Mean Babies Study Reveals Early Bias In Infants

mean babies study

Anyone who has been roused for a diaper change after a blissful 12 and a half minutes of sleep can tell you mean babies certainly exist, but a new study proves what new parents have secretly felt all along — babies are jerks and out to get us.

Okay, perhaps the last part is an exaggeration, but the “mean babies” study reveals some interesting insight into how we as human beings develop, among other things, prejudice, bias, and uncharitable inclination. Sometimes in the first year of life.

The study, published in the medical journal Psychological Science, found the mean babies phenomenon in young infants during the course of research at Yale. Kiley Hamlin and colleagues took infants at the ages of nine months and 14 months, recording a preference for either green beans or graham crackers.

Afterwards, the babies watched a puppet show — in which puppets also indicated a preference for graham crackers or green beans. ScienceDaily explains that “the puppets chose their foods, infants then watched another puppet show, in which either the similar puppet or the dissimilar puppet dropped its ball and wanted it back” and that during “alternating events, infants saw that one character always helped the ball-less puppet by returning the ball to him, while another character always harmed the ball-less puppet by stealing the ball away.”

Then, the babies were asked to choose the nice, giving puppet or the mean, thieving puppet — can you guess what happened next? The mean babies in the study tended to like the puppet that helped their puppet doppleganger — but nearly all of the wee tyrants also liked the “harmer” that was cruel to the dissimilar puppet.

Hamlin says that “like adults, infants incorporate information about not only what people do (e.g., acting nicely or meanly) but also whom they do it to (e.g., a person who is liked or disliked) when they make social evaluations.” A followup experiment involving a neutral puppet that had no preference, and in it, the older babies “preferred the character that harmed the dissimilar puppet over the neutral puppet, and the neutral puppet over the helper of the dissimilar puppet.”


Researchers surmise the “mean babies” phenomenon develops at some point between nine and 14 months, and Hamlin explains that “the fact that infants show these social biases before they can even speak suggests that the biases aren’t solely the result of experiencing a divided social world, but are based in part on basic aspects of human social evaluation.”


She adds: “Infants might experience something like schadenfreude at the suffering of an individual they dislike. Or perhaps they recognize the alliances that are implied by social interactions, identifying an ‘enemy of their enemy’ (i.e., the harmer of a dissimilar puppet) as their friend.”

Researchers have yet to determine the exact reason mean babies develop the biases.