayer, J. D., & Skimmyhorn, W. (2017). Personality attributes that predict cadet performance at West Point. Journal of Research in Personality, 66, 14-26.

Crede, Marcus; Tynan, Michael; Harms, Peter. "Much Ado About Grit: A Meta-Analytic Synthesis of the Grit Literature.". Journal of Personality and Social Psychology. doi:10.1037/pspp0000102. PMID 27845531


Is writing ability associated with IQ or intelligence? Is greater ability to write well i.e. analysis of books/literature/research papers associated with higher I.Q. scores?
Statistically speaking, is writing ability normally distributed like I.Q. is?

The second question (normality) is somewhat easier to answer because it depends less on the exact measures used.

  reading and writing abilities are normally distributed in the general education framework.

Meaning for people who are actually schooled and tested (in the US for the above study). The sample for the above was "316 boys and girls who were assessed annually in grades 1 through 4".

As for the first question (association between IQ and writing ability), the qualitative answer is obviously going to be yes. There is even one proposal to use samples of written text to estimate the writer's IQ!

  The primary focus of this research is to introduce a
  method of measuring an individual’s IQ by analyzing
  the vocabulary in said individual’s writing. In this
  paper, we show that the ratio of SAT words in a
  dataset of writing samples is roughly normally
  distributed, though with an obvious left skew. We go
  on to show a method that can be used to calculate an
  individual’s IQ with this ratio and provide samples
  with measured accuracy.

Alas, the claim isn't terribly well supported because the IQ was self-reported for the sample they used to test their assumption.

Found a study relating to 2nd laguage acquisition:

  The result of this study revealed that IQ made significant contribution in predicting reading comprehension (23.42%) and writing achievement (16.08%).

I don't have the full text, and the abstract isn't terribly clear, but presumably the amount of langauge education was standardized somehow... otherwise this result makes little sense.

From a more elaborate study (primary language) there are various intermediate factors affecting the various measures of writing quality... but most of these intermediate factors correlated with non-verbal IQ as well:

  As shown in Table 3, there were moderate correlations between the scores on the
  cognitive background tests, except for the measure of attention in dichotic listening
  which did not correlate significantly with any of the other variables. [...]

  While the narrative product measures were significantly correlated with a number of
  cognitive abilities, the narrative process measures were only correlated with reading
  and spelling skills (see Table 6). Children with better reading and spelling abilities
  made more online revisions than their peers. Moreover, children who were good
  spellers transcribed faster than their peers. The cognitive measure of selective
  attention was significantly associated with the ability to use capitalization and
  punctuation in writing.

  [...] Although narrative macrostructural quality was correlated with a number of cognitive measures, only oral language skills and spelling were significant
  predictors in the final model, implying that the other measures did not significantly add to the model’s prediction.


What happens in your brain when you see a dinosaur in this stenographic image? You might have come across stereographic Images like the one shown below (found here):

What happens in your brain when you observe the dinosaur? (as you put your face on the image by touching your nose and then slowly withdrawing from the image.)
Is this perception a particular trick that my eye performs or is it processing the visual data in an alternative way?
Is the effect of this percept measurable by an EEG?

The source I have quoted below gives an example of the following stenographic image:-

Is this perception a particular trick that my eye performs or is it processing the visual data in an alternative way?

  Stereograms can be viewed as three-dimensional images by providing two
  side-by-side views of a three-dimensional scene, rendered from
  slightly different viewpoints. Stereoscopes facilitate focusing of the
  eyes depths other than the surface of a two-dimensional stereogram
  image, allowing the two separate images to overlap in the center of
  the field of vision (Kimmel, 2002). Once the correct depth is
  achieved, it may seem to the viewer as if the two images are different
  due to the horizontal retinal disparities. Then the two images can
  fuse into a coherent three- dimensional percept where horizontal
  disparities in the images provide important depth cues.

Is the effect of this percept measurable by an EEG?

  Autostereograms have been used in recent research to investigate
  three-dimensional depth perception. These efforts have improved
  understanding of the various visual cues involved in forming
  three-dimensional percepts, perceiving motion in depth, attention-
  switching in the depth of field, and the neural correlates of forming
  and maintaining a unified three-dimensional structure in awareness.

  Revonsuo and colleagues (Revonsuo, et al., 1997) used neural
  synchronization to investigate the neural correlates of
  three-dimensional percept formations. They confirmed that
  autostereoscopic perception is primarily mediated by right
  parieto-temporal activity. Their research indicated a region of
  synchrony spanning portions of the right temporal, parietal and
  occipital lobes, with maximum power in the gamma (36-44Hz) frequency
  range. Also employing electroencephalogram (EEG) recording, Burgess,
  Rehman, and Williams (2003) located particular brain regions,
  including the left frontal (F7) and the right and midline occipital
  (Oz, O2) clusters, exhibiting functional clustering during
  autostereoscopic perception. Overall, neural complexity was highest
  with the most functional clustering of responses during observer
  awareness of the three-dimensional object. Additional clustering
  analyses revealed functional clusters of scalp recordings in the
  aforementioned areas that correlated with both phases of
  three-dimensional perception (search to three-dimensional and
  three-dimensional maintenance).

Sources

Autostereograms and Autostereoscopic Perception
Authors: Leslie Blaha, Christopher Honey, and Eric Nichols
Date: October 31, 2005
Burgess, A.P., Rehman, J., & Williams, J.D. (2003). Changes in neural complexity during the perception of three-dimensional images using random dot stereograms. International Journal of Psychophysiology, 48, 35-42.
Kimmel, R. (2002). Three-dimensional shape reconstruction from autostereograms and stereo. Journal of Visual Communication and Image Representation, 13, 324-333.


Involuntary misspelling while writing I'm a native Spanish speaker. In Spanish, the verb "to accept" is "aceptar". When I write it down, or type it on my phone, I tend to write "haceptar" (the H in Spanish is mute, so it'd be pronounced the same way), even though I know it isn't spelled with an H. This also happens to me with some other specific words I can't remember right now.

I thought this happened only to me, but today I found the same word misspelled the same way on a blog over the internet.

I directly tied this «condition» to the concept of a "lapsus", but I couldn't find anything about it.

I want to find a name for this, and I also want to know if it's some specific words that cause it on everyone or it's just casual coincidence.

PS: It's funny that I [almost] always realise I've misspelled the word just before sending it (if it was in a text message), so I always go back and correct it. But it's a hateful process, mostly when I've written a long text or used "aceptar" multiple times...

Edit: I have come up with an example in English as well. When I try to handwrite or type the word "rhythm", I tend to spell it "rythm" (even knowing it doesn't go that way). In this case the H is also mute (and I'm starting to see a pattern: every mistake I make is with a mute H).

TLDR: if it's a "graphotactic" mistake that children could make (and it is), adults could make it under time pressure, distraction etc. A technical term for your kind of error is "phonologically plausible error" (PPE)

This is rather speculative, but I suspect that having two different spelling sets/rules for things that sound the same is the main reason. There's an obvious source of confusion there that we must constantly fight. That's another reason why some linguists argue for phonemic writing (roughly one spelling for everything that sounds the same.) Spanish

It may even have something to do with the so-called dual process theories of cognition (intuitions vs "deep thought"). If you have to apply multiple rules, it takes more time to discern which, and under time pressure you're more likely to make such mistakes.

Why would you prefer the more elaborate spelling version instead of the simpler one, I don't know. It has been observed that children tend to do the opposite:

  by kindergarten, many children begin to apply their existing phonological knowledge of pronunciation combined with emerging orthographic knowledge to produce invented spellings. Hence, pack might be spelled as pak (Treiman & Bourassa, 2000), which then preserves the minimal phoneme representation, known as the phonological skeleton (Bourassa & Treiman, 2003).

The paper I quoted that from also discusses cluster interaction of vowels and consonants, which are also a source of spelling errors in children. That seems related to what you experience, except all the examples there are shortening/simplifying, e.g. misspelling sand as sad, because the n is hard(er) to hear.

What is also observed in children are more complex errors related to the [mis]application of more complex rules, e.g. press misspelled as ppres:

  As beginning spellers learn sound-letter correspondences, particular patterns of orthographic features become evident (Cassar & Treiman, 1997). One such pattern involves consonant doubling, which occurs when children understand that a word contains a doubled consonant but do not recognize its positional constraints. In written English, doubled consonants occur in medial or final positions after a short vowel but cannot occur in the initial position e.g., press. However, young children might mark the doubled consonant in the wrong position, such as ppres (see also Wright & Ehri, 2007), indicating an emerging awareness of the need for a doubled consonant and illustrating that beginning spellers are still mastering word-specific knowledge about positional constraints leading to integration of phonological and orthographic knowledge (Bourassa & Treiman, 2007; Cassar & Treiman, 1997).

