Babies may like to be smiled at, but they don't put undue effort into smiling at people in order to make that happen. That's one of the findings of a study conducted by a team of computer scientists, roboticists and developmental psychologists at the University of California, San Diego. To develop their theory, they enlisted the help of a robot you won't soon forget.
The study drew upon earlier research, in which the face-to-face interactions between 13 mothers and their infants were analyzed. In particular, it was noted when and how often the moms and babies smiled.
Using that data, the UCSD researchers programmed a robot known as Diego-san, which was initially created as a platform for studying the cognitive development of infants. Although Diego-san has a fairly robot-like body, its baby-like face is capable of reproducing a wide range of expressions in response to external stimuli.
Once the robot was programmed, 32 undergrad students interacted with it during a series of three-minute sessions. Using a robotics tool called optimal control theory, it was possible for the scientists to essentially reverse-engineer the behavior – they could establish what the babies' goals were, based on the modeled behavior.
Essentially, it was found that babies (and the robot) carefully timed their smiles, in order to get smiles back from the mothers or students. In situations where the chances of getting a return smile were slim, the infants tended not to bother smiling in the first place. That said, it's not at all clear if the infants were doing so knowingly.
It is hoped that these findings and others may ultimately give psychologists a tool for studying non-verbal children and adults, such as those with autism.