Question of the Week

Why do humans have such a variety of appearances?

Tue, 26th Jan 2016

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Ghayath asked:

Why do we as Homo sapiens have a huge variety of facial features, and is this exclusive to the Homo sapiens?!



We put Ghayath's question to population geneticist Sir Walter Bodner from Oxford Typical extended middle-class U.S. familyUniversity...

Walter - You've hardly ever, I imagine - unless youíre a pair of identical twins, seen anyone who looks just like you do.  We are enormously variable in facial features, and we donít definitely know why that is, but it obviously has strong evolutionary basis; there must be something thatís selected for that.  I think itís part of the way humans have evolved socially that it's been very important to be able to recognise people who are part of your own group, even your own family. There are very special regions of the brain for identifying faces and there are complex processes by which we analyse and discern what it is in a face that we recognise.

Felicity - How much of that variability is down to genetics?

Walter - Well nearly all of it.  If youíve ever seen identical twins, theyíve got exactly the same genetic makeup and when you see them the first time, if youíre not their parents or anything, theyíre almost impossible to distinguish from each other and that tells us that the face is very largely genetically determined.  You can vary it; you can have blue hair if you want; you can do things to your face if you go to the right sort of surgeon but, by and large, most of the features that we recognise in a face are very much genetically determined.

Felicity - When we look at other animals, we donít pick up on as much variability perhaps in their facial features.  Is this something which is unique to humans?

Walter - No I donít think it is, but remember if you go to another country; if you go to Africa or you go to China, you probably donít find it as easy to recognise the facial differences there as you do in your own group.  So thatís one thing, we donít necessarily know how to recognise that chimps may look very different to each other, so thereís undoubtedly a lot of variation there.  Of course, if you take domesticated animals like dogs, a lot of variation has been selected for, so I think there is quite a lot of variation out there; most of it we donít quite know how to recognise.


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We don't, IMHO.

Just ask any European from a generation ago - "Asians all look alike".
Then ask an Asian - "All Europeans look alike".

I think that we get good at detecting the small differences between the individuals and groups with which we are most familiar.

When we are faced with an unfamiliar ethnic group, the small differences are overpowered, and we can't distinguish individuals.

The remaining small differences within an ethnic group are due to the usual suspects - genetics and environment. Environmental factors includes exercise,  climate and nutrition (including before birth). Genetic changes can occur in any gene.

Humans are very genetically similar - the more visible differences like skin color and type of hair do not reflect much of an underlying difference.
See: evan_au, Wed, 20th Jan 2016

I read an experiment report where babies were taught to recognise different lemur faces that adults couldn't differentiate. Colin2B, Wed, 20th Jan 2016

"Why" is because humans take a long time to reach survivable maturity, so we have evolved to recognise our parents and tribe at an early age. We are therefore extremely good at facial recognition, to the extent that Heathrow Airport is going to replace its e-passport machines with more humans because we are far quicker at detecting a match (or a mismatch) despite variants due to makeup, spectacles, facial hair, etc., than any machine. 

The fact that machines aren't very good at it suggests that the variations in human appearance are actually very subtle - more subtle than any programmer has been able to codify! alancalverd, Wed, 20th Jan 2016

a/k/a RD, Wed, 20th Jan 2016

The two sides of the brain process data differently. We use both sides of the brain at the same time. However, we are only conscious of one side of the brain at a time. The other side will be unconscious but complementary. The left brain is more differential and allows us to see differences. The right brain is more integral and allows us to see what things have in common.

Like in math, differentiation finds the slope of a curve at a given point. If the curve is all the humans in the room, the slope of the curve, at a given point, is the unique face of one person. Integration is the area under the curve from A to B. If Europeans go to Asian and see a group of asian people, the right brain all integrate these people into common features; all look the same. If you stay in Asia for a few months or years, then you will begin to see differences.

The reason for this initial and long term reaction is, when we see something new or alien, that we can't fully see and explain we begin to rely on instinct and feelings. This may be fear of novelty. Feelings makes us more conscious of the right brain. This side will integrates the faces; all look the same.

If we stay in that location and begin to adapt, we have less unconscious emotion and more consciousness at the level of our intellect; we trust our observational details. We become more conscious of the left brain assessment; differential. Instead of the area under the curve, we focus at a point on the curve to get the slope.

This become even more complex, such as looking at political orientations, where we lump the other side into a stereo-type. People often believe their political POV will integrates everyone, even though the other side does not see this. The reason for this is since both sides of the brain work at the same time, and one is only conscious of one side, a preferred differential POV, will result in the unconscious mind using the integrator side. This may give us the gut feeling that our limited POV is the area under the entire curve; one side fits all. The moderate person will attempt to go into the right brain and look at this feeling of integration. From this side one can see the curve is only integrated from A to B, or B to C, but not A to C.

