Saturday May 27, 2017
Do I look fat in this face?
more stories from this episode
People often think certain kinds of clothing or hairstyles can be unflattering. But a new experiment shows that people tend to think their actual faces make them look fat. Dr. Laurence Harris, a neuroscientist and director of the York University Centre for Vision Research is trying to understand how we perceive and represent our own bodies. The research was published in PLOS One: Perceived face size in healthy adults.
The following interview has been condensed and edited for clarity.
Bob McDonald: Tell me the study of how we perceive faces. What were you looking for?
Laurence Harris: We were looking for how we perceive ourselves. So we were trying to get a measure of how people feel about their own face and how they perceive its size.
BM:How did you do the experiment?
LH: We used a psychophysical method. So we were quite rigorous about this rather than using just a questionnaire or something like that. We gave people two faces and they had to choose which one was most like themselves. And then we varied the size of one of these faces and found the ones that most corresponded to what the person thought that they actually look like.
BM: So they were looking at pictures of themselves?
LH: They were looking at pictures of themselves, lifesize images.
BM: And who were your subjects?
LH: They were just students at York University, so mostly in the age range of about 18 to 25. I should also emphasize that this work was the brainchild of my graduate student Sarah D'Amour who's the first author on the paper.
BM: So were the pictures the kind you see in the carnivals with the mirrors that are bent?
LH: Well they weren't that distorted. No, they were they were systematically just simply widened and or made more and more narrow.
BM: So what were your results?
LH: Well their results were very surprising. We originally thought that when the person was looking at their normal face reflected as if it were in a mirror, that they might be quite accurate because they see themselves in this orientation every time they look into a mirror.
But as a control we also put the faces on their side or upside down. So the same photograph but just re-oriented. And what we found was that when the face was on the side like, as if they were sideways, people were quite accurate.
They were able to judge the width correctly and choose a value that was not significantly different from the actual accurate value. But when they saw their face in an upright position, the one that they normally see in the mirror, that was these significant errors occurred. They judged their faces consistently as being a little wider than they really were.
BM: And by how much?
LH: Up to about five per cent. So quite a significant value.
BM: So you're saying that the people thought that they were fatter than they actually were. Why do you think people misperceive themselves so systematically like that?
LH: Well I think it draws attention to the fact that what we see is not entirely determined by what the information is coming in through our eyes. A huge amount of our perception depends on our beliefs and our expectations of what we're about to see. And this extends to our own selves. We have a representation in our brains that forms about our self, our bodies, and all the parts of our body: our face, the whole body, arms, hands, and so forth are all represented in the brain. And this is something that's built up in all sorts of different ways during development and also may have various distortions in it.
BM: So does this then go beyond faces?
LH: Yes it definitely does. And we've got lots of other experiments going on in the laboratory looking at hands and length of arms and the whole body and that sort of thing. I can tell you that there are systematic errors that are found in other areas but we're not quite ready to publicize those yet.
BM: We hear about disorders like anorexia and bulimia as being associated with people misperceiving their bodies, thinking that they're too fat or I guess too thin, but what do you think your findings say about that?
LH: I think it emphasizes the fact that the representation in the brain is not entirely produced by sensory information. So if there's something wrong with that creation then that might influence people's perception of their own body and be intimately connected to these sorts of syndromes.