Bayes and Bounds

[This is post 5 in the "Structure and Cognition" series; links to all the posts can be found  here ] I.  A major motivation for starting this blog was to clarify my thoughts about an idea that wouldn’t leave me alone. I see it everywhere, which is ironic, because the idea is about seeing (or not seeing) common structure lurking beneath different-seeming surfaces.  Framing is a big topic in the psychology of decision making. The way choices are presented can influence the decisions we make. This is why food sold in the supermarket is more likely to say '99% fat free' than '1% fat.' Sanitizing wipes 'kill 99.9% of germs,' they don’t 'only leave 0.1% of germs alive.' Obviously, these values are identical, so it shouldn’t matter one way or the other, but it does.  From the perspective of traditional economics, this is insane. People should prefer whatever they actually like – every product should have (or be translatable to) a utility value. You sh...

[This is post 4 in the "Structure and Cognition" series; links to all the posts can be found  here ] I.  If there were a contest for the scientific findings most embarrassing for human intelligence, the research comparing expert prediction to simple linear equations would be a strong contender. When this research program began in the 1940s, clinical psychologists were curious to see just how much better their clinical judgment would be than statistical models. Dawes and Corrigan (1974) note that “the statistical analysis was thought to provide the floor to which the judgment of the experienced clinician could be compared. The floor turned out to be a ceiling.” In summarizing this large body of literature, which repeatedly demonstrates the inferiority of human judgment, Nisbett and Ross (1980) write: "Human judges make less accurate predictions than formulas do, whether they have more information than is fed into the formula or precisely the same amount of information...

[This is post 3 in the "Structure and Cognition" series; links to all the posts can be found  here ] It’s pretty well known today that research in psychology has found humans to be irrational and biased. However, views in the field are actually much more subtle and nuanced – just kidding – it’s mostly vociferous debate and partisanship. The controversy concerns the use of heuristics, simple processes that often achieve pretty good results but tend to fail in certain situations. It seems that much of our cognition relies on these "quick and dirty" tricks to solve problems and make decisions. If using heuristics means missing an opportunity to apply a better algorithm, then heuristics are a problem and we shouldn't use them. Much of the debate turns on questions about how good heuristics actually are and how much better the alternatives could be. (If heuristics are actually amazing, or the alternatives terrible, then using heuristics is great and people are ration...

[This is post 2 in the "Structure and Cognition" series; links to all the posts can be found  here ] The doctrine of signatures was a theory of medicine dating back to 1400-1500 that attempted to cure disease using treatments that resembled either the patient’s symptoms or afflicted body part. For example, walnuts might treat afflictions of the mind and foxes’ lungs might be used to for respiratory problems because foxes were thought to be particularly fit animals. We’ve come a long way, medically, since the 1400s, but it seems pretty likely that this way of thinking is still with us. It’s probably implicated in conspiracy theorizing where complicated effects are thought to require complicated causes (Lehman & Cinnirella, 2007). I think it might be part of the reason people tend to view those who disagree with them politically as evil – the evil effects of [other party’s] policies must be due to evil causes. But I’m going to play it a bit safer than venturing into polit...