Humans often make snap judgements about who to trust. Most people will
say "I didn't like the look of that person," but what that means,
exactly, has been elusive. Now a robot is helping to tease that out.
At Northeastern University, psychology professor David DeSteno wanted to
see what was going on. Working with partners at MIT and Cornell University, he started by looking at what kinds of interactions make humans trust each other more. He had 86 Northeastern students conduct either a face-to-face conversation or a Web-based chat. The conversations were with people they didn't know and lasted five minutes. The live conversations were recorded on video and classified according to how much fidgeting the two people did.
DeSteno then had the two participants play the classic prisoner's dilemma game. You can betray your partner and get a profit for yourself, or work with her to get a smaller gain for both. Most people choose the latter when
they trusted the other person more. And as it turned
out, the players who met face-to-face rather than online were better at
picking out trustworthy people.
But what was it they were picking up on? That's where the robot comes in.
The experiment was repeated with an MIT-built robot — called Nexi — playing the
part of conversation partner. The robot was controlled by two people
behind a curtain. It turns out there were specific body motions that marked a person as being less trustworthy. For example, leaning away, crossing one's arms, touching one's hands together and touching one's own body. Each motion in isolation didn't seem to mean much, but together they were a good guide to how trustworthy a person was in the game. When Nexi crossed its arms or touched its
face, people trusted it less.
What this tells DeSteno is that there really are certain cues people see — and they can be measured. It also suggests something bigger: that
robots can build trusting relationships with humans.
The results of the research will be published this month in the journal Psychological Science.
Image: Northeastern University / Mary Knox Merrill