If people form opinions online before they fully evaluate whether information is true, then the fight against misinformation may begin far earlier than most platforms are designed to address. A new study published in Information Systems Research, a journal of INFORMS, suggests that social media users can begin developing stable opinions about unfamiliar topics after seeing only a handful of consistent posts. Researchers found that after roughly five exposures, users’ impressions often began stabilizing and shaping how they responded to future information.

Researchers have a better understanding of the nocebo effect and the neuroscience behind it all. Opposite of the better-known placebo effect, where positive expectations trigger genuine pain relief, the nocebo effect is the experience from negative expectations, created by prior experience, verbal suggestion, or social observation, which can drive anxiety and make pain worse. 

A new study published in Nature Communications, by researchers at the University of Toronto Mississauga and McGill University, identified a brain pathway through which negative expectations can amplify pain. The findings, generated independently by the two labs without prior coordination, converged on the neurochemical cholecystokinin (CCK), which has previously been linked to nocebo pain responses in humans.