Your example seems to be a misapplication of a more complex rule regarding the writing of silent consonants. No such examples are discussed in that paper, as far as I can tell. I'll try to find some more research on this but anecdotal evidence is that silent consonants are a frequent source of spelling errors in English as well.

The closest example in English I found is in a rather obscure thesis:

  The first level of misspelling is when a letter in a word is completely omitted or extra added. For example, in the word ‘ransom’ the misspelling is depicted as ‘ransome’ with an extra ‘e’ letter at the end. Silent letters might affect the correct spelling in terms of leaving them out.

This involves a vowel and in the final, not initial position, but it's conceptually the same "overcorrect" process as adding an initial silent consonant.

And I found something similar for French:

  Children are sensitive to the fact that
  many French words include a final silent consonant, which sometimes leads them
  to add a silent consonant erroneously to words that do not include such letters.

Since this apparently happens a lot in French, it has been more seriously studied, including what type of root words lead to this overapplication more often etc. (See link for details).


Long-Term (Not WM) Memory Norms Is there research on how long it takes an "average" person to memorize a piece of information?

Say a word or a license plate. Something along the lines of: "Given a license plate, and 100 repetitions of said license plate, 95% of all people are expected to remember it in 24 hours, 80% in 48 hours, etc"

Yes. A lot.

A possible place to get started is the wiki page for Ebbinghaus, skip to "Contributions to memory".

Ebbinghaus's work is kind of dated, like 1885 kind of dated, but the point is the discussion there will give you some handy search terms.

In particular, I think "forgetting curve / learning curve" on google scholar will get you where you're going faster than searching for 'memory'.

The question seems to suggest you're most interested in individual differences? Usually people study aggregates, because individuals are so noisy (Ebbinghaus famously did it with one participant, ramping up the number of trials instead, but his methodology wouldn't really fly today). One study that argues against that and does drill down to individuals is Avarell & Heathcote (2011). Their stimuli are short words. Not sure if that's quite what you're after, but might be worth a shot?

If basic research into memory is what you want though there's an embarrassment of riches out there. Good luck!

Averell, L., & Heathcote, A. (2011). The form of the forgetting curve and the fate of memories. Journal of Mathematical Psychology, 55(1), 25-35.


Is it counter-productive to study while tired? I've noticed I retain a much smaller fraction of the information I consume when I'm tired compared to when I'm well slept. Not only that, but I typically have to revisit the same material more times due to this issue, and at that point the information no longer seems new and exciting.

Outside the context of academia and deadlines, if one is self-studying new material is it more beneficial to wait till they're better slept or should they power through the fatigue?

Yes. When studying sleep is crucial in consolidating memories. Recently a wave of research and opinion has hit around optimizing learning, sleep is always mentioned as key. To prominent authors are Benedict Carey and Barbara Oakley. There work is much easier to process than the below research paper, but we like well researched answers!

So here we go, why studying while fatigued is counter-productive and the underlying mechanism of memory consolidation.

  Whereas older research concentrated on the role of rapid-eye-movement (REM) sleep, recent work has revealed the importance of slow-wave sleep (SWS) for memory consolidation and also enlightened some of the underlying electrophysiological, neurochemical, and genetic mechanisms, as well as developmental aspects in these processes. Specifically, newer findings characterize sleep as a brain state optimizing memory consolidation, in opposition to the waking brain being optimized for encoding of memories

Further

  Consolidation originates from reactivation of recently encoded neuronal memory representations, which occur during SWS and transform respective representations for integration into long-term memory.

This work is available for free from the NCBI here


Collective term for fun, relaxation and escapism I'm pondering the nature and relationship of several things that I think are at least loosely related: fun, rest/relaxation and escapism.

They are all things that might be loosely described as "humanistic;" things that you associate with happiness. They might also be described as "fringe needs;" we have to take care of more important things before we go into leisure mode. (However, rest is an exception, as we can hardly stay sane without sleep.)

So is there a collective term for these things? Or can they be placed in some kind of category that separates them from more familiar needs, such as security, social connections and esteem?

I do not believe that there is an actual term that encompasses the three, but if you look at the functions they fulfil, you will find that they tend to give you a "break" from the stimuli that memory is repeatedly exposed to and allow the brain to process those stimuli from memory.

My thoughts on it are: re-processing information that was processed before, trying again to find the patterns and bring the information you are exposed to onto consciousness is hard work that the brain shouldn't have to do. Instead, the same stimuli can be brought from memory and processed as such during lack of exposure.

The only scientific thing that comes to my mind is a thing that comes from imagery of the visual cortex during significant activities (memorising a picture) versus non-significant activities (like being exposed to a blank picture instead of repeating the significant picture). It is called refreshing. More about it, for the scientifically-minded, here

In laymen terms, at times of non-exposure to the real stimuli your brain will automatically expose you to self-made renditions of those stimuli. This particularity of the brain involves complex cognitive functions, of which visual imagery is just an example.

This might be an assumption and an over-generalising of the findings in the paper quoted here, but it might also be true that all the terms you mentioned in your question (fun, relaxation and escapism),can be linked to periods of time of non-exposure to the stimuli that need refreshed, aka. brought to memory by a cognitive representation rather than by repeated exposure.

Now, the big difference between my proposed term and the terms you used is the fact that, scientifically, attentional refreshing has only been  proven for stimuli that the brain was exposed to moments ago. For complex pieces of information and longer periods of time, it would be hard to measure the effect that non--exposure has, because of the nature of the experiments we are now conducting in cognitive and neuro psychology.


Is a Hopfield network with a continuous activation variable and a discrete time variable possible? I've found plenty of resources on Hopfield networks that use either discrete variables for both activation level and time or continuous variables for both activation level and time. Is it possible to construct a Hopfield neural network that uses a continuous variable for activation level and a discrete variable for time? If it is possible, can anyone offer resources and/or tips on how to construct one in software?

After doing some additional research, I think the answer is yes. It just means using a fixed timestep for the continuous-time activation equation (as described here). Since this is a differential equation, implementing it in software requires implementing a numerical integration method. I recommend the Exponential Euler Method as a starting point, because it's relatively simple and it's designed for differential equations of the sort that's used for the continuous Hopfield network.


Why do many people play Candy Crush without ever buying anything while some spend all their money on it? I'm trying to understand how free-to-play games like Candy Crush Saga use existing knowledge of the human brain to keep people engaged and how they convince players to pay money for in-game goods. Some of their game mechanics remind me of the Skinner box. Interestingly, some sources claim that a very small percentage of players contribute 50% of their revenue. I'm assuming this is because not everyone is as susceptible to their monetization tricks. Some addicted players dump all their money into the game, which puts pressure on game developers to protect vulnerable customers from themselves.

Research on big spenders in free-to-play games seems to be scarce, but are there any parallels with existing research (e.g. on gambling) that explain why many people will never spend a dime on these games while others are struggling not to spend their life savings on it? For example, is there a significant difference in how individuals respond to conditioning?

The economic concept of marginalism comes to mind. Actors will spend money to buy virtual goods if the marginal cost (price) is lower than the marginal (subjective) utility of the virtual good. If you have lots of money it's easier to spend $10 on extra lives. This explains some of it.

Most of the purchases are small, so the individual cost/utility analysis is biased, it's "just" $10. Over time it might become a problem.

It's a lot like any other kind of addiction, and I think (baseless speculation) that the "big whales" are more likely to be predisposed for addictions than the general population. The utility, positive affect generated by a feeling of progress and accomplishment, becomes harder to maintain and creates a "need" to keep playing. And when the individual transaction costs are so low it's that much harder to resist.

Edit: I've found some sources that might answer your question better.

This paper discusses how game designers might think about it. Not peer-reviewed.

From a different behavioural economics perspective.

Some other papers on the topic.

Note: Most of these discuss microtransactions and virtual goods. Candy crush is mostly lives, leading to different motivations than games like Team Fortress 2 with cosmetics like hats and skins (and keys).


