title: Is "brain training" effective?

text:
# Question
Title: Is "brain training" effective?
We've had quite a few questions about "brain training" on this site (see questions tagged ). And the effectiveness of "brain training" has been touched on in several questions (this question on the definition of brain training, this question about lumosity, and this question about n-back training).

That said, I agree with @Chuck's suggestion that it might be useful to have a canonical sceptics-style question about the effectiveness of brain training.

### Questions

* What is the effect of completing "brain training"?
* Is there any evidence for domain general benefits to cognitive functioning that extend beyond the specific task practiced?
* Is there anything particularly "neural" or "brain"-like about brain training?
* Is there any evidence that brain training prevents any neurological diseases?

Naturally, it would be good if any answers are backed up by independent scientific empirical research. References to and summaries of recent scientific review articles would also be particularly useful.

# Answer
I believe the hype about brain training got started with Susanne Jaeggi's paper on n-back training and its alleged improvements to fluid intelligence (Gf) and working memory (WM):

The experimental design was called into question by papers that followed and tried to replicate similar results. Most of them could not detect a maintained improvement in WM and Gf. Further, most studies did not find it to generalize to other skill domains.

I'm not sure how to interpret the third question.

Numerous studies have shown that mental stimulation is effective in reducing the risk of Alzheimer's disease. The more interesting question is probably whether brain training can ameliorate attention deficit...
> 9 votes

# Answer
> * What is the effect of completing "brain training"?
> * Is there any evidence for domain general benefits to cognitive functioning that extend beyond the specific task practiced?

Brain training at the very least improves skill levels in the domain being trained. That is now well established. The big challenge is of course to create forms of training whose effects generalize beyond the domain trained. Things have not been so promising to date in this regard. According to one recent study by Adrian Owen (Owen, A., et al., 2010, "Putting brain training to the test". *Nature 465*: 775–779) training effects barely generalize to even near similar domains. The weight of evidence is that as of yet no popular brain training methods can significantly increase mental ability in any domain. The only exciting exceptions are the well established effects of the dual *n*-back task on fluid intelligence (a subtype of intelligence measured using the Raven's matrices test), and the newly emerging relational frame training approach which seems to lead to large increases in full scale IQ, despite the fact that the training does not resemble IQ test content.

> * Is there any evidence that brain training prevents any neurological diseases?

Brain training critics are only too familiar with the ACTIVE studies that have all but dismissed the effects of brain training methods on cognitive decline in the elderly (e.g., Ball, K; Berch DB; Helmers KF; et al., 2002. "Effects of cognitive training interventions with older adults: A randomized controlled trial". *JAMA 288*(18): 2271–81. doi:10.1001/jama.288.18.2271. PMC 2916176. PMID 12425704). The public confusion around this issue stems from the fact that is it is not very well established that keeping our brains and minds active does protect against cognitive decline. The problem is that it is not yet known if brain training alone is sufficient to prevent decline in cognitive abilities as we age. So researchers are not incorrect that brain stimulation may well stem cognitive decline, but it does not follow from this that brain training can produce the same effects as perhaps decades of mental and physical stimulation across a wide variety of contexts. The theory certainly suggest that brain training should be able to have these positive effects, but it is too early to say for sure yet if we have developed techniques that can reliably do this.

> * Is there anything particularly "neural" or "brain"-like about brain training?

Everything we do "trains" our brains. We know this from decades of research on neuroplasticity or "neurogenesis". The problem, however, is that not all forms of mental stimulation lead to neural changes that allow us to perform new skills more easily. If we practice the piano, we get better at the piano, and in so doing our brain changes measurably. But the promise of brain training is that practicing a skill such as piano playing might make us better at math for example. This kind of generalization of skills across domains is not so easy to prove, even though it is now well established that neurogenesis does occur.

The general public is easily fooled that any training that changes our brain and builds grey matter must be good, but fails to understand that this is often of little consequence. More recent behavioral approaches, in the field of Relational Frame Theory are starting to show that generalization can be achieved across skill domains. Using a technique called relational training, researchers are starting to see changes in verbal ability, from training in forms of logical reasoning for example.
> 6 votes

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Tags: cognitive-psychology, learning, brain-training
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# Question
Title: Why do long range axons in mammals travel in white matter tracts?
I am curious to know as to why long range, myelinated axons prefer to convene and form white matter tracts, rather than simply reach its target in an arbitrary fashion. Is there some kind of evolutionary advantage to this phenomena? Or is this an ongoing research question?

# Answer
Wen & Chklovskii (2005) looked at exactly this question through a simulation study. They assumed that the segregation of white and gray matter was the the result of evolutionary pressure to maximize some aspect of connectivity. They tested the idea that simultaneously maximizing interconnectivity (neurons should be able to connect to all other neurons without too many intermediate steps) and minimizing conduction delay (time required for a signal to travel from one neuron to another) would result in the segregation of gray and white matter.

Through computational simulation, they were able to determine that these simultaneous pressure were sufficient to drive the white/gray matter divide. Part of what they were able to show is that, under some simple geometric assumptions, a mixed (homogeneous) design that had white matter interspersed with gray matter led to much higher conduction delays than a segregated design. The basic reason is that when white matter is mixed in with the gray matter, the short-range connections between nearby neurons in gray matter are longer to account for the interference of the white matter tracts.

Wen, Q., and Chklovskii, D.B. (2005). Segregation of the brain into gray and white matter: A design minimizing conduction delays. *PLoS Comput Biol*, *1*(7): e78. doi:10.1371/journal.pcbi.0010078
> 6 votes

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Tags: neuroscience, neural-network
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# Question
Title: Is there a term that describes the personality trait of always desiring more?
I see this kind of trait in **some** of the people who fear the commitment (in a marriage) since they don't want to have to renounce their vows when their feelings toward their spouses change.

I see this kind of trait also in those who go to discos to find a **better** partner, who looks for the **perfection**, who thinks they deserve more, they seem unable to be satisfied with what they have. It happens often with narcissism. I think it's a way to manage anxiety: "I'm not enough, I need external validation, I must be more and more to be sure I will always be loved, because I'm not good.. and the other will realize.. so he must love me really a lot".

Some people prefer not to build a **good** relationship because they are scared to lose the chance for their **better** relationship. Some expect to get **very strong** feelings and emotions from a relationship, and that they will find someone who is able to really "get" them.

**I would call it the illusion of being able to fully satisfy our expectations, without the ability to renounce the things they have, or to be easily satisfied by them.**

What could this phenomenon be named and related to?

# Answer
I'm not entirely sure what you mean by "renounce," but you may find some answers to your question in the fields of **social psychology** and b**ehavioral economics**. The first part of your question describes someone who is **unwilling to commit or make a decision** for fear of losing out on future opportunities. There has been research to indicate that having more options when making a decision is actually stressful and can provoke anxiety (Ackerman, Gross, & Celly, 2014).

One recent study found that individuals who were presented with all options at once were more satisfied than those who were shown options one at at time (Mogilner, Shiv, & Iyengar, 2013). The individuals who were given options one at a time tended to imagine a better, ideal option was yet to come; the authors noted that these participants were less happy with their choices in part because of that hope. The introduction to this paper references several other papers which found that individuals who were focused on possible options were less satisfied with the choices they may and were less likely to stick with those choices because of the hope for "something better." The paper specifically cites several articles which indicate that a person's commitment to their romantic partner is not necessarily influenced by the partner's characteristics, but by the person's focus on other options (Gange´ and Lydon 2001; Johnson and Rusbult 1989; Lydon et al. 1999; Rusbult, Martz, and Agnew 1998). Similarly, Miller (1997) found that awareness of and attention to alternative partners was the highest predictor of failure in romantic relationships.

**How people approach decisions also impacts how they address the options presented.** In choice deferral, a person puts off a decision that requires difficult compromises (such as committing to one partner and thus losing the freedom to continue dating) in order to avoid the negative emotions linked to that decision (Luce, 1998). Some people may be more prone to this behavior than others. **Schwartz** and colleagues (2002) have proposed that people fall into **two groups**: those who seek to maximize their decision by finding the very best option out of choices presented (**maximizers**), and those who have an idea in mind of what would be an "acceptable" option and settle for the first choice that surpasses their expectations (**satisficers**). Maximizers are always on the look out for "the best," are less satisfied with their choices, more likely to "socially compare" their options to others, and more likely to experience regret (Ma & Roese, 2014). Another recent publication proposed that when individuals experience "choice closure," and stop re-evaluating the non-selected alternative options, satisfaction with choice can increase (Gu, Botti, & Farro, 2013).

Again, I am not certain I understood all of your question, but I hope that this provides you with a starting point to find the answer.

Ackerman, D., Gross, B. L., & Celly, K. S. (2014). Having many choice options seems like a great idea, but...: Student perceptions about the level of choice for a project topic in a marketing course. *Journal of Marketing Education.* April, e-pub ahead of print. Doi: 10.1177/0273475314522038

Gagne, F. M., & Lydon, J. E. (2001). Mindset and relationship illusions: The moderating effects of domain specificity and relationship commitment. *Personality and Social Psychology Bulletin, 27*(9), 1144-1155.

Gu, Y., Botti, S., & Faro, D. (2013). Turning the page: The impact of choice closure on satisfaction. *Journal of Consumer Research, 40*(2), 268-283. DOI: 10.1086/670252

Johnson, D. J., & Rusbult, C. E. (1989). Resisting temptation: Devaluation of alternative partners as a means of maintaining commitment in close relationships. *Journal of Personality and Social Psychology, 57*(6), 967-980.

Luce, M. F. (1998). Choosing to avoid: Coping with negatively emotion-laden consumer decisions. *Journal of Consumer Research, 24*, 409-433.

