An excellent essay by Steven Pinker in The New Republic.
The response is not only emotional but involuntary. It's not just that we don't have earlids to shut out unwanted sounds. Once a word is seen or heard, we are incapable of treating it as a squiggle or noise; we reflexively look it up in memory and respond to its meaning, including its connotation. The classic demonstration is the Stroop effect, found in every introductory psychology textbook and the topic of more than four thousand scientific papers. People are asked to look through a list of letter strings and to say aloud the color of the ink in which each one is printed. Try it with this list, saying "red," "blue," or "green" for each item in turn from left to right:
red blue green blue green red
Easy. But this is much, much, harder:
red blue green blue green red
[Via Daring Fireball].