In terms of faces, one race can see differences in another, while also assuming they all look the same. The overlap of left and right brain creates a differential integration. If we did a brain scam both sides of the brain appear working.
puppypower, Fri, 22nd Jan 2016

"However, we are only conscious of one side of the brain at a time." Show me that study! Whales all look the same to me but whales know one another. Your basis has no facts so your conclusion is spurious. mrsmith2211, Sat, 23rd Jan 2016

Conventional studies of the brain observe the phenomena of consciousness in the third person. This is consistent with the scientific method since it allows verification. However, third person studies is not a valid way to see what I am saying. It needs to be done in the first person.

The reason is, consciousness is more like software, that it is like hardware. Third person studies are good with hardware, but not for software. The software will use the hardware, however, perturbations in the hardware, seen in the third person, will not tell you whether the software is a game or tax software, since both may use the same hardware.

This may be an interesting experiment. Having someone load various software and you try to guess which software is playing based on the hardware signal. This will not be easy to do. On the other hand, if you load the software and then you observe the hardware response, you may begin to see patterns. But beyond that, one will not be able to see which dragon the knight is slaying since they all the dragons may give the same hardware footprint. 

As another example, say you had a toothache. Although I can observe you in the third person, take a brain scan, and even infer that you have a toothache based on previous experiments, beyond that, what you feel inside is outside the study. I may empathize, based on a similar experience from my past, but there still is no way to tell if my perception of you is exactly the same as you feel in real time. It may be two similar software ,using similar hardware, but two different dragons are being fought by the knight.

If you look at pain management, some people react stronger to the pain from a standard injury and may appear to need narcotics to moderate the pain. Others deal with the pain with an aspirin. How do you know their exact pain level, especially if we add the wild card that some people can scam pain for drugs? One can't always tell using a third person approach.

There are no machines to read the minds and feelings of people. It not worth presenting papers whose methods are not up to the task of isolating rational and spatial thought; software. These studies can provide a way to begin, but not a way to close the deal. This has to be done in the first person. But you can't publish first person studies, because most people will assume there will be  subjective corruption. This is easier to avoid in the third person. But third person falls short with software.

As a first person test, go into a field of similar wild flowers. This is winter so go into a large open area covered in snow. Monitor any feelings you may feel as well as any thoughts that come to mind as you look around and notice the uniformity; integration. Stay in the field, for as long as it takes, until you begin to notice differences. What is happening is you are going from 3-D to 2-D thought; integration to differentiation.

Now observe your new feelings and thoughts. These details can't be seen in the third person, unless you relate them. With enough practice you should be able to generalize patterns.

When we go into an unknown area, the conscious mind is at a disadvantage, since it is not prepared. This is why outside the box spooks people. The result is the unconscious will take over, allowing us to react to the stimulus. The 3-D instinct will seek to generalize the situation. Once that general path is clear, the conscious mind can differentiate that general path. I call this going from right to left. The brain is still using both sides, but unconsciousness goes from actively reacting to offering a intuitive platform for thought.

A good example of this is connected to political bias. As another experiment, is watch a news program, from the other side, whose ideas you don't like. For many people, as soon as you turn on the opposition news, you will hate it. Their entire field of ideas is generalized with an unconscious feeling; integration from alpha to omega. As you adapt, you will begin to focus on certain points and pick them apart. There is switch to the conscious left. The right side feeling of integration still there in the background. It will make the entire news have the same level of doubt and distrust.

This schema can also apply to faces. The more unknown and mysterious, the more general the unconscious will become. Some will not get past the stereo-type. Others  , who are in the known, will be able to differentiate tiny details. puppypower, Mon, 25th Jan 2016

Please define consciousness. alancalverd, Mon, 25th Jan 2016

An old trick was to put an AM radio near the computer, and from the variety of buzzes and clicks, the operators could tell which software was currently running, and even which part of the software was currently executing.

PS: This worked better in the days before shielding for Radio Frequency Interference became mandatory, back when AM receivers were analog (rather than digital). evan_au, Mon, 25th Jan 2016

I've seen you post this several times, on various different threads.  I'll give it a go...

To be conscious, is to be awake.  However, if we consider that a person who is awake may not be conscious of their surroundings, and can still be taken unawares, ie: another might sneak up on them, this definition of being awake does not describe the whole story.
So...we can see that being conscious not only requires being awake, but also being aware.  Does this suffice as a full definition?  Let's see...

An awake and aware person may not be taken unawares by the sneaky arrival of a person, but a sneaky situation might still take them unawares.
In order to be conscious of that which may happen in the future, this requires that a person be conscious of that which happened in the past.  The more conscious a person is of what has already transpired, the more conscious they will be of the many possible futures that might transpire.

