Washington D.C.: There is a reason behind your baby's smiles. A new study suggests that toddlers time their smiles to make their moms smile in return.
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 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, one of the study's authors, adding that proving this is difficult.
Co-author Dan Messinger from the University of Miami said that what makes the study unique is that previous approaches to studying infant-parent interaction essentially describe patterns.
The study appears in PLOS ONE.