The surprising effect of presence hallucinations on social perception

The technodelics platform. EPFL / Alain Herzog EPFL neuroscientists have devised a way to alter our social perception and monitor specific types of hallucinations, both in healthy individuals and patients with Parkinson's disease. The test, which is also available online, provides the medical community with a tool to monitor hallucination susceptibility. If you had to estimate the number of people in a room, without counting them one-by-one, by nature you would overcount them. That's because, simply put from a Darwinian perspective of how we have evolved, it's better to overcount potentially harmful agents and predators than to underestimate them. This overcounting social behaviour is shown to be true in humans as well as animals. It's certainly better to detect too many tigers (even if absent) during a jungle excursion than to miss a hungry one! © 2024 EPFL / Alain Herzog Now, EPFL neuroscientists show that if you experience hallucinations, especially when related to an illness like Parkinson's disease, then you will over-estimate the number of people in a room to a greater degree.