# Question
Title: Understanding neuronal firing in the context of Spike Timing Dependent Plasticity
When discussing Spike Timing Dependent Plasticity in neurons, when we say that a neuron fires do we mean it fires only one spike? Or do we still say "the neuron has fired" when a train of n spikes was actually fired?

I find this detail a little confusing when we learn spike timing dependent plasticity (STDP), for example. If the neuron fires only one spike, then the time of firing is precise enough for relative timing between input and output signals to be well defined, and then the theory makes sense. Otherwise, one should give an approximation of the duration of the firing train of spikes and compare it with the duration of depolarization process in the dendrite that triggered this firing. But I can't find any of these anywhere.

# Answer
> 1 votes
> I find this detail a little confusing when we learn spike-timing-dependent plasticity for example.

In the original spike timing dependent plasticity work by Bi and Poo (1998), the focus is best understood as on **single spikes at a time**. This is because their protocol was to provide repeated stimulations of both pre- and post-synaptic neurons, each producing a single spike, and to do this for one minute, but, importantly, at a low frequency of just 1 Hz. Once every second may seem frequent at the macros scale of everyday life, but to a neuron, this is a rather low rate of firing. But what mattered to whether they were able to get potentiation or depression of the synapse was the precise timing of the two spikes: pre followed by post spiking produced potentiation; post followed by pre produced depression.

This is, to quote you, indeed

> "precise enough for relative timing between input and output signals to be well defined and then the theory makes sense."

Now, your confusion is when there is a higher rate of firing in a naturally occurring spike train--how are we to know which counts as a "post before pre" event vs. a "pre before post" event?

Your suggestion was to count the entire train of spikes as one unit:

> Otherwise one should give an approximation of the duration of the firing train of spikes and compare it with the duration of depolarization process in the dendrite that triggered this firing.

That's one possibility, but it essentially throws out the interesting STDP result itself, probably prematurely. What if, instead, we just let some spike trains happen, measure the precise times of every spike (pre and post) in them, and assess the effects on plasticity?

That was done. In 2002, Froemke and Dan published "Spike-timing-dependent synaptic modification induced by natural spike trains", which shows what actually happens, in terms of synaptic plasticity. Here's what they found (emphases mine):

> We found that in visual cortical slices the contribution of each pre-/postsynaptic spike pair to synaptic modification depends not only on the interval between the pair, but also on the timing of preceding spikes. **The efficacy of each spike in synaptic modification was suppressed by the preceding spike** in the same neuron, occurring within several tens of milliseconds. The direction and magnitude of synaptic modifications induced by spike patterns recorded in vivo in response to natural visual stimuli were well predicted by incorporating the suppressive inter-spike interaction within each neuron. Thus, activity-induced synaptic modification depends not only on the relative spike timing between the neurons, but also on the spiking pattern within each neuron. **For natural spike trains, the timing of the first spike in each burst is dominant in synaptic modification.**

To summarize, individual pre/post spike pairings in the train do matter, but they tend to cancel each other out in cases where the rate and pattern of spiking produces spikes close enough in time (10s of milliseconds), *with the exception of the first spike in each burst!* Very interesting.

# Answer
> 1 votes
Not sure I understand your question correctly. What is it you can't find anywhere? I would comment and ask for clarification, but that requires 50 rep which I don't have in this community. Just tell me if my reply doesn't answer your question and I'll update.

There are two basic ways to describe neurons' firing. One is rate-based and the other is spiking. In rate-based neural networks, we look at the *intensity*, as it were, of a neuron's response to a certain input. Within the framework of rate-based neural networks, we usually assign numbers to firing rates without attaching any units. That is, in the *model* of a neural network, we may say that the response of a neuron has a firing rate of 0.8, but we don't specify 0.8 of what this is (spikes per second, per 10 seconds, per minute...), and it usually doesn't matter either, because all that is important is that it is more or less than the response of another neuron or to a different stimulus. Note that this presumes that the rate is constant after the stimulus is presented.

In spiking neural networks, we model neurons' responses in much greater detail, designing differential equations which describe the time course of polarization and depolarization, such that a given depolarization can lead to explosive behavior which we call a 'spike'.

Now, many instances of neural information processing can be described very adequately using rate-based abstractions. This is convenient, because rate-based ANN tend to be much more stable and computationally more efficient. Also, biological neural firing can be measured much more easily in terms of intensity than in terms of spiking---especially for whole populations. Therefore, we know more about many of the phenomena we try to model in terms of firing rates than in terms of timing, so rate-based neural networks actually capture our knowledge better.

Only in those cases where we have information about the precise timing of responses, and where we believe it to be important for the phenomena we try to model, does it make sense to accept the much more specific and difficult ontological commitments of spiking neural networks. Otherwise, we understand what is happening in terms of intensity, not timing, and therefore the actual number of spikes per second do not matter.

The point is, 'firing' refers to related but very different concepts in the two abstractions of biological neurons, and they can't really be compared. Either you talk about individual spikes in a spiking model, or you talk about rates of spiking over some non-descript unit of time in a rate-based ANN, but trying too hard to compare the two concepts will lead to confusing and nonsensical situations.

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Tags: theoretical-neuroscience, neural-network, artificial-intelligence, electrophysiology
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title: Can suggestion change memories?

text:
# Question
Title: Can suggestion change memories?
I came up with this question because of my personal experience. I think it may help you understand my question better, so I will describe it briefly.

**Piece of metal**

When I was a kid, I (accidentally) watched a horror movie. There was a scene, in which one of characters was using a fork to take out small piece of metal from his body. It scared me very much.

After 15 years, I watched this horror again (and again - accidentally). I was very surprised that, when watching above scene, the small piece of metal was much, much smaller then I remembered. I estimate, that in reality it was about 3x smaller.

**Conclusion**

Until this experience, I though that memory is somehow 'fixed' since remembered. Was there any research conducted that would prove that memories are not fixed, not constant? It seems like feeling of fear somehow scaled up the source of fear (piece of metal) in my memory image, or some parts of memorised image grew with me. It was like my memory was 'updated'.

If memories are indid 'mutable' by experiences, the obvious question comes to mind - can suggestion influence or even change memories?

# Answer
> 11 votes
The answer to your question is yes, our memories are very malleable. Look into the research of Elizabeth Loftus. She is kind of the pioneer on this topic and has done a ton of research into false memories.

Here is a TED talk by her that you might find interesting and here is a review article

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Tags: cognitive-psychology, memory
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# Question
Title: Toolbox for modelling visual search performance
I'm looking for a toolbox to model visual search performance in a singleton search task based on line orientations (you need to find a line that is most different from all others in it's orientation).

The desirable features would be:

1. Feature-detectors that resemble real neurons.
2. Memory for distribution of distractors in feature space during previous trials.

Is there something like that? I also know that sometimes similar tasks are studied in texture discrimination. Maybe there is something close to what I need in that domain?

# Answer
> 1 votes
I'm assuming that you want some kind of "computer vision" model (in that you want to be able to provide the model with input stimuli in the form of an image), and that you want to predict some kind of behaviour? (e.g., RT from a search task). Fleshing out the different processes involved is not going to be trivial, so there probably isn't a "one-size-fits-all" "toolbox" for your problem.

Perhaps the "saliency map model" by Itti and Koch would be suitable. There are many more modern versions of this (including a MATLAB toolbox and a number of related models). While it is not necessarily the best, the advantages in this case are that Itti and Koch actually used an orientation pop-out task in their original paper (Vision Research, 2000). However, I'm not sure to what degree the feature detectors actually resemble neurons, and I don't think a memory component has been included.

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Tags: vision, cognitive-modeling, computational-modeling
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# Question
Title: How to foster an environment for appreciation
I'm a teacher at a highschool and currently we've been working on projects that are supposed to make the kids appreciate those around them especially the other teachers and workers at the school. During an advisory time earlier this year, we had the students write a letter of appreciation to someone who works at the school. Another project that we're going to start up is a student voted "employee of the month" and that teacher/worker will be somehow celebrated -we haven't worked out the details-. The problem with both of these ideas is that they're ineffective and the students all just wrote letters begrudgingly and I think this upcoming project won't make them feel appreciation for those who help them either.

Are there general steps, for either creating an environment for students to appreciate teachers and other workers? Or are there general ways that appreciation works in the mind so that we can come up with projects that will truly help them?

# Answer
> 1 votes
Firstly, this question sounds pretty clearly self-serving, like saying "I want people to like me more; how do I make them like me?". Secondly, school is a business, much like other businesses. When a company makes a product, of course the company hopes the market will "appreciate" the product. There are many marketing strategies used out there, but the long-term viability of a product requires that it provides clear value. Without that value, prospects cannot be expected to appreciate the product. In the case of high school, most students are probably aware that the product is not being sold to the students but instead to the parents. Hence, students are not the customer. Since students are not the customer, and since students had little to no say in the product's design, getting the students to appreciate the product is going to be very challenging.

One approach is to make the students believe they are the customer. You might, for example, use a bandwagon strategy wherein you explain that "There are many happy students from years prior who have attended this school and are now enjoying a life of success and freedom".

Another approach, which would be more honest, would be to actually **make the students into the customer**, such as by designing the curriculum around their needs and aspirations while providing **a clear value that cannot easily be found elsewhere**. If you are to be honest with yourself, this is the only noble approach. If a school cannot provide clear benefits that a student cannot find outside of school (such as on the Internet or in books alone), then that school is not doing its job. Sure, there are many types of rhetoric and trickery that can (and often are) employed by schools and governments, but these are nothing to be proud of.

In short: Provide a unique and worthwhile opportunity with a benefit that can be seen clearly. Engage the students in the curriculum -- make *them* the customer.

PS: While a bit off-topic, I just remembered a music video that critiques some of the curriculum focus in the recent if not current school system. This video had no bearing on my answer here as I only remembered the video afterward, but its topic is related enough to be worth mentioning here.

