At one of my brown belt tests for karate, the master (a 5th-degree black belt) made sure we all knew that he might only be standing by each student for a few seconds during any given drill or activity, but that would be more than enough time for him to gauge our martial arts skills. I have used a similar warning with my students, when a class featured a brief oral exam, by then firmly believing that yes, I can get a fairly good estimate of how well a student understands the material by their answers to a few quick questions.
The next time I use such a tactic, I will have some psychology terminology to back me up. There is an entire field of study about “thin slice” judgments, when people are asked to make some judgment based on as little as 5 seconds, and no more than 5 minutes. For example, 60 seconds of observation turns out to be enough to guess someone’s socio-economic status.
Thin-slice judgments are simultaneously impressive and disturbing. A 2-second glance at the face lets people make reasonable predictions about whether sex offenders are violent, and a 3-second glance at head shots of competing politicians – with faces removed, even, leaving mostly hair and clothes – could be used to predict the outcomes of actual elections. I can’t decide whether to praise our minds for their ability to discern violent tendencies, or flinch at how we might choose our leaders from such fleeting impressions.
I suppose turnabout is fair play; this is no doubt something similar to what my students feel at an oral exam. Scratch that; my students are probably all flinching in fear at being judged on so brief a performance, never thinking that it might be impressive that I could get a good picture of their understanding so quickly. Perhaps I should start by suggesting a 60-second snapshot, to make 10 minutes seem like a very thick slice indeed.