Is sexual objectification hard-wired? Our study used electrical brain stimulation to find out

When people view sexualised images of women, they tend to remember them less well than sexualised images of men; a quirk of memory that psychologists link to objectification. But in our new study, my colleagues and I found an unlikely “fix” – applying a mild electrical current to the forehead. Objectification means seeing someone as a body, or a set of body parts, rather than as a whole person. Our results, published in Social Neuroscience, suggest this bias in perception is not hard-wired and can be changed – at least for a while. Psychologists measure it with an upside-down test. People are much better at recognising faces and bodies the right way up – typically about 80% right, against 55% upside down – because we take in how all the parts fit together. With objects, such as houses, turning them over matters far less, because we recognise them by their parts. A 2012 study used this test on sexualised images. Volunteers briefly saw a photo, then had to pick it out from a pair: the photo itself and its mirror image. Men and women alike did far better with men in underwear when the photos were upright, but did about as well with women in similar poses either way – the pattern expected for objects. The finding has been debated, and some attempts to repeat it have failed. But a 2022 analysis pooling results from 41 papers found the “upright advantage” – how much better people recognise someone the right way up than upside down – is smaller for sexualised women than sexualised men. Sexually objectified women are seen as less competent and less fully human, and women who absorb this view of themselves tend to have poorer body image and worse mental, physical and sexual health. Exposure to sexualised media is also linked to greater tolerance of sexual violence against women. The bias also shifts with circumstances. In a 2015 study, blurring out women’s chests and groins, or describing them as medical graduates raising money for cancer research, made people recognise their bodies more like men’s. Power plays a part. In earlier research in Canada, a colleague and I asked people to spend ten minutes writing about a time they had power over someone, or when someone had power over them. An established way to make people feel powerful or powerless. Women who felt powerful showed the object-like pattern for sexualised men, and powerful men showed it for sexualised women. People who felt powerless showed the upright advantage for both. Power, rather than gender itself, may be central to objectification. Where the brain stimulation idea came from The idea of trying brain stimulation came from my lab’s work on a famous illusion. In the Thatcher illusion, first shown with a photo of the former British prime minister, a face with its eyes and mouth turned upside down looks grotesque the right way up but almost normal upside down. Turning “Thatcherised” faces upside down also hurts recognition much less than it does with ordinary faces – just as with sexualised women. We had found that the same weak current made Thatcherised faces easier to recognise the right way up, bringing back the usual difference. Would it do the same for sexualised women? The Thatcher illusion. In our new study, 76 university students tried to memorise photos of male and female models posing in underwear – half of them upside down. They then saw the same photos again, each the same way up as before and mixed with 32 new ones, and said whether they had seen each one before. Half the students received a weak current for ten minutes, using a technique called transcranial direct current stimulation. The others received a placebo that switched off after 30 seconds – a standard way of mimicking the tingle of the real thing. Neither the students nor the researchers testing them knew who got which. The placebo group showed the familiar pattern. They remembered men far better when the photos were upright than when upside down. For women, the difference was much smaller, mainly because they remembered upright women less well than upright men. In the stimulated group, recognition of upright images of women improved, and the gap between images of men and women disappeared. The current did not change the upright advantage for images of men. Why? Our best explanation comes from a theory of how people learn to see. With experience, the brain learns to play down features that all faces share and to pick out the details that tell one person from another. But some shared features grab attention instead, such as the flipped eyes and mouth of a Thatcherised face – or, we suspect, the body parts on display in sexualised images. They crowd out the details that tell one person from another. The current may weaken that pull. Our study was a single lab session with university students, and we only measured its immediate effects, not attitudes or behaviour. Because every image was sexualised, we also cannot say how much of the gap comes from sexualisation itself rather than other differences between the photos. Brain stimulation is no cure for sexism. But if ten minutes of a weak current – or ten minutes spent writing about feeling powerful or powerless – can shift how people see a body, objectification looks less like a fixed feature of human vision and more like a habit. And habits, unlike hard-wiring, can change.