Seeing red, do you feel sexy or stupid?

The color red has long been linked to sex and danger, blood and fire -- that's why we use it for scarlet lipstick and stop signs. (Just tell us this coffee cup doesn't make you think twice.) But new research in color psychology has found red may have another, unexpected result in communications -- it could decrease the intelligence of the target audience.

Seems researcher Andrew Elliott gave 71 U.S. college students an anagram test, where they were asked to unscramble 15 different word puzzles in 5 minutes. On the front of each test, a "participant number" was written in either red, green or black. Students who received a red number scored on average 20% lower than the other students. Elliott then repeated the experiment in Germany, with the same results. Researchers aren't sure why students had such a dramatic response; since red letters are often used to mark bad grades, perhaps the poor academics caught a bad vibe at the beginning of the test.

Cognitive Daily explored further, asking readers of its blog to name the primarily background color of their computer screen -- the hue we prefer when in "thought" mode. Most respondents said blue (38%), followed by green (13%) , with red near the bottom (3.5%). This finding may be a pure visual response: red is the hottest color on the visual spectrum, and staring at it can make the eyes uncomfortable.

Does red make us dumb? Psychologists point out there is no universal response to colors; death, for example, is symbolized by black in the West and by white in Eastern cultures. But patterns emerge. Red and yellow startle, and blue soothes. Babies have been shown to cry more in bright yellow rooms -- hot on the color spectrum -- while weightlifters focus more and lift greater weight in blue rooms -- cooler on the spectrum.

Red will get noticed in communications. But advertisers may wish to use red carefully, lest their target audience begin to feel stupid.