How well do you know what you look like? Research on self-perception, digested

By Emma Young

In 2020, we looked at the mistakes we make in seeing ourselves psychologically. But how well do you know what you physically look like? Given that you probably see yourself in a mirror every day, you might imagine that your judgements about your face and body should be pretty accurate. But it turns out that we make some often surprising mistakes about our physical appearance, too.

Facial errors

Most of us are incredibly familiar with the sight of our own faces. But that doesn’t stop us from making errors. If you become close friends with someone, you might well find it harder to tell apart their face from your own. The researchers behind this study suspect that this is because close friends become partially absorbed into our self-concept. A clever study published earlier this year also found that our perceptions of our own personalities affect how we see our face in our mind’s eye. For a self-reported extravert, say, their mental image of their own face had exaggerated facial features known to relate to extraversion. It seems, then, that there are clear links between how we see ourselves psychology and physically. And this holds not just for the face but the body, too…

Distorted bodies

The team behind the face and personality research also asked 39 young female students to produce a body shape self-portrait. They were terrible at it. In fact, there was a “negligible” relationship between the two main measures that the team analysed: perceived and actual hip width. In this study, levels of self-esteem were linked with these misperceptions — the lower a person’s self-esteem, the more likely they were to exaggerate their own hip size, and the slimmer they considered a “typical” woman to be.

We make all kinds of other body-related mistakes, too. For example, when people feel powerful, they’re more likely to think they are taller than they actually are. Also, typical healthy people have a distorted sense of their body volume and length, according to a paper in Cortex in 2019. The 40 young adults involved in this study tended to overestimate the length of various body parts (such as their hands and legs) but underestimate the volume of those parts. These findings add to growing evidence that, contrary to previous assumptions, healthy adults don’t in fact have a highly accurate understanding of their own body size, the team writes.

Strange body changes

You might not have a great grasp of your physical body, but you probably think of it as being pretty stable. Yet it’s surprisingly easy to make people feel as though they are drastically changing. The “magic shoes” experiments led by Ana Tajadura-Jimenez are a great example. Study participants wore sandals fitted with microphones that transmitted, via headphones, only the higher-pitched portion of their walking sounds. This had the effect of making the wearer feel physically lighter. Why? The team thinks it’s because higher-pitched walking sounds are generally made by small animals — so in an attempt to resolve the mismatch, participants’ brains reduced their perceived size.

Tajadura-Jimenez has also recently explored the “auditory Pinocchio illusion” : if adults pull up on their index finger while listening to brief sounds of rising pitch, they have the feeling that their finger is getting longer. Young children don’t succumb to this, however, so it’s likely to be something that we learn. Other research has found that we associate a “high” pitch with a high position in physical space. And so, Tajadura-Jiménez suspects, as we learn this link, it starts to influence perceptions more generally.

Third arm, anyone?

Feeling that we’re suddenly a bit lighter, or that one of our fingers is growing, is one thing. But we are vulnerable to even more extreme bodily illusions. While the “rubber hand illusion” is a classic, and the “three-arm illusion” is pretty cool, my own personal favourite is the Barbie illusion, in which people are made to feel that they are the size of a small doll. The participants in this study wore headsets that displayed a video feed of what the doll would see if it were able to look down at its body. Then the researchers repeatedly touched both the doll and the participant on the leg, in the same place, at the same time. The illusion worked because (as also shown in the Magic Shoes studies) our brains use input from our senses to build and update a mental representation of our “self” — and if the input changes, that representation does, too.   

Body-hopping

Very similar techniques can also lead people to flip into feeling that another person’s face, hand, or even entire body has become their own. And when we take on someone else’s body, we change in other ways, too. Psychologists have made people feel that they were inhabiting the body of Einstein (increasing cognitive performance for some) and also Freud (improving the quality of advice that they were able to offer themselves). As work published in 2021 revealed (again using similar techniques), it’s also possible to make people feel as though they have been duplicated, and that another version of themselves is in the same room.

Body-swapping experiments with pairs of friends have produced some fascinating results, too. Relating back to the findings on facial mental images and personality, Pawel Tacikowski at the Karolinksa Institute, Sweden and colleagues used the Barbie illusion procedure to lead one friend to “inhabit” the body of the other, and found that they took on some of their friend’s psychological attributes, too. So if they rated their friend as being really talkative and confident, for example, their self-reported scores on those traits became higher after the body swap. This is further evidence that our bodily and psychological self-representations are linked in our sense of who we “are”.

Voice

There’s another aspect of our physical selves that we often have trouble with: our voices. Many of us will have had the experience of hearing our voice in a recording for the first time — and hating the sound of it. This phenomenon of “voice confrontation” was documented by psychologists back in 1966. It’s thought to happen because when we talk, inner transmission of the sound through bone provides us with more low-frequency sounds than we get when hearing a voice only through air. So in a recording, our voice sounds higher-pitched than we’re used to, and that’s unsettling because it makes us question our self-concept.

However, there are also times when your voice is likely to actually be higher-pitched. A study in PLOSOne found that we tend to talk to high status people (bosses, high-achievers, and so on) with a higher pitch. Higher-pitched voices are perceived to be less dominant, so this could be a signal of subservience, which, depending on the circumstances, might be practically useful to you, or not — but either way, it’s worth knowing about. 

Body dysmorphic disorder

Some physical misconceptions are more extreme than others. Though healthy people do make mistakes, someone who becomes obsessed with a perceived flaw in their physical appearance — a flaw that either doesn’t exist, or that is over-exaggerated in their minds — suffers from body dysmorphic disorder. This is thought to affect up to about 1 in 50 people, and there are fears that selfie filters designed to “fix” imperfections actively encourage it. For some patients, their physical misperceptions relate to their body shape — they believe that it is either thinner and less muscular, or that they carry more weight, than they do in reality. This can have serious implications, as poor body image judgements are thought to play a part in various eating disorders, including anorexia.


What all this work shows is though we might imagine that we have a clear picture of our physical selves, the reality is very different. Not only are we vulnerable to misperceptions in just about every aspect of what we look like, our mental grip on our bodily self is pretty tenuous, too.

Emma Young (@EmmaELYoung) is a staff writer at BPS Research Digest