Movie sparks group brain responses.

A crowd of moviegoers might each develop a unique opinion about the film they're all watching, but audience members exhibit a surprising amount of synchronized brain activity, a new study finds.

Brains "tick collectively" as a group of people watches an event such as a movie, propose Uri Hasson of New York University and his coworkers.

The scientists used functional magnetic resonance imaging (fMRI) to track locations of blood-flow increases in the brains of five volunteers as they watched a 30-minute segment of The Good, the Bad, and the Ugly, starring Clint Eastwood. Scientists use blood flow as a reflection of brain activity.

At any point during the movie, an average of 30 percent of the localized blood-flow increases in a given volunteer's brain corresponded to those of any other volunteer, the researchers report in the March 12 Science.

To identify those brain areas that might respond to particular cinematic elements, Hasson's team collected fMRI data from 27 people who saw either still pictures or brief clips from The Good, the Bad, and the Ugly. A visual area known to respond to faces displayed intense activity as film watchers saw facial close-ups. Another visual structure responded vigorously to indoor and outdoor scenes, including buildings.--B.B.