Those adorable and curious stares babies give may indicate that they know a lot more about the world around them than previously thought, according to a new study conducted in the Northwestern psychology department.
The research is one of a growing number of findings opposing the notion that babies are born as “blank slates” who must depend on others to acquire knowledge, said psychology Prof. Susan Hespos, lead author of the study.
Hespos’ research follows up on 20 years of experimentation showing that young babies already have expectations of how solid objects behave in the real world.
“A three-month-old knows that an object shouldn’t float in mid-air,” she said. “If you were to rig up a puppet stage and show them an object floating in mid-air, they’ll look significantly longer at that than when an object falls like it should.”
Humans have a propensity to look longer at things that are novel or unexpected, Hespos said.
“When you’re walking down the street, your eyes rest longer on someone who has green hair rather than someone who doesn’t,” Hespos said.
The research studies babies’ knowledge of amorphous non-solids, such as water and sand, said Lance Rips, professor of psychology and co-investigator of the experiment.
“Babies haven’t been given credit about their knowledge of liquids,” he said.
In the preliminary trials of the experiment, researchers poured a liquid and a solid back and forth between two glasses. One group of five-month-old babies was shown the shape-shifting physical characteristics of blue water and the other group was shown a glass filled with a solid that looked like the blue water but exhibited very different physical characteristics.
Data from the following test trials showed that babies who saw liquid in their preliminary trial looked longer at the solid than the liquid in the test trial when it was being transferred between glasses. On the other hand, babies accustomed to the solid in the preliminary trial looked longer at the liquid during the test trial.
The findings were published in the May 2009 issue of Psychological Science.
