Risque Rubbernecking

Here's a reason to crack down on those smutty underwear billboards: They might cause car accidents.

Erotic images cause about a half second of distraction, which researchers call "emotion-induced blindness." Much the way rubbernecking drivers gawk at roadside accidents, subjects shown shocking photographs tend to miss the images that come right after. Gory photographs have the same effect, leading Steven Most, a Yale University postdoctoral fellow, to warn, "Maybe there are some areas of the road where graphic or risqué billboards aren't safe."

Not everyone is equally prone to distraction: Anxious individuals are more likely to experience temporary blindness.

Says Most: "It may help us understand why two people who witness the same event remember it differently."