Ma, J., & Roese, N. T. (2014). The maximizing mind-set. *Journal of Consumer Research, 41*(1), 71-92. DOI: 10.1086/674977

Miller, R. S. (1997). Inattentive and contented: Relationship commitment and attention to alternatives. *Journal of Personality and Social Psychology, 37*(4), 758-766.

Mogilner, C., Shiv, B., & Iyengar, S. S. (2013). Eternal quest for the best: Sequential (vs. simultaneous) option presentation undermines choice commitment. *Journal Of Consumer Research, 39*(6), 1300-1312. doi:10.1086/668534

Rusbult, C. E., Martz, J. M., & Agnew, C. R. (1998). The Investment Model Scale: Measuring commitment level, satisfaction level, quality of alternatives, and investment size. *Personal Relationships, 5*(4), 357-391.

Schwartz, B., Ward, A., Monterosso, J., Lyubomirsky, S., White, K., & Lehman, D. R. (2002). Maximizing versus satisficing: Happiness is a matter of choice. *Journal Of Personality And Social Psychology, 83*(5), 1178-1197. doi:10.1037/0022-3514.83.5.1178
> 8 votes

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Tags: cognitive-psychology, social-psychology, personality
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# Question
Title: Do we have a predisposition to view visual stimuli in a clockwise pattern?
I understand that we typically view the center of the image first and then are likely to move on a horizontal axis, but is there evidence that we tend to follow a clockwise path when viewing more complex visual stimuli?

Alternatively, for individuals who speak languages that are read and written from right to left (Urdu, Hebrew, etc.), is there evidence that they tend toward a counterclockwise visual path?

# Answer
> 3 votes
Abed, 1991 found cultural differences in visual scanning patterns that seem to reflect differences in the languages of the cultural groups.

* Individuals from cultures with languages than may be read vertically as opposed to horizontally tended to have more vertical eye movements than individuals from cultures with horizontally-read languages.
* Individuals from cultures with languages that are read right-to-left tended to show more right-to-left eye movements than individuals from cultures with languages that are read left-to-right.

Abed, F. (1991). Cultural influences on visual scanning patterns. *Journal of Cross Cultural Psychology*, *22*(4), 525-534. Link to article.

# Answer
> 1 votes
There is a large body of work researching eye movements and what drives viewing patterns. I'll put in some citations later, but it depends on what you're looking at. Things like viewing perspective can modulate how many vertical/horizontal saccades (eye movements) you make. It can depend on the context of the picture, say a face. Here you'll scan the eyes and then up and down towards the mouth if you're American, whereas research shows some Asian cultures focus more heavily on the mouth. A lot of research goes into scanning of emotional scenes. One in particular showing that in the first few hundred milliseconds we do broad scanning of the image, but then focus on the salient elements, or the 'good parts'. And that patterns of cycling through those interesting features will loop over and over. Basically you want to get your bearings and then pay attention to what may be informative or relevant to you. Now there is some research showing cultural differences due to reading, although there is also evidence against that. A thing such as clockwise viewing seems unlikely. In certain situations though there my be a bias to viewing the top or bottom half of an image more, but this may be attributed to inter-individual differences.

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Tags: perception, vision
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# Question
Title: When does anchoring improve our judgement?
Anchoring is the behavioral pattern where the first piece of information we receive about a situation is what all other data points are compared to. For example, the price of the first menu item we see at dinner, the degree of physical pain experienced when exercising, or perceived positivity or negativity in an interaction with a person -- whatever our first experience of these contexts might be, we're likely to view all information received afterward as being either worse or better than those initial impressions.

When I’ve read about anchoring, its been discussed as a cognitive bias, and it appears to be viewed as a huge blind spot in human reasoning. But if this is such a strong tendency, it must serve us in some contexts (or have served us at one point in time).

So, does anchoring ever improves our judgement, instead of deprecating it?

# Answer
The underlying cognitive process that produces the "anchoring bias" in decision-making is the same one that produces the "primacy and recency effect" in learning and memory. Your attention is drawn to novel, salient and recent stimuli, and are more likely to learn about and remember more about the first example of something and the last (most recent) example of something. This means that you are able to learn and adapt faster than you would be able to under an unbiased learning method; in some situations, you can effectively generalize from only one example (you only have to touch a hot stove once). For real-world situations, this speed of learning gives you an enormous advantage. For an additional set of real- and abstract- cases, you will have the opportunity to revise and improve your anchored estimate with small or zero penalty. In all of these cases, having a fast-learning, pattern-seeking heuristic-based cognitive system beats a slow-learning but unbiased cognitive system (which you still have, running on top of the faster system).

It is less powerful in cases where you are doing abstract numeric reasoning (for which there is no plausible estimate) or are negotiating competitively with another person who is faster/better/more informed/able to deceive you through anchoring or other techniques. In these cases, the drawbacks of the system predominate.
> 2 votes

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Tags: perception, behaviorism
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# Question
Title: Is sleep time related to any other characteristic?
Some people say that smart people sleep less, other say that smart people sleep more. I also heard that Napoleon used to sleep 4h/day.

Is sleep-time related to any other characteristics like intelligence, strength, etc. ?

# Answer
Both sleep time, onset and duration have been correlated in various studies, some hard and some soft with intelligence.

This study suggests that the more intelligent people tend to be night owls, and stay up later in the day. This is somewhat related to intelligent people tending to seek out things that are not the "norm" for stimulation.

Related to that, is a theory that smart people need less sleep, as their brains are more efficient while they are asleep. This study bears that out, as a group of 60 children from 7 to 11 years old exhibited higher cognitive function when getting less sleep.

Both of these tend to bear out the perception that smart people sleep less. Napoleon is estimated to have an IQ of 145, using various estimations of accomplishments versus age.

Conversely, physical activity is known for needing higher amounts of sleep, and lack of sleep can impact both physical and mental recovery. This study with basketball players showed both mental and physical improvements with extended (10 hour) sleep periods. However, I could not find anything suggesting that stronger people slept more or less as a condition of being strong.
> 3 votes

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Tags: sleep
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# Question
Title: What do we mean by saying: Narcissist are not empathetic?
I was amazed by finding out the dark triad But I have a doubt. I know some "narcissists" and I would not say that they cannot see other people emotions. I would say that they think they have the right to disrespect them or they cannot realize when they are disrespectful.

For example, I imagine the following beliefs from a narcyssist: People have to make effort Who doesn't make effort doesn't deserve pity

Or

Bullism is very bad Who is a bullist doen't deserve to live

Of course seeing emotions and respecting them is really different.. Narcyssism is ONLY about not perceiving other emotions?

# Answer
> 5 votes
The people you know may have narcissictic personality traits, but that doesn't mean that they meet all the criteria. Criteria lists can be very confusing. Most of the time, people who are diagnosed with mental illnesses *don't* meet all the clinical criteria, even if their pathology is quite severe.

I don't think the statements you give are necessarily narcissitic. A statement that describes the style of lack of empathy of a narcissicist might be something like, "I don't care if you want to eat pasta, because I want to eat sushi and what I want is more important." This is how psychology usually describes lack of empathy: a pathological inability to recognize that other people's feelings are equally as valid as one's own.

At any rate, lack of empathy is only one of several features of narcissicistic personality.

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Tags: clinical-psychology
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# Question
Title: How to temporarily induce low latent inhibition?
As the Wikipedia article says,

> High levels of the neurotransmitter dopamine (or its agonists) in the ventral tegmental area of the brain have been shown to decrease latent inhibition. Certain dysfunctions of the neurotransmitters glutamate, serotonin and acetylcholine have also been implicated.

Is it possible to decrease latent inhibition outside the laboratory using widely available products (such as certain foods or drugs) or regimens?

# Answer
Matt has the right direction but it's not the whole answer. As he explains, taking a metabolic precursor to dopamine will increase the amount of dopamine available to the brain. L-Dopa, tyrosine and tyrosine's precursor phenylalanine are possibilities.

Even if taking any of these precursors may raise the amount of dopamine available to the brain, it doesn't mean that significantly higher than baseline levels of dopamine will be released into synapses for an extended period. There's a few studies on the subject.

Although supplements alone won't necessarily decrease latent inhibition, other drugs can potentiate their effect.

The line you quoted from Wikipedia cites its source as a study which actually answers your question. In the study, administration of amphetamine disrupted visual latent inhibition in study subjects. Amphetamine is known as a reuptake inhibitor, and inhibits the re-uptake, or recycling process of various neurotransmitters, including dopamine, causing them to continually activate receptors.

Phenylalanine, tyrosine, and caffeine: caffeine is a stimulant and has been shown to increase dopamine release, supplementation of dopamine precursors ensures that there's extra dopamine to go around. Check your 5 hour energy ingredient label, they use this technique.

Another brain system to research would be the endocannabinoid system. The effect of the stimulant drugs which we just covered are actually blocked when cannabinoid receptors are blocked, suggesting the dopamine system is not the only variable in low latent inhibition. THC is a chemical that you've probably heard about, which activates cannabinoid receptors in the brain. THC can increase an individual's ability to link disparate ideas and concepts, and its use has shown to correlate with a slight increased risk for schizophrenia, a form of psychosis which some believe is related to too little latent inhibition.

I don't know of a study that directly links cannabinoids and latent inhibition.
> 7 votes

# Answer
According to your snippet, increasing dopamine in the brain will decrease latent inhibition.

Dopamine is produced in the body from the chemical L-dopa.

Wikpedia states that dopamine will not cross the blood-brain barrier, so to increase dopamine levels in the brain L-dopa must be used.

Wikipedia also says that there is a herbal extract containing L-dopa called velvet bean. Wikipedia provides another solution, which uses the amino acid Tyrosine which is the precursor to L-dopa, as well as dopamine, adrenaline and noradrenaline. So, be aware that use of this amino acid won't just increase your L-dopa levels.

