What is responsible for our general aversion to incest? Is it because the genes (if any) responsible for making someone prefer incest get weeded out by natural selection (because it often produces offspring that are unfit)? Is there some other reason?

https://en.wikipedia.org/wiki/Westermarck_effect
https://www.researchgate.net/publicatio ... _avoidance
https://pubmed.ncbi.nlm.nih.gov/26193096/
https://www.sciencedirect.com/science/a ... 3813000962

What's responsible for ?... runs into the same problem noted in another of your question threads. It's simply not the kind of thing that fossilizes, for example, so we have no means of establishing where, when, or why it occurred. It is, however, found in many species other than humans, ergo you can be reasonably confident in saying that it didn't originate in humans, and humans have had an aversion to incest from the very first instant of humanity's existence having inherited it from their forebears.

Spearthrower wrote:... having inherited it from their forebears.

...but not the threebears.

Spearthrower wrote:It is, however, found in many species other than humans

I'm not sure I get it. Is it incest or an aversion to incest that is found in other species?

murshid wrote:

Spearthrower wrote:It is, however, found in many species other than humans

I'm not sure I get it. Is it incest or an aversion to incest that is found in other species?

Both, just as both are found in humans. But I was referring to the Westermarck effect.

murshid wrote:What is responsible for our general aversion to incest?

AFAIK It is heavily disputed that there is such a general aversion. Many think it is purely cultural.

Thousands in UK born as result of ‘extreme inbreeding’, study suggests.

Rumraket wrote:

murshid wrote:What is responsible for our general aversion to incest?

AFAIK It is heavily disputed that there is such a general aversion. Many think it is purely cultural.

I don't think this is tenable given the amount of papers spanning decades of research about kin-recognition in a wide variety of species - it's a big area of study in behavioral ecology, and all social species have evolutionary strategies for avoiding incest, in apes this usually occurs by post-pubescent females leaving their group. Humans just have that extra human bit where we talk about it, and use the words to make cognitive rules atop pre-existing biological ones. In essence, when it comes to humans, everything is cultural.