Hu­man Universal

TagLast edit: 13 Mar 2012 6:33 UTC by Grognor

Complex adaptations within a sexually reproducing species need all of their parts, or almost all of their parts, to be universal within the gene pool.

Let’s say that you have a complex adaptation with six interdependent parts, and that each of the six genes is independently at ten percent frequency in the population. The chance of assembling a whole working adaptation is literally a million to one; and the average fitness of the genes is tiny, and they will not increase in frequency.

One bird may have slightly smoother feathers than another, but they will both have wings. A single mutation can be possessed by some lucky members of a species, and not by others—but single mutations don’t correspond to the sort of complex, powerful machinery that underlies the potency of biology. By the time an adaptation gets to be really sophisticated with dozens of genes supporting its highly refined activity, every member of the species has some version of it—barring single mutations that knock out the whole complex.

Applying this logic to human brains in particular, we arrive at the explanation for what is called the psychic unity of mankind. (Though Eliezer Yudkowsky has used the phrase “psychological unity of humankind” instead.) In every known culture, humans seem to experience joy, sadness, fear, disgust, anger, and surprise. In every known culture, these emotions are indicated by the same facial expressions. (Citation needed to Paul Ekman.)

Donald E. Brown has compiled a list of over a hundred human universals—traits found in every culture ever studied, most of them so universal that anthropologists don’t even bother to note them explicitly.

Blog posts

See also

The Psy­cholog­i­cal Diver­sity of Mankind

Kaj_Sotala9 May 2010 5:53 UTC
143 points
162 comments7 min readLW link

The Psy­cholog­i­cal Unity of Humankind

Eliezer Yudkowsky24 Jun 2008 7:12 UTC
57 points
23 comments4 min readLW link

Hu­mans in Funny Suits

Eliezer Yudkowsky30 Jul 2008 23:54 UTC
70 points
132 comments7 min readLW link

Open-ended ethics of phe­nom­ena (a desider­ata with uni­ver­sal moral­ity)

Ryo 8 Nov 2023 20:10 UTC
1 point
0 comments8 min readLW link
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