Babies are trying
their moms smiles as much as possible,
while they smile
as little as possible.
Toddler-like robot allows researchers to confirm their
findings
(September 24, 2015) Why
do babies smile when they interact with their parents? Could their smiles have
a purpose? In the Sept. 23 issue of PLOS ONE, a team of computer scientists,
roboticists and developmental psychologists confirm what most parents already
suspect: when babies smile, they do so with a purpose—to make the person they
interact with smile in return.
In addition, babies reach that goal by using sophisticated
timing, much like comedians who time their jokes to maximize audience response.
But there is a twist: babies seem to be doing this while smiling as little as
possible.
Researchers detail their findings in an innovative study
that combines developmental psychology, computer science and robotics—an
approach that has never been tried before, to the best of the researchers’
knowledge. The study is part of an effort funded by the National Science
Foundation to use robots to better understand human development. It gives
developmental psychologists a tool for studying non-verbal children and adults,
such as those with autism, researchers said.
To verify their findings, researchers programmed a
toddler-like robot to behave like the babies they studied and had the robot
interact with undergraduate students. They obtained the same results: the robot
got the undergraduates to smile as much as possible, while smiling as little as
possible.
“If you’ve ever interacted with babies, you suspect that
they’re up to something when they’re smiling. They’re not just smiling
randomly,” said Javier Movellan, a research scientist in the Machine Perception
Laboratory at the University of California, San Diego, and one of the study’s
authors. “But proving this is difficult.”
Diego-san, a
toddler-like robot, interacted with undergraduates during three-minute
sessions.
To find out what babies are really up to, researchers turned
to optimal control theory, a tool often used in robotics. The method allows
researchers to design and program robots to perform a specific behavior based
on specific goals. In this study, the researchers used the method to reverse
engineer what the babies’ goals were based on their behavior.
Researchers used data from a previous study that observed
the face to face interactions of 13 pairs of mothers and infants under the age
of four months, including when and how often the mothers and babies smiled.
After running the data through their reverse-control theory algorithms,
researchers were actually surprised by the findings, said Paul Ruvolo, a
professor at Olin College of Engineering and an alumnus of the Jacobs School of
Engineering at UC San Diego. “We thought either the babies had no goal or it
was about mutual smiling,” he said. Researchers are careful to point out that
they can’t determine if the babies are conscious of what they’re doing. “We are
not claiming that a particular cognitive mechanism, for instance conscious
deliberation, is responsible for the observed behaviors. Our methods are
agnostic to this question.” Ruvolo said.