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Tags: social-psychology, educational-psychology, positive-psychology
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# Question
Title: Are inhibitory synapses the cause of not doing something?
Imagine you are driving your car, in front of you, you see a wall. What prevents us from driving against the wall? Is this accomplished by the brain having inhibitory synapses established here?

# Answer
> 3 votes
Inhibitory synapses allows one brain region to suppress activity in another. Since the car is in motion per the laws of motion and momentum, it would be incorrect to say that suppressing one brain region would cause the car to stop moving toward the wall. The closest thing would be if those inhibitory synapses caused one part of your brain to inhibit the part that causes your foot to press the accelerator pedal. For example, dopaminergic neural processes from the *basal ganglia* (particularly the *substantia nigra*) indeed suppress motor impulse indirectly (see here and here). However, more activity than simply releasing the pedal is required in most cases to avoid hitting something. In short, you most certainly need both inhibitory and excitatory synapses to help you avoid running into something on the road or on your path as you walk. These functions are probably very complex, involving a great many of both types of synapses in several brain regions.

It is important to remember that many if not most neural circuits are primarily for very specific actions in the body or mind. Most "actions" in the common sense that a person can undertake are the result of a great many action potentials in the brain. Perhaps in some very small (such as microscopic) creatures, a single action potential is needed to initiate an activity such as feeding, but larger creatures with bigger brains have so many neural pathways that most observable actions of the animal require many internal actions of the processing system.

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Tags: brain-development, behavior
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# Question
Title: Does anger lower a person's cognitive ability?
For me it seems that getting angry or irritated makes me less intelligent but it didn't try testing it. Has there indeed been such tests or anything else about testing IQ levels of different moods for the same subject?

# Answer
> 4 votes
The first question that should be asked is, do you mean cognitive ability or IQ? They are intertwined, but different. Unfortunately, I can not comment. I'm going to answer based on the question in the title.

Yes. Walter Mischels work on self-control indicates that anger, a "hot" emotion led by the amygdala in the limbic system, will provoke more immediate response. Limiting cognitive abilities like working memory, judgment and evaluation, reasoning and "computation", decision making, and comprehension.

> The limbic system consists of primitive brain structures located under the cortex on top of the brain stem, which developed early in our evolution. These structures regulate basic drives and emotions essential for survival, from fear and **anger** to hunger and sex... Within the limbic system, the amygdala is especially important. It plays a key role in fear responses and in sexual and appetitive behavior. The amygdala rapidly mobilizes the body for action. **It does not pause to think and reflect or worry about long term consequences.** (Pg 43)
>
> The hot system is ... Reflexive, simple, emotional, it automatically and quickly triggers consumptive behavior, arousal, and impulsive action (Pg 44-45)
>
> This hot response is not useful when success in a given situation depends on staying cool, planning ahead, and problem-solving rationally. (Pg 45)

(Emphasis mine)

The "cool" cognitive system, where we find our cognitive abilities.

> Closely interconnected with the brain's hot system is its cool system, which is **cognitive**, complex, reflective, and slower to activate. It is centered primarily in the prefrontal cortex (PFC). It's important to note that stress attenuates the cool system and accentuates the hot system. The hot and cool systems continuously and seamlessly interact in a reciprocal relationship: as one becomes more active the other becomes less active. (Pg 46)
>
> The PFC is the most evolved region of the brain. It enables and supports the highest-order cognitive abilities that make us distinctly human. ...Unlike the hot system, the cool system is attuned to the informational aspects of stimuli and enables rational, reflective, and strategic behavior. (Pg 46)

Here we have a pretty clear description of how anger, "hot", limits the cognitive abilities of the prefrontal cortex, or the "cold" system.

Finally,

> Prolonged stress impairs the PFC, which is essential... for things like surviving high school, holding down a job, pursuing an advanced degree... and refraining from decisions that seem intuitively right but on closer examination are really stupid. (Pg 49)

In the same book, research done by nueroscientist Amy Arnsten at Yale is mentioned,

> "Even quite mild acute uncontrollable stress (*like that caused by anger*) can cause rapid and dramatic loss of prefrontal cognitive abilities." The longer stress persists, the more those cognitive abilities are hurt and the more permanent the damage, ultimately leading to mental as well as physical illness.

(Italicized content is a personal addition to clarify how anger can cause uncontrollable stress)

Demonstrating long term and short term impacts of stress caused by anger and irritation.

Walter Mischel. "The Marshmallow Test: Why Self-Control is the Engine of Success". 2014.

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Tags: emotion, iq
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# Question
Title: relation of substantive/verb to declarative/procedural memory
Is there a relation between "declarative vs. procedural memory" and "substantive vs. verb"? For example, are substantives (as a kind of information entities) stored in the declarative memory whereas verbs define capabilities/behavior and hence stored in the procedural memory?

Example:

Tree: a substantive, can directly be stored in declarative memory

to climb: a verb, defines a capability/behavior and can be stored in the procedural memory

# Answer
> 1 votes
While it's true that universal nouns will link mostly to other universal nouns (*a tree is a plant*), and universal verbs will link mostly to other universal verbs (*to climb is to move*), it is not necessary that they be in separate memory areas from each other; or even that they be separate from event memory (*one cat did climb one tree*). The most efficient memory scheme would minimize the length of all links. One way would be to store all new memories in a fairly linear structure, and then use an off-line process (sleep) to spread them around to minimize total link lengths {or to optimize lengths around importance of fast access}.

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Tags: cognitive-modeling, brain-development, linguistics
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title: How do we learn to count syllables?

text:
# Question
Title: How do we learn to count syllables?
When I was young, I was told that to count syllables in a word, you could clap them. One clap for each syllable.

You would say it aloud like this: cu-shion.

I was not taught rules about how to pick out each syllable from a word. I just figured it out.

The funky thing with this is that syllables have no defined length, and some words are only one syllable while others are a few.

Learning how to count syllables is unlike math because in math, one can't do something until they have learned all the rules for how it should be done properly. I was never taught rules like this for counting syllables, I just figured it out.

My question: how do humans learn this skill without being taught? Is it like learning to walk?

# Answer
> 1 votes
Like most of language, we have an innate ability to learn by exposure, with the rules remaining subconscious until someone forces us to explain them.

Syllables are based on phonemes, so we need to know the rules of spelling if we don't already know the word by sound. Each syllable consists of an **onset** and a **rime**.
The onset is a cluster of consonants (or it is null, at the beginning of some words).
The rime is a cluster of vowels {or diphthongs...}, plus an optional cluster of consonants {typically at the end of a word}.

Thus: cushion: \[c\] (u) + \[sh\] (io\[n\]) = 2 syllables

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Tags: cognitive-psychology, linguistics
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title: How common are aromantics?

text:
# Question
Title: How common are aromantics?
(Aromantic means lacking romantic attraction to others.)

What percent of people are aromantic? While the percentage of people who are asexual seems to be 1%, I couldn't find anything on what percent of people were aromantic.

And a follow-up question: Is there a correlation between aromanticism and sexual orientation. E.g., are asexual people more likely to be aromantic than heterosexual people?

# Answer
> 2 votes
From "How Many People Are Aromantic?" from the blog *The Thinking Aro*:

> Based on the 2014 Asexual Community Census data provided here:
>
> **25.9%** of asexuals are aromantic.
>
> If we run with the studies performed on self-reporting asexuals currently on the books, approximately **one percent of the human population is asexual.**
>
> This means that in the United States alone, there are approximately **3,161,000 asexuals.**
>
> The number of aromantic asexuals in the U.S. should be about **818,699.**
>
> \[...\]
>
> (The one dilemma we have in arriving at accurate numbers is that we can’t know if the 1% of people who are asexual includes demisexuals and gray-asexuals or not. The 2014 Asexual Census reports that 25.9% of asexuals are aromantic; **9.1%** of gray-asexuals are aromantic and **3.5%** of demisexuals are aromantic. When dividing the entire asexual spectrum by romantic orientation, aromantics make up 19% total, so if gray-asexuals and demisexuals would be part of the 1% of “asexuals” in the human population, then the number of aromantics would be lower than what I listed above. But if they aren’t part of that 1%, then the numbers would actually be higher.)
>
> Now, the data collected through the 2014 census from sexual people (anyone who isn’t asexual, demisexual, or gray-asexual) is obviously tough to accept as accurately representative of the real sexual population because sexual people who completed the census would obviously be a specific type who has exposure to the asexual community online and therefore is aware of romantic and sexual orientations and information that most people in the world at large don’t have. But just for the hell of it, let’s consider the numbers that come of the data.
>
> Of the sexual people who took the census, **4.3%** identified as aromantic.
>
> So if 4.3% of sexual people are aromantic (which might at first seem high but then again, maybe not), that means there should be around **13,456,377 aromantic sexual people in the United States.**
>
> Add that to the more reliable stat we have for aromantic asexuals, and there are roughly **14,275,076 aromantic people currently living in the U.S.**

The author seems to place the population of the U.S. at 316,100,00, so these (highly uncertain) figures imply **4.5%** of population is aromantic.

> Again, this is assuming that 99% of human beings are sexual, excluding demisexuals and gray-asexuals. If we were to lump in demisexuals and gray-asexuals as part of that 99% of everyone who is not asexual, then the number of aromantics rises because we add the 9.1% of gray-aces who are aro and the 3.5% of demisexuals who are aro to the 4.3% of sexual people who are aro.
>
> These numbers do not include anyone, asexual-spectrum or sexual, who are demiromantic, grayromantic, or WTFromantic. Those are just the aromantics.
>
> \[...\]

As for whether the aromanticism rate is different among sexual orientations, it is according to Cross-orientations among non-aces from the *Asexual Census Blog*, which much of the above blog post was based on. The post states that 25.9% of asexuals, 3.5% of demisexuals, 9.1% of gray-asexuals, and 4.3% of non-aces are aromantic. It doesn't break down non-ace orientations though for their individual rates of aromanticism.

