When you're on the edge of your seat watching a thriller movie, it often feels like you must see what happens next and nothing going on around you could be more important.

Researchers found by scanning people's brains that suspenseful scenes in movies cause significant changes in brain activity that essentially give movie-watchers tunnel vision, they report in the journal Neuroscience.

"Many people have a feeling that we get lost in the story while watching a good movie and that the theater disappears around us," lead author Matt Bezdek of Georgia Tech said in a statement. "Now we have brain evidence to support the idea that people are figuratively transported into the narrative. "

Participants in the study got to watch scenes from suspenseful movies including Hitchcock's North by Northwest and The Man Who Knew Too Much. But as you can see in the video below, there was a catch: they had to watch them while an obnoxious checkerboard pattern spun around the edges of the scene.

The other catch was that participants had to watch while laying in an MRI machine so that the researchers could monitor their brain activity. What they found was that the activity in the calcarine sulcus, the sort of gatekeeper for visual information, changed according to the level of suspense of the scene.

As suspense mounted, the calcarine sulcus concentrated its activity into the areas that process information from the center of the visual field, and decreased activity in the regions that process information from the periphery. Eric Schumacher of Georgia Tech calls this, "a neural signature of tunnel vision."

"During the most suspenseful moments, participants focused on the movie and subconsciously ignored the checker boards. The brain narrowed the participants' attention, steering them to the center of the screen and into the story," Schumacher said in a statement.

Previous studies by this research group suggest that this narrowing of attention helps us remember stories.

Photo: Nick Nichols | Flickr