Is pleasure synonymous to positive reinforcement? I'm thinking about what pleasure is from the perspective of the integrated information theory of consciousness. As I understand it, according to the appraisal theory of emotions, the orientation on the good-bad spectrum is essential for every emotion. From the point of view of these theories, it seems pleasure should occur every time whenever a decision leads to a state evaluated as positive. Is this what modern research suggests or is there a better theory on what pleasure is information-wise?
In other words, what is the algorithm of pleasure according to contemporary science?

Before I even start to try answering this question, it should be said that there is no clear and definitive answer. Endless debates are everywhere on the subject of consciousness but nothing has come close to becoming concrete, since many fields of knowledge have very different thing to say (like biology, philosophy, and of course, psychology).
So, as a psychologist, I will give information to try to give the best answer I can from my perspective:
Going to early psychology, in behaviorism (the works of mostly Pavlov, Skinner and Watson) have come to the conclusion that human behaviour will always steer in direction of receiving rewards and avoiding punishment, in other words, yes: our decisions are always in search of pleasure and escaping,reducing eliminating and (preferably) staying away of stressful stimuli.
The feelings of pleasure are tied to the neurotransmitter of dopamine, as it is well known, and the feelings of stress and discomfort are tied to cortisol (It is a lot more complicated than that, but I am trying to be simple and to keep it short). These hormones are released when the enviroment interacts with a person in a certain way, meaning that the objects or actions themselves are not what bring these emotions, but our perceptions and appreciation of the stimuli in question. This is the foundation of the intrinsic and extrinsic motivations.
Thanks to everyone's definition of pleasure and stress being different, and our own definitions of these terms can evolve and change (Mostly to our ever-changing perspective and more accurately, our neurotransmitter receptors adapting accordingly to the amounts of dopamine or cortisol being received) is that we don't make the same choices than the rest of humanity or even that our decisions are not always constant, since we make decisions are in the moment, and our solution to the problem "What is going to give me the most pleasure?" is made somethings in the split of a second.
These hormones have been guides to ensure our survival as a species, making us feel good about things that are good for us (Like good food and sex) and making us flee or solve bad situations (Like the pressence of a predator, or being socially rejected). But as we grew smarter, we learn to "cheat" our innate reward system to make us feel good a in much more ways and situations. Smoking, drugs, and junk food does sure give a rush of dopamine, but the pleasure it gives surely contradict the effects they do to our health, so dopamine and cortisol are no longer reliable indicators that we are doing a "good choice."
We can even make this MORE complicated if we start bringing in to this discussion the psychodinamics theories of Consciousness and the Unconscious, since if these ideas are to be believed, we could be making decisions that bring us stress and discomfort subconsciously, trying to appease the desires that we are not aware, giving some form of pleasure that we do not even accept.
And bringing this wall of text to a conclusion, you COULD try to make a formula of behaviour with the variables of stress and pleasure, but would it be scientifically accurate and consistent? I don't think it can be done, by the very nature of biology and neural science, there is an constant evolution of pleasure and our understanding, and too many variables to be an effective algorithm to be applied to a considerable size of persons. But it surely has been theorized.
So far my links have been Wikipedia articles, to make researching a bit simpler if you are not willing to read entire books and articles, but I do not recommend this if you are serious about your learning of the subjects. Here I will list some books and explain how they relate to your question:

The Principles of Learning and Behaviour by Michael Domjan. This detailed book can help you understand every facet of the more earlier works of behaviorism and some of the more present ideas.

Neurochemistry of Consciousness by Elaine Perry. It surely is a heavy read, but very insightful and detailed if you are for the task.

Unconscious Influences on Decision making by Géraldine Coppin. While I am not usually font of psychodinamics theories of decisions, I feel obligated to link at least an article to let you read on it and make your own conclusions.

Hope this helps.


How can I test reaction time? How can I measure someone's ability for the speed to which they react to something? Is their a way to test something like a person's reaction timing that doesn't involve something as simple as the ruler test, but rather something a bit more complex.

Edited: The ruler test: https://www.youtube.com/watch?v=yn6WRm6TiPk
I have not yet done initial research on this topic because I want some good opinions on sources that I can use to better my understanding of this topic. I apologize if I was not clear at first.

It is very typical to record response times. Usually using a computer keyboard. It's easy to program or some software can do it for you (e.g. e-prime). You can also use already-made response boxes (e.g. RTbox), or make your own (e.g. with an arduino). As pointed out, it is usually good to control for performance to prevent speed-accuracy tradeoff confounds.

Li, X., Liang, Z., Kleiner, M., & Lu, Z. L. (2010). RTbox: a device for highly accurate response time measurements. Behavior Research Methods, 42(1), 212-225.

Schubert, T. W., D’Ausilio, A., & Canto, R. (2013). Using Arduino microcontroller boards to measure response latencies. Behavior research methods, 45(4), 1332-1346.


Evidence that positive rewards are learnt faster than negative rewards? Its folk psychology wisdom that its easier to reward positive behavior than punish negative behavior (e.g. any book on parenting or dog training), but is there any evidence in the cognitive science literature that this is indeed the case? And if so, then have possible mechanisms for this phenomena been proposed?

For some context, I'm asking this because coming from a computational perspective this doesn't really make sense. The typical reinforcement learning algorithm tries to maximize the expected discounted cumulative reward of behavior, and it makes no difference if that entails avoiding negative rewards or seeking out positive rewards.

This is a great question.

Short answer: No, the evidence does not suggest that positive reinforcement is universally more effective than negative reinforcement or punishment.  However, there are still good reasons to focus on rewards over punishment in real-life training/learning situations.

Long answer:

The trouble for folk psychology began with Skinner's somewhat unfortunate choice of terminology...  While Skinner advocated positive reinforcement over negative reinforcement or punishment, it seems to have remained an industry secret that what he meant by those terms is not what the general public thinks he meant.

The modern view of positive and negative reinforcement is that they are essentially synonyms.  They are different ways of looking at the same thing, like describing a glass of water based on how full or how empty it is.  Computationally, as you say, learning algorithms that assign positive values to targets or negative values to non-targets are mathematically equivalent.

Although they are often confused with positive and negative reinforcement, rewards and aversives are different terms with different meanings.  Testing whether one is more effective than the other is tricky, as in practice they are usually qualitatively different.  For example, is ice cream or spanking more effective for getting your kid to do their homework?  The answer is: It depends - how much ice cream, how much spanking...?  Surely we can find a ratio of ice cream to spanking at which they are equally effective.  The type of research that examines this question is interested in determining where that boundary is (here is an example).  Thought experiment: How can qualitatively different feedback mechanisms be applied in machine learning?

Research more likely to answer your question compares positive and negative feedback that is arguably qualitatively equivalent.  For example, compare gaining money to avoiding loss of money, reducing risk to avoiding increase in risk, and it's even possible to compare the effects on animals that are trained in a token economy.  In recent years, the folk psychology idea that positive feedback is universally superior to negative feedback has been called into question by such research.  A few examples:

Michael Perone reviews research demonstrating undesirable effects of positive reinforcement.
Comparing "well done!" to "got it wrong this time", Eveline Crone et al found that before the age of twelve, children perform better with positive feedback, but older children and adults do better with negative feedback.
A study comparing "keep the word Good on the screen" to "keep the word Bad off the screen" found that negative reinforcement may be more effective for some types of learning.
Ayelet Fishbach and Stacey Finkelstein review research that suggests that negative feedback is more effective for experts, and motivates goal pursuit when it signals insufficient progress.
Lots of research into Loss Aversion suggests that avoiding the loss of money is a more powerful motivator than gaining an equivalent amount of money.  However, this phenomenon may not translate to an effect on learning.
Despite all this, note that the evidence in favour of positive reinforcement is much greater - these are just some notable exceptions.

Neurological reasons for the difference in effectiveness between positive and negative feedback have been proposed - for example by Eveline Crone in the study cited above.

Training using rewards is preferred for animal trainers, parents, and teachers in most practical situations:

There is usually a much wider range of undesirable behaviour to punish than desirable behaviour to reward.  Animals and young children have difficulty determining what the desirable behaviour is with only clues about what behaviours are undesirable.  Adults are easier to work with because you can explain the desirable behaviour in words.
Punishment must be applied to all undesirable behaviour to be effective, while reward need only be applied to desirable behaviour, and even then only intermittently, to be effective.
Due to classical conditioning, subjects may attribute punishment to factors unrelated to their behaviour, such as the trainer or the classroom.  They may learn to avoid the trainer, or avoid getting caught, rather than the desirable behaviour.
Notice how none of these points apply to machine learning, where the process is structured, constrained, and automated.