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Tags: sexuality
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# Question
Title: How do neuro transmitters interact with neurons in the brain?
I think emotions and hormones frames the overall thinking processes of the brain. However, I'm interested in how this works on a neuronal level. For example, dopamine is some kind of reward signal for the brain. How does it interact with individual neurons or synapses and affect the way they behave?

# Answer
Actually it's a bit complicated but in simple terms :

Neurotransmitters are stored in a synapse in synaptic vesicles, clustered beneath the membrane in the axon terminal located at the presynaptic side of the synapse. Neurotransmitters are released into and diffused across the synaptic cleft, where they bind to specific receptors in the membrane on the postsynaptic side of the synapse.

Most neurotransmitters are about the size of a single amino acid, however, some neurotransmitters may be the size of larger proteins or peptides. A released neurotransmitter is typically available in the synaptic cleft for a short time before it is metabolized by enzymes, pulled back into the presynaptic neuron through reuptake, or bound to a postsynaptic receptor. Nevertheless, short-term exposure of the receptor to a neurotransmitter is typically sufficient for causing a postsynaptic response by way of synaptic transmission.

In response to a threshold action potential or graded electrical potential, a neurotransmitter is released at the presynaptic terminal. Low level "baseline" release also occurs without electrical stimulation. The released neurotransmitter may then move across the synapse to be detected by and bind with receptors in the postsynaptic neuron. Binding of neurotransmitters may influence the postsynaptic neuron in either an inhibitory or excitatory way. This neuron may be connected to many more neurons, and if the total of excitatory influences are greater than those of inhibitory influences, the neuron will also "fire". Ultimately it will create a new action potential at its axon hillock to release neurotransmitters and pass on the information to yet another neighboring neuron.
> 1 votes

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Tags: neuroscience, cognitive-neuroscience, emotion, cognitive-modeling, neuro-transmitters
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title: Denial of evidence and reason

text:
# Question
Title: Denial of evidence and reason
Some people form a belief and become absolutely resistant to any contrary evidence or reasoning. Even in the face of overwhelming evidence, these people stick to their beliefs. I'm pretty sure this is something that has been investigated by cognitive sciences, and I'd like to know what this phenomenon is called as I'd like to learn more about it.

So, what is the mechanism of this denial-of-evidence called?

I recently came to the conclusion that a lot of people who hold onto conspiracies and the like show similar behaviors to religious fanatics. The way these conspiracy-believers argue and the way they react when confronted with critique or even evidence seems to be similar, no matter what conspiracy-topic it's about (with varying degrees of fanaticism, of course; some *can* still be reached with reason while others are so deep into their belief-system that they cannot be reached any longer). I find this strangely fascinating and would like to understand the "mechanics" of this phenomenon.

# Answer
> 6 votes
Confirmation bias:

> Confirmation bias, also called confirmatory bias or myside bias, is the tendency to search for, interpret, favor, and recall information in a way that confirms one's beliefs or hypotheses, while giving disproportionately less consideration to alternative possibilities.

A feature of this bias is belief perseverance:

> ... when beliefs persist after the evidence for them is shown to be false ...

Confirmation bias is an umbrella term for a variety of strategies and effects that may be applicable in different situations, including self-justification, self-verification, attitude polarization, escalation of commitment, cherry picking, etc, etc. See the duplicate questions I listed in the comments above for more varieties of these. You may find that some sub-category of confirmation bias is more apt to your question.

Note: Cognitive dissonance refers to the cause of a number of possible inconsistency reduction strategies, of which belief perseverance is one.

Note: Denial refers to an ego-defence mechanism \- ie, it applies only if the person feels personally threatened by the inconsistency.

# Answer
> 5 votes
According to the Wikipedia's page on Cognitive Dissonance :

> In psychology, cognitive dissonance is the mental stress or discomfort experienced by an individual who holds two or more contradictory beliefs, ideas, or values at the same time, performs an action that is contradictory to one or more beliefs, ideas or values, **or is confronted by new information that conflicts with existing beliefs, ideas, or values**.

Therefore, individuals try to reduce the discomfort by having the attitude you described:

> If the dissonance is not reduced by changing one's belief, the dissonance can result in restoring consonance through misperception, rejection or refutation of the information, seeking support from others who share the beliefs, and attempting to persuade others.

# Answer
> 1 votes
Actually it is simply called denial as a defense mechanism . as you may have already know, most of our cognition happens in a subconscious and semiconscious level. a belief system is usually what people learn in their childhood and from their parents so it really sticks to brain and goes underlying the whole subconscious and semiconscious thought. So, when you try to convince them that their belief is wrong, they simply alter their perception in advantage of their belief and since they don't do it on a conscious level they are not aware of it. The whole point of this mechanism is to avoid distress over the organization of thoughts and behavior. Some people lives are based on their beliefs so it's so simplistic that one assumes it can be changed overnight, because if it does, mental distress will result in a mental breakdown.

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Tags: social-psychology
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# Question
Title: Which parts of the brain are affected by dopamine?
Does dopamine spread and interact across the whole brain? If not, which areas are affected most and which least?

# Answer
Quoting my thesis:

> CNS Dopamine/DA projections primarily emerge from two subcortical basal ganglia nuclei in the brain stem, travelling along three major pathways (Purves et al., 2004).
>
> The nigrostriatal pathway, connecting the substantia nigra and the striatum, is mainly implicated in higher motor control. The mesolimbic pathway contains DA projections from the Ventral Tegmental Area/VTA and the pars compacta of the Substantia Nigra (SNc) to limbic systems including hip- pocampus, amgydala and thalamus, and is critical in learning and memory in a mechanism that is well-investigated (Lisman & Grace, 2005). The mesocortical pathway connects the VTA and SNc to the cortex. In contrast to the extensive noradrenergic innervation of the cortex, DA therefore reaches only selected areas (Foote & Morrison, 1987). DA density is extensive in prefrontal and anterior cingulate areas, and falls off rapidly across an rostro-caudal gradient. The temporal lobe is only weakly innvervated (including the enthorinal cortex), and little to no innervation reaches parietal and especially occipital lobes, though DA fibers in monkey area 7 have been reported (Foote & Morrison, 1987).

So basically, subcortical innervation is rich, but cortical innervation is focused on frontal areas. DA is often depicted as having *zero* cortical presence outside of frontal areas, but this is false; while DA innervation density falls off sharply outside of the frontal lobes, at least in humans and other apes, there is some DA reaching at least as far back as the temporal lobes.

Of course, this is only the *direct* effect of DA. In principle, all of the brain is strongly affected by the effects of DA, because frontal cortices, who are strongly influenced by DA, in turn strongly influence the rest of the bain.

Sources (obviously): Foote, S. L., & Morrison, J. H. (1987). Extrathalamic modulation of cortical function. Annual review of neuroscience, 10, 67–95.
> 3 votes

# Answer
1. Parts of the brain affected by dopamine Dopamine exerts different effects in different regions and pathways throughout the brain. In the **mesolimbic pathway**, dopamine is believed to be involved in motivation and addiction due to the feelings of reward and pleasure associated with dopamine release here. In the **mesocortical pathway**, dopamine is linked to emotional and motivational activities. In the **nigrostriatal pathway** dopamine is responsible for regulating and initiating motor activity. In the **tuberoinfundibular pathway**, dopamine regulates the release of hormones from the pituitary gland.
2. Interaction with the brain and where (already answered by @shayankabiri)
> 2 votes

# Answer
No, unlike norepinephrine and serotonin, dopamine's pathway is limited.actually it affects two part of cognition, reward and motor functions. As part of the reward pathway, dopamine is manufactured in nerve cell bodies located within the ventral tegmental area (VTA) and is released in the nucleus accumbens and the prefrontal cortex. The motor functions of dopamine are linked to a separate pathway, with cell bodies in the substantia nigra that manufacture and release dopamine into the striatum.
> 1 votes

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Tags: neuroscience, emotion, neuro-transmitters
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# Question
Title: Why being ignored is 'painful' for human beings?
Ignoring someone is a manipulatory technique used at times. Ignoring the attacks of someone else through emotional detachment has a very strong effect on the attacker.

Is there a name for this kind of manipulative behavior?

# Answer
Ignoring is a type of social rejection see extracts from wiki:

> Social rejection occurs when an individual is deliberately excluded from a social relationship or social interaction. ... rejection can be either active, by bullying, teasing, or ridiculing, or passive, by ignoring a person, or giving the "silent treatment."
>
> ...
>
> Researchers have also investigated how the brain responds to social rejection. One study found that the dorsal anterior cingulate cortex is active when people are experiencing both physical pain and "social pain," in response to social rejection.
> 1 votes

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Tags: social-psychology, terminology
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title: Is the heart conscious?

text:
# Question
Title: Is the heart conscious?
I have read that our heart can think like our brain. Of course it doesn't have complete functionality of brain but it has its own consciousness. Is it true?

# Answer
The general consensus of the scientific community would be that the human heart is not capable of consciousness.

The machinery behind consciousness is not well understood, of course, and there is quite a bit of debate, but it is thought that some minimum level of complexity is required in order for consciousness to arise. The human heart, while containing some neural circuitry, is very unlikely to reach this minimum level of complexity.

Here is a Quora discussion that further explores this issue.
> 2 votes

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Tags: neuroscience, consciousness
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# Question
Title: If a person constantly invalidates your feelings is he/she a narcissist?
If someone constantly invalidates your experiences and feelings does that mean they are a narcissist?

