A new paper on which has some results on life satisfaction, intelligence and the number of social interactions one has has generated some mainstream buzz. For example, at The Washington Post, Why smart people are better off with fewer friends. I looked at the original paper: Country roads, take me home… to my friends: How intelligence, population density, and friendship affect modern happiness. The figure above shows the interaction effect between intelligence, life satisfaction, and number of times you meet up with friends over the week. What you see is that among the less intelligent more interactions means more life satisfaction and among the more intelligent you see the reverse.
But take a look at the y-axis. It cuts off at 4.10. The scale is: 1 = very dissatisfied, 2 = dissatisfied, 3 = neither satisfied nor dissatisfied, 4 = satisfied, and 5 = very satisfied. The effect here is very small. The less intelligent group had a mean IQ of 81. This is over 1 standard deviation below the norm, at about the 10th percentile. The intelligent had a mean IQ of 115, 1 standard deviation above the norm, so at the 84th percentile. When looking at the two groups divided between the prosocial (nearly 1 interaction per day) and antisocial (about 2 per week), the Cohen’s d for the low IQ was 0.05 and for the high IQ was 0.03. A d of 1 would mean one standard deviation difference between the two distributions in life satisfaction. In other words, the difference here is very minor.
The authors corrected for a bunch of variables, like sex, marital status, education, and ethnicity. But the data were from the NLSY, so the mean age was about 22. I wonder if the results would be different if you had an older age cohort. The authors themselves are quite guarded about their interpretation: “Given that our data are correlational and frequency of socialization with friends and life satisfaction were measured at the same time, we cannot rule out an opposite causal order to what we hypothesize, where happier people choose to socialize with their friends more frequently.”
The study may be reporting a true result, even if the effect is modest. But I’m quite confident that my inverted title may also be correct, though again, I suspect the effect will be modest. These are not actionable results for anyone. That is all.