A couple of days ago, during a hiking tour close to Luzern, I met a medical doctor from Israel who decided to join me for my hike for the rest of the day. After some time, when I made fun of her taking so many pictures, she pointed out that she had a rare neurological condition that prevented her from recalling pictures and that she did not have a picture of anything in her mind when she closes the eyes. Curious about that, I asked her some obvious questions, and it turned out that she could, however, identify faces. And it also turned out that she was not very good at navigation and orientation. One interesting thing she mentioned is that she believed that this condition is not a black-or-white story, but that there might be a large spectrum from those who cannot imagine any visual picture at all, over those who can recall dim shadows of previously seen sceneries, to those who see with their inner eye as lively as with their normal ones. This is very plausible to me and mirrors some of my personal impressions, but it is also clear that such graded distributions of the liveliness of visual imaginations can go unnoticed for hundreds of years in a population, since there is no real need in daily life to speak about this sort of differential experiences. For example, I never relied too much on visual aspects when trying to memorize facts, whereas I know that other people do; maybe these kinds of preferences are not purely random, but have some psycho-physiological causes and reflect a graded spectrum of a neurological condition like this.
It turned out that this neurological condition has been discovered or re-discovered and gone more or less viral quite recently, and it has been termed ‘aphantasia’ by the authors of a short report (link). I do not quite like the term ‘aphantasia’ – to me, it makes the impression as if the affected person had no imagination nor creativity, which is not the case from my personal experience (n=1). However, there seems to be a well-established community that is using this name, with its own webpage (link) and an associated facebook group.
During the hike, which required quite some orientation in the end, I was highly tempted to speculate about a parallel between non-functional imagery and the inability or impairment to orient oneself, i.e., to create an inner map of the surroundings. When you think of it, there’s not a big difference between creating a spatial map of newly discovered surroundings (through active pathfinding) and creating an image or a scenery from multiple single elements – it’s the act of putting things and locations in a context, the latter being defined by proximity between the objects and geometry. Maybe, adding speculations to already existing speculations about the role of the hippocampus in memory and navigation (link), it would be tempting to think of a visual memory action not as of a recall of the whole picture, but a reconstruction of small elements into a relational context, with the relations as the only part of the memory that is memorized. Similarly, navigation based on maps could be founded on the same principle. To go one step further, something like aphantasia might be a condition where this reconstruction would be impaired, and it would be definitely interesting to study this in more depth, and first to find out at which scale of the brain the effect is created, whether a brain region or a specific projection pattern, or a neurotransmitter expression in a subset of cells is affected. Of course, in a human subject, the brain would compensate for the lacking ability by some way, and therefore controls would be difficult, but overall I’m optimistic that this special condition could be of high interest for understanding how imagination works.