For example, if I am really hurt by someone and I go to a friend for support and my friend *always* invalidates everything I tell them does that mean they lack empathy? The interaction is always confusing and the fact of the matter is always deflected. They say things like 'I'm sure he didn't mean it. That wasn't his intention. etc.' Always!

Is that a sign of narcissism? They can't feel the pain themselves or they can't see it so they dismiss it?

But they say they care then impose what they think you should feel onto you. Self-absorbed?

# Answer
> 2 votes
It really depends. first of all, the problem might be in the person who asks, maybe they really are super sensitive and what they are upset about is not rational.

Also you can never know from someones words that they lack empathy or not. Some people are just tough, maybe he was in some back breaking situations in life that yours seem minor.

And also lack of empathy is just a small part of narcissism and is not a "only and only" determinant.

If you wanna see if others have empathy or not, you better watch their acts rather than analyzing their words. do they have criminal tendencies or ever were accused of criminal act? are they non-empathetic in their job? are they careless about others life situations? are they reckless? do they put others in trouble to get something they want? and so on.

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Tags: perception, validation
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# Question
Title: Valence conveyed in simple geometric shapes
I've seen neuroscience and facial recognition studies that give evidence for this idea of simple geometric shapes causing emotional responses or quicker recognition of negative affect.

Are there studies exploring the other end? (i.e. positive valence of simple geometric shapes)

<sub> Larson, C. L., Aronoff, J., Sarinopoulos, I. C., & Zhu, D. C. (2009). Recognizing threat: A simple geometric shape activates neural circuitry for threat detection. Journal of cognitive neuroscience, 21(8), 1523-1535. Watson, D. G., Blagrove, E., Evans, C., & Moore, L. (2012). Negative triangles: Simple geometric shapes convey emotional valence. Emotion, 12(1), 18-22. doi:10.1037/a0024495 </sub>

# Answer
> 2 votes
I love this kind of research because it shows how there's an affective undercurrent to essentially every part of our lives. This is formalized in **microvalence theory** (Lebrecht et al., 2012), which posits that all objects, even ordinary ones, are imbued with valence (e.g., explaining why you prefer one chair over another).

As far as positive geometric shapes, there is evidence for consistent positive reactions to circular and curvilinear shapes (e.g., Bar & Neta, 2006; see also Larson, Aronoff, & Steuer, 2011). There may be some obvious top-down mechanisms mediating this effect, such as positive associations with a smile (vs. a frown; Salgado-Montejo, 2015).

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Tags: cognitive-psychology, cognitive-neuroscience, emotion, reference-request, experimental-psychology
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title: Split Brain Experiments on Animals

text:
# Question
Title: Split Brain Experiments on Animals
I was wondering what would happen if you took a split brain person and stimulated the pleasure center of one hemisphere and the pain center of the other hemisphere in conjunction with an external stimulus... basically Pavlov's Dog but applied differently to the two halves of the brain of the same person. Of course, such an experiment is highly cruel and unethical, so it's safe to assume it was never done on a human.

So, that got me wondering... we often experiment on animals when a procedure is too cruel to perform on humans (for better or worse, I'm not here to debate the ethics of animal experimentation). Are there any split brain experiments that we've done on animals that we haven't tried on humans? What have we learned from these experiments?

# Answer
Split-brain syndrome is caused when the corpus callosum is cut to prevent epileptic seizures from spreading from one side of the brain to the other. After some time passes from the procedure most patients are indistinguishable from a "normal" person because they adapt.

> In a typical split-brain experiment, two stimuli are presented to the patient in such a way that one will be processed by the left hemisphere and the other by the right hemisphere. For example, the word ‘key-ring’ might be projected such that ‘key’ is restricted to the patient’s left visual field (LVF) and ‘ring’ is restricted to the patient’s right visual field (RVF). The contralateral structure of the visual system ensures that stimuli projected to the LVF are processed in the right hemisphere and vice-versa. Other perceptual systems can be studied in a similar manner. For example, tactile perception is examined by asking the patient to compare, either by verbal report or by pointing, objects presented to each hand.
>
> Such studies have revealed two kinds of disunities in the split-brain: behavioral disunities and representational disunities. Behavioral disunities are most striking. When asked to report what she sees the patient in the key-ring experiment will typically say that she sees only the word ‘ring’; yet, with her left hand, the patient may select a picture of a key and ignore pictures of both a ring and a key-ring. Generally speaking, visual information projected to the RVF cannot be verbally reported, and visual information projected to the LVF is unavailable for behavior involving the right hand. In the tactile modality, the patient cannot describe, or use her right hand to respond to, objects palpitated by her left hand, and objects palpitated by the right hand cannot be reported via left-handed actions.
>
> Representational disunities involve a lack of integration between the contents of the patient’s conscious states. These states do not enjoy the inferential promiscuity that conscious states typically enjoy. The patient in the key-ring experiment appears to have representations of the words ‘key’ and ‘ring’ without having a representation of the word ‘key-ring’. Similarly, a patient might appear to be conscious of the identity of the objects palpitated by each hand but have no conjoint awareness of both objects. ***As we shall see, the precise nature of behavioral and representational disunities differs from patient to patient, but the foregoing description captures the core features of the split-brain syndrome.***

-The Unity of Consciousness and the Split-Brain Syndrome

Your question specifically asks about what happens when there is conflict between the hemispheres. One side being pleasured and another side being tortured. In general the response mode will determine which action is taken. The right typically responding to visuo-structural similarities between two stimuli and the left functional-conceptual similarities according to Levy J (1976). However the left side of the brain tends to remain dominate in determining what the end result is during conflicting stimuli.

> In general, not only partially but also fully split-brain patients behave in a coordinated, purposeful and consistent manner, belying the independent, parallel, usually different and occasionally conflicting processing of the same information from the environment by the two disconnected hemispheres. Free field performance often resembles that of the superior hemisphere (horse race), especially when the task is linguistic and performed better in the disconnected LH. Occasionally the LH dominates free field responses even when it is inferior to the RH. On rare occasions the RH dominates in spite of being inferior, particularly when the task has prominent visuospatial components. Thus, hemispheric dominance in responding is not al ways the same as the superior unilateral competence (Levy and Trevarthen, 1976).
>
> When the two hemispheres receive competing stimuli at the same time, the response mode tends to determine which hemisphere controls behavior: Lh responses reflect RH decisions and Rh responses reflect LH decisions, even when these decisions are in mutual conflict. A variant of this technique presents brief chimeras consisting of competing half stimuli around fixation, divided along the vertical meridian (Levy and Trevarthen 2). In this case, both the nature of the task and the response mode interact to select a behaviorally dominant hemisphere.
>
> Bimanual responses facilitate interhemispheric cooperation for compatible stimuli in the two VFs even in the split brain. It seems that motor responses tend to be unified so that in the chronic condition the two hands do not respond in conflict with each other even when the two hemispheres make conflicting decisions.
>
> The disconnected LH can be said to be generally dominant for several reasons. First, it is more likely than the RH to assume control over behavior in unlateralized situations. Second, it has better ipsilateral visual and tactile-kinesthetic sensory motor control than the RH. Third, LH performance is more stable and less sensitive to small task differences. Fourth, although each disconnected hemisphere is hemianopic with respect to ipsilateral half space and does not deny ipsilateral perceptual experience, the disconnected LH does routinely express disbelief of correct RH responses to left sensory field stimuli.

-The Split brain
> 3 votes

# Answer
I definitely agree, and so have many of my intro psych classes! I'm only as familiar with split brain research as my intro students are though (okay, maybe a little more than that), so I'd love to see more answers here. As for mine, I don't have any references to contribute from comparative (animal) psychology...All I have to offer is an Intro Psych classic with which you might already be familiar: an episode of Scientific American Frontiers that features Mike Gazzaniga's research. My personal favorite among the brief series of tests (quasi-experiments at best) portrayed here is the one that starts at about 5 minutes and 40 seconds in, because it involves a rationalization by the "Man with two brains" of his own subjective experience. Serious mental gymnastics on display right there.

**Edit:** The parts of the question I answered mostly have just been edited out. I should add that anyone interested in split-brain research in general might find other questions here that mention "split brain" or "split-brain" interesting as well.
> 1 votes

# Answer
They did it on a monkey. It was trained to pick up something with its left or right hand according to a signal. Then they split its brain and tested it. I can't remember all the details but the experiment did not bring more to the human experiments. If you are still interested I can find the link or article.
> 1 votes

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Tags: experimental-psychology
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# Question
Title: Why are people biased against overweight people?
Several studies have shown that alot of **people are biased to underestimate\undervalue overweight people**: http://www.npr.org/sections/13.7/2013/06/06/188891906/the-fat-shaming-professor-a-twitter-fueled-firestorm

Why is this?

# Answer
It is easy to fall into an interpretive bias when evaluating the capabilities of overweight people. In other words, we understand that they are not as physically capable, and therefore undervalued/underestimated due to the interpretive bias.

Another thing is, similar to the idea of racism, Positive Distinctiveness kicks in. This is where, as humans, we see ourselves as part of a group (in this case, a non-overweight group) and we like to perceive our group as the more significant one. Unfortunately, one of the ways to perceive ourselves that way is by looking down on other groups (overweight people), and therefore they are undervalued.
> 2 votes

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Tags: social-psychology, bias
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# Question
Title: Are there specific neurotransmitters for specific sensations?
Nerves can detect pressure, temperature, light (eyes), sound, friction- at least. Does each sensation have its own neurotransmitter?

I'm only a little familiar with neurotransmitters. This page pretty well sums up what I know about neurotransmitters.

So it seems like its a combination of neurotransmitters that flow from any single perception area.

# Answer
> 2 votes
No. For example, the neurotransmitter at the first stage of auditory processing (the inner hair cell VII cranial nerve synapse) and visual processing (rod and cone synapses with a bipolar cells) is glutamate.

