Outliers is getting a kick out of new research that shows babies display “Mean Girls” tendencies from an early age—that cliquish behavior that causes people to bond over, say, a mutual love of pink outfits and ostracize others who prefer math.
In a study published in the journal Psychological Science, graduate students at Yale University had 9- and 14-month-old infants select either graham crackers or green beans. Then, the infants watched a puppet show where one puppet liked graham crackers and the other, green beans.
After that, the infants watched another puppet show where both puppets dropped their balls and wanted them back. Two additional characters—one good, one apparently evil—either returned the balls or stole them.