John Maag summarizes reasons to promote positive reinforcement in schools: Namely that teachers often find it convenient and effective (in the short-term) to administer punishment and are overly reliant on it in many situations where positive reinforcement would be more effective and desirable.

Nice video on the topic.


What is the phenomenon that one can recognize a movie after seeing a scene for a fraction of second called? I have experiences that while I was walking around the street, I saw a scene on a TV for a fraction of second, and I instantly recognized the correspondent movie. This is very interesting since at the time I didn't fully comprehend what I saw, but the name of movie came up anyway.

What is this very fast recollection phenomenon called? What is the type of memory involved? Where can I learn more about this cognitive function?

The subliminal recollection is called involuntary memory retrieval.

This triggers an implicit memory.

Further reading:

http://en.wikipedia.org/wiki/Subliminal_stimuli#Images

http://en.wikipedia.org/wiki/Subliminal_stimuli#Auditory_stimuli
http://en.wikipedia.org/wiki/Spreading_activation


Put a fixation cross on top of a image in Expyriment? I wanted to try to put a fixation cross on top of images presented to avoid subject eye movements as much as possible.

I am using Python's Expyriment package and thought that after present with a expyriment.stimuli.Picture I could do a present with an expyriment.stimuli.FixCross object using the clearor update input arguments. But this does not seem to work.

This should work:

picture = expyriment.stimuli.Picture("/path/to/picture.jpg")
fixcross = expyriment.stimuli.FixCross()
picture.present(update=False)
fixcross.present(clear=False)

Alternatively, you can first plot the fixation cross on top of the picture and then present it:

picture = expyriment.stimuli.Picture("/path/to/picture.jpg")
fixcross = expyriment.stimuli.FixCross()
fixcross.plot(picture)
picture.present()


What information does the connectome actually contain? I am not a brain scientist but the following question seems reasonable to me.

Prof. Sebastian Seung has given a TED talk named "I Am My Connectome". If I understand correctly, connectome is basically the graph whose vertices are neurons and whose edges are synapses (strictly speaking, there are many different kinds of neurons so the vertices of the graph should be colored, but let us forget it for now).

The title then appears to be a (probably intentional) oversimplification, since even though we do not understand how exactly memories are stored in the brain (and there are many different kinds of memories), things I will roughy call "electrical and chemical variables" play some role in it (so simply remembering whether there is a link or not between two neurons is not going to fly). I understand that studying these "electrical and chemical variables" is like over a half of the brain science but the exact definition is not particularly important for this question. If my understanding is correct, then one should not get overly excited about the present achievements of the Brain Preservation Foundation (the most promising one is, I think, preserving the connectome of a mammal for some time after its death using a chemical solution/freezing), since they have not shown that they can preserve any of the "electrical and chemical variables".

The question is: what information can you actually extract out of a connectome, assuming you do not know anything else about the brain? Like something about a person's health, personality, anything? The chance of them having schizophrenia? Their most likely age?

Well, regarding this short definition of a connectome from Wiki:

A connectome (/kəˈnɛktoʊm/) is a comprehensive map of neural
connections in the brain, and may be thought of as its "wiring
diagram". More broadly, a connectome would include the mapping of all
neural connections within an organism's nervous system.

Therefore you could read out all information, assuming you have enough computational power. (A perfect connectome would represent all information processes in the brain. Because processing information through connections is all the brain does, right? :D)
In the real world however, we need 'models' as simplifications to deal with these phenomena. A connectome is nothing else than such a model.
Influential Factors to consider

To make predictions of real-world constructs, you need to assess real-world phenomena. F.i. you need to have
postulated some outcome-variables (for lets say Schizophrenia) that need to
be quantified in the real-world (external validity) to be related to
inner-brain processes. These real-world concepts of psychological
processes, speaking of the behavioral, emotional and cognitive
aspects (which can be measured), are inherently fuzzy, which raises
the question, to which certainty we will be able to predict
psycho-physiological correlates.

Not to forget, memories are mainly coded as 'processes over-time',
something like chains of activation (other than distinct anatomy and
brain-areas who would define thoughts). Also noisyness and
randomness is always a variable you need to consider. (I think the
Hippocampus functioning of neurons induces randomness by design, but
I have no source right now.)

Also to mention:
The individuality of brains leads to decreased prediction of the model or a general model that would hold for every individual

The plasticity of the brain states states the ability to change and
evolve over time.  (Concepts like Imprinting and so on). A static
model might also not be sufficient to represent these (also highly
individualized) processes.

Situational- or environmental dependency also influences your
current state of mind. (It is not possible to 'control' all
environmental factors, unless you had infinite computational power.)

Also the brain and toughts are highly self-/auto-activating, recurring and in parallel.
Millions of neurons firing at the same time and oscillating in
rhythms. Thoughts that become conscious might only be the tip of the
iceberg in a sea of thoughts that are below a certain threshold.

My proposal to your question: "What exactly can you get from a connectome?"
In principle everything is possible, but practically we might never truely decode everything from a philosopical and mathematical point-of-view (we needed to create a perfect connectome, which would be a perfect simulation of the entire brain). We might however be able to find very accurate brain-markers that help in predicting real-world concepts that seem relevant for humans :)
Resources
Because it is great: Video of synchronizing fireflies
Buszaki: Rhythms of the Brain is a nice read on some how information is created in the brain and different processes


Why does "bulk" yellow ink look red? A transparent blue inkjet cartridge looks deep blue, a red one looks deep red, but a yellow one looks red. Tea also looks yellowish when it's shallow and reddish otherwise. Red is another colour, a different wavelength, so why does deep yellow look red?

Not all liquid or things that are yellow become red when they exist in large quantity. For example, beer, vegetable oil, and normal urine never look red even in large quantity, like in a vat. It really depends on the optical properties of the liquid and the suspended particles in it.

The optical properties of something depend on both its intrinsic factors such as its reflectance, transmittance, and absorptance of the light and the extrinsic factors such as its thickness, the surface that it’s on, the angle of light incidence, and the polarization of the incident light. (This is not to mention psychological factors like the mood when you look at that thing or the surroundings colors or compositions of that thing, which can make that thing look different.)

That’s why a thin film of water is colorless but a large body of water like the lake looks blue. And that’s why there is a phenomenon called iridescence – the phenomenon that certain surfaces appear to change color as the angle of view or the angle of illumination changes – like changing rainbow colors on a soap bubble or on a colorless CD surface.

In your case, I think the color reflection and transmission properties of the ink are different. The ink probably reflects mainly the yellow color, so it looks yellow when reflection of colors is the major event – as when the ink is painted on a surface. But the ink probably transmits more of the red color than the yellow color, so it looks red when transmission of colors is the major event – as when you look through it.

N.B. I think you’ll probably get better answers than mine by posting the question on the Physics forum.

References.

II.8. Reflection, Transmission, and Absorption Gigahertz-Optik.
Elements that Affect the Appearance of Color Konica Minolta.
Iridescence Wikipedia.


Does an electrical stimulation of a right claustrum leads to a temporary loss of consciousness? In a study by Koubeissi et al. (2014) there was an experiment on a patient to find out which part of the brain caused her epilepsy. In this experiment they have found out that if they electrically stimulate her left claustrum, the person would lose consciousness.

My question is: If they have stimulated her right claustrum, would that caused her a loss of consciousness as well? In other words: Are both claustrums necessary for a conciousness to appear in an ordinary healthy human brain?

Koubeissi, M. Z., Bartolomei, F., Beltagy, A., & Picard, F. (2014). Electrical stimulation of a small brain area reversibly disrupts consciousness. Epilepsy & Behavior, 37, 32-35.

It's probably a bit more complicated than that. Cortical areas tend to be highly connected with their contralateral counterparts, so it's not really fair to expect that the effects of stimulation on one side of the brain doesn't impact the contralateral side.

The claustrum is itself a small gray matter region, but it is surrounded by white matter as well. Koubeissi et al used a fairly strong stimulus when they saw effects on consciousness; I have a hard time believing this stimulation was only affecting the claustrum and not fibers of passage at that stimulation intensity.

A recent study of 5 epilepsy patients attempted to replicate the Koubeissi finding, stimulating the claustrum (bilaterally in 4/5) in epilepsy patients, but none of the patients lost consciousness despite experiencing other effects. The authors suggest that the results presented in the earlier case study could be based on the unique circumstances of that patient, which include their epilepsy history and prior resection, and that the stimulation location in that Koubeissi case was not really directly in the claustrum. Additionally, Bickel & Parvizi were unable to use a stimulus as strong as the prior case report because their patients experienced negative side effects like painful muscle responses that Koubeissi did not see.