A red herring I found were melanocytes, which produce L-dopa as part of the melanin synthetic cascade, however the amount produced is negligible.

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Aside from chemical alteration, what lowering latent inhibition entails is ignoring fewer things. Making cognitive filters less strict. Essentially this becomes a problem of attention - how to attended to things that haven't helped (haven't been reinforced) in similar situations.

It just so happens that there is a psychological phenomenon called latent learning. The classic experiment is one where some rats are allowed to roam freely in a maze with no objective, while the rest aren't. Later, when each rat is put into the maze to find food, the ones that have previously been in the maze find food more quickly. The rats learnt about the maze without reinforcement.

I would therefore suggest that to decrease latent inhibition you must deliberately pay more attention to your surroundings.
> 7 votes

# Answer
It isn't humanly possible to pay more attention to your surroundings to level like someone who has LLI can. I have LLI and saying that people can make a conscious decision to absorb more in their surroundings is like telling someone they can breath more oxygen than their lungs normally can by thinking really hard about it. It isn't possible to induce LLI and it can only be something you are born with. You can train yourself to be more aware of your surroundings, but your body will naturally block out the stimuli after it reaches its natural max. People with LLI can't block out incoming stimuli which is why sometimes it can lead to severe mental illness.
> 1 votes

# Answer
I wouldn't recommend anyone purposefully attempting to induce low latent inhibition as if they haven't lived with it their entire lives, it will be extremely overwhelming for their brain as it basically wont at all be used to handling the sheer volume of stimuli. That is often why those who smoke marijuana can experience paranoia, they have lowered their latent inhibition by taking marijuana due to the dopamine and THC, and their brain then starts to pick up on forms of stimuli it doesn't usually - for example the person may notice sounds that they haven't previously noticed and will usually assume those sounds are to do with them as an individual (hence bringing about paranoia). Someone who's lived with LLI in the same circumstance as the one mentioned above would however have been noticing those sounds their entire life and would be able to objectively categorize them rather than experiencing the sort of "What are these sounds to do with me and why are they now here" effect. The sounds have always been there, they just haven't noticed them without having low latent inhibition.

That is what life is like for those with low latent inhibition - they notice things all around them that the majority of others simply do not.
> 1 votes

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Tags: perception, psychopharmacology
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# Question
Title: Variables in positive reinforcement in human beings
I've been thinking about positive reinforcement occasionally, and I've always found myself wondering about various things that can influence it.

So, I'm looking for information (results of empirical studies) about the variables affecting positive reinforcement, in hopes of finding answers to my questions and questions that I haven't even thought of, such as:

1. How does knowing what the positive stimulus is for affect the change? What happens if I did two things, and I don't know which one of them led to the positive stimulus? e.g. I solved a math problem and won some game, and then I received a prize, and I don't know for which one of these things

What happens If (as far as I'm concerned) I did nothing, and then I receive a prize?

1. If I receive a prize for something I did an hour earlier, for example, will it still change my behavior?
2. Does receiving a prize while I do a task has a stronger effect? weaker?

Any other interesting questions (as well as answers to them) are welcome

(And since someone is probably going to make a few changes and add tags - thank you and forgive me. English is not my native language, and I don't have much of a background in psychology)

# Answer
> 2 votes
Your question is, in essence, a request for a mathematical model of Temporal Difference Reinforcement Learning. In a nutshell, temporal difference models add a notion of time to reinforcement learning models, which describe reinforcement learning as a comparison between what was expected and what actually occurred.

I think most of your answers can be found in the article above. =)

**Edit** re: my insistence on mathematical models providing the answer to your question:

Just to be clear, mathematical models don't exist in a vaccuum. *Good* models are:

1. built from constraints imposed by experimental observation
2. tractable; that is, they reflect the (presumed) underlying implementation

Case and point, the Rescorla-Wagner model's1 `delta` (prediction error) parameter has been correlated to the phasic activity of dopaminergic neurons. This is precisely why the model is so hugely successful; it describes not only the experimental data, but the apparent neurological underpinnings, at least superficially.

Note that this is a very important kind of validity for neurological models, so much so, in fact, that there is an entire class of neuroimaging papers dedicated to finding functional activations that correspond to various parameters in such high-quality models. Exhibit B.

I think your confusion arises from a lack of familiarity with the modelling approach to cognitive neuroscience (and that's okay! It's not obvious!), as well as a non-trivial distinction between the questions "what happens", "how does it happen" and "where does it happen". You specifically asked *what* happens, which is the realm of formal mathematics. *What happens*, as best we can tell, is that learning is driven by updating a prediction about what will happen concomitantly with (or shortly after) a stimulus, with what *actually happens when that stimulus is sensed*. The models describe the exact nature of this interaction. If you want to be more specific than this, you need to dive into the math. If you want to know where or how these computations are performed, then that's another question entirely.

**1.** this model doesn't integrate any notion of time, contrary to the above TDRL model

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Tags: cognitive-psychology, positive-psychology
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# Question
Title: Are there any proven ways to increase concentration and focus?
There are lots of popular articles out there giving listings of steps one can do to concentrate and focus better. But they seldom or never give links to studies that prove any of the steps work, at least to back up their lists.

I want to know if science proved that any of the possible exercises, diets, behavior changes, etc. can do something positive for the concentration and focus?

I don't have much access to certain studies, and I'm not even competent enough to read those science papers. So I need someone, who already read about this (so he/she knows where to look and isn't bothered much) to explain to me in plain english (not to plain) what can I do on my own to increase concentration and focus. What is proven to work.

NOTE: Tag appropriately if needed. Thank you :)

# Answer
> 2 votes
Spark: The Revolutionary New Science of Exercise and the Brain details a number of studies that link exercise to concentration and students' results. The accompanying website is a good primer.

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Tags: concentration
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# Question
Title: How does an understanding of the brain explain why people experience strong emotional responses to major sporting events?
Anyone know studies or theories that explain how massive competition events between countries or parties, like the Soccer World Cup Tournament finals or Olympic Games affect our brains? Why do people suffer so much over these events?

I want to understand the fact that people get so excited or so depressed about that events that have no real impact in their lives. Seeing people cry because their teams lose is incredible, and I think that these reactions are unconscious and must have an explanation involving how these events affect out brains.

# Answer
This is only a partial answer (since the question scope is so large) but it is one of my favorite empirical findings.

It turns out that simply *watching* your favorite team win or lose has physiological impacts. Specifically, if a team you are rooting for wins, your testosterone levels will increase, and they will decrease if your team loses. This was demonstrated by Bernhardt, Dabbs Jr., Fielden, & Lutter (1998). In two experiments, they measured testosterone levels in male sports fans before and after watching their team win or lose. In both experiments, people who were rooting for the winning team showed an increase in testosterone relative to their testosterone level before the match, while people who were rooting for the losing team showed a corresponding decrease in testosterone.

This doesn't explain *why* we get so invested in sports, but it might help us understand some of the extreme reactions that sports fans have after a particularly exciting match.
> 1 votes

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Tags: social-psychology, neuroscience, emotion, cognitive-neuroscience
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# Question
Title: Is there a method to count objects without a pattern?
Is there a method in mnemonics to quickly find out the number of objects in, for example, a heap of tooth picks.

There is this scene in the movie *Rain Man*, where the autistic protagonist can tell the number of toothpicks at a glance. Is something similar possible for "normal" people with the right kind of training or technique?

# Answer
> 2 votes
The act of perceiving quantity without actually counting is known as subitizing, and it's something we can all do up to quantities of about 4 (i.e. you can tell how many fingers someone is holding up without counting them, right?).

This open access article seems to review the idea quite nicely (although I've only skimmed it), including reference to so called "savants". There's also this paper, claiming that transcranial magnetic stimulation can temporarily induce subitizing abilities for larger numbers in participants, though personally I'm dubious.

Finally, to the best of my knowledge, the original, and definitive account of this ability (on which the scene in Rain Man was apparently based; Kim Peek, the inspiration for most of the film, apparently didn't couldn't, or didn't subitize like this) was by Oliver Sachs, in this wonderful book, but basically summarized in this article. If you really are interested, I can't recommend the book strongly enough, it's the reason I did psychology in the first place. It should probably be noted that I've heard criticisms of Sachs' account of the Twins somewhere, but I can't currently find a reference for them, so I don't think it's universally accepted that anyone **can** actually do this in reality.

# Answer
> 0 votes
No. This amazing ability is not well explained nowadays and it is a characteristic of individuals usually called the idiot savants. Most of them suffer from autism. One of the explanations is about their extreme attention and memory to details.

# Answer
> 0 votes
This is typical of a group of people that have what is properly known as savant syndrome. It is not limited to autistic people, although it is most prevalent among them. People that display these abilities are usually elevated on the autism scale, and have had some sort of traumatic brain injury or neurodevelopmental disorders.

Unfortunately, the methods by which they appear and function are not understood, although several theories (usually regarding the lower functions of the brain, inaccessible to normal conscious control) have tried to explain it.

The term "idiot savant" was originally used starting in the late 1800s, but isn't used now because not all savants fit the definition of idiot (severe mental retardation). While most savants are limited in scope of ability (i.e. one or two abilities), there have been some with multiple. The character in *Rain Man* is based on one, Kim Peek.

As far as mnemonics go, there have been many methods developed for being able to do things quickly (such as reading or memorizing items), but none have been able to approach the speed and completeness of a savant's ability.

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Tags: memory, measurement, procedural-memory
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# Question
Title: Best way to capture effect of making people upset?
I am an undergrad, I am planning to do some research to see how much I enjoy it before I apply for grad programs.

I am researching the effects of a certain characteristic of a presenter making people upset, uncomfortable, aggravated or displeased during a short clip like a TV commercial. My plan is to have subjects watch a short clip with a presenter and see if they are they aggravated, upset, uncomfortable with the presenter based on that one characteristic changing and compare this across demographics. I do not have much experience with setting up and performing experiments so any help would be much appreciated.

