Recent Research Findings

Alda’s ‘Brains on Trial’ Tapped Dartmouth’s Expertise

Bill Platt

Neuroscience plays a starring role in a two-part series Brains on Trial With Alan Alda, airing on PBS Wednesday, September 11, and Wednesday, September 18, from 10 to 11 p.m., a project that Dartmouth Professor Thalia Wheatley, an expert in brain science and social intelligence, worked on as a consultant.

Brains on Trial centers on the trial of a fictional crime: a robbery staged in a convenience store. A teenager stands accused of the attempted murder of the store clerk’s wife, who was shot during the crime. While the crime is fictional, the trial is conducted before a real federal judge and argued by real practicing attorneys.

Familiar Faces (ScienceNews)

In a story about “super recognizers”—people who have an exceptional ability to remember faces—ScienceNews turns for comment to Dartmouth’s Bradley Duchaine.

Duchaine, an associate professor of psychological and brain sciences, and colleagues in England are studying super recognizers to understand how some people are able to recognize nearly everyone they’ve ever seen, the magazine writes. Knowledge gained from such studies may aid in police work and other fields that rely on identifying people by how they look, notes the magazine.

“By identifying strategies used by super recognizers, we may find ways to train others who have problems with face recognition, or help people who are in the normal range but have professional demands in which superior face recognition would be beneficial,” Duchaine tells ScienceNews.

Read the full story, published 8/23/13 by ScienceNews.

Scientists Identify an Off Switch for Bad Habits

What if the brain had a light switch that could be flipped to turn off a bad habit?

Research by Assistant Professor Kyle Smith, who joined the faculty of Dartmouth’s Department of Psychological and Brain Sciences last month, has found just that in lab rats. Smith and others have identified brain cells involved in habit formation and inhibition. Researchers introduced DNA for photosensitive molecules into the brain’s cortex to make specific neurons respond to light from a fiber optic implant. Then, by flashing a light on these key cells, researchers managed to abruptly halt habits and inhibit the formation of new habitual behaviors. 

Smith and his colleagues trained rats to run a maze for a reward. They then overtrained the animals so they ran the pattern even after the behavior brought negative results—in this case, food that tasted bad. So the rats continued the habit, in a sense, against their better judgment. It is not unlike a person continuing to bite his fingernails even though he wants to stop, Smith says.

Rare Disorder Leaves Woman Lost in Familiar Places

In a story about a rare disorder that makes it difficult for people to recognize even familiar places, NBC’s The Today Show interviews Dartmouth’s Jeffrey Taube, who studies the navigational processes used by rats.

Taube, a professor of psychological and brain sciences, says “the rat’s—and probably people’s—brain cells fire like a compass. There is a neuron that fires any time the rat heads north and another that fires when the rat heads south-southeast.”

When everything is working properly, he says, the brain constructs a map that allows us to find our way through familiar surroundings without needing directions.

“There’s a system that’s important for perceiving where you are, another for keeping track of where you are heading and another for keeping track of the distance you’ve moved,” he tells The Today Show. “Any one of these without the others won’t do you any good.”

Read the full story, published 5/13/13 by The Today Show.

Neuroscientist Says Humans Are Wired for Free Will

Dartmouth’s Peter Tse ’84, an associate professor of psychological and brain sciences, says he has identified a neurological basis for free will in the human brain, challenging a majority opinion that has dominated neuroscience for the last 40 years.

Measurements of human brain signals on the level of neurons and synapses have long shown that acts of will are preceded by a buildup of neural activity in the brain. These signals can begin up to seconds before a person is consciously aware of the exercise of volition, according to the weight of data, Tse explains.

Until now, neuroscientists have argued that because this buildup of signals comes before a person acts, or is even conscious of having decided to act, free will cannot exist, because it would require that a thought causes itself to exist before it exists.

“How can something cause its own physical basis? It is this ‘you can’t pick yourself up by your own bootstraps’ idea that has been the main argument against the possibility of free will,” Tse says.

How Music and Movement Communicate Emotion

Joe Blumberg

Music and movement reflect the rhythm of life, stirring human emotions in societies around the world. Even infants display signs of the interconnectedness of music and movement as they bounce up and down to musical rhythms. Music and movement might be characterized as two sides of the same coin—the coin being emotion.

Gaining an understanding of the connections between these behavioral expressions is a quest Dartmouth researchers have undertaken. The research team in Cambodia included (from left) Thalia Wheatley, Stanford graduate student Trent Walker (Khmer translator), Yam Pan (the commune village chief and translator from Khmer to Kreung—the tribal language), and Dartmouth graduate students Beau Sievers and Carolyn Parkinson. (Photo courtesy of Thalia Wheatley)