How many times have you been disappointed by the adaptation of a book for film or television, when a scene did not quite correspond to what you had imagined? Or that a character did not look at all like what you had envisioned?
Most people, when asked to form an image of someone familiar to them, can “see” it in their mind. In other words, it is a mental representation visual similar to what we would see if the person was in front of us.
But it turns out that this is not the case for everyone. Some people, when asked to picture a mental image, say that
they can’t “see” anything. This recently identified phenomenon of the human mind was referred to in 2015 as
aphantasy. It is estimated that 2 to 5% of the population are unable, throughout their life, to generate the slightest mental image.
But how do you remember the details of an object or event if you can’t “see” it in your mind? This is a question that my colleagues and I have sought to study in one of the our recent studies.
The study of aphantasy
We evaluated the performance of the visual memory in individuals with aphantasia compared to those with a typical visual imagination.
In the study, participants were shown three pictures: those of a living room, a kitchen and a bedroom, and were asked to draw them from memory.
Their drawings were objectively reviewed online by over 2,700 external reviewers who compared object details (how they look) and spatial details (the size and location of objects).
We expected that subjects with aphantasia would have difficulty drawing an image from memory because they could not conjure up these images in their minds.
Example of a drawing of an aphantasy participant, from memory, and by observation © Zoë Pounder
In fact, our results showed that they correctly sketched the size and location of objects, but provided noticeably less visual detail, such as color. They also represented a smaller number of objects compared to the drawings of the witnesses.
Some, finally, noted what the object was by language – for example by writing the words “bed” or “chair” – rather than drawing it. This suggests the use of alternative strategies, such as verbal representations, which do not require visual memory. These differences in the details of objects and space were not due to differences in artistic ability or a lack of concentration.
All of this suggests that people with aphantasia have intact spatial cerebral imagination abilities: the ability to represent the size, location and position of objects in relation to each other is preserved. A finding reinforced by another of our studies devoted to their performance in exercises related to memory and its effects on mental representation.
We then found that people who did not have the ability to generate visual images performed as well in these exercises as those with good visual mental representation. We have also seen similar performance with the classic technique of mental rotation (RM), where you observe different figures and, by mentally rotating them, determine which are the same.
These results suggest that it is not necessary to have a good visual imagination to perform these tasks. In contrast, it has been shown that some people with aphantasia – but not all – are more likely to have difficulty recognizing faces and poor autobiographical memory – the memory of life events – a type of memory that it is believed to rely heavily on mental images.
Some people don’t have a mental picture of past events © Sun Ok / Shutterstock (via The Conversation)
Living with aphantasy
People with aphantasia also describe other disparities. Thus, some have only a partial absence of a mental image at the level of the senses and will be able to hear a melody in their head… but not have visual images associated with it.
Likewise, research has shown that despite their inability to generate visual images on demand at will, subjects report having mental images in their dreams. Others say their dreams are non-visual, consisting only of conceptual or emotional content.
These disparities are fascinating and recall to what extent the distinctions between individuals are still largely unrecognized, especially at the level of perception of the world. And difference does not necessarily mean less integration. Many people with aphantasia are not aware of seeing the world differently, and have a very classic working life. They have even been shown to work in a number of scientific and creative industries.
For many, mental images are an integral part of their way of thinking, remembering past events, and planning for the future – a process in which they engage and live unconsciously. We do not yet understand why there are differences in the visual mental representation, nor what is the root cause. But what aphantasy testifies to is that many of our major mental experiences are in fact not universally shared. There are therefore many unrecognized and disconcerting disparities between us, which have continued to titillate scientists.
This analysis was written by Zoë Pounder, postdoctoral researcher in visual imagery at the University of Westminster (England).
The original article was published on the website of The Conversation.
