A missing gadget ?
Brothers and sisters I have none, but that man’s father is my father’s son
Most people can solve this familiar puzzle if they think about it for a little while, but only slightly more complex versions have them floundering. Yet the problem described isn’t much more difficult than naming the day after the day after yesterday, which (I think) most people can do instantly. The fact that such a simple problem can be posed as a puzzle is just one piece of evidence that people (at least people in modern/Western societies) have trouble learning about and reasoning about kinship relations.
I’m generally sympathetic to the Cosmides-Tooby idea of the mind as a collection of special-purpose gadgets rather than a general-purpose computer. The work of Kahneman and Tversky on probability judgements (also my own main area of theoretical research) supports this idea. And I’ve occasionally put forward evolutionary arguments to support the view that people are likely to overweight low-probability extreme events.
So, there is a bigger puzzle here for me. Assuming that the set of gadgets with which our minds are now equipped is the product of evolution, shouldn’t we (at least in some phase of our lives) be as good at learning about kinship systems as young children are at learning about languages? After all, it’s hard to imagine that we can be acting to promote the survival of our genes if we don’t know who is carrying them.
It’s often asserted that modern/Western society has a particularly minimal kinship system and that the systems prevailing in other societies are considerably more complex. This certainly seems to be true of the Aboriginal Australian systems I’ve seen described, but I don’t know whether it’s true more generally. Has the kinship instinct atrophied over time, and, if so, what are the implications?