1) Name the capital of India, a city that has seen a dramatic decrease in a certain type of air pollution as an inadvertent side effect of the coronavirus lockdown.
2) What North African city, whose name means "the victorious," is located near the only existing Wonder of the Ancient World?
3) Researchers in Florida have observed less human impact on what kind of reptile, which nests on beaches and whose gestation period is about 60 days?

1) The capital of India is New Delhi

2) The city is Cairo, Egypt and it's near the Great Pyramid of Giza

3) I'm not sure about that one

as university of miami psychologists debra lieberman and adam smith pointed out in a recent article in the journal current directions in psychological science, humans have social and psychological mechanisms to deter incest. with very few exceptions, marriages between brothers and sisters and between parents and their children are verboten in every human culture. the primary psychological anti-incest mechanism is the yuck response. even the idea of sex with their mom or dad, bro or sis is upsetting to most people. the psychologist jonathan haidt has found that nearly everyone is repelled by the prospect of brother-sister sex, even in hypothetical situations in which there is no chance of pregnancy).

the biological cost of incest

this raises an interesting question: just what’s so bad about incest? sure, having sex with your dad or your sister seems gross — but why? some anthropologists have argued that incest taboos are learned social conventions. this explanation, however, doesn’t make sense to me as it does not explain the widespread existence of anti-incest mechanisms in creatures ranging from cockroaches to chimpanzees. second, the incest taboo is about as close to a universal law as human moral rules get.

why should mechanisms to avoid incest be so widespread both in nature and across human societies? the answer is simple. the problem with having sex close with relatives is that there is an astonishingly high chance that your offspring will be born with a serious birth defect.