The journal of Proceedings of the National Academy of Sciences recently published the findings of a study exploring how people visually process and remember information about similar and dissimilar objects. This study was led by Michael A Coben of Harvard University’s psychology department.
The new research findings seem to show that our brains use different sites in the visual cortex to interpret different categories of visual stimuli. This indicates that when people are visually shown too much of the similar visual images (stimuli), those visual circuits can become overloaded. When we gain many similar memories for long term storage, we tend to exclude memories gathered at the same time that are irrelevant to the current visual upload.
For instance, when viewing a series of tools, one image after another, hammer, chisel, screw driver, — but then an image of an apple, then back to more tools, wrench, pliers, drill, etc., people tend to forget about the apple, when questioned at a later time abut what images they saw. The apple did not “fit” into the overall memory information. Thus how we instinctively are set up to store our visual memories may be efficient, but not accurate.
One study involved showing participants a grouping of four things flashed for less than a second. Sometimes the groupings were all of a similar group, such as the tools mentioned above, or scenes, or faces, or bodies. Researchers also used groupings were of two alike images, such as scenes and two other images, such as faces.
The participants were more likely to accurately recall four similar images than four dissimilar images even when questioned immediately after the viewing.
Brain scans were then conducted, which revealed evidence of the memory differences. When the participants viewed faces neurons were activated in one part of the occipitotemporal cortex. Viewing scenes activated neurons in a wholly separate part of the region. The sight of bodies or objects stimulated still different clusters of brain cells.
That we use different areas of our brains to store different kinds of memories has been previously explored, and explains certain kinds of blindness such as prosopagnosia, also known as face blindness.
However, there are only so many routes into those places in the brain where faces, scenes, objects or scenes are represented. The study results suggest that attempting to remember too many different kinds of images at the same time creates a kind of brain traffic jam or overload.
This new understanding would also help explain some differences in the accounts of eye witnesses. Witnesses may have retained different memories, even though they witnessed the same events.
As an artist and museum and gallery visitor this also makes sense . I am always discovering new visual ideas in great works, such as those of Vincent Van Gogh or Pablo Picasso. Maybe this is because I have changed and seen more, thus added to my visual ability to actually see, but perhaps, the new visual information was perceived but not retained as during the prior encounters with a work, I was focused on other areas.