The predictive power of marshmallows

I have gone through the back catalogue of podcasts for WNYC’s Radiolab for a couple of months now. I got into it after ABC radio substituted it for the Science Show for two weeks in late June. It is sensational – great content and entertaining.

I just listened to the Radiolab podcast on Walter Mischel’s marshmallow experiment . The basic idea of the experiment concerned testing the ability of four-year olds to delay gratification. The experimenters left the children in a featureless room with a marshmallow (or Oreo cookie in later experiments) with a promise of more if they waited. The interesting outcome from the experiment has been how the ability to delay is a strong indicator of future success. For example, the average difference between those who waited 10 seconds and those who waited 15 minutes was around 210 points on the SAT. 210 points is roughly the difference between the 60th and 85th percentile.

I was familiar with this experiment from earlier readings, but was not aware on how this had become such a strong indicator of future success. Mischel and his colleagues are still following a number of the subjects, so there should be more to come.

So what we can take from this experiment? One (optimistic) possibility is that by training children to delay gratification (those who delayed used a variety of tricks) there may be lifelong benefits. Another possibility, and the one to which I lean, is that the experiment is an indicator of a broader personality trait, and that teaching a technique to delay gratification in such a case will not have much long-term impact. I consider that it is more like testing children for IQ – you can do something but it will take some effort.

An interesting question is whether patience is a cause of the delayer’s future success or a symptom of the underlying cause. For example, is this test simply a proxy for intelligence, with more intelligent children able to foresee the consequences of their actions and devise methods to help them delay?

It's a risky business attracting a mate

Last week, ABC’s Catalyst had a story on skateboarders taking extra risks based on the presence of an attractive researcher. This was based on article published earlier in the year (Ronay, R. & von Hippel, W. (2010). The presence of an attractive woman elevates testosterone and physical risk-taking in young men. Social Psychological and Personality Science, 1, 57-64).

I haven’t been able to access the article yet, but in the Catalyst story, von Hippel proposed that it could be explained through the role risk taking plays as a signal of fitness. It demonstrates skill or (in case of failure) robustness.

Another evolutionary explanation, and one that applies particularly to young males, was put forward in 1979 by Rubin & Paul (An Evolutionary Model of Taste for Risk, Economic Inquiry, 17:4).They noted that adolescents, having attracted zero mates, have little to lose from risk seeking activity. By taking the risk, they have a chance of increasing their number of mates from zero. Failure to take the risk leaves them with zero mates with a probability of one. The ‘risky’ activity is not risky from the perspective of the desired result.

An extension of the skateboarding experiment to test this other hypothesis could involve using older males or males with long-term partners. It would be interesting to see their testosterone response compared to the young, single cohort.

If this hypothesis were true, you would expect to see more risk taking where there were, say, an excess of males or some males monopolising the females. Some cross-society analysis could be interesting.