This Week in Behavioral #2

The "hot hand" fallacy is a… fallacy? And increasing evidence that growing up poor affects brain development, maybe at shockingly early ages.

The Hot Hand Fallacy Fallacy

As anyone who played basketball will tell you (and yes, five year-old YMCA counts), the hot hand is real — Sometimes a basketball shooter is "feelin' it" and shoots better than normal. But all of the research (and there has been a lot) had shown this was a silly cognitive bias. People like finding patterns in random data when there are none. Sometimes shooters just hit 5 in a row at random; this does not mean they are on fire… So the story went.

It turns out the analysis was all wrong and a hot hand is real. (cue a huge sigh from everyone thinking about that one game in high school where they were definitely on fire)

Though the paper is pretty high level, the mistake they identify the other authors made is simple. Say Steph Curry takes twenty shots. And he typically hits half of them, so about ten. Now, to test if Steph is ever on fire, you want to see if his probability of a make is higher than 50% after he hits three in a row. But if you take a make-make-make sequence out of Steph's data, then there are 17 shots left, and only seven (on average) are makes! So it looks like he's a worse shooter if you ask what happens after he hits three in a row, because you've taken three makes out of the data set.

After controlling for this bias, the new study recalibrates all of the old data sets, and find existence of a hot hand in all but one. The study with the hottest hands of all? The original, most famous paper that disproved it originally. Awesome.

The Neuroscience of Poverty

Another thought-provoking piece — but in a completely different way — was in the Proceedings of the National Academy of Sciences this week. They summarize a tragic, but robust, finding in the neuroscience of socioeconomics.

Low socioeconomic status groups face a lot of challenges — access to quality schools, low-interest credit, and so on — but it may be that the playing field is un-leveled at a much earlier age.

Looking at brain images of children,they find less development in general, especially in the hippocampus.

Though the root cause is not known — it could be stress, undernourishment, under-stimulation or something else — the findings were consistent across fairly different populations. Further studies suggest the developmental deficiencies identified map into worse outcomes later in life.

We can't wait to see what happens when the Duncan and Noble research team see the results from randomly providing poor mothers with babies with an extra $333 per month.

Frank - Luke Coffman

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