Ever wonder why you instinctively wince when you see physical harm come to a TV or movie character on screen?

There’s a scientific explanation for why we flinch when watching painful events, even though we know it’s not real, researchers reported Nov. 26 in the journal Nature.

It turns out that such scenes activate hidden links between the parts of the brain that process vision and touch, researchers found.

“When you watch someone being tickled or getting hurt, areas of the brain that process touch light up in patterns that match the body part involved,” lead researcher Nicholas Hedger, a lecturer with the University of Reading’s Center for Integrative Neuroscience and Neurodynamics in Berkshire, England, said in a news release. Along with Hedger, researchers at the University of Minnesota in Minneapolis and Amsterdam, The Netherlands worked on the study.

“Your brain maps what you see onto your own body, ’simulating’ a touch sensation even though nothing physical happened to you,” Hedger said.

For the study, researchers analyzed MRI brain scans taken of 174 people while they watched movies like "The Social Network" and "Inception."

Brain regions originally thought to process only vision responded to movie scenes involving touch, researchers found.

Further, these responses reflected sensations on the viewer’s own body. Essentially, what a person saw triggered echoes of touch.

It turns out there are maps of the body baked into humans’ visual systems, allowing a deep connection between vision and touch, results show.

“This cross-talk works in the other direction too,” Hedger said. “For example, when you navigate to the bathroom in the dark, touch sensations help your visual system create an internal map of where things are, even with minimal visual input. This ‘filling in’ reflects our different senses cooperating to generate a coherent picture of the world.”

This discovery could transform our understanding of conditions like autism, in which people respond differently to physical contact, Hedger said.

“Many theories suggest that internally simulating what we see helps us understand other people's experiences, and these processes may work differently in autistic people,” Hedger said.

“Traditional sensory tests are exhausting, especially for children or people with clinical conditions,” Hedger continued. “We can now measure these brain mechanisms while someone simply watches a film, opening up new possibilities for research and diagnosis.”