Matthew Hutson in Scientific American:
Psychologists have lots of evidence that implicit social biases—our unconscious, knee-jerk attitudes associated with specific races, sexes and other categories—are widespread, and many assumed they do not evolve. The feelings are just too deep. But a new study finds that over roughly the past decade, both implicit and explicit, or conscious, attitudes toward several social groups have grown warmer.
The study used data from a standard test of implicit attitudes collected via a Web site called Project Implicit. Participants were asked to quickly press a certain computer key in response to positive words, such as “happy,” and a different key in response to negative words, such as “tragic,” that appeared on a screen. These words were interspersed with images or words that represented two categories of people, such as blacks and whites, and participants were asked to flag these using the same keys. Faster reactions when, for example, black rather than white faces shared a key with negative words suggested a racial bias.
Tessa Charlesworth and Mahzarin Banaji, psychologists at Harvard University, analyzed more than four million results collected over a 10-year period from U.S. adults who had taken implicit association tests for sexuality, race, skin tone (in which faces differ in color but not shape), age, disability and body weight.