How do I quantify how upset, uncomfortable, aggravated or displeased the subject felt?

How do I make sure that every subjects experience is the same expect for that one factor?

Do I have to do anything special because I will not be able to run the same test on the same exact subject?

I really want to know how to best perform this experiment.

# Answer
> 2 votes
Without knowing exactly what the factor you are interested in is, it is hard to predict how feasible it would be to manipulate it. For example, is it possible to make two videos of the speaker, one with the factor, and one without, with nothing else changing? My guess is that you probably can't do this, so I'm going to focus on how you might be able to run the experiment without that kind of very specific control.

One option would be to make several videos, half of them with the critical factor, and half without. There will be lots of other things that vary between these videos, but as long as the only thing that varies systematically is the factor you are interested in, then you can run an informative experiment.

You asked: How do I make sure that every subjects experience is the same expect for that one factor? The answer is that you can't really do this. You can try to get close, but subjects will always have slightly different experiences. This is why we need to run many subjects to determine if an effect is reliable. Any given subject may just be tired/hungry/cranky when they come to the experiment and this will affect your results. But, if you run lots of subjects then it is likely that tired/hungry/cranky subjects will be in both conditions, and therefore on average won't impact your conclusions.

Depending on how long the videos are, you could potentially show multiple videos to a single subject, and measure their emotional responses to each one. This is a within-subject design, and the advantage of this is that it controls for some of the random variation (tired/hungry/crankiness) between different subjects in your experiment. If subject A tends to be crankier than subject B, it will introduce noise into your results if each subject only sees one kind of video. But if subjects see both kinds of videos, you can test whether videos with the factor tended to make subjects more aggravated, controlling for their 'baseline' level of aggravation. If the videos are longer, then you could just show one kind of video to each subject (a between-subjects design) but this will probably require collecting data from more subjects to wash out the noise of some subjects being more prone to aggravation than others.

# Answer
> 1 votes
Polygraph-style measurements might be useful to get some hard data - emotional excitement and stress have biological effects, and measuring+recording heart rate and blood pressure can be done rather simply.

For qualitative analysis, it would be useful to capture as much as you can of the experiment - e.g. a video recording of the face to analyse expression changes, as well as a whole body video recording. You also need to have a solid way to sync the recording with the shown stimulus, so you can match the event times afterwards.

# Answer
> 0 votes
I see you want to measure reactions based on viewing a clip by demographics.

> How do I quantify how upset, uncomfortable, aggravated or displeased the subject felt?

You quantify it by gathering hard data: heart rate, blood pressure, pupil dilation (if you can get it in the video), and whatever other similar experiments have measured. You have a standard questionnaire. But you should also attempt to get some qualitative data.

> How do I make sure that every subjects experience is the same except for that one factor?

You do the best you can, document any possible failure points, and have a system to randomize who gets what.

> Do I have to do anything special because I will not be able to run the same test on the same exact subject?

You should review the literature on these types of experiments and try to follow the safeguards other experimenters used. I recall a leading theoretician complained that no-one follows the safeguards established by the person who established different ways rats had of sensing where the food was. You've got to take great pains to ensure you follow the best practices of doing this research, or you'll undermine your credibility as a researcher and the credibility of your results.

# Answer
> 0 votes
Another experimental approach is to have the subjects perform some task *before and after viewing the video*, where their individual task performance varies according to the subject's emotional state: comfort vs discomfort, relaxation vs agitation, calm vs upset. Ideally, the task is simple and not something that involves thought or skill. In this setup, your goal is to have subjects reveal their emotional state through their performance in this task, and not through any direct revelation or awareness.

The other advantage of this approach is that you aren't signaling to the subjects that you are testing for their emotional state.

An example of such a task is interpreting the emotional state of another person's facial expression. For example, the task might be to evaluate a series of photos with ambiguous facial expressions and put them into two categories: "Trusted" vs. "Not trusted". (You can put this in a simple setting: "Imagine that you are in the library. You need to step outside to take a call. Would you trust this person to watch your valuables (computers, books) for a few minutes?")

Though I don't have a reference for you, I believe I read some research on this that found that subjects were more likely to interpret ambiguous facial expressions positively if the subject was in a positive emotional state.

There are even simpler tasks that might be good candidates. You could probably find a list of candidates by reading the experimental research literature.

Again, all you care about in this experiment is the *difference* between each individual's performance when they are upset vs. at ease.

You can test the validity of this experimental method independently. Recruit some subjects for a randomized control trial. Instead of showing them the video, you will directly irritate them (stimulus group) or not (control group). Your stimulus could be 15 second audio recording of fingernails scraping over a blackboard. For the control, you could use 15 second audio recording of a sin wave tone (around 400 hz). Your performance on pre- and post-tasks should be very different for the stimulus group and show no change in the control group. (For best results, you should randomly assign subjects to groups, and even you should not know who is in what group -- "double blind".)

The besides validity testing, this experiment will give you a standard of comparison to evaluate just how irritating or upsetting your videos are, compared to fingernails scraping over a blackboard.

**EDIT**: If you know the TV show "Mythbusters", they have done experiments involving sleep deprivation and also drinking where the subjects had to perform the same task before and after the stimulus. As I recall, the "beer goggles" episode involved a task of scoring faces for attractiveness before and after drinking heavily.

**EDIT**: The other answers advise you to measure physiological phenomena through direct sensors. Even if you can get the sensors and data recorders, analyzing the data can be more complicated than it sounds. It's not so easy to aggregate those data into a reliable overall assessment of emotional state along a single dimension: at ease vs upset. Inferring emotional state from physiological variables is a whole research field in itself!

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Tags: emotion, measurement, methodology
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# Question
Title: How higher/lower taxes can affect reward system and overall satisfaction of someone
I'm curious about how the tax system affects the reward center in the brain and how that influences the perception of happiness with one's life.

My hypothesis is that subject `A` would make \\$3500 a month doing something he/she loves in a city he/she likes, etc. The subject pays a 20% overall tax in order to receive the \\$3500, so the actual value before tax would be \\$4200. Subject `B` makes the same amount of money, doing exactly the same in the same city, etc. What I'm interested in is in isolating the tax variable, so in this case Subject `B` would pay 50% tax (that would make it $7000 before tax).

So both subjects have the same life-style and make the same amount of money, but what I'm guessing is that `A` feels more rewarded than `B`, and if so, Subject `B` would feel more entitled to pursue more money (reward) because he feels that the reward is lower than what he should be getting. By pursuing this extra reward then, Subject `B` would fall into the trap of constantly struggling to feel rewarded (because of the high tax value marked on his payslip and this alone). On the other hand, to prove that Subject `A` was "happier", we could actually launch a second hypothesis where `A` would make \\$3000 and `B` the same \\$3500, and `A` would again feel more rewarded because of the lower tax rate he paid to get his salary (20% on `A` vs. 50% on `B`).

This in turn would open a bunch of other interesting questions, like how to navigate the thin, invisible line that might trigger minor/major complaints on people about the feeling of being happy with their salary/government.

My question then is: has this been studied in depth before (I imagine so), and if so, where can I read about it?

# Answer
This is pretty close to being a classic example of a **framing effect** (wikipedia), originally described in the literature by Tversky & Kahneman (1986).

In essence, our subjective valuation of a choice or outcome isn't invariant, as economic theory says it should be, but instead *is influenced by contextual effects, such as **riskiness**, and if the outcome is **seen as a loss or a gain**.*

I don't know much specifically about framing effects and framing effects and taxation, and haven't time to do any research, but a Google Scholar search for the terms throws up this and this, among other articles, which seem to cover what you're talking about (although they may be behind a paywall, I don't know).

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Looking back at your question, your hypothesis seems about right: while both people end up with the same amount of money, person B will perceive a greater loss due to taxation, and so, when both are thinking about their earning from this perspective, should be less satisfied.

However, if decades of research have shown us one thing, it's that high-level cognitive effects like this are extremely context dependent. What happens when both individuals aren't thinking about their income in terms of taxation, but with reference to the minimum, or average, wage in that region? Or what if the comparison happens in a context where public services, like education, are salient? Would person B be happier, because they feel they have contributed more to their community? Where I'm going with this basically that psychology can be **very very hard**, and that context **always** matters.
> 2 votes

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Tags: social-psychology, perception, emotion, economics
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title: NEO-FFI $t$-score calculation

text:
# Question
Title: NEO-FFI $t$-score calculation
I am a CS student who has to do an analysis on the NEO-FFI test. I have the results of the questionnaire, however, I couldn't find how to calculate *t*-scores or raw scores. There are lots of academic papers, but no one has the calculations in them.

There is an example from McCrae's paper. Like in this example, I have the answers, but can't calculate the scores.

# Answer
### NEO FFI Scoring

The test manual describes how to calculate raw scores for the NEO-FFI. If you have been asked to do an analysis of the NEO-FFI then you should be given access to relevant details in the test manual. If you don't have access, you may wish to contact your local psychology department. They will often have a test library with the NEO-FFI manual. Alternatively, you can contact a test distributor, although there are often educational requirements in order to be allowed to purchase such a manual.

This website seems to provide a web description of how to obtain raw scores for the NEO FFI. For norm referenced scores such as t-scores, presumably you would need access to norm tables supplied in the test manual. One exception would be where you are using your own sample norms as the distribution. In this case of t-scores, you would convert raw scores to z-scores and then multiply by 10 and then add 50. See for example this article on standard scores.

### General scoring advice

In general, when scoring psychological tests, the most common approach is to use a unit weighted sum or mean of items after item reversal. I have a post that describes this in more detail with reference to SPSS and R. So, you simply need to know which items belong to which scales and which items need reversing.
> 2 votes

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Tags: personality, test, statistics
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# Question
Title: What indicates an extreme worry about privacy?
Some persons pretends that to be curious of other's people life facts is disrespectful.

