Vision is useful because it informs us about the physical environment. In the case of colm~ two distinct functions are generally emphasized (e.g., Jacobs, 1981; Mollon, 1989). First, color helps to segment objects from each other and the background. A canonical task for this function is locating fruit in foliage (Regan et al., 2001; Sumner & Mollon, 2000). Second, color provides infm' mation ab...

and other STDs. Men in their 20s are more likely to be sexually active and are less likely to use condoms than teenagers.4 Their high-risk sexual behavior also leads to increased risk for disease: Half of all new HIV infections in the United States are among people younger than 25,5 and young men aged 20–24 have the highest rate of gonorrhea infection among all male age-groups.6 In contrast to ...