Bickel, S., & Parvizi, J. (2019). Electrical stimulation of the human claustrum. Epilepsy & Behavior.

Damasio et al, 2013 is another case study, where the patient had bilateral damage to a substantial portion of the brain, including the claustrum bilaterally. This patient had quite a bit of impact to various functions due to this damage, but they were still conscious. Therefore the answer to "Are both claustrums necessary for a conciousness" seems to be "no"; in a healthy brain it's a bit harder to say, because it's not ethical to damage the claustrum in healthy brains.

Damasio, A., Damasio, H. & Tranel, D. Persistence of feelings and sentience after bilateral damage of the insula. Cereb. Cortex 23, 833–846 (2013).

There are also other papers showing suppression or recovery of consciousness through stimulation of other brain regions besides the claustrum.

Redinbaugh, M. J., Phillips, J. M., Kambi, N. A., Mohanta, S., Andryk, S., Dooley, G. L., ... & Saalmann, Y. B. (2019). Central thalamus modulates consciousness by controlling layer-specific cortical interactions. bioRxiv, 776591.

Schiff, N. D., Giacino, J. T., Kalmar, K., Victor, J. D., Baker, K., Gerber, M., ... & Farris, S. (2007). Behavioural improvements with thalamic stimulation after severe traumatic brain injury. Nature, 448(7153), 600-603.


What does "The brain has its own language for testing the structure and consistency of the world." refer to? The late Dr. Carl Sagan is famous for many different contributions to both scientific research and science education.

One memorable line is discussed in Are we really star-stuff from the interior of collapsing stars?

In the video Carl Sagan - 'A Glorious Dawn' ft Stephen Hawking (Symphony of Science) at about 01:30 Dr. Sagan can be heard to say:

  “But the brain does much more than just recollect it inter-compares, it synthesizes, it analyzes, it generates abstractions. The simplest thought like the concept of the number one has an elaborate logical underpinning. The brain has its own language for testing the structure and consistency of the world.”

This quote can also be found in goodreads and in the script of Season 1, Episode 11 of the TV show Cosmos circa 1980.

What might Dr. Sagan be referring to in the sentence "The brain has its own language for testing the structure and consistency of the world."?

Question: Is this hypothetical "language" a way that information is exchanged between different parts of the brain? Is this concept part of some well known theory of brain function at the time? How is this viewed now, nearly forty years later?

A longer quote (from the episode) for context:

  The brain is a very big place in a very small space. Most of the books in the brain are up here in the cerebral cortex. Down there, in the basement of the brain are the functions that our ancestors mainly depended on for survival: Aggression, child rearing, sex the willingness to follow leaders blindly. Lots of things that we can still recognize in our lives today.

  Of the higher brain functions some of them, like reading, writing, speaking seem to be located in particular places in the cerebral cortex.

  On the other hand, each memory seems to be stored in many separate locales in the brain. Old memories are in lots of places. Here is one of my earliest memories.

    (POURS LIQUID) MOTHER: That's a good boy.
    Lunch is almost ready.
    (CLICKS ON RADIO) (MUSIC PLAYS)

  That was a long time ago. But its imprint has not faded in the library of this brain. But the brain does much more than just recollect. It inter-compares. It synthesizes. It analyzes. It generates abstractions. The simplest thought, like the concept of the number one has an elaborate, logical underpinning.

  The brain has its own language for testing the world's structure and consistency. But we never see the machinery of logical analysis only the conclusions. There is so much more that we must figure out than the genes can know. That's why the brain library has 10,000 times more information in it than the gene library. Our passion for learning is the tool for our survival. And unlike the musty bindings of our gene library in which hardly a word changes in a century the brain library is made of loose-leaf books.

  We're constantly adding new pages and new volumes. Emotions and ritual behavior patterns are built very deeply into us. They're part of our humanity. But they're not characteristically human.

  Many other animals have feelings. What distinguishes our species is thought. The cerebral cortex is, in a way, a liberation. We need no longer be trapped in the genetically inherited behavior patterns of lizards and baboons: Territoriality and aggression and dominance hierarchies. We are, each of us largely responsible for what gets put into our brains for what, as adults, we wind up caring for and knowing about.

  No longer at the mercy of the reptile brain we can change ourselves.

  Think of the possibilities.

Dr. Sagan is referring to the brain's ability to produce models of the world in order to test predictions.

In terms of psychology contemporary with Carl Sagan, he may have been referring to, in part, the theory of schemas. This is a general representation of a thing or idea that is used in classifying or identifying the thing or idea. In developmental psychology, the idea of Jean Piaget's schema might appear as a young child identifying all four-legged animals as "doggies." As the child grows, they will begin to differentiate, and for example, know horse vs. dog (but might classify a zebra as a horse).

The "language" of the brain seems to be an emergent property of neuronal firing. When a neuron elicits an action potential, it produces a voltage pulse that (usually) travels down the axon. Neurons can stimulate each other when synapses are triggered by an action potential of the pre-synaptic neuron. This is a simplified explanation: there are also graded synapses that aren't action potential-triggered.

Dr. Sagan might also have been thinking of the 1981 Nobel Prize-winning research by Hubel, Wiesel, and Sperry, whose mid-twentieth century research demonstrates how receptive fields for retinal neurons map onto the visual cortex. Retinotopic maps show how the brain putatively represents visual stimuli in the cortex.

In the early 1990s, researchers began investigating the "neural code" in earnest. A rate code is the idea that information is carried in the particular firing rate of a neuron, that is, the mean number of action potentials per second. A temporal code is when information is contained in the timing of spikes, not just the mean firing rate. Charles Frye has a great explanation with citations.

Symbolic processing in the brain is an active field of research. The problem can be approached from top-down neuropsychological assays, or from down-up electrophysiology. There is little doubt that symbolic processing is performed by neurons working in concert, though the exact mechanisms for all but the crudest processes are unknown.

Here are some examples: Theoretical models [1, 2] have shown how layers of neurons with different properties can be used to filter or transform data. In addition, high-level models have demonstrated possible methods by which cognitive units comprised of one or more neurons can determine the solution to symbolic problems [3]. In addition, electrophysiological assays show how cells in the cortex of mammals "record" and represent physical data for use in navigation [4].

[1] Gjorgjieva, Julijana & Drion, Guillaume & Marder, Eve. (2016). Computational Implications of Biophysical Diversity and Multiple Timescales in Neurons and Synapses for Circuit Performance. Current Opinion in Neurobiology. 37. 44-52. 10.1016/j.conb.2015.12.008.

[2] Shankar, K. H., and Howard, M. W. (2012). A scale-invariant internal representation of time, Neural Computation, 24, 134–193.

[3] Hasselmo ME, Stern CE (2018) A network model of behavioural performance in a rule learning task. Phil. Trans. R. Soc. B 373 : 20170275. PMCID: PMC5832697. PDF

[4] Hinman JR, Dannenberg H, Alexander A, Hasselmo ME. (2018) Neural mechanisms of navigation involving interactions of cortical and subcortical structures. J. Neurophysiol. 119(6):2007-2029. PDF


Can a person control their brain's electrical activity? In a brain-computer interface paper, I found the following paragraph:

  Effective assessment of BCI performance requires two levels of evaluation: the user and the system. The user must control the signal features ..."

My question is how can a person control the signal features of his/her brain signal? Does this mean, for example, that a person can give more attention to increase signal to noise ratio for the P300 signal, and be able to look more carefully at the screen that shows flashes in an SSVEP experiment?

Yes, and no.  Biofeedback has been an active field of research since the 70s, but has been a bit "fringified" as a cure for ADHD, etc.

It is possible to fine tune the brain activity for specific tasks.  To borrow an example from BCI, the Rolandic Mu Rhythm can be used to "train" a user to refine the movement of a cursor or other pointing device.

Jonathan Wolpaw has been doing BCI work long before it was "cool", so his work on BCIs for ALS patients is definitely worth checking out.

As to whether you could train the P300, this signal is seen most prevalently in the "oddball" paradigm, which by nature relies on the stimulus that evokes it being of low probability. Letting the user know that a low probability stimulus is about to occur would eliminate most of the response.