I imagined that this belief comes from coherence and a projection on others of our worrying about privacy.

I'm strongly worried about my privacy =\> others could be as well =\> curiosity is disrespectful

Is this hypothesis correct?

# Answer
I'm by no means an expert or qualified, but here's my thoughts. I believe there are a few factors at play:

**Our Privacy**

The first is the perception that the information carries some threat to their lifestyle or reputation, e.g. an adult who views pornography or a cheating spouse, for both of whom this causes that initial concern of the threat of exposure (and we may over-estimate their impact upon exposure as a form of impact bias).

Second, narcissism: they're worried their actions could be considered damaging to their image and believe that those who invade their privacy (a government / a social network selling aggregate topic stats to marketers, etc.) would take great delight in exposing their behaviour. Of course they wouldn't, but people generally like to think their own lives are of importance to everyone, and so why wouldn't their "important" secrets be of importance to everyone else?

**Others' Privacy**

First I'll throw in that the person may remember the last time they were burnt by their privacy being invaded by others (such as malicious gossip), which may serve as a negative reinforcement to not infringe on others'. You remember the last time and how much it hurt you and don't wish to knowingly inflict that on someone else, especially for no personal gain.

There is also the thought that if we do a good deed that others will reward us for it...or if we deem ourselves to have done something selfless, we derive gratification from it. This is also closely linked to narcissism. I read something ages ago that inferred there is never a truly selfless act, as we often do it to feed our ego.

If legislative changes are made to protect privacy generally (e.g. social networks' usage of private messages are tightly controlled), then we also could benefit from this, so there is also potentially some selfish gain in concern over other people's privacy, and we can project how we are annoyed at a particular company doing something with our data on "behalf of a friend".

Finally, if we believe strongly that our own "privacy" is important (when in reality most people are just referring to morally questionable behaviour they would like to suppress), then we also see others' as just as important as some way to justify that our own belief in the protection of our privacy is founded. A "bias blind spot" and "confirmation bias" appear in the list of cognitive biases.
> 2 votes

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Tags: cognitive-psychology
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# Question
Title: What is the impact of showing the amount of unattended notifications to the user?
What is the difference in cognitive effects on the user between simply showing that there are 'some' unattended notifications, or showing how many notifications there are?

Take Facebook's notification count for example,

as opposed to Windows' PC issues notification in the system tray.

Of course depending on what the notification is notifying you of, people will respond differently, which is not something I'm interested in. However, I suspect there could be a difference based on where it is being displayed, e.g. whether it is always visible or not. Would one be preferred over the other in different situations?

I'm mainly interested in a comparative study between the two, but any research which might give additional insights in the two separate representations would help me out as well.

# Answer
For me it is the inference that the more notifications I have the more value I will have in bothering to click it.

That 1 notification on a social networking site might be a request to play some terrible game.. however 24 notifications are likely to yield at least something beneficial for me to justify having bothered clicking it.

The higher the number the increased urgency I feel to check them (maybe the same person is repeatedly trying to make contact and I am unintentionally ignoring them!).

As for there being a notification with no number, that is easier for me to ignore. In the case of the Windows' PC issues (Action Center) in the task-bar, there is always a notification in it for me, so I have learnt to dismiss it.. I have become de-sensitised to seeing that alert. If however the icon increased in number and I detected this change, then I would deem that to be an increase in urgency and would be more likely to click it again.

I think if I kept clicking Action Center and felt it yielded little value to me then I would be able to filter out if the numbers were to keep increasing, but I would find it more difficult to ignore and feel tricked by it just in-case this new state meant something important this time round..
> 1 votes

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Tags: cognitive-psychology, hci
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# Question
Title: A type of long-term memory where I can remember full dialogues
My female colleague cannot remember a discussion (dialogue) from a couple days ago or even yesterday, much less the full, exact sentences spoken. She jokes about having sclerosis. I can remember many dialogues from the last couple of years and even further, including the exact sentences – not all the dialogues from my life, but like 80% of those which were interesting, odd, or very funny, or made at least small impact in my life. Is this kind of long memory normal in people? Does it have a name? Thanks.

# Answer
the cognitive skills of a human population have a great variance. I am more like your friend, with episodic memory below average but semantic memory above average. You seem to have episodic memory above average (I envy you on that, because a large part of our feeling of self identity depends on episodic memory). There are extreme cases of people that remember almost everything they experience or read, or hear. A nice book on the topic is Luria's book "the mind of a mnemonist". It is a short book, and I'm sure you'll find it pretty interesting.
> 2 votes

# Answer
The remembering of specific events is known as Episodic memory, and you can find plenty about it online. It's usually contrasted with Semantic memory, which is generalized knowledge such as that "Paris is the capital of France".

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I'm going to leave it to other users, or myself at a later date, to provide additional references/explanation, but those are the terms you're looking for.
> 1 votes

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Tags: memory, long-term-memory
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# Question
Title: What study showed that humans can successfully detect objects within images once they are able to recognize those objects?
A professor in an online lecture I was watching referenced a study which he said showed that our ability as humans to detect objects within scenes (especially complex scenes) was very much connected with our familiarity to the objects in the scene.

In particular, one of the images in the study was this one:

He said that the study reported that if the subjects had never seen a dalmation before then they often failed to segment the picture accurately.

# Answer
Using Google's search by image feature, I found that the image is usually entitled Richard Gregory dalmatian.

From there, I found this page, which cites the image as coming from Gregory's 1970 book *The Intelligent Eye*. There's also, incidentally, a good list of Gregory's publications on this personal web page, which is probably worth looking at.

From a theoretical perspective, the image is a demonstration of the role of top-down expectations in perception - we see not what's there, but a combination of the input to our retinas and what our prior knowledge tells us should be there. This is a case of Bayesian perception, and can be read up on in Kersten et al (2004), amongst many other places.
> 3 votes

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Tags: cognitive-psychology, perception, reference-request, vision
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# Question
Title: Difference between brain disease and brain disorder
Is there any difference between the terms `brain disease` and `brain disorder`? They are often used in combination without specifying the difference, e.g. here.

# Answer
> 3 votes
There are many who will tell you authoritatively that a disease is acquired (e.g. infection, cancer, etc.) whereas disorder is something curable or genetic. These are imprecise and untrue. Basically a disturbance in normal functioning can be either a disorder or a disease, regardless of it's curability or method of acquisition.

From your link, the second entry (for acid lipase disease) contains this information:

> Two rare lipid storage *diseases* are caused by the deficiency of the enzyme lysosomal acid lipase: Wolman’s *disease*... is an autosomal recessive *disorder*... Infants with the *disorder* appear normal at birth... Cholesteryl ester storage *disease* (CESD) is an extremely rare *disorder*...

and

> Alexander *disease* is one of a group of neurological conditions known as the leukodystrophies, *disorders* that are the result of abnormalities in myelin... Alexander disease is a progressive and often fatal disease.

This might lead you to deduce that the disease is the manifestation, whereas disorder is the source. Though I would say that this is as close to a real distinction you'll find, even that doesn't consistently hold up. We talk about infectious *diseases* though we know the etiology and pathology, and inherited *diseases* and *disorders*. Mental *diseases* are mostly *disorders* regardless of their genetics.

The truth is that nomenclature is subjective. It has something to do with history (if the person who discovers or elucidates the disorder an illness names it a disease, a disease it will tend to remain, e.g. Huntington's disease/Crohn's disease), precedent, and advances in understanding. I think there is a tendency to name things *disorders* today, as *disease* carries certain connotations. It is all very subjective.

Edited to add: no disease or disorder occurs without some change in underlying structure. Creutzfeldt-Jakob disease (closely related to Bovine Spongiform Encephalopathy - also known as Mad Cow Disease) occurs in an inherited form, a sporadic form, and a transmitted form. In all cases, the etiologic agent is thought to be a self-replicating tiny bit of protein called a prion. Prions occur normally, and are replicated and broken down. When the abnormal prion (same chemical structure but a different spatial structure) is introduced, this new prion, because of it's different shape, cannot be broken down, accumulating in the brain, eventually to the extent that normal brain cells are destroyed by the stores of prion within the brain. The same can be said of any illness: something of normal order is disturbed (e.g. smokers and Chronic Obstructive Pulmonary Disease.)

# Answer
> 1 votes
The Oxford English Dictionary lists the following definitions:

> **disease, *n.***
>
> 1 Absence of ease; uneasiness, discomfort; inconvenience, annoyance; disquiet, disturbance; trouble. (For long *Obs.* but revived in modern use with the spelling dis-ease.)
>
> 2 A condition of the body, or of some part or organ of the body, in which its functions are disturbed or deranged; a morbid physical condition; ‘a departure from the state of health, especially when caused by structural change’ *(New Sydenham Soc. Lexicon)*. Also applied to a disordered condition in plants.
>
> 3 *fig.* A deranged, depraved, or morbid condition (of mind or disposition, of the affairs of a community, etc.); an evil affection or tendency.
>
> **disorder, *n.***
>
> 1-3 Absence or undoing of order or regular arrangement; confusion; confused state or condition. ... Disturbance, commotion, tumult; *esp.* a breach of public order, riot, mutiny, outrage.
>
> †4 Disturbance or agitation of mind, discomposure. *Obs.*
>
> 5 A disturbance of the bodily (or mental) functions; an ailment, disease. (Usually a weaker term than disease *n.*, and not implying structural change.)

