What aphantasia can teach us about episodic memory
What aphantasia can teach us about episodic memory
Margherita Arcangeli (Institut Jean Nicod)
Please try to remember the last time you saw an intriguing bird. What details can you recall? Can you see the colour of its plumage? Did it make any sound? Did you touch it? Was there a particular smell in the air? Where were you?
If you could not conjure up any image, sound, or other sensory representation, you are probably aphantasic (like about 3-4% of the world’s population).
The term “aphantasia” was coined in 2015 to describe a condition of absent or reduced mental imagery. Such a condition has been known and studied long before, at least since the late nineteenth century, but it is now receiving much research attention.
The cognitive performance profile delineated by the current empirical literature on lifelong aphantasia is quite puzzling:
Aphantasics are unable to form mental images and have difficulty mentally projecting themselves into the past and into the future.
Yet, they are otherwise healthy individuals and exhibit quite typical behaviour in several contexts that are taken to require the use of mental imagery, such as mental rotation tasks (e.g., two geometrical figures are presented to a subject who has to say whether the two are identical when rotated), and pictorial memory tests like mentally counting the windows in one’s house (more soon!).
Moreover, some aphantasics report having flashes of colour or fleeting visual representations (both in dreams and when awake), though they are unable to voluntarily induce such visualisations or to sustain them.
Aphantasia has prompted a re-examination, among both academic and non-academic circles, of certain concepts, notably visualisation (or, more broadly, mental imagery) and imagination. Elsewhere I have explored this topic.
Here I would like to focus on what aphantasia can teach us about episodic memory: the type of memory of personal events specifically located in time and space.
Episodic memory often manifests itself in the form of a sort of travel in the past: in recollecting a certain episode of our life, we mentally project ourselves into the past and try to re-live it, to re-experience what we experienced.
We are, thus, able to offer a wide array of details about what happened, perspectival, self-related information about where and when the given past event occurred. Aphantasics report lacking this experience of feeling that they are back in another time, and not only for childhood memories, but also for what happened to them in the recent past.
This is how Blake Ross, one of the creators of Firefox, describes his memories in a now popular Facebook post about his condition of aphantasia:
What was it like growing up in Miami? I don’t know. What were some of your favorite experiences at Facebook? I don’t know. What did you do today? I don’t know. I don’t know what I did today. Answering questions like this requires me to ‘do mental work,’ the way you might if you’re struggling to recall what happened in the Battle of Trafalgar. If I haven’t prepared, I can’t begin to answer. But chitchat is the lubricant of everyday life. I learned early that you can’t excuse yourself from the party to focus on recalling what you did 2 hours ago.
Ross draws an analogy between recollections of his own personal past and of historical facts, suggesting that he has only factual, semantic memory and lacks episodic memory.
Indeed, scientific studies have confirmed that aphantasics have troubles in re-living their past while maintaining their semantic abilities. So it might be tempting to say that aphantasia is not only, and perhaps not even primarily, a mental imagery condition, but an episodic memory condition (Blomkvist 2023; Monzel et al. 2024).
Can we really say that aphantasics lack episodic memory?
At least three strands of research challenge this idea and emphasise the necessity for a more in-depth understanding of episodic memory in aphantasics. Moreover, these studies prompt a reflection on the very definition of episodic memory.
The three pathways to episodic memory in aphantasia concern: (1) pictorial memory tests, (2) memory accuracy, and (3) amnesia. Let me briefly expand on each of these in turn.
1. Pictorial memory tests
If asked to mentally count the number of windows in their house or apartment, aphantasics would perform as good as non-aphantasics, but they would rely more on non-visualisation strategies.
One might suggest that aphantasics exploit semantic, rather than episodic, information and processes. Indeed, aphantasics claim to draw on sources such as their knowledge or factual (i.e., semantic) memory to perform the task.
However, they also make reference to spatial and experiential information, such as knowledge of the direction from which the light is coming, previous experience with the windows (e.g., from cleaning them), and seeming to move (without visualising) around the house.
These non-visualisation strategies suggest that, in counting the windows, aphantasics are not merely retrieving a known fact via semantic memory, but rather forming a new belief thanks to the spatio-temporally rich experiential information coming from episodic memory.
Hence, it is too hasty to claim that pictorial memory tasks do not recruit episodic information and processes.
2. Memory accuracy
One of the primary functions of episodic memory is to provide accurate information about personally experienced past events. In the context of criminal investigations, it is of fundamental importance that witnesses and victims provide as much detailed and accurate information as possible about the criminal event in question.
If aphantasics have poor episodic memory, we might expect them to be less reliable witnesses. However, aphantasics’ testimonies are not so bad, as shown by Dando and colleagues. They found that, compared to non-aphantasics, aphantasics recalled less correct episodic information and their accounts were less complete.
Yet there was no increase in the number of errors, which is typically associated with an impoverished correct recall, thus suggesting that memory accuracy (and episodic memory) is preserved in aphantasics.
That said, aphantasics seem to use alternative retrieval strategies. Dando and colleagues employed two supportive techniques that are used in investigative interviews to improve episodic recall, but they were only effective with non-aphantasics participants.
3. Amnesia
If aphantasia is an episodic memory condition, then a comparison with other types of episodic memory deficit should be instructive.
One of the main deficits in episodic memory is amnesia, which, in its neurological form, is commonly associated with hippocampal damage. This brain region is widely recognized as playing a pivotal role in the recollection of past events, as well as the episodic anticipation of future events.
A recent study by Monzel and colleagues examined the neural correlates of aphantasics during episodic retrieval. In this study too, aphantasics reported fewer episodic details of what they recalled, and also showed less confidence in their memories.
With respect to the solicited brain areas, however, Monzel and colleagues found that aphantasics showed activation in all areas typically related to episodic retrieval, including the hippocampus. Only one specific region of the latter was significantly less active in aphantasics than non-aphantasics.
Thus, aphantasia cannot be really compared to amnesia and further research is needed to assess the extent to which the hippocampus is dysfunctional in subjects with aphantasia.
To come back to our initial question: Do aphantasics lack episodic memory?
I hope I have shown you that a positive answer is anything but straightforward, even though aphantasics tend to recall fewer details (especially visual) and have trouble projecting themselves into their own personal past.
Future research is called to better understand the type of episodic details retained by aphantasics beyond the visual, their retrieval strategies, and the phenomenological aspects associated with them.
The fact that aphantasics do not feel reliving their past does not mean that they do not feel anything.
An aphantasic participant in the study by Monzel and colleagues reported being able to put her “consciousness” in her kitchen and to “feel all around but there is no visual image attached to this feeling”.
Journalist Shayla Love, wrote that she “can remember visual details, just not visually”, mostly, she remembers “how experiences felt – emotionally and physically”.
Describing a childhood memory “representative of its peak happiness”, philosopher Mette Leonard Høeg admits “seeing” anything, but he knows that “those visual elements were there”, they are stored in his mind “as knowledge and concepts” and he has “particular and strong emotional responses to the thought of the light and colours”.
Aphantasia pushes us to resize the different aspects that make up episodic memory: there is more to the latter than visual (perceptual) details, and its specific phenomenological profile may not be fully captured by the metaphor of mentally travelling back in time.