# Answer
> 2 votes
There are neurotransmitters that are associated with specific functions within a neural circuit, but I would not associate a specific neurotransmitter with a specific sensation. There is also more complexity to this, because there is a plenty of receptors for each neurotransmitter. These receptors have slightly different properties, which may influence the effect on the post-synaptic neuron and consequently the percept. Another concept is the effect of neuromodulators that regulate larger areas of the brain, e.g. noradrenaline, or serotonin. These have broad effects that change the brain state and are associated with a certain 'feeling'. For example, release of noradrenaline would lead to higher ventilation, higher heart rate, sweating etc.

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Tags: neuroscience, neuro-transmitters
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# Question
Title: What is happening neurochemically when we seek to reduce stress by taking aggressive action?
As a layman, it seems to me that humans have **2 primary strategies for controlling stress** (cortisol). I tend to use the words “connection” and “aggression” to refer to these strategies.

The “**connection strategy**” involves *deepening an empathetic connection with others*. This deeper connection enables us to be aware of their current emotional state and thus to set them at ease which opens them up to be influenced. Because we can now feel their emotional state in real time, we can calibrate our interactions with them to influence their thoughts, feelings and actions more skillfully.

I like to think of this as the Non Violent Communication strategy used by Gandhi, Martin Luther King, Nelson Mandela, etc. to remain calm even when threatened with danger.

It seems that oxytocin is involved in this connection strategy. When our response to stress involves shifting our focus and intention to connection, oxytocin increases and cortisol decreases. (I think)

The “**aggression strategy**”, on the other hand, seems to involve involves taking determined action to conquer something that we believe to be causing the stress.

I am guessing that hormones like adrenaline and maybe testosterone are involved in this process but I’m not sure.

What is actually happening neurochemically when we get aggressive?

I believe that serotonin is involved in both strategies. Serotonin being the neurochemical that is released when we have confidence that our needs can be met. I believe that both the connection and aggression strategies seek to reduce cortisol and increase serotonin, but I would really like to understand exactly how this works. Especially for the case of aggression.

# Answer
> 4 votes
So there's a lot of things to talk about here.

First off, there are many strategies one can use to regulate stress. James Gross, for example, has put forward an incredibly influential process model of the strategies we might use. His work and others have pointed to:

* Distraction
* Reappraisal (reinterpreting the situation)
* Expressive suppression
* Thought suppression (Wegner)
* Rumination (Nolen-Hoeksema)
* Worry
* Self-distancing (Ayduk, Kross)
* Situation selection
* Situation modification
* Interpersonal regulation (social support)
* Acceptance (Linehan)
* Exercise
* Social sharing (Rimé)
* Externalizing behavior (e.g., aggression)
* Drugs
* And more…

Not all of these are "effective," but you can see that there are a lot of ways to cope with stress.

When talking about aggression, there's likely a bunch of processes going on that could change depending on the context and individual. The psychophysiology and neurochemical changes from one instance to another, and from one person to another, are likely not going to be the same. **So there's not really one answer to your question.**

Indeed, aggression:

* can be negatively or positively valenced (i.e., it can feel good or bad; e.g., Chester & DeWall, 2015)
* might involve some sort of external or internal focus (recruiting relatively more exteroceptive attentional networks, e.g., Wager et al., 2015 or interoceptive cortex, e.g., Dambacher et al., 2015, respectively)
* might involve a lot of top-down regulation (e.g., Achterberg et al., 2016) or be largely impulsive
* might motivate approach or withdrawal behaviors

And this logic extends to neurotransmitters, neuropeptides, and hormones. Their activity depends on the context and the person (over time). **In general, you can probably expect a complex interaction among these things, and involvement of practically all of them.**

So as with most things in psychology, the answer is: **it depends!**

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Tags: cognitive-psychology, abnormal-psychology, stress
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# Question
Title: How would the blind experience a hallucinogen like LSD?
I have heard that LSD allows you to see ridiculous things. But they are things that you have seen, or can imagine to see. If you've never seen before (like a blind person), what effect will LSD have on you? Articles on google do not go into the specifics of the brain functionality when the drug is taken. I'm looking for a more detailed explanation

# Answer
> 3 votes
**Short answer**
Based on a dated and small study, early-blind individuals do not experience drug-induced hallucinations, while the late-blind can, but not necessarily do so.

**Background**
Krill *et al*. (1963) investigated the effects of LSD on totally blind people (i.e., no residual vision) and they report visual hallucinations in 13 out of 24 subjects. This study shortly reviews three other studies in this field (LSD and mescalin administered to blind people) and the consensus the authors reach is that blind folks do experience visual hallucinations.

However, as @JoeBathelt very rightfully notes, it is important to acknowledge the difference between **congenitally** blind and **late blind** people that lost vision later in life. Late-blind individuals often experience visual imagery, while congenitally blind do not and cannot. In the Krill *et al.* study linked, they included four congenitally blind subjects. The remainder were acquired blind that had lost their eye sight later in life. The congenitally blind group had lost their vision at, or before the age of two (which I would call early blind, but that's debatable). None of these 4 subjects experienced hallucinations. Given that half of their study group experienced hallucinations, one would expect two of these four to have experienced hallucinations. Although the congenitally (i.e., early-blind) group was small, it leads me hence to believe that prior visual experience at least early in life is a prerequisite for visual hallucinations to occur. However, not many studies have been published on the topic and I am most curious to see more answers to this most interesting question.

<sub>**Reference**
**-** Krill *et al*., *Arch Ophthal* (1963); **6**: 180-5</sub>

# Answer
> 2 votes
I'm not sure about any reliable research on hallucinations in blind people per se. However, there is a large body of literature on visual imagery in congenitally blind groups. This is assuming that hallucinations are based on typical representations, but are usually held in check through inhibition.

Research conducted by Pring et al. found that congenitally blind people experienced non-visual imagery in a memory recall task, but the imagery was less vivid in comparison to typically-sighted controls (Goddard & Pring, 2001). A review by Cattaneo and colleagues also indicated that imagery does exist in congenitally blind people, but that it may rely more on verbal or haptic representations.

Extrapolating from this research, one would assume that congenitally blind individuals experience hallucinations that are based on non-visual experiences and that these may be less vivid compared to visual hallucinations in sighted people.

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Tags: neuroscience, hallucinations
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# Question
Title: Do dissolving myelinated connections explain learning?
In order to understand how we get rid of established habits/behavior: Can myelinated connections be dissolved or are new connections created that bypass those connections?

# Answer
Myelin is a greatly extended and modified plasma membrane wrapped around the nerve **axon** in a spiral fashion (Morell & Quarles, 1999). It typically forms on long axons to increase conduction speed and efficiency.

Learning predominantly takes place in cortical areas and it is believed that it mainly depends on synaptic changes, such as long-term potentiation (LTP) of **synapses**. Forgetting things is believed to be mediated through long-term depression (LTD).

Both LTP and LTD are synaptic processes and do not involve myelin, as that substance is found around axons. Although there is a lot more to learning than I can cover here, I dare say it doesn't involve myelination, and forgetting things doesn't involve demyelination, or *vice versa*.

Demyelination typically results in disease. The most common one being multiple sclerosis, characterized by blurred or double vision, thinking problems, lack of coordination, loss of balance, numbness, tingling and weakness in an arm or leg.

**References**
**-** Morell & Quarles. The Myelin Sheath. In: Siegel GJ *et al*., (eds). Basic Neurochemistry. 6th ed. Philadelphia: Lippincott-Raven (1999)
**-** Purves *et al*., (eds). Neuroscience. 2nd edition. Sunderland (MA): Sinauer Associates; 2001
> 4 votes

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Tags: cognitive-psychology, neuroscience, learning, theoretical-neuroscience
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# Question
Title: During synchronized waves oscillation (alpha beta etc...) do neurons fire only once for each wave cycle?
Or can they fire few times then pause and again, firefew times and pause periodically? If the second case happens then do we know if the neurons that fire in synchronity fire the same number of times at each wave cycle?

# Answer
> 2 votes
Probably, the "oscillation" refers to the signals of eeg/ecog/meg? If this is the case, then the answer is NO, individual neurons in a local network are firing with much higher rate then the frequency of the oscillatory field produced by the network. (Otherwise, the oscillations would look more like a ripples, not like the periodic function.) The exact number of spikes of any given individual neuron is vary over time within a certain range and most probably different from one cycle of the network-level oscillation to another.

In general, individual neuronal activity is probabilistic, not deterministic. So, any natural situation is changing the probability of the spike, but it is never 100% predictable.

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Tags: neuroscience, theoretical-neuroscience, neural-network
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# Question
Title: Emotional detachment as a reaction can be considered an aggressive behavior?
Social Rejection from Wikipedia

> rejection can be passive, by ignoring a person, or giving the "silent treatment".

Is it possible to say that the **victim of a verbal aggression** who **hide** or repress (negate) the **negative emotions** like fear, anger, sadness through the emotional detouchment showing himself as secure, not hurted **can lead the other to feel impotent** and thus become even more aggressive to get an emotional reaction?

**Can emotional detachment be considered as a dysfunctional behavior for the victim of a verbal aggression?** Opposed to demanding empathy.

Emotional detachment can be considered a kind of hostile / aggressive behavior?

**EDIT**

Is there any evidence that most of people would suffer from these kind of other's behaviours so that they can be considered a way to hurt people?

# Answer
It is not clear the context in which you expect an answer. For example, should it be considered from a legal, ethical, survival, or psychological standpoint? I would expect the answers aimed at different philosophies to differ quite a bit. Let me address a few of your questions, at least as I understood them in your posting.

Can the person being "ignored" feel impotent as a result of this "silent treatment"? Of course this can happen. However, this reaction is not something that should be blamed on the person doing the ignoring. After all, if you look at someone funny and they throw a tantrum, is it your fault they cannot control themselves?