Therefore I deduce that consciousness can be defined as a state of awake-ness and awareness, that operates on a sliding scale of knowledge. timey, Tue, 26th Jan 2016

Sensory-rational feedback. alysdexia, Sat, 30th Jan 2016

To answer the original question, many factors must be considered.
Individuals look different because their genes are different, but why are they different? And why so much variety in differences?
Genes, in general, differ from one another due to differences in how they evolved, plenty have evolved different ways because humans come from almost every part of the world, and the environment of a place is what determines which traits animals will evolve to have. We see this (appearance wise) on a major scale when we look at the different races.
But you asked why people within the same race can look so different from each other
The answer comes down to not only the different genes that people within the same race have due to ancestral roots, random mutations, etc. but also to the differences in nutrition that people get, past illnesses, how fit they are, and things like that.
A final thing to add is the fact that almost all humans are a mix of quite a few races and lineages, giving them a mix of those appearance genes at birth. Colton_Jones, Tue, 1st Mar 2016

An extrapolated question to why humans have such a variety of appearances, is why are the insides of humans, more uniform than the outsides? Why is the heart more uniform looking than the face? One would be hard pressed to tell a pretty person from an ugly person, by looking at the stomach or heart. Maybe a doctor can see these differences, but it will take a more trained eye than it takes to differentiate a face. A child can do that.

One possible correlation has to do with the amount or number of nerves and nerve endings. The human face has 43 muscles and a very large number of sensory nerves. The hands and feet also contain a lot of nerve endings and contain unique finger and toe prints. 

My belief is, the brain is more than the sum of its genetic parts. This allows consciousness. Consciousness is restricted to the brain and not just any cell or any organ. The affect is similar to the team, where the team can add up to more than the sum of it parts. Some ball teams may not have the best players (parts) in terms of game statistics, But as a team, they work together so well this allows them to exceed.

In we assume this premise, brain is more than the sum of its parts, for the sake of argument, the team (brain) can now place a stamp on the body, in places where there are plenty of nerves for feedback control, that reflects its unique team nature. Once a team becomes a champion, all the players of any statistical skill level, now walk with their heads higher.

If you look in terms of natural selection, how do unique finger prints help survival? These are not really necessary, since it is trivial compared to other things. If all finger prints were the same, it would not matter to survival. Finger prints are more useful for identification. The brain by being more than the sum of its survival parts, can add extra spin to the body, which are more useful to the brain (team), than the genetic based players which have been selected for survival.

Free will is at the ability to make choices. Some choices can be apart from the unconscious natural instincts developed over the eons by natural selection. Humans can freely choose to do things that can lower their selective advantage; stay drunk. The team (brain) creates a higher platform that allows artificial selection. Being drunk is not part of natural selection, but is based on choice and will; artificial selection. You could not do that, if the team equals the sum of the parts. The natural animal does not deviate freely from natural selective instincts.
puppypower, Tue, 1st Mar 2016

One question that was asked is what is consciousness?

The answer is, it depends on which of the two centers of consciousness one is talking about. Humans have two centers of consciousness. The foundation center is has been called the inner self. This center is connected to natural instincts and therefore is common even to animals. The secondary is the ego center connected to the conscious mind. This is more connected to humans. However, humans can induce a virtual ego or secondary in some animal species, such as dogs and apes. I can make my dog unnatural with lots of treats. He will lose his instincts or rather he will represses these.

Say I told you to meet me somewhere. As you walk down the sidewalk, I jump out from behind a tree to scare you. If I take you by surprise, the inner self or primary center will react first, with natural instinct. You will instinctively jump. A fraction of a second later you; ego secondary center, will become aware it was me, with hands ready to punch. You might get mad for being induced into a strong anxiety feeling, you would not choose to feel. You might also give off a weird yelp that can be embarrassing, if I make fun of it. The inner self does not care since this center of consciousness is all about survival.

The two sides of the brain will also make use of both the faster inner self, and the slower ego secondary. If we see something new for the first time, we may get startled; boo! Then the ego secondary becomes aware and can come into focus as the adrenaline begins to lower. One side is already active and primed and will be reflected in the other side for a quick differentia thought; it is him.

One advantage of this binary arrangement, which is essential for consciousness, is the secondary can be induced to perceive virtual real time. This affects is often called consciousness. When we look at a tree, there is a small time delay for the light from the tree to move over distance to reach the eyes. There is also further times delays as this triggers the eyes, which sends signals to the brain, which is then interpreted and sent tot he body for action.

When you have a primary and secondary, the primary or inner will deal with the time delay, since subliminal is faster and can use a higher data density. It then transfers the conclusion to the ego conscious center. What the ego gets it; awareness appears, it sort of cuts out the middleman, allowing a more real time feeling of the tree.

An analogy is the scientist has a theory, but still needs to verify this in the lab. There is a long time delay between cause; idea and final affect; proof. After he is done, he gives a summary to his boss, who sees the premise and result in a 20 seconds read.  The perception changes from time lag for data crunching, to nearly real time summary, where cause and affect appear to merge, with the feeling from the inner self merging past and present. After I scare you, your body is already for fight or flight when you become aware like you just woke up and the action is in real time. puppypower, Tue, 1st Mar 2016

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