As we can see, the common meanings of *disease* and *disorder*, in our context, tend towards:

### Disease

* a physiological dysfunction *caused by structural change*

### Disorder

* a physiological dysfunction *not* caused by structural change, or
* a psychological dysfunction (caused by a physiological dysfunction, learning or the environment)

The use of the words *disease* and *disorder* by medical experts will likely be influenced by this lay meaning of the two words. Here are some definitions given by medical dictionaries:

Dorian, A. F. (1987). *Elsevier's Encyclopaedic Dictionary of Medicine*

> * **disease** Any impairment of the normal state of the organism, interrupting or affecting the performance of its vital functions. More specifically, all physical and mental reactions to some noxious agent, an injury, a defect, a deficiency, or a degenerative process.
> * **disorder** A condition characterized by a derangement of normal functions of the body.

Stedman, T. L. (1995). *Stedman's Medical Dictionary* (26th ed.)

> * **disease** **1.** An interruption, cessation, or disorder of body functions, system, or organs. SYN illness, morbus, sickness. **2.** A morbid entity characterized usually by at least two of these criteria: recognized etiologic agent(s), identifiable group of signs and symptoms, or consistent anatomical alterations. SEE ALSO syndrome. **3.** Literally, dis-ease, the opposite of ease, when something is wrong with a bodily function.
> * **disorder** A disturbance of function, structure, or both, resulting from a genetic or embryologic failure in development or from exogenous factor such as poison, trauma, or disease.

Becker, E. L., et al. (eds). (1986). *International Dictionary of Medicine and Biology*

> * **disease** A condition which alters or interferes with the normal state of an organism and is usually characterised by the abnormal functioning of one or more of the host's systems, parts, or organs. It may be due to an unknown cause or may result from an inherent metabolic or structural deficiency, including congenital and hereditary defects and degenerative processes, or from such factors as stress, noxious stimuli, toxic agents, injury, or infection. A given disease is often manifested by a characteristic set of signs and symptoms, although a host organism can be asymptomatic while having microscopic, serologic, or immuniologic evidence of diseease. • *Disease* is usually distinguished from *injury*, the disruption of an organism's integrity, espeially by an external agent, and often from *syndrome*, a complex of symptoms descriptive of a disorder, especially a particular combination of phenotypic manifestations.
> * **disorder** An alteration of the function or struture of an organ or the body as a whole.

Dorland, W. A. N. (1994). *Dorland's Illustrated Medical Dictionary* (28th ed.)

> * **disease** any deviation from or interruption of the normal structure or function of any part, organ, or system (or combination thereof) of he body that is manifested by a characteristic set of symptoms and signs and whose etiology, pathology, and prognosis may be known or unknown.
> * **disorder** a derangement or abnormality of function; a morbid physical or mental state.

As you can see, medical experts love clear, distinct, and unambiguous, definitions.

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Tags: neuroscience, abnormal-psychology, terminology, clinical-psychology, neurology
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# Question
Title: Importance of Neural Synchrony to Cognition
Is there a consensus on whether computation using Neural Synchrony is reasonable or not? In "How to Build a Brain", Chris Eliasmisth cites Yuko Munakata and R. C. O'Reilly as saying that "the available evidence does not establish that the observed synchrony of firing is actually used for binding,instead of being an epiphenomenon" to dismiss current architectures such as LISA and DORA which use synchrony. Yet, there still seems to be papers published on using neural synchrony for computation. Additionally, Thagard still seems convinced of their importance saying that "spiking neurons have psychologically important qualitative properties such as becoming synchronized with each other, and neural synchrony has been proposed as a crucial ingredient in inference, analogy, and consciousness".

Are the authors of these new papers naive or is there convincing evidence for the meaningfulness of synchrony that Chris and I are missing here?

**References:**

O’Reilly, R. C. & Munakata, Y. (2000).Computational Explorations in Cognitive Neuroscience: Understanding the Mind by Simulating the Brain (1 ed.). Cambridge, MA: The MIT Press.

# Answer
> 11 votes
As you have already hinted at, the issue is controversial. I could leave it at that and say "no, there is no consensus", and it would be a true answer, but it wouldn't be satisfying, wouldn't it? Instead, I'll briefly define the topic, give a few examples, and then a few recent criticisms. My answer will be weighted somewhat towards "cognition" instead of "computation", however different you consider them. It's more of a safari than a good answer I fear, I hope you're getting something out of this.

Neural synchrony is usually used to refer to oscillatory alignment; that means, some sort of oscillation occurs in a population of neurons, for example, an alpha rhythm as a ~10 Hz pulse; and neuronal synchrony is both, on the individual level, the degree to which individual neurons either take part in this oscillations, and/or align their spiking behaviour to certain parts of this oscillation, and on the population level, how other neuronal populations are aligned with this oscillation.

What is doubtlessly true is that the brain is full of oscillations. We know that at the very least since Hans Berger discovered the alpha wave back in the 1920s. When someone closes their eyes, we quickly see the 10 Hz rhythm. But once they open the eyes, or are disturbed in any way, it quickly disappears. Are these oscillations important per se, or just an epiphenomenon? Berger himself assume them to be the direct manifestation of unified brain state. But Berger was a bit of a crank. The well-respected British researcher and Nobel price laureate Lord Adrian who first replicated this finding assumed the 10 Hz rhythm was simply the "idling of the brain", the very absence of computation.

One contemporary researcher who assigns a functional and active role to the alpha rhythm is VanRullen, and I think much of his work is very interesting.

Let's look at some of the rather basic ways how oscillations and timing are relevant in the brain. First, timing in general. Our original understanding of neural communication (in part unveiled by aforementioned Lord Adrian!) focuses on the concept of *rate coding* and *population coding*; the net amount of spiking activity in a neuron, or in a population, is what matters. This is for example what happens in the peripheral nerve cells; when heat or pressure or pain are applied to the skin, the responding neurons directly communicate the degree of heat or pressure or pain by how much they ramp up their firing (at least at first, before Spike Frequency Adaption sets in).

Initially, this was seen as fully consistent with Hebbian learning \- the more one neuron fires, the stronger the synapses with its targets become. But then Bi & Poo discovered Spike-Time Dependent Plasticity (STDP), and now everything is a bit more complicated. Remember Hebb's Law says

> When an axon of cell A is near enough to excite a cell B and repeatedly or persistently takes part in firing it, some growth process or metabolic change takes place in one or both cells such that A's efficiency, as one of the cells firing B, is increased.

Hebb's Law goes beyond saying A has to fire lots. It says, A's firing has to *cause* B's firing. And one component of causation is temporal precedence; so A's firing has to occur before B's firing for increasing synaptic strength. And this is just what Bi & Poo observed; only when A's spikes arrive in a short temporal window *before* B's own spike does Long-Term Potentation occur. If however B's spikes happen a bit before A's spikes, Long-Term *Depression* occurs.

So the temporal order of spikes matters. Neurons causing others to spike gain more influence over them, and neurons who're followers, not leaders are demoted.

Another bound for plasticity is of a neurochemical nature. Levels of catecholamines (neuromodulators) regulate if the hippocampus will encode an incoming stimulus, depending, for example, on its novelty. So *only* if neuromodulator levels are up does incoming information lead to lasting adaptations. During sleep, were we assume reconsolidating to happen, we observe that the brain stem sources of catecholamines (like the neurotransmitter norepinephrin and dopamine) are temporally correlated with the slow wave occurring during sleep. Specifically, Locus Coeruleus neurons spike right at the onset of the transition to the Up state. It seems the cortical oscillation is timed so that active states co-occur with high catecholamine levels. This is a form of temporal coding called *phase coding*. The phase of the ongoing oscillation matters with respect to the incoming spike. It is also observed, for example, in the theta oscillation in the hippocampus. A range of theories exist for a possible function of theta phase locking; examples are that certain theta phases again indicate more receptive states (so that incoming information has a higher chance of being encoded during certain parts of the theta oscillations), or that the part of a theta phase a neuron spikes at indicates how important the information this neuron is encoding is.

Beyond phase coding, we find Singer's very popular *binding by synchrony*. How do to parts of the brain communicate to each other that they are "talking" about the same thing? Well, by alignment in the gamma band, that is, by phase locking of the two populations to the same ~40 Hz rhythm.

**But how believable is all this?**

There are many theoretical objections to specifically high-frequency binding by synchrony. For example, the power of oscillations fall of over distance as a function of its frequency; that means, slow oscillations travel far, but synchrony in fast oscillations cannot be sustained over long distances. (Slow oscillations are simply too slow for *binding by synchrony*.)

Another question is if there are even any gamma oscillations at all, if they are truly clock-like wave patterns or if they are simply a methodological artefact - traces of the sensitivity of the Fourier transformation to asynchronous activity, or *filtered noise*.

At least for humans, gamma band synchrony findings have become strongly suspect as it was shown that these patterns are better explained as the EEG traces of small eye movements or micro-saccades.

But this must not spell the death of all theories for a functional role of timing and oscillations, of all *temporal codes* and *phase codes*. In STDP, we have clear, anatomically sound evidence for the importance of temporal order in spiking, and simple evolutionary principles suggest neuronal populations will exploit such phenomena. However, the field is diverse and controversial. There is no universally accepted phenomenology, methodology, or theory. We have tidbits and fascinating findings, but nothing coherent. Cortical oscillations are sill mostly a riddle.

I think most recent contribution is the discovery of Cross-Frequency Phase Coupling by Canolty et al. They observe that the *amplitude* of the fast (gamma) oscillations depends on the *phase* of the slower theta or delta rhythms. The basic finding is quite similar to the observation of LC spike/cortical state phase coupling noted earlier, but now we observe this in the awake animal. And a clear proposal for a functional role of this mechanism has been made, too; I can simply quote the abstract of Lakatos et al.:

> Whereas gamma-band neuronal oscillations clearly appear integral to visual attention, the role of lower-frequency oscillations is still being debated. Mounting evidence indicates that a key functional property of these oscillations is the rhythmic shifting of excitability in local neuronal ensembles. Here, we show that when attended stimuli are in a rhythmic stream, delta-band oscillations in the primary visual cortex entrain to the rhythm of the stream, resulting in increased response gain for task-relevant events and decreased reaction times. Because of hierarchical cross-frequency coupling, delta phase also determines momentary power in higher-frequency activity. These instrumental functions of low-frequency oscillations support a conceptual framework that integrates numerous earlier findings.

