People with ‘mental blindness’ are more difficult to frighten, study shows

People with afhantasia – that is, the inability to view mental images – are more difficult to frighten with frightening stories, shows a new UNSW study in Sydney.

The study, published today in Proceedings of the Royal Society B, tested how fascinating people react to reading distressing scenarios, such as being chased by a shark, falling off a cliff or being on a plane that is about to fall.

The researchers were able to physically measure each participant’s fear response by monitoring changing skin conductivity levels – in other words, how much the story made a person sweat. This type of test is commonly used in psychology research to measure the physical expression of emotion in the body.

According to the findings, scary stories lost their fear factor when readers were unable to imagine the scene visually – suggesting that images may have a closer connection to emotions than scientists previously thought.

“We found the strongest evidence that mental images play a key role in linking thoughts and emotions,” said Professor Joel Pearson, senior author of the article and director of the Future Minds Laboratory at UNSW Science.

“In all of our research to date, this is by far the biggest difference that we find between people with aphantasia and the general population.”

To test the role of visual images in fear, the researchers guided 46 study participants (22 with aphasia and 24 with images) to a darkened room before placing several electrodes on their skin. The skin is known to become a better conductor of electricity when a person feels strong emotions, such as fear.

The scientists then left the room and turned off the light, leaving the participants alone as a story began to appear on the screen in front of them.

In the beginning, the stories started harmlessly – for example, “Are you on the beach, in the water ‘or” Are you on a plane, near the window. “But as the stories continued, the suspense slowly grew a dark flash in the distant waves and people on the beach pointing, or the cabin lights dimming when the plane starts to shake.

“The skin’s conductivity levels began to rise rapidly for people who could see the stories,” says Professor Pearson. “The longer the stories went on, the more their skin reacted.

“But for people with aphantasia, the skin’s conductivity levels practically stabilize.”

To see if differences in the limits of fear did not cause the answer, the experiment was repeated using a series of scary images instead of text, such as a photo of a corpse or a snake with its fangs.

But this time, the photos made the skin prickle equally in both groups of people.

“These two sets of results suggest that aphantasia is not linked to the reduction of emotion in general, but is specific for participants who read scary stories”, says Prof. Pearson. “The emotional fear response was present when the participants actually saw the scary material unfold in front of them.

“The findings suggest that imagination is an amplifier of emotional thinking. We can think of all sorts of things, but without imagination, thoughts will not have that emotional boom.”

Living with afhantasia

Afhantasia affects 2 to 5% of the population, but very little is known about the disease.

A UNSW study published last year found that aphantasia is linked to a widespread pattern of changes in other cognitive processes, such as remembering, dreaming and imagining.

But while most previous research on aphantasia focused on behavioral studies, this study used an objective measure of skin conductance.

“This evidence further supports afhantasia as a unique and verifiable phenomenon,” says study co-author Dr. Rebecca Keogh, a postdoctoral fellow who worked at UNSW and now works at Macquarie University.

“This work may provide a potential new objective tool that can be used to help confirm and diagnose aphantasia in the future.”

The idea for this experiment came after the research team noticed a recurring feeling in the discussion forums about aphantasia that many people with the disease did not like to read fiction.

Although the findings suggest that reading may not have as much emotional impact for people with aphantasia, Prof. Pearson says it is important to note that the findings are based on averages, and not everyone with aphantasia will have the same reading experience.

The study also focused on fear, and other emotional responses to fiction may be different.

“Aphantasia comes in different shapes and sizes,” he says. “Some people don’t have visual images, while others don’t have images in one or all of the other senses. Some people dream, others don’t.

“So don’t worry if you have afhantasia and it doesn’t fit that mold. There are all kinds of variations of afhantasia that we are just discovering.”

Then, Prof. Pearson and his team at Future Minds Lab plan to investigate how disorders such as anxiety and post-traumatic stress disorder can be experienced differently by people with aphasia.

“Aphantasia is neural diversity”, says Prof. Pearson. “It’s an incredible example of how different our brains and minds can be.”