Candy Machines: Not Guilty

Could it be that vending machines in schools aren't a big deal, after all? Looking at students from kindergarten through eighth grade, researchers found no connection between obesity and whether a school sold snacks.

Could it be that vending machines in schools aren't a big deal, after all? Oliver Munday

All of the nearly 20,000 students began kindergarten in the fall of 1998, at which point their height and weight were recorded, with follow-up data collected in the fifth and eighth grades. The study controlled for students' socioeconomic status, ethnicity and the resources of their schools (including whether they had gyms). There was no shortage of overweight kids in the sample—35% of eighth graders qualified as obese—but also no discernible link with snack policies.

The researchers suggested that eating habits learned and practiced at home swamp the effects of school snacks and, what's more, that regimented school-days limit students' opportunities to go back for seconds and thirds.

"Competitive Food Sales in Schools and Childhood Obesity: A Longitudinal Study," Jennifer Van Hook and Claire E. Altman, Sociology of Education (January)

Feel-Good Gossip

Gossip can relieve anxiety caused by watching others behave badly, a study finds. Researchers recruited more than 200 participants to watch "cooperation" games involving small amounts of cash. In these cases, participants watched staged games in which one player pursued a relentlessly self-interested strategy over one or more rounds.

Watching selfish play irritated people and boosted their heart rates. But the distress was eased when participants got the chance to send a note to a subsequent player, warning of the bad actor.

The observers even proved willing to pay a portion of their participation fee in order to send such a note—although the information wouldn't punish the offending player, only protect an innocent player from harm. These positive, "prosocial" aspects of gossip are seldom described or fully appreciated, the researchers said.

"The Virtues of Gossip: Reputational Information Sharing as Prosocial Behavior," Matthew Feinberg, Robb Willer, Jennifer Stellar and Dacher Keltner, Journal of Personality and Social Psychology (forthcoming)

Criminal Justice
Questions Erase Memory

Witnesses asked about the characteristics of perpetrators tend to forget other details, a study shows.

Witnesses asked about the characteristics of perpetrators tend to forget other details, a study shows. Oliver Munday

Researchers had 76 students watch a video of a man being robbed at a cash machine by two other men—one blond, one dark-haired. The scientists made a list of 10 attributes for each man—hair color, clothes, etc.—and asked groups of students five questions about one of the men. After a break, each student was asked about all 10 attributes of both robbers, including the five previously cited.

If the students had been queried first about the blond, their recall suffered for those details about him that they hadn't been asked about before. Also, focusing on one of the blond robber's attributes—say, his haircut—led to worse recall of the dark-haired man's corresponding attribute.

"Can Questioning Induce Forgetting? Retrieval-Induced Forgetting of Eyewitness Information," Gino Camp, Henrieke Wesstein and Anique B.H. De Bruin, Applied Cognitive Psychology (forthcoming)

Dear I.D. Scanner, It's Still Me

Face-recognition technology is crossing a new threshold: identifying people even after they've had plastic surgery.

A new I.D. system counters surgical effects by focusing on parts of the face. American Society for Aesthetic Plastic Surgery

Current I.D. methods that take a "holistic" approach can be thrown off by face-lifts, Botox and bee-stung lips. But working on the theory that small regions of the face would be less altered by surgery than overall facial proportions, researchers at the University of Notre Dame created a system that begins by breaking faces down into constituent parts. Using images of 900 cosmetic surgery patients, the new system proved slightly more accurate than existing software when it tried to match a single part—an eye, say—but its accuracy rose to an impressive 78% when predictions based on the various parts were pooled.