By the age of 4 months, babies can assign new objects to animate or inanimate categories

Babies can do more than a lot of people think, often misinformed to the old but incorrect theories by e.g. Jean Piaget (more about this in our forthcoming book). This new study adds insights to this. By studying the gaze of 100 infants, scientists have demonstrated that, by the age of four months, babies can assign objects that they have never seen to the animate or inanimate category. But the researchers learned more:

Using a methodological approach that allows for a comparison of findings obtained with behavioral and brain measures in infants and adults, we identify the transition from visual exploration guided by perceptual salience to an organization of objects by categories, which begins with the animate–inanimate distinction in the first months of life and continues with a spurt of biologically relevant categories (human bodies, nonhuman bodies, nonhuman faces, small natural objects) through the second year of life.

From the press release:

The way babies look at the world is a great mystery. What do they really see? What information do they get from seeing? One might think they look at things that stand out the most — by virtue of size or colour, for example. But when do babies begin to see and interpret the world like adults?

To answer this question, researchers from the Institut des Sciences Cognitives Marc Jeannerod (CNRS / Université Claude Bernard Lyon 1) studied one hundred babies aged between 4 and 19 months. The scientists recorded the babies’ eye movements and the durations of their gaze as they looked at pairs of pictures representing animate or inanimate things from eight different categories (e.g., human faces and natural or artificial objects). The data obtained from eye tracking on babies were matched with measures of brain activity obtained from a group of adults using fMRI, in order to determine the correspondence between the categorical object organisation emerging from the babies’ eyes and that mapped on the adults’ visual cortex.

The methodology used in the study has revealed the transition from the visual exploration guided by the salience of objects, in the youngest babies, to an object representation towards the mature categorical organisation of the adult brain, in the older babies. Already at four months, babies can distinguish between animate and inanimate objects. For instance, they can tell that a man and a crocodile, being animals, are more similar to each other than they are to a tree, which is an inanimate object. This ability appears astonishing as, at that age, babies are unlikely to know what a tree or crocodile is.

Between 10 and 19 months of age, more refined categories emerge and the infants’ organisation of objects into categories increasingly approaches that in the adult brain. Children in this age range immediately recognise a soft, furry object with a face as a nonhuman animal.

This study shows that humans are born with a neural organisation predisposed to representing object categories crucial to their survival. Categorisation is the mechanism that enables us to go beyond what we see and make inferences, analogies, and predictions — for example, if that “soft, furry object” is a cat, it needs to be fed — and thus think about the world around us, from the earliest age.

Abstract of the study:

Humans make sense of the world by organizing things into categories. When and how does this process begin? We investigated whether real-world object categories that spontaneously emerge in the first months of life match categorical representations of objects in the human visual cortex. Using eye tracking, we measured the differential looking time of 4-, 10-, and 19-mo-olds as they looked at pairs of pictures belonging to eight animate or inanimate categories (human/nonhuman, faces/bodies, real-world size big/small, natural/artificial). Taking infants’ looking times as a measure of similarity, for each age group, we defined a representational space where each object was defined in relation to others of the same or of a different category. This space was compared with hypothesis-based and functional MRI-based models of visual object categorization in the adults’ visual cortex. Analyses across different age groups showed that, as infants grow older, their looking behavior matches neural representations in ever-larger portions of the adult visual cortex, suggesting progressive recruitment and integration of more and more feature spaces distributed over the visual cortex. Moreover, the results characterize infants’ visual categorization as an incremental process with two milestones. Between 4 and 10 mo, visual exploration guided by saliency gives way to an organization according to the animate–inanimate distinction. Between 10 and 19 mo, a category spurt leads toward a mature organization. We propose that these changes underlie the coupling between seeing and thinking in the developing mind.

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