The capacity of the human brain for visual images is seriously limited.

Imagine that you choose a sofa for your new apartment in the IKEA store. You have found a double-colored sofa sofa you like with large soft pillows. You imagine how it will look together with the furniture that you already have, and decide that you need this particular sofa. Continuing to wander around the store, you find a nice little industrial-style lamp and coffee table, and try to imagine how they will look with the sofa. But to represent all three subjects together is much more difficult than to represent one sofa. How many pieces of furniture do you think you can process in your mind? Is there a limit to what we can imagine, or is our imagination truly limitless?



It was this question recently that my supervisor and I tried to get an answer in the laboratory of the University of New South Wales. Instead of furniture, we used simple shapes, known as “Gabor spots,” which are essentially circles with lines. We also used visual illusions called “binocular competition”. Binocular competition arises when you are shown different pictures for each eye, and instead of seeing a mixture of two images, you see one of them - either what is given for the left eye or what is for the right one. My curator Joel Pearson’s previous works have shown that if you first imagine Gabor’s spot or you see his dim image, then the likelihood that you’ll see this spot in the subsequent test for binocular competition will increase.



For example, if I asked you to imagine a red spot of Gabor for a few seconds, and then give you an image with the binocular competition of the red and green spots of Gabor, you would be much more likely to see a red image, rather than a green one. In psychology, this is known as setting fixation (priming), and is often measured as a percentage (the percentage of the number of times a person sees an image that he previously represented, in relation to the number of all images in a test for binocular competition). Since this task was studied only with the help of one image, we decided to check how many different things you can imagine at the same time. If we were able to imagine an unlimited number of things, then the level of priming for one or several images should be the same.



We enthusiastically started the work, offering participants to imagine images in any quantity to choose from, but in the range from one to seven. We gave them clues indicating how many stains of Gabor they need to represent, what color and what orientation. It is important that these tips were present all the time while the participants imagined the images, that is, the participants did not get confused and did not forget exactly how many spots they needed to present. We found that our subjects were limited in the number of images they were able to present, and their priming level dropped to a statistically random when they tried to keep from three to four images in memory. Then we did a few more experiments, and found that our subjects noted visual images they imagined as less vivid when they had to imagine more objects, moreover, the accuracy of the objects in the mind decreased if they needed to be imagined in the numbers more than one.



So in fact, it is possible to show the existence of serious limitations in our visual imagination. Why it happens? Most likely, restrictions on the volume of visual imagery appear somewhere in the visual network of the brain, extending through the frontal and rear visual areas. It is believed that the frontal areas are responsible for managing and creating visual images through top-down connections that feed data to sensory areas of the brain. These connections manipulate the response rate of neurons in the visual areas of the brain, which leads to the appearance of a visual image sensation. These top-down links create maps of the images that we imagine. When we imagine several images, we create several maps, and they compete for space in the brain. This competition and interaction between the cards may reveal our limitations.



Why are these restrictions important? Visual images are involved not only in the purchase of sofas and tables in IKEA. Take the treatment of mental disorders. Phobias are usually treated by displaying images. Therapy works through a repeated demonstration to a person of what causes him to experience, for example, spiders, airplane flights, public speaking, heights, etc., and this repeated demonstration leads to a weakening of the fear response. For obvious practical reasons, it can be difficult to put people in these situations, so doctors use imagination instead of real situations. The patient imagines a fearful stimulus as detailed as possible, and this is considered to work almost as much as meeting a real stimulus.



Another form of treatment in clinical psychology that uses visual imagery is mental rewriting, which is used to treat such deviations as depression, anxiety, obsessive-compulsive disorder , and eating disorders. Mental rewriting implies that participants imagine or simulate scenarios from the past or the future that cause them anxiety or fear. They present them in as much detail as possible, and then they are asked to present an alternative scenario with a more positive end - they “rewrite” memory or thought. They are also taught how to change their thinking towards these scenarios.



Although it has been shown that image-based treatments, such as displaying images or rewriting, are among the best options for treating cognitive behavior, they are not 100% effective. It is possible that one of the factors affecting their work is that the scenarios created in the head are not very real, which is influenced by both the limitations of the imagination and the individual characteristics of people in creating such scenarios.



In addition to therapy, we use visual images when we recall the past and plan the future; when we hold and process visual information in working memory; they even play a role in moral judgments and intentions to help others. The limitations of the volume of visual images that we discovered are likely to affect the quantity and quality of information that we are able to maintain and process in any of these situations. These limitations can constrain our possible achievements, both in everyday life and in therapeutic treatment.



It is not quite clear yet whether it is possible to increase our abilities concerning visual images (I am working on this issue now). But we know that by studying and creating new, objective ways of numerical evaluation of the limitations of our visual images, we can get closer to understanding the limitations of human imagination and reason, and develop new ways to overcome them.