'Infants understand gravity with innate sense of physics'

It's said that every child is a born scientist. Now, a new study has found that infants as young as two months old have the basic knowledge of "intuitive physics".

"We believe that infants are born with expectations about the objects around them, even though that knowledge is a skill that's never been taught," said study author Kristy vanMarle of psychology at the University of Missouri.

"As the child develops, this knowledge is refined and eventually leads to the abilities we use as adults," vanMarle was quoted as saying by LiveScience.

To reach this theory, vanMarle and her colleague Susan Hespos, a psychologist at Northwestern University, reviewed infant cognition studies of the past 30 years.
They found that infants already have an intuitive understanding of certain physical laws by two months of age, when they start to track moving objects with both eyes consistently and can be tested with eye-tracking technology.

For instance, at this age they understand that unsupported objects will fall (gravity) and hidden objects don't cease to exist. In one test, researchers placed an object inside of a container and moved the container; two-month-old infants knew that the hidden object moved with the container.

This innate "physics" knowledge only grows as the infants experience their surroundings and interact more with the world. By five months of age, they are able to understand that solid objects have different properties than non-cohesive substances, such as water, found the researchers who detailed their study in the journal WIREs Cognitive Science.

In a 2009 study, a research team (which included Hespos) habituated five-month-old infants to either a blue solid or a blue liquid in a glass cup, which appeared to be the same when at rest.

They tipped the glasses left and right, and poured the contents into other glasses, allowing the infants to form ideas about how the substances worked. Infants habituated to the liquid (but not the solid) weren't surprised that straws could penetrate it, but were confused when straws couldn't penetrate the blue solid. The opposite happened with infants habituated to the solid.

Hespos and vanMarle also learned that babies have rudimentary math abilities: Six-month-old infants can discriminate between numbers of dots and 10-month-olds can pick out which of two cups holds more liquid.

Also at 10 months of age, babies will consistently choose larger amounts of food -- such as crackers -- in cups, though only if there are no more than three items in any cup. While infants appear to be born with intuitive physics knowledge, the researchers believe that parents can further assist their children in developing expectations about the world through normal interactions, such as talking, playing peek-a-boo or letting them handle various safe objects.

"Natural interaction with the parent and objects in the world gives the child all the input that evolution has prepared the child to seek, accept and use to develop intuitive physics," vanMarle added.