Can scary movies trigger fight or flight and why can a person enjoy this while another does not? Essentially, I understand the release of adrenaline can be addictive and that scary movies and events are a safe way of experiencing the drama without all the actual mess. but

However, if we are triggering our fight or flight response, then isn't suppressing it a separate chemical reaction, or at least an alternate one?

Is the release experienced more pleasurable for some people then others? Or is it a simple matter that staying in one's comfort zone is more enjoyable then the potential joy of a release?

I imagine individual differences in enjoyment derived from horror films would be multifaceted as with most preferences regarding consumption of different media. Some of the research mentions how males, teenagers/young adults, sensation seekers, and those who have a history of exposure to horror films (although this may be both cause and effect) tend to like horror films more.

Sensation seeking: You might want to look into the personality trait sensation seeking. To quote Wikipedia quoting the originator of the concept, Marvin Zuckerman.

  Sensation seeking is a personality trait defined by the search for
  experiences and feelings, that are "varied, novel, complex and
  intense", and by the readiness to "take physical, social, legal, and
  financial risks for the sake of such experiences." (Zuckerman, 2009). Risk is not an
  essential part of the trait, as many activities associated with it are
  not risky.

Zuckerman discusses the psychology of horror films in this video (see transcript here). He frames sensation seeking in terms of habituation. Thus, the more horror films that a person has seen, the more intense the horror would need to be in order to induce the same rewarding level of arousal.

Exploring the concept of sensation seeking may also move you more towards a more primary concept of why people seek such arousal inducing experiences. You could for instance read Roberti's (2004) literature review of the biological and behavioural correlates of sensation seeking. In particular, see section 4 on biological characteristics related to sensation seeking:

  Zuckerman (1994, 1996) has proposed a multi-level approach in which
  sensation is a product of interactions between neurotransmitter
  systems (Zuckerman, 1996). Agonistic and antagonistic interactions of
  biological correlates are related to sensation seeking. Biochemical
  mechanisms provide major support for the relation of sensation seeking
  and associated biological systems (Balada et al., 1993; Ballenger et
  al., 1983; Daitzman & Zuckerman, 1980; Dellu et al., 1996; Gerra et
  al., 1999; Netter et al., 1996; Piazza et al., 1993; Ruegg et al.,
  1997; Zuckerman, 1984, 1991a; Zuckerman et al., 1980).

Tamborini and Stiff (1987) studied the appeal of horror movies:

  A survey was conducted to determine the antecedents of the exposure to
  and appeal of horror films. Audience members leaving the theater after
  viewing Halloween II were interviewed using a questionnaire that
  contained measures of specific reasons for liking horror films as well
  as measures of several individual-difference variables. A model
  emerged from structural equation analysis indicating that three
  important factors in the appeal of horror films are (a) the audience's
  desire to experience the satisfying resolutions usually provided in
  these films, (b) the audience's desire to see the destruction often
  found in these films, and (c) the sensation-seeking personality traits
  of audience members for these films. In addition, age and gender were
  important predictors. Horror films were enjoyed more by males and by
  younger viewers.

Tamborini, Stiff and Zillman (2006) summarise existing research linking sensation seeking with horror film preference:

  Several studies  have  attempted to  investigate  the  relationship
  between the attraction to horror films and sensation seeking. The
  first  attempt to  look at  this  issue was reported by  Sparks
  (1984), who  correlated his own 20-item scale measuring Enjoyment of
  Frightening  Films (EFF) with the Sensation-Seeking Scale, and found
  an overall  positive correlation between the two for both males (r=
  .22,p= .01) and  females (r = .28, p = .01). A second study (Tamborini
  & Stiff, 1984) also  found an association between the liking of horror
  films and a measure of  sensation seeking computed from  the
  combination of  disinhibition,  experience seeking, and thrill and
  adventure seeking scores (r= .14,p=  .05).  Finally, Edwards (1984)
  found a strong correlation between the  entire Sensation-Seeking Scale
  and interest in horror movies (r = 51, p  < .001). Unfortunately, the
  articles by Sparks (1984) and Tamborini and  Stiff  (1984) do  not
  report the  correlations between  the  individual  subdimensions of
  the Sensation-Seeking Scale and their measures of  attraction to
  horror films. This information is of particular interest to us  if  we
  want  to understand the  appeal found  in  horror  since  these
  subdimensions are thought to be unique. The study by Edwards (1984)
  does  provide  information  in  this  regard,  however.  According  to
  Edwards, each of  the subdimensions is correlated to interest in
  horror  films with disinhibition having the strongest relationship (r
  = .54, p <  .001), followed by boredom susceptibility (r = .41,p < .001), experience  seeking (r= .39,p < .001), and thrill and adventure
  seeking (r= .24, P <   .01).

References

Balada, F., Torrubia, R., & Maria Arque, J. (1993). Gonadal hormone correlates of sensation seeking and
anxiety in healthy human females. Neuropsychobiology, 27, 91–96.
Ballenger, J. C., Post, R. M., Jimerson, D. C., Lake, C. R., Murphy, D., Zuckerman, M., & Cronin, C.
(1983). Biochemical correlates of personality traits in normals: An exploratory study. Personality and
Individual Diﬀerences, 4, 615–625.
Daitzman, R. J., & Zuckerman, M. (1980). Disinhibitory sensation seeking and gonadal hormones.
Dellu, F., Piazza, P. V., Mayo, W., Le Moal, M., & Simon, H. (1996). Novelty-seeking in rats:
Biobehavioral characteristics and possible relationship with the sensation seeking trait in man.
Neuropsychobiology, 34, 136–145.
Personality and Individual Diﬀerences, 1, 103–110.
Gerra, G., Avanzini, P., Zaimovic, A., Sartori, R., Bocchi, C., Timpano, M., Zambelli, U., Delsignore, R.,
Gardini, F., Talarico, E., & Brambilla, F. (1999). Neurotransmitters, neuroendocrine correlates of
sensation-seeking temperament in normal humans. Neuropsychobiology, 39, 207–213.
Netter, P., Hennig, J., & Roed, I. S. (1996). Serotonin and dopamine as mediators of sensation seeking
behavior. Neuropsychobiology, 34, 155–165.
Piazza, P. V., Deroche, V., Deminiere, J. M., Maccari, S., Le Moal, M., & Simon, H. (1993).
Corticosterone in the range of stress-induced levels possesses reinforcing properties: Implications for
sensation seeking behaviors. National Academy of Science, 90, 11738–11742.
Roberti, J.W. (2004). A review of behavioral and biological correlates of sensation seeking. Journal of research in personality, 38, 256-279. PDF
Ruegg, R. G., Gilmore, J., Ekstrom, R. D., Corrigan, M., Knight, B., Tancer, M., Leatherman, M. E.,
Carson, S. W., & Golden, R. N. (1997). Clomipramine challenge responses covary with tridimensional
personality questionnaire scores in healthy subjects. Biological Psychiatry, 42, 1123–1129.
Tamborini, R. & Stiff, J. (1987). Predictors of Horror Film Attendance and Appeal An Analysis of the Audience for Frightening Films. Communication Research, 14, 415-436.
Tamborini, R., Stiff, J. & ZILLMAN, D. (2006). Preference for graphic horror featuring male versus female victimization. Human Communication Research, 13, 529-552.
Zuckerman, M. (1984). Sensation seeking: A comparative approach to a human trait. Behavioral and Brain
Sciences, 7, 413–471.
Zuckerman (2009). "Chapter 31. Sensation seeking". In Leary, Mark R. & Hoyle, Rick H.. Handbook of Individual Differences in Social behavior. New York/London: The Guildford Press. pp. 455–465.
Zuckerman, M. (1991a). Psychobiology of personality. New York: Cambridge University Press.
Zuckerman, M. (1994). Behavioral expressions and biosocial bases of sensation seeking. New York:
Cambridge Press.
Zuckerman, M. (1996). The psychobiological model for impulsive unsocialized sensation seeking: A
comparative approach. Neuropsychobiology, 34, 125–129.
Zuckerman, M., & Neeb, M. (1980). Demographic inﬂuences in sensation seeking and expressions of
sensation seeking in religion, smoking and driving habits. Personality and Individual Diﬀerences, 1,
197–206.


Can memorising a new thing erase existing memories? Homer: But every time I learn something new, it pushes out something old. Remember that time I took a home wine-making course and forgot how to drive?
Marge: That's because you were drunk.

