Are you easily spooked? Then you probably don't have aphantasia, the inability to picture images into one's mind. New research suggests that people who suffer from aphantasia show a reduced response to scary stories, suggesting that there's a much stronger link between emotions and imagery than we assumed.
A study that pitted people against (made-up) distressing scenarios found that participants with aphantasia didn't have much of a physical fear response to these situations, whereas the other participants did. The team says this is "the biggest difference" we've yet found between people with aphantasia and those without.
Fantasy no-fly zone
"These two sets of results suggest that aphantasia isn't linked to reduced emotion in general, but is specific to participants reading scary stories," says Professor Joel Pearson, senior author on the paper and Director of UNSW Science's Future Minds Lab. "The emotional fear response was present when participants actually saw the scary material play out in front of them."
"[This] suggests that imagery is an emotional thought amplifier. We can think all kinds of things, but without imagery, the thoughts aren't going to have that emotional 'boom'."
"Aphantasia is neural diversity," he adds. "It's an amazing example of how different our brain and minds can be."
The team measured each participant's fear response through the changes in conductivity levels of their skin. This is influenced by how much a person sweats, and sweating is a physical reaction to states of fear or stress. It's a commonly-used method of gauging an individual's emotional state in psychology.
The study involved 46 participants, 22 of whom had aphantasia. Each participant was led to a darkened room, where they were seated and electrodes applied to their skin. That's already kind of spooky, but then the participants were left alone, the lights were completely turned off, and a story was played in text form out on a screen for them.
In the beginning these were quite mundane, starting with scenarios such as "you are at the beach, in the water" or "you're on a plane, by the window". As they progressed, however, suspense was slowly mixed in. The participants were told of "dark flashes in the distant waves", of "people on the beach pointing", or the aircraft's "cabin lights dimming" as the vehicle started to shake.
"Skin conductivity levels quickly started to grow for people who were able to visualize the stories," says Prof Pearson. "The more the stories went on, the more their skin reacted."
"But for people with aphantasia, the skin conductivity levels pretty much flatlined."
Later on, the team also performed a control round in which the text stories were replaced with a series of scary or disturbing images, like a photo of a cadaver or a snake baring its fangs. This was meant to check whether the differences in response seen in the study were caused by aphanthasia, not by each participant's threshold for response to fear. This time, the authors note, all participants showed a roughly equal physical response to the images.
According to Prof. Pearson, this is "the strongest evidence yet that mental imagery plays a key role in linking thoughts and emotions", and "by far the biggest difference we've found between people with aphantasia and the general population" to date.
Aphanthasia affects an estimated 2-5% of the population, but it's still very poorly understood. It seems to be associated with wide-ranging changes in other cognitive processes as well, most notably remembering, dreaming, and imagining. Not surprising, given that these activities often involve picturing events in your mind.
"This work may provide a potential new objective tool which could be used to help to confirm and diagnose aphantasia in the future," says study co-author Dr Rebecca Keogh, a postdoctoral fellow formerly of UNSW and now based at Macquarie University, and it "supports aphantasia as a unique, verifiable phenomenon". The authors say they got the idea for this study after noticing many members on aphantasia discussion boards mentioning that they don't enjoy reading fiction.
Still, the team underscores that their results are based on averages, and that not every individual with aphantasia will experience it the same.
"Aphantasia comes in different shapes and sizes," says Prof. Pearson. "Some people have no visual imagery, while other people have no imagery in one or all of their other senses. Some people dream while others don't. "
"So don't be concerned if you have aphantasia and don't fit this mould. There are all kinds of variations to aphantasia that we're only just discovering."
The paper "The critical role of mental imagery in human emotion: insights from fear-based imagery and aphantasia" has been published in the journal Proceedings of the Royal Society B: Biological Sciences.