When do you really become you? The most accurate answer may be: never, really. Research suggests that your personality starts showing up soon after you’re born, and it begins to stabilize more fully around the time you hit 30, but it never becomes fully calcified — with a little work and a therapist’s help, it’s possible to change your personality, if you want to. And in our earliest years, according to a new study in the Journal of Personality and Social Psychology, the company we keep can make a big difference, too.
The study authors followed two classes of preschool students across the school year, observing the personality of each kid as well as whom they chose to play with. They focused specifically on three things: “positive emotionality,” a sort of proto-extraversion; “negative emotionality,” a precursor for anxiousness; and “effortful control,” the early-childhood equivalent of a willingness to work hard. (As my colleague Drake Baer has explained, some psychologists consider these three elements to be the building blocks of temperament, developing over time into full-fledged personality traits.)
Over the course of the experiment, the researchers found, their subjects took on the traits of their playmates – with a caveat: Only positive emotionality and effortful control were “contagious”; negative emotionality, on the other hand, didn’t seem to transmit from kid to kid.
It’s a finding based on a small study, but if it holds up in future research, it could be a helpful snippet of information for anyone who’s trying to raise a decent human: “Parents spend a lot of their time trying to teach their child to be patient, to be a good listener, not to be impulsive,” co-author Emily Durbin, a psychology professor at Michigan State University, said in a statement. “But this wasn’t their parents or their teachers affecting them — it was their friends. It turns out that 3- and 4-year-olds are being change agents.” All those parental lessons, in other words, may be best supplemented with a strategic playdate or two.