Put on a virtual reality headset, watch a stranger’s cheek being stroked while a researcher strokes your own in perfect time, and something strange happens. The other face starts to feel like yours. Not metaphorically. The brain, fed matching signals from eye and skin, quietly files the borrowed features under “me”. It is one of the older tricks in cognitive neuroscience, and it works on almost everyone to some degree.
What a team at the Università Cattolica del Sacro Cuore in Milan wanted to know was whether some people fall for it more easily than others. And whether the years you have spent scrolling Instagram might be quietly tipping the odds.
The reasoning runs like this. Your sense of owning a body is not handed to you at birth and left alone. It is stitched together, moment by moment, from signals arriving inside (heartbeat, the position of a limb, the churn of the gut) and signals arriving from outside (what you see, what touches your skin). The brain fuses the two streams into a single, unshakeable conviction: this body is mine, and I am someone distinct from everyone else. When that fusion drifts, the borders of the self get a little porous. Body illusions are a way to measure exactly how porous.
So the researchers, led by Maria Sansoni with Giuseppe Riva supervising, recruited 95 young adults and ran them through two such illusions. One targeting the face, one the whole body.
The participants averaged nearly eight years on Instagram and around an hour a day on the platform. After the synchronous stroking, they rated how much the virtual face or body felt like their own. Then the team checked those ratings against how long each person had been an Instagram user, how much time they spent daily, and whether they used beauty filters.
Here is the bit that surprised even the authors. The longer someone’s history on Instagram, the more readily they accepted the stranger’s face as theirs. A sort of dose effect, building over years rather than minutes.
Why the Face and Not the Body
That the effect showed up on the face, specifically, is what gives the finding its bite. Faces are not like elbows. They are the part of us most freighted with identity, the thing we scan in a mirror, the thing that lets other people pick us out of a crowd. Bodies, for all their bulk, carry far less of that identity load, which is roughly why the same illusion is harder to pull off on a whole body than on a face. Riva puts it plainly: “it is through our faces that we recognize ourselves in the mirror, construct our individuality, and are recognized by others. In other words, the association does not emerge in any bodily representation, but precisely in the part of the body most closely linked to the sense of who we are.”
The team has a name for what they think is going on: the Digital Erosion of Bodily Identity Hypothesis. Spend years marinating in a feed where, thanks to the same filters and the same beauty ideals, everyone sort of looks the same, and the perceptual line between your face and other faces may slowly blur. If everyone looks the same, the logic goes, then on some pre-conscious level everyone is the same. Including you.
There was a second, shakier signal. People who used beauty filters were more susceptible to the full-body illusion, in the dimension of agency (the feeling of controlling the virtual body). But only 12 participants reported using filters at all, so the authors flag this one as exploratory, the kind of result that needs a much bigger sample before anyone leans on it.
What the Study Pointedly Did Not Find
Now for the genuinely counterintuitive part. You might expect heavy Instagram use to come with worse body image, more dissatisfaction, more of the appearance anxiety the platform is endlessly blamed for. It didn’t. Time on the app showed no link to body image concerns, and none to interoception, the brain’s read on its own internal signals. The cracks the researchers found weren’t in how people felt about their looks, but a layer beneath that, in how coherently the body gets assembled into a self at all. Which is a different, and arguably stranger, kind of worry.
A few caveats sit heavily here, and the authors don’t hide from them. The study is cross-sectional, a single snapshot, so it cannot show that Instagram causes any of this; heavy users might simply have more malleable bodily selves to begin with. The sample was small, mostly White, mostly university-educated. And nobody is claiming the platform makes people ill.
What the work does is shift the question. For a decade the debate over social media and the body has been about appearance, about comparison and dissatisfaction and the gap between the filtered and the real. This nudges it somewhere deeper, toward identity itself, toward the machinery that lets you feel at home in your own skin.
Sansoni is already looking past her own participants, who were, after all, relative latecomers. “The participants involved in the study belong to the first generation to grow up with social media: they began using these platforms in late adolescence and have integrated them into their daily lives for almost a decade. If associations with processes fundamental to the construction of bodily identity are already emerging in these young adults, the question that arises concerns the new generations and new adolescents, who come into contact with these technologies at an increasingly early age and for increasingly longer periods of time.”
Frequently Asked Questions
Does this mean Instagram is damaging my sense of self?
Not as such, no. The study found a statistical association between years of use and how easily people accepted a stranger’s face as their own in a VR illusion, but it was a single snapshot in time and cannot establish cause. It is entirely possible the relationship runs the other way, or that some third factor explains both. The authors are careful to say it proves no harm.
Why does it matter that the effect showed up on the face rather than the body?
Because the face is the body part most tightly bound to identity. It is how we recognise ourselves and how others recognise us, so a loosening of the brain’s “that’s my face” signal touches something closer to the core of selfhood than, say, a looser sense of where your arm is. That specificity is what the researchers found most striking.
What is a body illusion actually measuring?
It measures how readily your brain will accept external sensory evidence over internal evidence when deciding what counts as your body. Stroke a fake hand and your real hand in sync and many people start to feel the fake one is theirs. How strongly you feel it is taken as an index of how flexible, or how porous, the boundaries of your bodily self are.
What about beauty filters specifically?
There was a hint that filter users were more susceptible to the full-body illusion, but only twelve people in the study used filters, so it is firmly in early-days territory. Treat it as a thread to pull on, not a conclusion.
