Last year’s movie Changeling tells the story, from the late 1920s, of a mother whose son is kidnapped. Then, six months later, the police say they’ve found the boy and return him to his mother, who immediately claims that the boy they returned was not her son. She’s then coerced into taking this child in, and doctors are brought forward to convince her that this is really her son. People change, she is told, and she’s has been through severe mental trauma. Surely the best medical minds in the country know better than a single mother.
The film ends up being a scathing indictment of the LAPD, but even more, the sad state of what passed for psychiatric care in that era. But it also brings up a very different question: what does it mean to be an “expert” at recognizing an individual? Does a mother have a special ability not shared by others? In another scene, the kidnapper’s nephew is asked to identify pictures of the children he was forced to abduct. He recognized a photo of our heroine’s son. Can we trust him?
Several studies have shown that people are better at recognizing others who look like themselves (same race, same age) compared to those who look different. The same-race effect has been studied more extensively (and we’ve discussed some of it here), but the same-age effect is quite strong too.
But what causes the effect? Are we better at recognizing faces we see more often, so since whites are less likely to encounter black people, they’re simply not as good at recognizing black faces? Or do we have separate process for people who are in our group, versus outside it? Or are we better at recognizing the faces we care about more? This would explain one study, which found that while white South African university students were better at recognizing white faces than black faces, the reverse did not hold true for black students. Arguably, it’s more important for black people to be able to identify white people, since whites are the dominant social group in that setting.
A recent study by Virginia Harrison and Graham J. Hole was able to address some of these questions. They showed faces of boys (age 8-11) and adult men to 66 university students. Half of these students were in a teacher-training program and had been working with kids this age for an average of more than a year. The other half had very limited contact with children.
Everyone saw 32 pictures of faces, 16 from each age group (either smiling or neutral), flashed for three seconds at a time. They were told to memorize the faces for a test. They were then distracted for three minutes, and tested on a new set of photos: 32 different people, plus 32 of the original group, but in a different pose (smiling or neutral). For each photo, the students had to say, as quickly and accurately as possible, whether they had seen that face before. Here are the results:
There was no difference in recognition of their own age group, but the teacher trainees were significantly better at recognizing kids’ faces than the non-teachers. There were similar results for reaction time.
So age-related differences in face recognition appear NOT to be due to an in-group/out-group process. Teachers clearly aren’t in the same group as their students, but teachers still recognize kids better than other adults their age. But it’s possible that exposure to people in a different age group may be what causes the results we see (since teachers spend more time with kids). It’s also possible that teachers do better because are just more motivated to recognize kids. This study can’t tell which of these explanations is more important (or whether both contribute), but the researchers say they’re working on a new study which can answer that question.
By the way, it almost goes without saying this work also suggests that a mother like the woman Angelina Jolie portrays in Changeling should be exceptionally well-qualified to recognize her own child, even months later. What better training at recognizing an individual could there be than rearing him or her from birth?
Harrison, V., & Hole, G. (2009). Evidence for a contact-based explanation of the own-age bias in face recognition Psychonomic Bulletin & Review, 16 (2), 264-269 DOI: 10.3758/PBR.16.2.264