"Can emotional detachment be considered as a dysfunctional behavior for the victim of a verbal aggression?" *Dysfunctional* is not a term that can be legitimately applied here without context. There are many cases where ignoring a verbally abusive person can be extremely useful or even necessary to carry on with daily activities. For example, if people talking on forums got caught up responding to trolls, they would not be able to have reasonable discussions with non-trolls. A troll is a perfect example of a verbally abusive person for which silent treatment is clearly not "dysfunctional". The key thing you have to understand here is the *intent* of the verbal abuse. If the abuser is simply trying to reason or convey a message, with no hidden agenda, then reasoning in response may be fine. However, if the verbal abuser is *socially sadistic*, such as a troll, then the worst thing you can do is to get emotional in response to his or her provocation. After all, that would be accepting the damage they are trying to inflict for their sadistic pleasure.

Should a person "demand empathy" instead of ignoring the abuser? Successfully demanding and receiving empathy requires two things: (1) You must be deserving of empathy, which is highly subjective, and (2) the abuser must be able to feel empathy. The former requirement could necessitate skills in persuasion, which not everyone has. Furthermore, if you are being verbally abused because you legitimately did something wrong, you would need to show that you understand your wrongdoing and truly intend to make things right. The latter requirement depends on the personality and mental state of the abuser. A psychopath, for example, would not be able to feel empathy, so there would be essentially no point in trying to demand empathy from them. In fact, it would be dysfunctional to demand empathy from a psychopath. Such would be like demanding a shower head to dry you.

"\[Can\] emotional detachment can be considered hostile / aggressive?" Hostile perhaps, but I cannot see it being "aggressive" since it is in the very definition of the word that force be involved, which clearly is not the case in reactionary abstinence. Sure, there is such as thing as "passive aggressive", but the term itself is practically oxymoron. A more correct term would be "passive hostility".
> 1 votes

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Tags: cognitive-psychology, abnormal-psychology
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# Question
Title: how to see prefrontal cortex is functioning well by a test?
Is there a test to see if the Prefrontal cortex of someone works normally? especially a simple test like a questionnaire that you give the individuals to fill out and based on their answer you obtain results.

My next question, if someone's prefrontal cortex does not work normally, how that can be cured? I am looking for natural ways, natural medicines, or methods.

# Answer
> 1 votes
I'll tackle the first part of the question as cognitive training is a whole can of worms on its own:

The function of the prefrontal cortex should be assessed by a trained neuropsychologist, who can administer the appropriate tests and compare results to reference data from the broader population.

One commonly used test associated with prefrontal cortex function is the Wisconsin Card Sorting Task (WCST) \[1\]. For this test, the participant has to match cards according to changing rules. This test has been used extensively with patients with various neurological deficits and psychiatric disorders and seems to be sensitive to pathology of the prefrontal cortex.

Questionnaire measures are generally quite crude and are usually only used as a screening instrument for more detailed tests.

Reference:

\[1\] http://www.cognitiveatlas.org/task/Wisconsin\_card\_sorting\_test

# Answer
> 0 votes
This article might interest you. It discusses some of the anatomy, functions, and neuropsychological tests related to the prefrontal cortex (PFC).

The prefrontal cortex (PFC) is a relatively big area and serves many functions, so there's not going to be a single test that evaluates PFC function. Some tests will look at inhibition (the ability to avoid an automatic or trained behavior), task switching (like the WCST mentioned above), attention (PFC is thought to be important for controlling directed attention), working memory (memory of a small set of items for a short period of time). Self control is a really important function served by the PFC, especially in modern society. Remember that everyone is different, so someone will a lack of inhibition might not necessarily fall into the category of having a brain disorder. A neuropsychologist will do their best to use the limited tools available to categorize you based on some generally agreed upon diagnostic criteria, and if you fall into a gray area then that diagnosis might not mean much.

As far as how to cure an abnormal PFC? If you are under 25 years old or so, time will help. Many people's PFC is not fully developed until their mid 20s. Cognitive training is unproven, but the human brain is really good at learning and changing. It seems that people can learn maladaptive behavioral patterns over time, so why can't they train themselves toward better patterns? If you want to improve your self control (say to stick with a diet), then use every opportunity you get to train your self control. Make it like a game and give yourself a pat on the back when you do well. If you really stick to it, your brain could eventually learn to prioritize this type of behavior and get better at it. Note that this type of training hasn't necessarily been scientifically proven, but it makes sense and it sure hasn't been disproven either.

P.S. I'd recommend that you skip any natural medicines that might be advertised as improving cognition. Best bet nutritionally is to eat well and drink a lot of water.

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Tags: cognitive-psychology, cognitive-neuroscience, clinical-psychology
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# Question
Title: How far can a signal travel in the neocortex without passing through the white matter?
Correct me if I am wrong please, from what I understand horizontal communication spans very short distance in all layers of the neocortex but layers I and II. In these two layers dendrites and axons can travel horizontally a little farther, but how far? Also the question can have different subcases. First one, how far can one single dendrite or axon travel horizontally in the neocortex ? Second one, how far can a signal travel (possibly going through several synapses) horizontally in the neocortex?

# Answer
> 4 votes
The distance of horizontal communication depends on species, cortical region, and cortical layer. Very few combinations of those 3 factors have ever been studied. For the combinations with which I am familiar, most horizontal connections are limited to a few hundred microns, though some are as long as a few millimeters. Most of that distance is axonal because dendrites are generally much shorter than axons. Of all the connections I've read about, none span an entire region. To get across a region, a connected series of signals would have to make several hops through several neurons and across several synapses, as you suggested in your question.

The direct path of an axon connecting two cortical areas (or an axon from a subcortical area to a cortical area) is through the white matter, but sometimes an axon will additionally ascend to layer I of the target area before branching, presumably to save space. This is the main use of layer I, and the lengths of these connections is several millimeters or centimeters.

I have never heard of the longer-distance horizontal connections that you suggest occur in layer II; layers II through VI contain neurons with short horizontal and vertical connections.

### References

> * Alonso, J.-M. (2002) Neural Connections and Receptive Field Properties in the Primary Visual Cortex. The Neuroscientist. 8(5): 443-456.
> * Feldmeyer, D. (2012) Excitatory Neuronal Connectivity in the Barrel Cortex. Frontiers in Neuroanatomy. 6: 1-22.
> * Rockland, K.S. and Virga, A. (1989) Terminal Arbors of Individual Feedback Axons Projecting from Area V2 to V1 in the Macaque Monkey: A Study Using Immunohistochemistry of Anterogradely Transported Phaseolus vulgaris-leucoagglutinin. The Journal of Comparative Neurology. 285: 54-72.

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Tags: neuroscience, neural-network, neuroanatomy
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# Question
Title: What is input resistance and how to interpret its values?
For example, this site gives a distribution of values of the input resistance of various cells. The values are in MOhms. The definition says that "input resistance measured at steady-state voltage response to current injection".

How can its value be interpreted? What do high or low values indicate? Does it relate to other cell properties?

# Answer
> 3 votes
Ohm's law famously states V=IR, the voltage change (V) across a resistor generated by a current (I) equals the current multiplied by the resistance (R).

The resistor in this case is the cell membrane. When an experimenter injects a known amount of current through an electrode, the voltage change that occurs is related to that current by the resistance of the cell membrane. A high value indicates that the cell membrane does not let current pass easily so a given amount of current requires a large voltage changes.

The size of the cell and the number of open ion channels affect the input resistance. Larger size means lower resistance (more surface area for current to flow through) and more open ion channels means lower resistance (the conductance g=1/R increases when you open ion channels so the resistance decreases).

As for relevance to neural computation, higher input resistance means that less synaptic input (current injection) can lead to larger voltage changes. Manipulating input resistance (say by opening Cl- channels, which don't change the voltage of the cell much but do decrease the resistance) can change the responsiveness of the neuron to other inputs. This phenomenon is called shunting inhibition.

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Tags: neuroscience, electrophysiology
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# Question
Title: Why do we say that some animals have consciousness and some don't?
For example, I have heard many say that ants don't have consciousness but humans do. I have always thought that our bodies/brain works more like computers (inputs and outputs). An analogy I can give (may not be the best) is that ants are like calculators and humans are like computers. It's the same idea of input and output but the outputs we give are a lot more complex.

How can we definitely say that we are conscious and not responding to inputs albeit much more complexly than ants?

# Answer
This reminds me of a similar question I answered a few weeks ago. Not exactly the same situation, but the leading theory is that it comes down to complexity.

I'll start out by saying that we don't know for sure what animals are conscious or even what consciousness is, exactly. In fact, it's not even possible to prove without a doubt that you or I are conscious.

We do mostly seem to have a general intuition of what consciousness is, and which things are or are not conscious. Probably most people would say that an ant does not possess consciousness, and the complexity argument would back that up. While ants do have brains, the structure of their brains is very different from the brain of a mammal. Most people would say that a human has consciousness; from experience for one thing. How about a killer whale, a monkey, or even a human infant? There might be less of a consensus in these cases. In my opinion, we should err on the side of consciousness whenever possible.

Lastly, I get what you're saying with the computer analogy, but the human brain is **so** much more complex than a computer and it definitely works differently than any kind of man made computer. Even some of the new chips that are built to mimic networks of neurons are missing a lot of what is going on in vivo. There are interactions occurring between living neurons that aren't fully understood yet. A more accurate analogy would be that the human brain is like a high-end future computer-like object and an ant nervous system is like a very low-end future computer-like object. One difference between high-end and low-end future computer-like objects might be the ability to experience consciousness.
> 1 votes

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Tags: cognitive-psychology, consciousness
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# Question
Title: What does it even mean to have a male/female brain?
I have began taking a class on the sociology of gender and how gender is more malleable than previously thought and that femininity and masculinity exists in a continuum. What does this actually imply for the observable activity of people? For example, are women born with more male brains more likely to be lesbian? or prefer male friends? or prefer a more feminine sexual partner? And Can you tell from physical appearances that an individual has a more masculine or feminine brain? (ex: a man with a more feminine voice or a woman with more masculine features)

# Answer
> 5 votes
I don't think the idea of a male/female brain is well established in the neurosciences.

If you read a book like Delusions of Gender you'll get a critical perspective on the status of sex differences in the brain.