Here is a video presentation on the topic.

Further one type of neural synchrony is spike frequency adaptation, A recent paper tried to explain its relevance for cognitive computing in Here . Many neurons in frontal cortex exert this behavior.

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Tags: neuroscience, reference-request, theoretical-neuroscience, computational-modeling
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title: Why is it hard to simulate a neuron?

text:
# Question
Title: Why is it hard to simulate a neuron?
I read a NY Times article about the European effort to simulate a human brain and the criticism regarding the (non-)feasibility of such an endeavor (not to mention the astronomical costs).

In this article, there's mention of the current inability to simulate the 302 neurons in a nematode brain, so my (layman's) question is simple:

why is it so hard to simulate a neuron?

# Answer
Complexity. That is, the fundamental laws governing the behavior isn't terribly difficult to comprehend or model. However, putting it all together and hoping it reproduces the correct behavior is a great challenge.

Once you develop a model that has the appropriate underlying mechanisms in it's components, you still have to put them all together and choose the right parameters and hope you didn't miss anything in terms of modulators that would actively adjust those parameters. So even if the functional mathematical form of your model is correct, you still have 5-10 parameters for each neuron in the network that you have to get to the right value, including the parameters describing the strength and dynamics of the coupling between neurons. Just being off by values as small as .001 can sometimes mean the difference between a working model and a failing model. Now you have 5-10 parameters for 300 neurons... that's 1500-3000 parameters that all need to be "correct" at the same time.

That being said, it's not like we are exceedingly accurate in our models of even single neurons. We make simplifications and take averages. There's lots of second messenger and genetic processes involved in neuron function that many models neglect. This isn't meant to disparage modeling. It implies that no complex mathematical model will probably ever be able to generalize the neuron for all cases. Instead, we make models focused on asking specific questions. We investigate two or three mechanisms at a time and hold all the other considerations constant in order to isolate those mechanisms we're interested in. So a model I develop to study the effects of the diversity of calcium channels on neuron excitability will have many differences (in parameters selection) from the same model used by somebody studying diversity of potassium channels. And in some cases, we may even simplify less relevant aspects of the model, e.g., I may only have one potassium channel in my neuron to generalize and average all potassium channels so that I can focus only on calcium diversity and not fuss with more parameters.
> 5 votes

# Answer
I don't think it *is* hard to simulate a neuron. See NEURON.

Simulating a *brain* however is a much more difficult (and unaccomplished) task, even if the brain only consists of 302 neurons.
> 0 votes

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Tags: neuroscience, neuroimaging
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# Question
Title: How does the timing work out for dopamine to affect the development of long-term potentiation?
I just recently learned (indirectly from this source) that long-term potentiation/depression only takes place when you have large/small amounts of dopamine present at the relevant synapse. However, my understanding is that early in the process of learning behavior, dopamine isn't released until after a reward is received. If I'm a monkey who has to look one way or the other to get some juice, by the time I drink the juice and get the resulting dopamine, the neurons I used to move my eye are presumably not firing any more, right? So then how does this work? Is it that:

1. There's a slow bootstrapping process. Something like: first the monkey has to learn that the taste of juice leads to the reward of sugar. Then the monkey has to learn that the sight of juice correlates to the taste, and extend the chain one step further, etc., etc., such that by the time you actually have the monkey in the lab there's a very small inferential step needed to plug into a larger reward chain.
2. The neurons don't actually stop firing. There is some sort of system in play that keeps the neurons firing afterwards, waiting for fluctuations in dopamine level to tell it whether or not it should increase or decrease long term potentiation.
3. Something I haven't thought of?

# Answer
> 1 votes
The ability of dopamine to work on different time scales is discussed by Schultz. More generally, the basic idea of prediction error reinforcement based learning and DA is that the prediction error signal "propagates back in time". There is some doubt for how temporally precise this DA signal actually is, and if DA is fast enough to support RPE TD learning.

Does that answer the question?

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Tags: plasticity, ltp, dopamine
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# Question
Title: OCD Motivation and Dopamine Motivation, is there a connection?
I understand that OCD is something that causes sufferers to perform irrational behavour consciously, I also understand that the motivation comes from performing the irrational behaviour/behaviours to release the anxiety experienced.

Although, what causes sufferers to pursue specific goals whether it be career choice, physical achievement, etc. ? According to my (hopefully trustworthy) sources the neurotransmitter "dopamine" plays a huge part in motivation, setting the bar high and making people do whatever it takes to reach that goal of "happiness" or "achievement".

I believe OCD is somewhat related with "serotonin", but all I know is that there is an allele gene Alpha 2 which causes some sort of susceptibility to a few different disorders, OCD being one of them. Does OCD motivation have any correlation with the neurotransmitter "dopamine"? Thanks in advance!

# Answer
Your information is basically sound. Serotonin and dopamine are both neurotransmittors that are connected, in different ways, with positive feelings or elevated mood. The buzzword for dopamine (in this context, as it has many functions) is "reward" - the presence of dopamine in the brain modulates the feeling of satisfaction from achievement, and encourages people to pursue the course of action that produced it. Meanwhile serotonin has been linked to positive moods, for example in clinical depression which is often treated with medication that affects serotonin action in the brain.

OCD has traditionally been linked to serotonin, as it is classified as an anxiety disorder and sometimes treated with antidepressents. However, there has also been research linking *certain kinds* of OCD to an imbalance between the functions of serotonin and dopamine (see for example The role of dopamine in obsessive-compulsive disorder: preclinical and clinical evidence). From what I have read, research on this subject has led to the use of antipsychotics in treatments, in particular in cases where patients don't respond well to SSRIs (antidepressents) alone.

In summary: yes, there is a connection between dopamine, the "reward chemical", and obsessive compulsive disorder. It appears the connection is stronger or more apparent in patients who also have Tourette's syndrome. With respect to genetic markers, as far as I know the genetic research is in an early stage. It cannot be said that any one gene "causes" a specific illness, only that there is a statistical link between them. Correlation does not imply causation, and genetic researchers are unlikely to say that a gene causes an illness if they can't demonstrate a mechanism by which it does so.
> 3 votes

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Tags: cognitive-psychology, neuroscience, cognitive-neuroscience
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# Question
Title: Why are some people attracted to people of other races?
1. Is it true that we were evolved to dislike people of other races genetically?
2. If so, why are some people attracted to people of races other than their own?

# Answer
*This is in reply to your first question.*

Taste – in food, music, and sex – is in part a result of **imprinting**. You find women or men attractive that are like your parents or the community you grew up in because of sexual imprinting (e.g. Aronsson, 2011).

Aronsson writes of a *sensitive period* where this imprinting happens, but I am not so sure that the development of aesthetic taste is actually limited to certain phases in a child's development. Caton et al. (2014) showed that children can acquire the taste for "greens" if they are repeatedly exposed to the food (e.g. having to eat one spoon every time spinach is served). And tobacco, beer, and coffee are prime examples for voluntarily "acquired tastes" later in life. Nevertheless, even an acquired taste is a result of exposure and habituation. Coffee, beer and tobacco are not "exotic" in our culture.

Bem (1996) posited the theory that adults find erotic what was exotic in their early childhood. Thus, a girl that felt different from other girls in childhood would become a lesbian, being attracted to what she was not. This theory has been refuted (e.g. Peplau et al., 1998) on the grounds that it was not supported by empirical evidence.

I could not find anything more substantial in psychological research during a cursory search. What I found are books and articles in cultural theory that look at the popularity of exotic women in the media (e.g. Mendible, 2010). Scanning the contents of those books, I thought that maybe men who are attracted to exotic women are not only attracted to their physical appearance, but also to what these women *represent*. Thus, Latin women may signify lust for life, African men might stand for physical prowess, Asian women might signify servility, or Oriental women might siginify sophistication and mystery. I'm just quoting some common stereotpyes here as examples for how attraction happens not only on the visual level but also in what we project into the person we desire. Men who like women with glasses might not find them visually beautiful, but might be attracted to the idea of an intelligent or "bookish" and shy person, and this fantasy and eroticsim will even hold despite a contradicting personality.

What I want to suggest with this is that reasons for some kinds of attractions might not be systematic (i.e. the same for a large enought group of persons to discover this connection through empirical studies) but widely different between individuals: one white man loving black women might love them for reasons completely unlike those of any other white man loving black women.

But maybe someone else has the time for a more thorough search and will find a study on this subject.

---

Sources:
> 12 votes

# Answer
It is said that American society up to around 1950 came in three flavors, vanilla, chocolate and strawberry. That America was intolerant of interracial marriage, which was against the law in many states.

An ice-cream metaphor for modern American society is Baskin-Robbins' 31 flavors. That society puts a premium on "diversity," including in dating and marriage.

Some people will want "variety" and will seek it through interracial marriage. Others will prefer uniformity and shun it. A third group may be swayed by a "side" factor, such as the chance to upgrade one's genes, or simply because they like a particular person, regardless of race.

But society defines and sometimes restricts our choices. The America of 1950 suppressed the "variety-seeking" type of people, meaning that only the bravest would violate then-prevailing taboos. It was only in the 1970s and later that one found many couples like the parents of (Yankees' baseball player) Derek Jeter (black father, white mother). But the success of that one couple may have encouraged many more.
> 2 votes

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Tags: social-psychology, evolution, physical-attraction, cross-cultural-psychology
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# Question
Title: What to call measures obtained between pre-test and post-test?
We term pre-test as the data collection/measures before conducting an experiment and post-test is data collection/measures after the experiment. How do we term the process of data collection/measures during the experiment (such as physiological measures)? I am looking for a specific "term" to describe the "during-test" event.