Yeah, but all jokes aside, when all other conditions are equal, does  memorising a new thing increase the chance of losing existing memories that are not directly related to the new memory (different subjects)?
If there is no OS that keeps track of data (i.e.,file system), and each program writes small data anywhere on a large hard disk it wants, as the data grows, the chance of overwriting existing data will increase. And even if OS keeps track of data, when there is no more space it must delete some existing files.

Although this is quite an old question, I thought I would add additional
information regarding this topic for consideration.

As already noted, the storage capacity of the human brain is certainly very impressive. However, there are also some interesting quirks to human memory worth noting.

  does memorising a new thing increase the chance of losing existing memories that are not directly related to the new memory (different subjects)?

No -- and in fact, when something approaching the phenomenon you are describing occurs, quite the opposite appears to be true.

Before I clarify this, it's important to note that one should not think of memory as something that is "lost" in the same way that one might record over a VHS cassette tape and lose the old content in the process.

When one encodes new information ("learns a new factoid"), there is a greater chance of that new information adversely affecting their ability to retrieve and recall semantically related memories.

Memory interference is more likely to occur with similar material than different material.

Two main types of interference are thought to affect memory:

Proactive interference. Previously learned information affects our ability to recall newly learned information.

Retroactive interference. Newly learned information affects our ability to recall earlier learned information.

In effect, what you might observe is precisely the opposite of what you are suggesting in your original question: when you memorise information about a "different subject" you are in fact less likely to "lose existing memories" relative to memorising information about the "same or similar subject".

Again, it's important to recall that you're not actually overwriting or erasing the older memories, but more likely merging them together and confusing them with other memories.

This has relevance to how one might chose to structure their learning e.g. revise for exams. After revising organic chemistry, one might derive greater benefit from subsequently revising a foreign language, rather than say, following it with inorganic chemistry.

So, as it relates to your Simpsons reference, the following would be more likely to be correct:

  Remember that time I took a home wine-making course and forgot how to drive brew beer?

Below is a screenshot from a introductory psychology textbook detailing describing the role of interference in forgetting. It also refers to empirical research supporting the phenomenon:

From: "A Level Psychology Through Diagrams" By Grahame Hill
(My apologies, I had to use my undergrad textbooks in a bonfire when I was homeless and had been reduced to eating catfood)


Do people "subvocalize" during thinking or "internal monologue"? I've recently became aware of the concept of subvocalization, where people make tiny motions with their vocal cords when reading. I'm looking for a clarification on the subject:

Does subvocalization only take place when reading, or does it take place during thinking too?

I found a some articles on the subject of detection of subvocalization

  Modern technology can detect the small movements made during
  subvocalization by monitoring electrical impulses. As of 2011, the
  National Aeronautics and Space Administration (NASA) is working on
  technology to detect these forms of silent speech. By reading these
  faint electrical impulses that occur during the process of
  subvocalization, machines could appear to read a person's mind and
  respond seemingly without the person saying anything. All the person
  would need to do is clearly think the command he wants the machine to
  carry out.

The last statement makes it seem as if subvocalization can be detected during thought.

Short answer
Sub-vocalization can also be detected during cognitive demanding tasks other than reading.

Background
As far as I can see, most literature acknowledges sub-vocalizing as being only detectable by measuring the electrical nerve activity that drive the speech organs (e.g., Parnin (2011) and NASA Research). When people perform complex tasks, these sub-vocal utterances can be recorded as electrical signals sent to the tongue, lips, or vocal cords, and these can be detected.

Sub-vocalizing has been mostly described in terms of reading (e.g. Slowiaczek & Clifton, 1980). Nonetheless, more recent literature also associates and acknowledges sub-vocalization when people perform mental tasks that claim a lot of mental processing, such as software programming (e.g., Parnin (2011), so the answer to your question is yes, it also occurs during thinking.

Interestingly, as a side note, stutterers sub vocalize more slowly, reflecting the fact that indeed much of the same mechanisms are at work during sub-vocalization as during normal speech (Bosshardt, 1990).

References
- Bosshardt, J Speech Hear Res (1990); 33(4): 776-85
- Parnin, IEEE 19th International Conference on Program Comprehension (2011)
- J Verbal Learning Verbal Behav (1980); 19(5): 573-82


List of psychological conditions, disorders and illnesses I would be grateful to anyone who takes some time to answer. Is there any up-to-date list of all psychological conditions, disorders and illnesses, in the strict neuro-psychiatric scientific definition?
Would a list of such conditions, disorders and illnesses be different under the context of contemporary psychoanalysis (not of-course pure Freud based from the 1900s)? Or would they be included in the above-mentioned list? If not, is there the second list, psychoanalytical oriented, but still based on scientific publications?
Any form of such a list (or catalog), including wikipedia, medpud or other major Journal publication or even a scientific book, would work.
Thanks and please do understand the "anonymous" posting

The DSM-5 is the current version of the diagnostic manual of the APA.
It's hard to say there is any such thing as a "strict neuro-psychiatric" definition; these definitions are by their nature not strict at all, but the DSM is probably the closest thing to some level of unified understanding in the field. That doesn't mean everyone agrees with it - they certainly don't - and you can infer from changes from edition to edition that it is all far from settled.


Subliminal Persuasion: best chances of success A lot of people are skeptic about the impact of subliminal messages. Good research and experiments on this topic are hard to find.

Therefore, I want to execute an experiment on this topic. To do this right, I'm curious what the best ways are to influence someone's decision making via subliminal messages / priming.

Does anyone have experience or helpful research that will increase the chance of successfully persuading people subliminally in my experiment?

For the sake of "Hail Mary" answers: there's a recent (2016) paper by Ruch et al. claiming unprecedented results:

  Subliminal influence did not significantly decay if probed after 25 versus 15 min. This is unprecedented evidence of the longevity and impact of subliminal messages on conscious, rational decision-making.

You could try to replicate their experiment(s).


Which Machine Learning classifiers do humans use? Background: In many situations, people use to classify objects without knowing Machine Learning theory. For example, if small children see an unknown animal in the wild, (s)he tries to classify it as dangerous or not dangerous (based on previous "data").

Question: Obviously, humans use any classifier. My question is: Which?

This is of course a big question and I don't believe that there is a definite answer to it. A very thorough investigation of this matter comes from Rogers and McClelland (2004), who have a developed a parallel distributed theory of acquisition, representation and use of human semantic knowledge. As the name implies, this effort comes from the realm of parallel distributed processing, which is also called connectionism. The books that @DikranMarsupial cited can be seen as the foundations of the field. As far as I understand, the two volumes and their authors (McClelland is only one of them, at least two other important names are David Rumelhart and Geoffrey Hinton) had an enormous impact on the revival of neural networks within cognitive science and on the development of the parallel distributed approach.

Rogers & McClelland (2004) offer an interesting account of how things are grouped into categories, which is what you are asling about. To give a very brief explanation: according to their theory, all objects have certain attributes. For example, a canary has feet, wings and feathers. A robin also has all these things. A pine, on the other hand, has leaves, roots and roots. The same is true for an oak. In reality, there are much more attributes, but this should be enough to make the point.

Objects that tend to covary with one another in a coherent way (because they have similar attributes) are perceived as similar and are classified as belonging to a category, like the canary and the robin. Other objects, that do not covary with those from this first group, but that do covary coherently with other objects, are classified as belonging to another group, like the pine and the oak. It is these coherent categories that are important for classifying objects.

Rogers and McClelland (2004) used a neural network to demonstrate and test their theory. Their findings are consistent with a range of findings from developmental studies. They also have an article, which is basically a short summary of the book (Rogers & McClelland, 2008). If you are interested, you might want to check out this first. The article has peer reviewers commentaries that point out weaknesses of the theory, which is also very interesting.

Since you refered to machine learning in your question: the learning algorithm used in the simulation studies was the backpropagation of error - algorithm. As was also mentioned by @DikranMarsupial, this is not an especially biologically plausible algorithm. Interestingly though, as is also explained in much detail in the book, it is possible to predict the order in which the objects within the training corpus could be classified by an eigenvector decomposition of a special variant of the covariance matrix of the objects. I'm not an expert here, but to me there seems to be a connection to the so called covariance rule (unfortunately I don't have a citation here), which to my knowledge is biologically plausible.

