Researchers shed light on why people trust

August 11, 2015, Dartmouth College
Credit: Rice University

Trust matters whether it's love, money or another part of our everyday lives that requires risk, and a new study by a Dartmouth brain researcher and his collaborators sheds light on what motivates people to make that leap of faith.

The findings appear in The Journal of Neuroscience.

Collaboration is essential to human life, fostering that are intrinsically rewarding, fulfill a basic social need to belong and promote positive physical and mental health. One critical aspect of collaboration is trust, or assuming mutual risk with a partner.

In the new study, participants thought they were playing an economic investment game with a close friend, a stranger or a slot machine. In reality, they were playing with a simple algorithm that reciprocated trust 50 percent of the time. The researchers developed a computational model that predicted each player's decision for each round given their previous experiences in the game.

Results showed that participants found positive interactions with a close friend more rewarding than interactions with a stranger or , and that the researchers' "social value" model predicted participants' investment decisions better than models that only considered financial payoffs. Neuroimaging also showed that specific brain signals—in the and medial prefrontal cortex—correlated with social value signals when the participants made their decisions.

The ventral striatum is a key pathway in reward processing, while the is associated with representing another person's mental state. Together, these regions provide additional evidence that players receive a greater social reward signal when they learn their friend reciprocated than the other two players in the game. This occurs despite participants learning that each player is only reciprocating 50 percent of the time. But because players receive this additional reward signal, they end up trusting their friend more than the other players throughout the game.

"These findings show the importance of social relationships in how we make everyday decisions and specifically how relationships can change our perceived value associated with a given decision," says co-author Luke Chang, an assistant professor in Psychological and Brain Sciences at Dartmouth. "This is a very important finding as most macroeconomic models of individual decision-making are based solely on financial rewards and strongly influence policy decisions. Our findings also provide a new method to test computational models using brain imaging data, which might be useful for studying amorphous concepts such as trust and reciprocity."

Explore further: Character traits outweigh material benefits in assessing value others bring us

More information: Computational Substrates of Social Value in Interpersonal Collaboration, The Journal of Neuroscience, May 27, 2015. 35(21):8170 – 8180. cosanlab.com/static/papers/Far … rietal2015JNeuro.pdf

Related Stories

Character traits outweigh material benefits in assessing value others bring us

August 3, 2015
When it comes to making decisions involving others, the impression we have of their character weighs more heavily than do our assessments of how they can benefit us, a team of New York University researchers has found.

Altruism is simpler than we thought, brain study shows

July 15, 2015
A new computational model of how the brain makes altruistic choices is able to predict when a person will act generously in a scenario involving the sacrifice of money. The work, led by California Institute of Technology ...

What is more rewarding: A soccer goal or prize money?

April 15, 2015
Soccer fans hold their breath in situations like these: Two players on a team are in front of the opponent's goal with the attacking player having to make an important decision: Is it better to pass the ball to the teammate ...

Sense of obligation leads to trusting strangers, study says

May 15, 2014
Trusting a stranger may have more to do with feeling morally obligated to show respect for someone else's character than actually believing the person is trustworthy, according to new research published by the American Psychological ...

Recommended for you

How the brain tells our limbs apart

February 21, 2018
Legs and arms perform very different functions. Our legs are responsible primarily for repetitive locomotion, like walking and running. Our arms and hands, by contrast, must be able to execute many highly specialized jobs—picking ...

Schizophrenia a side effect of human development

February 21, 2018
Schizophrenia may have evolved as an "unwanted side effect" of the development of the complex human brain, a new study has found.

Cognitive benefits of 'young blood' linked to brain protein in mice

February 21, 2018
Loss of an enzyme that modifies gene activity to promote brain regeneration may be partly responsible for age-related cognitive decline, according to new research in laboratory mice by UC San Francisco scientists, who also ...

Therapeutic antibodies protected nerve–muscle connections in a mouse model of Lou Gehrig's disease

February 20, 2018
Amyotrophic lateral sclerosis (ALS), also known as Lou Gehrig's disease, causes lethal respiratory paralysis within several years of diagnosis. There are no effective treatments to slow or halt this devastating disease. Mouse ...

Brain liquefaction after stroke is toxic to surviving brain: study

February 20, 2018
Scientists have known for years that the brain liquefies after a stroke. If cut off from blood and oxygen for a long enough period, a portion of the brain will die, slowly morphing from a hard, rubbery substance into liquid ...

Brain immune system is key to recovery from motor neuron degeneration

February 20, 2018
The selective demise of motor neurons is the hallmark of Lou Gehrig's disease, also known as amyotrophic lateral sclerosis (ALS). Yet neurologists have suspected there are other types of brain cells involved in the progression ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.