# Answer
> 3 votes
People use a wide range of language to describe measurement points in repeated measures design.

For example if you measured some dependent variable on multiple occasions you might have something like:

1. baseline (B)
2. treatment week 1 (T1)
3. treatment week 2 (T2)
4. post treatment (F0)
5. six month follow up (F6)
6. one year follow (F12)

Obviously such a design has aspects that are consistent with a pre-post test design, but it has more time points than just that. So my suggestion is to just have clear descriptive labels for the measurement points.

# Answer
> 1 votes
I believe the prefix you're looking for is *per*. In latin, *pre* means "in front of", *per* means "through" and *post* means behind.

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Tags: experimental-psychology, test
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# Question
Title: Why do we rely on others in dangerous situations?
\*This question is based on my observations.

**Q:** What is the reason people trust their peers implicitly in extreme (or not) situations?

Example:

> I am walking with a friend, and I am telling him something. Now we need to cross a road to the other side (not at the crosswalk; we both know that, so this fact is not communicated – we just proceed to the other side) while I am still telling him something. Unconsciously I understand that we are crossing a road at this point, and I am aware of the possible dangers even at that same point when I am thinking about it, but still I do not look to the right or left and continue following my friend, putting my well-being on his shoulders for that moment.

This may not be the worst case scenario and maybe not so extreme, but it is imaginable, and such a pattern is common in many different situations when one person relies on others' awareness of the dangers the current situation possesses without analysing and watching out for such dangers himself, thus dismissing the self-preservation instinct.

# Answer
> Q: What is the reason for people to implicitly trust their peers in extreme (or not) situations?

Reliance is basically the dependence or trust in someone, to each lies a limited capability of being relied on due to our limited capacity as human beings. What I'm trying to imply is that your friend might have been able to consciously lead you across the road without you questioning his judgement, but in a time of crisis would you let that same friend tell you that it's best to invest all of your money into a shoe shining company?

We depend, or rely on specific people for specific things. Growing up we rely on our mother to provide us with the maternal support and experience required, just as we rely on our father (or father figure) to teaching us what it means to be a man. (Assuming the example human is a male..)

If you were a CEO of a huge company, you would have no trouble relying on your employees to do a specific job in which you ordered them to complete, but only knowing them on a work-basis what are the chances of you trusting them to the extent of looking after your children for a week while you're on holiday? (Also assuming the example human is a parent..).

Trust is a huge factor in the concept of persuasion, and to pursuade someone is to induce someone to do somthing through reasoning or argument. You are more likely to be pursuaded by someone whom you trust in, rather than someone you don't. That person you have relied on has shown to prove the actuality of being credible and knowledgable in the field in which you have decided to trust them in, thus allowing them to lead or guide you as an authority figure.

Also, childhood experience highly influence who we trust and to what extent, but that is an area in which I have little knowledge available to answer you question. I hope I made my message clear. Nonetheless, these are based off of opinion, although @denniswennen had a similar argument.
> 1 votes

# Answer
One human-being reliance on other(s) awareness is defined by the level of trust between the humans.

The idea is that the reliance has differents degrees and is dependent of the level of trust established with their peers. In your example your talking about a *friend* and so the level of trust - and so the degree to follow his instructions - is higher than when you would be walking with a random stranger. Then you'll probably ask yourself more questions at every move *the peer* takes.

A second factor is the context. It's not possible to describe an actor without describing it's environment. It depends if the environment is familiar or new. A new environment will trigger our (own) instinct more to check it for potential dangers.
> 0 votes

# Answer
There are many harding / flocking dynamics that reinforce this behavior: in birds, fish, cattle, and more.

These dynamics reinforce safety. Seeing animal precedent may influence human decisions.

Study of these group utility functions has been studied:

A major area of research that includes this topic is Ecological Psychology
> 0 votes

# Answer
In poker, this is called a "protected pot."

That is, if you are alone with an opponent who bets, you may "call" his bet with a weak hand, because there is a very good chance he is bluffing.

On the other hand, if it is "three way," the opponent bets, a second person calls, you can "fold" a weak hand with a lot more assurance that the bettor is not bluffing.

Because the bettor is betting against two people (one of whom has called), there is a greater chance that he has a strong (dangerous) hand, and you're not "missing out" by folding.
> 0 votes

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Tags: social-psychology, behaviorism, attention
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# Question
Title: Why only 16 Jungian types? Combinatorially it should be 2 * 4! = 48
The seeming elegance and symmetry of the table of functions prompted me to use a technical side of my brain to ask a "what if" question about the other possible Jungian functions.

I used combinatorics(math) to calculate all possibilities of arranging letters F,S,T,N as well as adding an alternating i/e "flavor". There are two options for the flavors (once we know the i/e "flavor" of the first function, the rest are determined because they alternate).

For illustration, I enumerated one quarter of all possibilities (only those starting with an F but you can keep going yourself if you like). The original 16 types are listed below that. As you can see, there are many gaps - only 4 of 12 used here and 16 of 48 used overall. So, exactly 1/3 utilization. The mathematical elegance is a tease, makes me think that this theory is based on something real, but is it? Could it be an elegant accident or an elaborate hoax instead? Why are some combinations not possible?

```
E/I 1   2   3   4   functions   MBTI?
e   F   N   S   T   FeNiSeTi    ENFJ
i   F   N   S   T   FiNeSiTe    INFP
e   F   N   T   S   FeNiTeSi    ?
i   F   N   T   S   FiNeTiSe    ?
e   F   S   N   T   FeSiNeTi    ESFJ
i   F   S   N   T   FiSeNiTe    ISFP
e   F   S   T   N   FeSiTeNi    ?
i   F   S   T   N   FiSeTiNe    ?
e   F   T   N   S   FeTiNeSi    ?
i   F   T   N   S   FiTeNiSe    ?
e   F   T   S   N   FeTiSeNi    ?
i   F   T   S   N   FiTeSiNe    ?
.................................

MBTI    1   2   3   4
INTP    Ti  Ne  Si  Fe
ISTP    Ti  Se  Ni  Fe
ENTP    Ne  Ti  Fe  Si
ENFP    Ne  Fi  Te  Si
ISFP    Fi  Se  Ni  Te
INFP    Fi  Ne  Si  Te
INTJ    Ni  Te  Fi  Se
INFJ    Ni  Fe  Ti  Se
ESTJ    Te  Si  Ne  Fi
ENTJ    Te  Ni  Se  Fi
ESFJ    Fe  Si  Ne  Ti
ENFJ    Fe  Ni  Se  Ti
ISTJ    Si  Te  Fi  Ne
ISFJ    Si  Fe  Ti  Ne
ESTP    Se  Ti  Fe  Ni
ESFP    Se  Fi  Te  Ni

```

# Answer
> 4 votes
There are not 16 Jungian types. There are 16 MBTI combinations and 16 Kersian (sub-)temperament types. All are related and easily confused.

Jung, in Psychological Types (Collected Works, Book 6), defines two Attitude Types and four functions, splitting the latter into two groups of two.

Attitude Type is Extraversion and Introversion and takes up 9 of the 10 chapters in the work. In the 10th chapter, he explains the four functions: Sensation, Intuition, Thinking, and Feeling. The first two are irrational functions, the second two, rational functions. This makes a total of three groups of two. Though, Jung treats all four functions as one group, it is helpful to remember they can be bifurcated thusly.

Of both the two Attitude Types and the four functions, one is *preferred* from each. That is, everyone has all the types and functions, but everyone *prefers* one from each group.

Chapter 10 then explains how the functions play out within the two Attitude Types, leading to 8 explanations, which are Extraversion and Introversion with each of the four functions. He *also* explains the role of the secondary function. The secondary function will be the opposite of the primary function. That is, if the primary is irrational, the secondary will be rational, and vice-versa.

--

Before Jung published Psychological Types, but based on his works, Meyers-Briggs created the MBTI (Meyers-Briggs Type inventory), a personality inventory based on Jung's functions. The first letter is the preferred Attitude Type, the second letter is the preferred irrational function, the third letter is the preferred rational function, and the fourth letter indicates which function is preferred to be extraverted. Note, the fourth letter does not indicate the primary function. It indicates whether the preferred extraverted function is irrational or rational, which is the inverse of the introvert's primary function.

The combination of one of two Attitude Types, one of two irrational functions, one of two rational functions, and one of two preferred extraverted functions, makes 16 combinations.

In Gifts Differing, Meyers-Briggs defined four function groups (ST, SF, NT, NF) which are like groups to the 16 types.

--

Keirsey, working on Temperament theory (reactions to the external environment), found a connection between his work and the MBTI. Note, he did not find a connection between Temperament and Jung's theory. Indeed, he could not, because Jung did not have the fourth letter defined by the MBTI, which is integral to the connection Keirsey found. He also grouped the letters differently than the MBTI.

Keirsey's groups are SP, SJ, NF, NT, which can be matched to the four historical temperaments: Artisan, Guardian, Idealist, Rational. The history of Temperament theory gives many different names for these groups, so Keirsey, in his main work, Please Understand Me II, says he based it on The Republic. In Keirsey's last work, Personology, however, he focuses much less on those names and uses his own.

With a connection between the MBTI and Temperament theory established, Keirsey *extended* Temperament theory to include four sub-types for each of the four temperaments. This makes a total of 16 sub-types.

# Answer
> 3 votes
It's because order doesn't matter with the types:

ENTJ == ENJT

When you remove the permutations of order, there are only 16 possibilities.

Another way to think about it is that there are 4 traits, and each trait can take one of two values, so there should be 2 x 2 x 2 x 2 possibilities, which is 16.

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Tags: personality, jung
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