At some level, sex differences in behaviour must be mediated through the brain. But there are major debates about the degree to which such behavioural differences are influenced by social versus biological factors. Likewise, the image of the brain can create an excessive sense in which we are talking about a fixed entity. In addition, with regards to a range of behaviours and brain factors, there is often more overlap than there are differences between the sexes.

None of this aims to deny the value of a deep study of the neuroscience of sex differences. It's just that I don't think the concept of the "female brain" makes sense, certainly not at this point in our understanding.

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Tags: cognitive-psychology, social-psychology, gender, sociology
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# Question
Title: How much our visual limitations are instrument(eye)-based, and how much are they brain-based?
Are the limitations to our vision like the field of view and singular focus entirely based on the limitations of the eye?

It seems like it's possible to feed an artificial signal into the brain through the optic nerve. What would happen if you fed a 360 video through such interface?

What kinds of differences in experience would this provide, regarding the ability to focus on particular object for example? Seems like moving the eye would not be substantial anymore (no need for optical focusing), which introduces another curious situation on it's own. Would the brain be able to adapt to operate with multiple (mental-visual) focus points in such setting?

# Answer
> 1 votes
My understanding is that the eyes are actually quite poor in terms of providing the brain with a clean image. Perhaps the only areas where eyes are better than cameras are with simultaneously viewing light and dark together (high-contrast), being quite fast at focusing, and being able to see reasonably in low-light. Each eye has a full-on blind spot, and the ability to see colours in the periphery is quite limited. Almost everything about our clean visual perception is a result of the brain's compensatory mechanisms -- such as filling in holes and choosing colours based on memories.

Although an unscientific perspective, when I dream, I can see clearly not only in the centre but also in my periphery. Moreover, my vision does not have the static-like overlay in my dreams like it does in real life. (I am often consciously aware when I am dreaming, wherein I have done various tests in my dreams) Hence, my guess is that the brain is capable of handling a fair bit more data than the eyes provide.

When you consider all the people born with abnormalities, and when you consider the array of change that your body goes through during development all the way through old age, it should be capable of handling all sorts of unnatural situations. Even looking at a computer screen and understanding the idea of windows being behind other windows and the idea of a webpage being like a long scroll for which you can see only a part of it are rather unnatural. Many of those brought up before the time of computers have a great deal of difficulty understanding the virtual realm that resides inside the screen (of computers, smartphones, and other modern gadgets).

The concentration of receptors is vastly greater near the centre of visual fixation. While I doubt the brain could handle seeing in full definition in the periphery, it could probably handle quite a bit more than it currently does. I do believe the brain could handle mentally focusing on multiple regions simultaneously. I can focus mentally on three or four areas of my periphery at once, despite the image being quite unclear. At the same time, the brain has limited capacity. For example, they say that the human brain can handle tracking up to 60 moving objects within something like 30deg of visual field. If we could see all the way around us at once, I imagine it would be quite demanding of our attention -- but I am sure we could grow to become accustomed to it.

# Answer
> 1 votes
The distinction that you draw between "instrument"/eye and brain is not particularly clear, and to some people it makes more sense to think of the eye as *part of* the brain.

Regardless, let me try and summarise some visual limitations and their causes. Our visual acuity and contrast sensitivity are limited by the optics of the eye (e.g., the lens), the arrangement of photoreceptors on the retina, and the centre-surround organisation of receptive fields (in the retina, but also in V1 and other parts of the visual brain). Some good sources for this are: http://webvision.med.utah.edu/book/part-viii-gabac-receptors/visual-acuity/ https://foundationsofvision.stanford.edu/chapter-6-the-cortical-representation/ (the second of these, Wandell's book, has plenty about the organisation of visual cortex).

As I think you are hinting, we also move our eyes (fixations and saccades), so that we process a sequence of locations at high (foveal) spatial resolution. I suppose you could also look at this as a limitation (though it is one that is shared by almost all species, which is quite interesting in itself).

Answers to the rest of your question are obviously going to be speculative. On the one hand, the brain is quite plastic and shows (sometimes amazing) re-organisation if it is given different visual inputs (for example there is evidence that the visual cortex of blind people takes on different functions). On the other hand, I find it very unlikely that our visual cortex would cope with the increase in information that you are suggesting, or that it would allow us to behave any differently. It would mean a dramatic re-organisation of the way it is currently set up (which reflects the receptive fields and the field of view we normally have). Bear in mind that there are far fewer responding neurons in V1 than there are photoreceptors in the retina, so the brain is already filtering and compressing the information. There simply wouldn't be enough to perform the same computations across a far wider area, though I suppose we might have poorer resolution over a wider area. As for the other point and the answer about "mentally focusing", in natural conditions both fixation and covert attention tend to be on a single location. This probably has numerous benefits (e.g., mapping coordinates in space so that we can plan actions) and a much wider field or multiple pointers would probably be less efficient.

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Tags: vision, optical-illusion, brain-computer-interface
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# Question
Title: give me concrete example of mindless and mindful activity
Can you give me concrete example of mindless activity and mindful activity? which category "watching movie" or "reading novel" belongs to?

my definition of mindful and mindless? mindful to me is being aware of things I am doing. mindless is doing it without being aware of that activity (like auto pilot)

how to measure mindful and mindless objectively? I honestly don't know the answer to that. but if i may try, maybe from the way I can retrace it back in my memory to the detail information.

I have been doing a lot of activity throughout my daily routine. a lot of those activities has been done mindlessly out of habit. how can I do it mindfully?

# Answer
> 2 votes
In think what you are referring to automaticity Vs explicit processes, which according to the dual processing theory are performed from system 1 and system 2 respectively.

> Automaticity is the ability to do things without occupying the mind with the low-level details required, allowing it to become an automatic response pattern or habit. It is usually the result of learning, repetition, and practice.
>
> Examples of automaticity are common activities such as walking, speaking, bicycle-riding, assembly-line work, and driving a car (the last of these sometimes being termed "highway hypnosis"). After an activity is sufficiently practiced, it is possible to focus the mind on other activities or thoughts while undertaking an automatized activity (for example, holding a conversation or planning a speech while driving a car).

.

> System 2 is evolutionarily recent and specific to humans. It is also known as the explicit system, the rule-based system, the rational system, or the analytic system. It performs the more slow and sequential thinking. It is domain-general, performed in the central working memory system. Because of this, it has a limited capacity and is slower than System 1 which correlates it with general intelligence. It is known as the rational system because it reasons according to logical standards. Some overall properties associated with System 2 are that it is rule-based, analytic, controlled, demanding of cognitive capacity, and slow.

Examples of explicit processes is finding the result of 312x254, learning a new physics theory etc

# Answer
> 2 votes
I'm not sure that a "concrete example" of mindless activity vs. mindful activity is possible, because it requires the use of subjective interpretations of what constitutes either of those two notions.

### Mindfulness

> Mindfulness is a state of active, open attention on the present. When you're mindful, you observe your thoughts and feelings from a distance, without judging them good or bad. Instead of letting your life pass you by, mindfulness means living in the moment and awakening to experience.

Using this definition, it seems as though there are relatively few activities one can perform while being *mindful*. If an activity requires a high level of concentration to perform, than it would be difficult or impossible to simultaneously focus on the meditative internal and external reflection implied by 'mindfulness.'

Examples of some activities that might be more favorable to such meditation:

* Going for a walk or hike somewhere
* Going to a quiet, secluded location
* Doing chores around the house that require little concentration

Examples of some activities that might *not* be favorable to such meditation:

* Socializing
* Working on a task that requires a lot of concentration or creative problem-solving
* Watching an interesting movie or reading an interesting book, (unless perhaps you pause for self-reflection from time to time.)

### Mindlessness

This is also tricky because it may mean different things to different people. Mindlessness might mean simply the opposite of mindfulness, in which case the counter-examples I listed above might be considered 'mindless.'

However, it seems a bit strange to include things like creative problem-solving and socializing as a "mindless" activity; because your mind is absolutely engaged in what's going on, just not in the same sense as it is for a mindful / introspective reflection.

Perhaps a fair definition of "mindlessness" is if you're by yourself with some free time; instead of choosing to engage in some social and/or mental activity, or meditate in a mindful way, you just sit around; being bored, thinking about how boring something is, etc.

Yet even "mindlessness" with it's negative connotations may have some importance. Sometimes when you're undergoing great stress, mindful meditation may be good and useful but you're not ready to do it; you may need to distract yourself from something that's troubling you. You might have to try something "mindless" to clear your head a bit before you can even be "mindful."

### Conclusion

The truth is; the human brain never truly slows down while you're alive. There's a persistent myth that we only use 10% of our brain; but while it's true that only portions of our brain are active at any given moment, we actually use 100% of our brain, just not all at the same time. It would be destructive and/or impossible to use 100% of your brain at once, that's not how the brain is designed to work. http://ed.ted.com/lessons/what-percentage-of-your-brain-do-you-use-richard-e-cytowic

In this sense, the question of "mindfulness vs. mindlessness" isn't necessarily about whether or not you're using your mind. You use your mind regardless, even in your sleep. The question becomes whether or not you're using your mind *well*, and that ultimately is a personal, subjective question.

The closest I can say to understanding it objectively is that it's probably healthiest to strive for balance in how you live your life.

