— From book ‘Why Is Sex Fun?: The Evolution of Human Sexuality’ by Jared Diamond
Those disgusting humans have sex any day of the month! Barbara proposes sex even when she knows perfectly well that she isn’t fertile—like just after her period. John is eager for sex all the time, without caring whether his efforts could result in a baby or not. But if you want to hear something really gross—Barbara and John kept on having sex while she was pregnant! That’s as bad as all the times when John’s parents come for a visit, and I can hear them too having sex, although John’s mother went through this thing they call menopause years ago. Now she can’t have babies anymore, but she still wants sex, and John’s father obliges her. What a waste of effort! Here’s the weirdest thing of all: Barbara and John, and John’s parents, close the bedroom door and have sex in private, instead of doing it in front of their friends like any self-respecting dog!”
Humans tend to think by analogy, which can create some cognitive trouble. One issue is that a single analogy, or even a handful of analogies, may fail to reflect a full reference class of relevant cases. For example, rather than asking whether this turnaround is similar to a prior turnaround, it is useful to ask for the base rate of success for all turnarounds. Psychologists have shown that properly integrating the outcomes from an appropriate reference class improves the quality of forecasts.
Another challenge with using analogies is that we see similarities when we focus on similarities and see differences when we focus on differences. The emphasis of the comparison colors the outcome. For example, Amos Tversky, a psychologist known for his collaboration with Daniel Kahneman, asked subjects which pair of countries they deemed more similar, West Germany and East Germany or Nepal and Ceylon (the study was done in the early 1970s and Ceylon changed its name to Sri Lanka in 1972). Two-thirds of the subjects selected West Germany and East Germany.
Tversky then asked subjects which pair of countries they deemed more different. Logic suggests an answer that is the complement of the first response, hence two-thirds finding Nepal and Ceylon more different. But that’s not what Tversky found. Seventy percent of the subjects rated West Germany and East Germany more different than the other pair. What you are looking for dictates what you see.”