Some people have no visual idea, they are virtually blind to the inner eye. Researchers at the University of New South Wales in Sydney have now been able to provide physiological evidence of this “fantasy” for the first time, as they report in the journal “eLife”. The team led by neuroscientist Joel Pearson initially presented patterns of different brightness to 42 students with normal imagination and 18 participants with a lack of imagination. The pupils reacted in the same way in both groups: they became larger with darker images, and more light caused them to contract. All participants were then asked to re-imagine what they had just seen and how vivid the memory was in their mind’s eye.
In the control subjects, the pupil size changed in accordance with the imagined brightness and the vividness of their imagination. The situation was different in the group with afantasy: Nothing moved here. Could it be that they simply didn’t even try to imagine the objects? To test this, the team varied the level of difficulty by increasing the number of patterns to be imagined. Pupil size is known to be related to cognitive effort. In fact, when performing particularly difficult tasks, subjects with afantasy had their pupils dilated, but not in relation to the brightness of the pattern.
“This suggests that they were actually trying to imagine something, just not in a visual way,” says Lachlan Kay, lead author of the study. Pupil response could be a new measure of afantasy, Pearson says, because: “One of the problems with many existing methods of measuring visual imagination is that they are subjective. They rest on people being able to evaluate their own imagination.”