The Canadian Press

Can robots and computers take the place of a human being? A new study involving research on brain activity in humans provides some food for thought in the evolving debate about interactions between man and machine - people seem to prefer people.

German scientists used an MRI scanner to see how the brain reacted when subjects thought they were playing a game against four different opponents - a laptop computer, a functional robot with no human shape except for artificial hands, a robot with a humanlike shape and another person.

The 20 participants were also asked about their enjoyment levels after playing the Prisoner's Dilemma Game, which is similar to the Rock Paper Scissors game.

"We were interested in what's going on in the brain when you play an interaction game, when you need to think what your opponent is thinking," said Soren Krach, a psychologist in the department of psychiatry at RWTH Aachen University.

In social cognitive neuroscience, the ability to attribute intentions and desires to others is referred to as having a Theory of Mind, according to the study.

"We found out that the activity in the cortical network related to Theory of Mind ... was increasingly engaged the more the opponents exhibited humanlike features," Krach explained.

Before going into the MRI scanner, the subjects played against the laptop, the two robots and the human. Once inside the scanner, they played again, using special video glasses, and they were told which opponent they were playing against at any given time.

Later, they were asked about the interaction.

"They indicated that the more humanlike the opponent was, the more they had perceived fun during the game and they more attributed intelligence to their opponent," Krach said.

The study was published Tuesday in the online open-access journal PLoS ONE.