Who's got guts? Young infants expect animals to have insides

Who's got guts? Young infants expect animals to have insides
In a new study, University of Illinois professor of psychology Renee Baillargeon, right, and graduate student Peipei Setoh showed that infants expect objects they identify as animals to have insides. Credit: L. Brian Stauffer

A team of researchers has shown that 8-month-old infants expect objects they identify as animals to have insides. The study appears in the Proceedings of the National Academy of Sciences.

University of Illinois professor of psychology Renée Baillargeon, who led the new study with Peipei Setoh, said that many have theorized that babies are born with core physical and psychological frameworks that help them navigate the world.

For instance, when babies see a self-propelled object, their core physical framework leads them to understand that the object has internal energy. And when babies see that an object has control over its actions (that is, responds to changes in its environment), their core psychological framework leads them to view the object as an agent that has .

"In each case, babies seem to be born equipped with abstract expectations that drive their reasoning," Baillargeon said.

For a long time, researchers debated whether in addition to these physical and psychological expectations, infants also possess biological expectations that orient them to think about the right way.

"Our contribution was to find a way to tackle this question experimentally, by asking what young babies know about animals' insides," Baillargeon said.

Researchers have previously found that preschool-age children possess biological knowledge about animals' insides. "Young children expect animals to have different insides from inanimate objects, and they realize that an animal's insides are important for its survival," Setoh said. "They know that if you remove the insides, the animal can't function."

The team decided to test whether 8-month-old babies already understand that animals have insides.

Setoh designed an experiment utilizing the violation-of- method: If babies see something happen that they don't expect, they look at it longer than they otherwise would. The researchers first familiarized the babies in the experiments with objects that had different characteristics. Some objects appeared to be self-propelled and agentive, other objects had only one of these properties, and other objects had neither of these properties. The researchers then tested the babies' expectations by revealing that the objects were hollow.

The infants looked longer at the hollow objects only if the objects were previously shown to be both self-propelled and agentive, indicating that those objects' hollowness violated the infants' expectations, Baillargeon said.

"When babies encounter a novel object that is both self-propelled and agentive, they categorize it as an animal, and they assume it has insides," Baillargeon said. "It cannot be hollow."

Another experiment the group preformed took advantage of the fact that by eight months, most babies have learned to use fur as a cue that an object might be an animal. When shown a novel, self-propelled object covered with beaver fur, babies again identified the as an animal, expected it to have insides, and were surprised when it was shown to be hollow.

The researchers theorized babies expect animals to have insides because they possess a core understanding of biology in addition to their core understandings of physics and psychology.

"These findings go against previous claims that babies have no core understanding of biology," Baillargeon said. "Now that we have shown babies expect totally novel animals to have insides, it calls these claims into question."

A second explanation for this behavior is that babies' expectations about animals and their insides are tied to the cognitive systems humans evolved to deal with predators and prey – in other words, to deal with animals as a food source.

"Understanding that animals are capable of both self-propulsion and agency would have greatly helped our human ancestors to evade predators and to capture prey," Baillargeon said. "And insides would have played a critical role in their interactions with all animals. A predator whose insides have been removed is no longer a threat. And of course, eating the insides of a predator or prey provides nutritious food."

Baillargeon believes the findings will help scientists and others better understand how babies see the world.

"It's interesting to know now that when go to the park and see rabbits and dogs and birds, they think all of them have stuff inside!"

More information: "Young infants have biological expectations about animals," www.pnas.org/content/early/201… /1314075110.abstract

Related Stories

What do infants remember when they forget?

Sep 27, 2011

Six-month-old babies are severely limited in what they can remember about the objects they see in the world; if you hide several objects from an infant, they will only remember one of those objects with any detail. But a ...

Study shows sitting up helps babies learn

Dec 05, 2012

(Medical Xpress)—A new study by Rebecca J. Woods, assistant professor in the human development and family science department at North Dakota State University, shows sitting up, whether by themselves or with assistance, ...

Babies remember even as they seem to forget

Dec 19, 2011

Fifteen years ago, textbooks on human development stated that babies 6 months of age or younger had no sense of "object permanence" – the psychological term that describes an infant's belief that an object still exists ...

Even before language, babies learn the world through sounds

Jul 11, 2011

It's not just the words, but the sounds of words that have meaning for us. This is true for children and adults, who can associate the strictly auditory parts of language -- vowels produced in the front or the back of the ...

Recommended for you

User comments

Adjust slider to filter visible comments by rank

Display comments: newest first

Lorentz Descartes
1 / 5 (5) Sep 12, 2013
Weird study.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.