Healthy is beautiful, unhealthy is scary.
Actually our dislike for disabilities or any abnormalities in look or behavior is easily explainable by natural selection. Just keep in mind that modern times, that we live in now, are very different from environment of our ancestors. Our long evolutionary past as hominids happened in small groups, around pure nature - not in controlled space like home or city, without plentiful food and other things, without hospitals and doctors and social network. To understand our behavior we need to forget about last 10 or even 20 thousand years, and go back to stone and stick age, and look through 4 million years of our ancestor's lives.
In small group scenario and environment of limited food supply to have infirm person around was a big disadvantage. It meant taking care of one more person who doesn't hunt, gather or is unable to protect the group. Person, who consumes scarce food, which could be used to feed hungry growing children, the next generation. On top of it the person might require full time attention of healthy and productive members, taking them away from food gathering. In case of nomadic life style, person with disability or otherwise not fit, was even more hindrance for the whole group.
Also many serious infectious and parasitic diseases manifest themselves in disfigurements of face, body or skin. Keeping such unhealthy person around was very risky for the whole group and could mean demise of a group. Also, having offspring with such person would rarely end up with kids being fed and protected till adulthood, if they happened at all.
Nature, not to rely on human logic in determining if group should keep such cumbersome person, gave us emotions of disgust and fear for these unfortunate individuals. Group being directed with such feelings had easier job to remove unproductive individuals. Anyway, the bottom line was, don't take any chances, and remove all the “weird ones”, before sickness will affect the wellbeing and survival of the group.
Today, it is easy for us to act on feeling of compassion, share our wealth, and help unfortunate people. Living in times of plenty we have much to share with unfortunate people and still enough for comfortable life. However, for our ancestors, to extend their limited resources, it was life or death issue for the whole group, even failure of next generation.
Let's stress here that the main goal of every group, even every species, is offspring, the next generation. Without next generation whole group is gone, their DNA is wiped out. By these standards, anyone who is not helping in making next generation successful is a distraction from the main goal, and a drain on scarce resources.
On top of emotions of fear and disgust, people were able to use spirituality to further influence and explain their rejection, and easier removal, of the "weird ones". In group eyes, they were possessed by bad spirits; they were punished by gods, or just jinxed. Even more reasons to avoid such people.
It is hard to show example of said behavior from Stone Age, but we have many examples from antiquity.
The most known is example of Spartans who sacrificed, the old and infirm to gods by pushing them off the high banks. Other words, they’ve got rid of unproductive members of society and pleased gods at the same time. How convenient, isn't it? I would be surprised if they didn't think of it as of "a moral thing to do". From very recent records we know that most of baggers (isolated from society) were the infirm, lepers, blind and people with other chronic illness. We stopped throwing them to death but life expectancy of baggers was not long. Sick, homeless and malnourished they didn’t last longer than couple of years, I supposed.
It is not all the story though. On opposite side of feeling disgust is sense of beauty, and opposite to fear (of someone) is feeling of attraction and love. The beauty and attraction we feel when looking at healthy human body. People from all different cultures on this planet agree on few things in regard to human beauty. Smooth healthy skin is beautiful, hourglass shape for women and masculine men are attractive, symmetrical bodies and faces are perceived most beautiful.
But why don't we see all the people on this planet beautiful though?
Unfortunately blind nature makes people not perfect. Many of us are born sick, deformed, and predisposed to many chronic illnesses. The more imperfections in our bodies, the more asymmetrical we are, the more out of physical shape, and more blemishes on our skin. Because of this nature’s screw-ups natural selection “developed tools” to help us finding the healthy once, to increase odds in survival of next generation. These tools are sense of beauty and attraction, emotional intelligence if you will, implemented into our brains by nature, so we can pick the healthiest, most fertile, stronger and most productive partners.
Surely we can use logic selecting a mate, but our big brains are just recent development in human evolution, therefore still very easily overwritten by emotional and ancient parts of our brain. Form the times when we were very emotional and not very logical.
After millions of year of nature’s experiments with life, we can feel nature’s best suggestions by experiencing pleasant emotions when we see beautiful people, and unpleasant emotions when seeing unhealthy ones. That’s why healthy is beautiful, unhealthy is scary.
PS. Please don't kick the messenger. I would like to see all people on this planet healthy, beautiful and happy. However, nature has cruel ways of dealing with life. I'm just explaining her ways.
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Physical and Mental