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Tags: cognitive-psychology
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# Question
Title: Using Cognitive biases for behavior change?
I'm interested in using cognitive biases as basis for behavior change, similar to what we see in gaminfication (e.g. instant gratification to hook people to continue playing). I'm new to the field and I wonder if there are some underlying theories I should be aware of. I found Cognitive bias modification however they seem to focus on clinical applications helping patients with depression, anxiety or addiction.

Is there a theory about how to apply cognitive biases for more general or other behavior change directions (not clinical applications)? Let's say I have a certain unwanted habit I want to get rid off, depending on the habit and my background, there might be cognitive biases to help me change the habit.

# Answer
> 1 votes
CBM is not so much a theoretical framework but rather a label attached to a collection of methods and biases. In a way, this reflects the state of research on heuristics and biases, at least in behavioral economics. As many famed findings in the field have come from attempts to "disprove" traditional economic theory, the resulting effects (biases) have often remained without a satisfying explanation in the form of a plausible cognitive process. This has hindered
the formulation of a common theoretical framework in which various biases could be classified (according to, e.g., underlying cognitive mechanisms, preconditions w.r.t. context and subject, effective interventions).

(To name an exception, a framework covering comparison selection was recently proposed by Simonson, Bettman, Kramer & Payne 2012. The authors cover a number of effects which may commonly be labeled "biases". In addition, various frameworks based on some form of dual-process theory have been proposed, but there is a lot of redundancy between them.)

In addition, the "heuristics and biases" literature has remained largely separate from the psychology of behavior change and, arguably, from cognitive psychology. Look no further than the popular "Nudge" by Richard Thaler and Cass Sunstein: almost all of their implications are derived directly from the biases "as effects" rather than being derived within a more general framework grounded in cognitive process theory.

In short, to the best of my knowledge, the framework that you seek does not exist. I expect that you will find it necessary to devise behavior change strategies one bias at a time.

*As a final remark, the heuristics and biases literature has been criticized for tarnishing what may actually be highly adaptative and efficient cognitive strategies (see the illuminating works by Gerd Gigerenzer). Accordingly, many a bias may be exploitable only under rather specific and unusual circumstances.*

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Tags: cognitive-psychology, bias, theory-of-mind, behavioral-economics
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title: How can I make a speller with BCI?

text:
# Question
Title: How can I make a speller with BCI?
I am trying to make a speller with BCI using EEG (SSVEP or P300, whichever is easier). I would be really grateful if someone could give me a plan of action so as to where do I get started and what skills or tools I might require. As for now, I have access to a cognitive neuroscience lab and EEG. Thanks.

# Answer
Yeah this is a very common and effective approach. Try doing a google search for: ***P300 speller github*** for some implementations. One issue that you should pay attention to is the limited refresh rate of computer monitors. You are going to want very accurate synchronization between what is shown on a monitor and the EEG being recorded. You'll want to use some type of framework that allows for this synchronization such as PsychoPy (for Python) or Psychtoolbox (for Matlab).

Here is a great writeup of how to implement a P300 speller in Python. Looks like they use Pyff.

First step, in my opinion, is to look at some examples that have already been implemented:

Here is a Matlab framework for BCI with an example P300 speller that uses PsychToolbox for good event timing. Looks like the repository is actively maintained.

Also, look at OpenVibe. Another framework for BCI. There are a lot of examples available there.

Try one or a few of these out and see if you can get something that has already been made working. Then you'll be in a much better position to implement your own speller.
> 1 votes

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Tags: cognitive-neuroscience, eeg
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# Question
Title: When does reward occur? When dopamine is released or when it is binded?
I know this is a silly question, but I'm curious as to what is the exact phase when we experience of the thrill of doing an exciting activity.

I believe this briefly describes the whole process. So, what is the exact point where we feel like "rewarded", when dopamine is released or when it is binded to one of its intended receptors?

# Answer
> 1 votes
My understanding of feed forward systems is that the uptake of transmitter would induce the effect. Though, the simultaneous release of more dopamine is part of its effect. The synaptic gap has no mechanism of inducing a response to a transmitter besides the reuptake on the other side. I am no sort of professional so take what I say with a grain.

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Tags: neuroscience, neurophysiology
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# Question
Title: Looking for a name of a theory or reason behind a seeming cognitive mistake or error
**Setting:** Bathroom, you've just brushed your teeth, turned the water on to let the remainder drift into the drain. After a moment you know there is something that needs to happen(obviously turning off the sink) but instead you flick the light switch off, for no apparent reason.
I realize it's an odd situation but it can be compared to other events where there are multiple options for action and 'accidentally' choose the one you don't mean to.
**Question**
Would this be regarded as cognitive dissonance or is there a better name for this type of action? Thank you.

# Answer
> 1 votes
I think what you describe is a capture error.

> Capture errors refer to frequently performed tasks that take over the correct intended action. Wickens & Hollands clearly define capture errors as resulting from two primary reasons: (1) the intended action and the resulted action share somewhat characteristics that are closely related: and (2) the action sequence is resulted from automated behaviour and therefore, not closely monitored by attention. The example stated earlier about pouring orange juice instead of milk is a capture error by itself.

You had the intention to close the sink, but instead you closed the light. Both actions share the characteristic of closing, closing the light is the most frequent.

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Tags: cognitive-psychology
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title: Why I dont like music?

text:
# Question
Title: Why I dont like music?
I'm not sure, if I'm alone, but I never liked music, any kind of music. It never made me happy or sad. Actually it never ever had any effects on me right from my childhood days. My iPod(received as a gift) is filled with audio version of movies and dramas, but never songs.

Is it some kind of mental illness?

# Answer
I wouldn't call it a disorder, unless it significantly affects your life. Not enjoying music or not being able to produce music is known as "amusia". It probably has to do with differences in perceiving pitch \[1\]. It can also occur in people with recently fitted hearing aids or cochlear implants \[2\].

If you are interested in this, there is a chapter about cases of amusia in Oliver Sack's book Musicophilia \[3\].

References:
\[1\] Liu F, Patel AD, Fourcin A, Stewart L. (2010). Intonation processing in congenital amusia: discrimination, identification and imitation. Brain. 133(Pt 6):1682-93. doi:10.1093/brain/awq089
\[2\] Cooper, W., Tobey, E., & Loizou, P. (2008). Music Perception by Cochlear Implant and Normal Hearing Listeners as Measured by the Montreal Battery for Evaluation of Amusia. Ear and Hearing, 29(4), 618. doi:10.1097/AUD.0b013e318174e787
\[3\] http://www.oliversacks.com/books-by-oliver-sacks/musicophilia/
> 5 votes

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Tags: music, phobia
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# Question
Title: How can I fit a psychometric function such that the minimum is 50% (chance level)?
I have data from the behavioral component of an fMRI study in which subjects are asked to perform a 2AFC discrimination task with targets at variable contrast. That is, a target will be presented at one of several possible contrasts, and the subject must later identify which of two possible responses has the same orientation as the target stimulus.

Below is an example of data from one subject:

Note that I've attempted to fit a psychometric function, using the following procedure (in Python):

```
import numpy as np
import pylab
from scipy.optimize import curve_fit

def sigmoid(x, x0, k):
     y = 1 / (1 + np.exp(-k*(x-x0)))
     return y

xdata = np.array([0.0,   1.0,  3.0, 4.3, 7.0,   8.0,   8.5, 10.0, 12.0])
ydata = np.array([0.01, 0.02, 0.04, 0.11, 0.43,  0.7, 0.89, 0.95, 0.99])

popt, pcov = curve_fit(sigmoid, xdata, ydata)
print popt

x = np.linspace(-1, 15, 50)
y = sigmoid(x, *popt)

pylab.plot(xdata, ydata, 'o', label='data')
pylab.plot(x,y, label='fit')
pylab.ylim(0, 1.05)
pylab.legend(loc='best')
pylab.show()

```

Of particular note is the sigmoid formula I'm using: `1 / (1 + exp(-k * (x - x0)))`.

The problem with this approach is that the fit will pass through zero, wheras with 2AFC data, the minimum value is theoretically .5 -- the guessing rate.

### How can I fit a sigmoid function such that the fit spans from .5 to 1.0?

# Answer
Add 0.5 to the intercept and multiply the sigmoid by 0.5 since it now only spans a y-range half of before:

`y = 0.5 + 0.5 / (1 + np.exp(-k*(x-x0)))`

Generally, for any chance level:

```
chance = 0.5  # between 0 and 1
y = chance + (1-chance) / (1 + np.exp(-k*(x-x0)))

```
> 5 votes

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Tags: psychophysics
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# Question
Title: Are people able to accurately judge body shape and size from images of the face?
I have noticed that when I look at a cropped picture of someone's face, I fill in the remaining image of his/her body in a manner that is consistent with the face (wider face, larger body, skinnier face, frail body, large jaw, more muscular body, etc). Does the human brain immediately and accurately fill in such information and guess what a persons's body looks like from just images of the face?

# Answer
> 1 votes
Yes, barring weird instances of swelling that is localised to the face, for example. Evolutionary psychologists argue that facial cues, including adiposity and skin pigmentation, to name but two, serves as a cue for general health. If this argument holds true, it means that humans developed a fine-tuned ability to make quick judgments about someone's fitness to mate based on various factors related to health, of which facial features happens to be a big one. This might also explain why we find highly symmetrical faces more attractive, as facial symmetry is positively correlated with genetic health markers.

Another example is the seemingly robust correlation between testosterone levels and the square jaw that you mentioned. In turn, testosterone and muscle mass are linked. Ao seeing someone with a square jaw, you automatically infer their testosterone levels as well.

Apart from that, there is an obvious correlation between facial adiposity and BMI, which heavily influences judgments about general health and mating preference.

Short answer: You have this ability because it's highly advantageous when it comes to making judgments about choosing good mates.

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Tags: cognitive-psychology, perception
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