References:

Rogers, T. T, & McClelland, J. L. (2004). Semantic cognition: A parallel distributed processing approach. Cambridge, MA: MIT Press.  PDF
Rogers, Timothy T., & McClelland, J. L. (2008). Précis of Semantic Cognition: A Parallel Distributed Processing Approach. Behavioral and Brain Sciences, 31(06), 689. doi:10.1017/S0140525X0800589X PDF


Does each sensory neuron type have a characteristic spike sequence pattern? Background
It is known that all sensory information is input to the brain as neural spike sequences. Now, to distinguish between the spike sequences generated by retinal red/blue/green cone cells from each other, and these from the cochlear (inner ear) hair cells, and so on, some sort of encoding scheme must be used.
To further clarify, in the case of retinal cone cells, the rate of incident light quanta in a given energy range, is the primary information that is coded. But, if all 3 types of cone cells generated identical responses for a given rate-of-incidence, like the CCD pixels in our digital cameras do, then there would be no way for upstream neurons to tell what type of cone cell a spike sequence came from. Instead, my guess is that, each type of cone cell encodes the rate-of-incidence in its own characteristic way, similar to how different types of musical instruments sound differently, even when playing the same pitch at the same intensity, via timbre.

An oversimplified illustration of Timbre
Question
Is there evidence that each sensory neuron type has a characteristic spike sequence pattern?
Why message type must be encoded in the message itself
During the development of the visual system, the retina, the LGN and the visual cortex develop separately initially and sometime later, axons from the retinal ganglions grow into LGN, and optic radiations from the LGN grow and reach into the cortex. As far as we can tell it is not guaranteed that a specific ganglion will project its axon to a specific neuron in the LGN. All that is guaranteed by the growth process is that ganglions close together will project to LGN neurons that are also close together.
Given this development process, when a higher region say in the V1 receives a spike stream from a neuron somewhere lower, the question arises: how does it know that this spike stream means, red, blue or green? A simple idea that occurred to me from information theory is that the message type could somehow be encoded in the message itself.
Motivation
Evidence for characteristic spike patterns for each sensory neuron type would take us one more step towards understanding qualia, the hard problem of consciousness. My speculation is that qualia are the neuronal analogs of timbre in musical instruments.
Erwin Schrödinger thought we'd never get there. He said, "The sensation of color cannot be accounted for by the physicist's objective picture of light [as] waves [or as quanta]. Could the physiologist account for it, if he had fuller knowledge than he has of the processes in the retina and the nervous processes set up by them in the optical nerve bundles and in the brain? I do not think so."
I guess he's right in the sense that we will never be able to fully wrap our minds around the mysterious and ineffable nature of qualia.
However, evidence of characteristic spike patterns would offer resolutions to qualia related thought experiments, such as Is there something about Mary?, that philosophers seem to be pulling their hair out over.

This is an interesting idea, but I do not think it's correct. One piece of information that goes against the idea is this: auditory information is encoded by both frequency and amplitude modulation of neural spiking. The idea of spiking rate directly correlating with frequency is at odds with the idea of spiking rate containing this sort of "meta" information about the source of the activity.

We know quite a lot about how sensory information is represented in the nervous system. The simple fact of myelinated axons that don't interfere with each other already accounts for the problem you've proposed a solution for.

  if all 3 types of cone cells generated identical responses for a given rate-of-incidence... then there would be no way for upstream neurons to tell what type of cone cell a spike sequence came from

Here I believe is where you've made an error. The transmission of activity from the sensory neuron itself to an upstream neuron inherently conveys information about the sensation. The firing of the sensory neuron is a translation of the external phenomena to an internal neural code. No extra information is needed to represent the source of the activity.

References

Li Liang, L., Lu, T., & Wang, X. (2002) Neural Representations of Sinusoidal Amplitude and Frequency Modulations in the Primary Auditory Cortex of Awake Primates. J. Neurophysiol 87:2237-2261.


what are the components of logical mathematical intelligence? what are the components of logical mathematical intelligence?
The logical mathematic intelligence is one among the multiple intelligences suggested by Howard Gardner. I require the components of the same to make a test to measure logical mathematical intelligence of my students.

This question may be too complex to answer specifically as there are several components that identify Logical-Mathematical intelligence.

In terms of behaviour high LMI people need things to explore and think about, and are often seen as manipulative and often seek new experiences or topic matter to discover.  These people love to experiment, question, figure out and calculate and often excel in logical or mathematical topics (as the name implies).

Testing for this in isolation may prove to be difficult as question sets focusing on logical reasoning and mathematical prowess may be skewed due to several reasons, including insufficient education to master the mathematics and the fact that given time most people have the ability to respond to LMI based questions.  Its is also very common that people may have a high L sub-component and a low M sub-component and vice-versa.

May I suggest a more holistic way of measuring MI in all it's facets, and then extracting the top LMI performers.  There are a few commercial tests and testing bodies that can help you here.


Is it possible to develop immunity to mental health drugs? After watching The Princess Bride, I discovered this word: Mithridatism, "the practice of protecting oneself against a poison by gradually self-administering non-lethal amounts."

Is it possible for people to become immune to mental health drugs after sometime of taking them?

It seems that it is possible.

Norman Sussman, MD (2017) discusses pharmacological and non-pharmacological causes of treatment resistance.

  Treatment resistance is addressed in the latest edition of the [Kaplan and Sadock's] Comprehensive Textbook of Psychiatry as follows: “Some patients fail to respond to repeated trials of medication. No single factor can explain the ineffectiveness of the various interventions in these cases. Strategies in these cases include the use of drug combinations, high-dose therapy, and use of unconventional drugs. Limited evidence is available on the comparative success rates associated with any given strategy (Sadock et al., 2017).” This Special Report on treatment resistance provides expert guidance on how to treat patients who are still unresponsive after multiple unsuccessful attempts at intervention for some common mental disorders. ADHD, PTSD, panic disorder, and bipolar disorder are especially difficult to treat successfully, for a number of reasons...

References

Sadock, B. J., Sadock, V. A., & Ruiz, P. (2017). Kaplan and Sadock's Comprehensive Textbook of Psychiatry 10th ed. Philadelphia: Wolters Kluwer Health/Lippincott Williams & Wilkins.

Sussman, N. (2017). Treatment Resistance in Psychiatry. Psychiatric Times 34(11) Special Report Retrieved from: http://www.psychiatrictimes.com/special-reports/introduction-treatment-resistance-psychiatry


Due to Gestalt Psychology, is the face an illusion? Gestalt Psychology maintains that we perceive a whole from parts, and that we fill in missing gaps.  The "whole" we perceive is more than the sum of parts we perceive - it also involves what our minds add in.

Given this, is the concept of a "face" a result of Gestalt psychology on our minds?  All that's on the face are eyes, ears, a mouth, and a nose.  Yet we combine all these parts (which objectively seem discrete from each other) and come up with the concept of a face (the "whole" in this example).

Is this kind of reasoning correct?

Dependent on your definition of an illusion, there is truth in your claim.

A definition of an illusion is:

  [A] perception, as of visual stimuli (optical illusion) that represents what is perceived in a way different from the way it is in reality.

But then - what is reality?

First off, Bach-y-Rita famously proclaimed, 'We don't see with our eyes, we see with our brains' (Abrams & Winters, 2003). The reason he said that is that everything we perceive is generated within our brain; it's a synthesis of visual information (photons) flowing from the photoreceptors in the eye (rods & cones) to the visual cortices. For instance, color and shape are mere reflections of brain activity. Colors do not exist - the brain synthesizes them by combining information from three classes of photoreceptors, each sensitive to another peak wavelength.

Secondly, the rabbit hole goes a lot deeper than the Gestalt Principles. The retinal image is actively completed by the brain (Ramachandran & Ramachandran, 2005). There are two relatively large gaps in each of our retinae, namely the place where the optic nerve head leaves the retina, called the optic disc, or the blind spot. No sensations, and hence no conscious perceptions can be generated by these regions which are devoid of photoreceptors. Yet, we do not notice those gaps in the visual field, because the brain interpolates what it guesses might be there in the visual field and actively fills up the empty spaces in the conscious image.

As a consequence of this, people suffering from retinal degeneration might not even notice it, only when they start hitting street signs and bump stuff from the table. Even then, they often do not perceive the patchy dead regions in their retinae, instead, they know there must be a gap, because they are hitting things. The brain simply fills the gaps such that they are not noticeable in the visual percept. Nonetheless, entire road signs or entire crystal bowls or glasses on the table might be erased, as the brain simply extends the table image in our minds.

References
- Abrams & Winters, Discover, June 2003
- Ramachandran & Ramachandran, Sci Am, April 2005