The Gap in the Middle

In 2007 a team of psychologists sat Russian speakers and English speakers in front of a screen and showed them three blue squares - one above, two below. Press a key, they were told, to say which of the two below is identical to the one above. Russian has no single word for blue. It has goluboy for the light end of the range and siniy for the dark. On the hardest comparisons, where the two lower squares sat close together, the Russian speakers were faster when the pair happened to straddle the boundary between those two words. Faster by about 124 milliseconds.
That eighth of a second has since been asked to carry an extraordinary amount of weight. It has been offered as evidence that Russians and Americans see color differently, that they inhabit different perceptual worlds, and that the language a person learned as a child decides what the world looks like.
The Gap in the Middle is about the distance between what an experiment showed and what it had become by the time it reached the public.
Zahir Hasan works through the evidence on color, space, time, number, memory, bilingualism and the brain, then follows the argument out into classrooms, institutions, translation and machine language models. Along the way: a man who worked in fire insurance and noticed what the word empty was doing on a store of gasoline drums; a psychologist who published the universalist result in 1969 and a relativist one in 1984, and stated his limits carefully both times; three men whose grammar had been devastated by left-hemisphere damage and who could still handle nested arithmetic; a bilingual advantage that thinned out under 891 effect sizes.
What survives is narrower than the headlines and more interesting than either side's slogan. Name the linguistic feature. Name the cognitive operation. State the conditions. Say how far the conclusion travels. Language can matter a great deal without ever becoming a prison for the mind.