People who lack a mind’s eye, a condition known as aphantasia, tend to struggle with recognizing faces. A recent study published in the journal Cortex provides evidence that these individuals have specific difficulties with perceiving and remembering faces, but not with visually matching them. The findings help explain the underlying mechanics of face blindness that many people with aphantasia experience.
Aphantasia is a psychological condition where a person has an absent or severely reduced ability to form visual images in their mind. When someone with typical visual imagery thinks of an apple, they can picture its shape and color. A person with aphantasia cannot produce this mental picture.
This lack of visual imagery suggests possible effects on other cognitive functions. Past research indicates that many people with aphantasia self-report difficulties with facial recognition. Some even meet the criteria for prosopagnosia, which is a neurological condition commonly known as face blindness.
Recognizing a face is not a single, simple action. It relies on a combination of different cognitive processes working together. Breaking down these individual steps helps scientists understand where cognitive deficits originate.
Mirta Stantić, a lecturer at Royal Holloway, University of London, and co-author of the study, explained the motivation behind the research. “We’ve been investigating profiles of face recognition abilities in different populations for years, and have already looked at populations of people who have face blindness, autism, or who are exceptionally good at remembering faces,” Stantić said. “Here, we were interested in figuring out how aphantasia, inability to form mental imagery, influences various phases of face recognition.”
The authors wanted to isolate specific sub-processes. “We wanted to understand whether some steps in this complex mental process are more affected than others, and whether this differs across individuals,” Stantić noted.
The researchers recruited 34 adults with congenital aphantasia, meaning they were born with the condition. They also recruited a control group of 41 adults with typical visual imagery abilities. The participants were roughly matched in age, with an average age of about 40 to 42 years old.
To confirm their group placements, participants completed the Vividness of Visual Imagery Questionnaire. This assessment asks people to rate the vividness of the mental images they can produce. People scoring very low were placed in the aphantasia group, and those scoring high were placed in the typical imagery group.
To test face matching and face perception, the participants completed the Oxford Face Matching Test. During this task, individuals saw 200 pairs of faces shown on a computer screen for just over one and a half seconds each. Half of the pairs showed two different photos of the same person, and half showed photos of two different people.
Participants first had to decide if the two faces belonged to the same person or different people. Then, they rated how perceptually similar the two faces looked on a scale from zero to one hundred. These ratings helped separate their basic decision-making from their visual perception.
To get a pure measurement of face perception, the scientists used a novel analytical strategy. They compared the human participants’ similarity ratings to similarity scores generated by three highly advanced facial recognition computer algorithms. If a participant’s rating deviated heavily from the computer algorithm’s objective rating, it indicated lower face perception abilities.
Next, the scientists tested face memory using the Cambridge Face Memory Test. In this assessment, participants learned to recognize six novel faces. They then had to identify these target faces among distractors across 72 trials, with the test growing progressively harder as the imagery changed.
The memory test is divided into three stages. The first stage presents faces with identical lighting and viewpoints. The later stages introduce drastic changes in how the faces are illuminated and oriented, forcing the brain to rely on a deep memory of the facial structure rather than a simple snapshot.
The researchers also asked participants to complete self-report surveys about their face recognition abilities in daily life. This included a twenty-item survey that asked them to rate statements about struggling to recognize classmates or friends. Finally, they conducted a visual acuity task where participants read shrinking rows of letters to ensure basic eyesight differences did not affect the outcomes.
The data showed that individuals with aphantasia reported much higher levels of face recognition difficulty in their everyday lives. About 26 percent of the aphantasia group scored above the strict threshold for face blindness on their self-report surveys. None of the typical imagers met this threshold.
Basic eyesight did not differ between the two groups on the visual acuity task. In addition, the participants completed a survey designed to measure autistic traits in adults. The researchers did not find a statistically significant difference in autistic traits between the aphantasia group and the control group, though the aphantasia group trended slightly higher.
The aphantasia group showed a noticeable impairment in face perception. Their similarity ratings on the paired face task deviated significantly more from the objective computer algorithm scores. This suggests that their basic perceptual processing of complex facial features is less precise.
This finding was somewhat unexpected based on past literature. “Some earlier research has suggested that visual perception is largely intact in aphantasia, but we found that participants with it were less accurate at perceptual face tasks,” Stantić told PsyPost. She suggested this might be because faces are highly complex visual stimuli.
“Additionally, this task required participants to make a judgment in a relatively short period of time and was designed to be challenging,” she added.
When it came to basic face matching, the aphantasia group performed just as well as the typical imagers. Both groups were equally accurate at deciding if two side-by-side photos showed the same person.
“Perhaps you would expect that, given difficulties in face perception and face memory, people with aphantasia would also struggle to accurately do face matching tasks,” Stantić said. “However, our results suggest that’s not the case.”
“Interestingly, their ability to disambiguate between two photographs (whether they show the same person or different people) is intact once we take into account their perceptual difficulties,” she noted.
To separate these intertwined skills, the researchers used statistical regression models. They were able to isolate memory performance by mathematically removing the influence of a person’s matching and perception scores. This allowed them to see the true, independent contribution of face memory.
The aphantasia group scored significantly lower on the memory test. Even after factoring out perception and matching abilities, the individuals with aphantasia still exhibited worse face memory than the control group.
“Aphantasia does not appear to cause a general inability to process faces, but people with aphantasia do have more difficulties with faces, as you would expect,” Stantić said.
“More broadly, this underscores the importance of understanding that face recognition is not a singular skill,” she added. “People can struggle with (or excel at) different aspects of this ability.”
One potential misinterpretation of this study is the assumption that all people with aphantasia have severe, clinical face blindness. The data shows that the majority of participants with aphantasia did not score low enough on the objective memory tests to be formally classified as having prosopagnosia. Their performance was simply weaker on average compared to typical imagers.
“Sometimes people think that folks with aphantasia have the same difficulties as people with prosopagnosia (who are often referred to as “face blind”) but this is not the case,” Stantić said. “There are distinct differences between the two populations and they face unique challenges.”
“Our data confirm this, as only about 10 percent of this sample with aphantasia scored clinically low on standard tests for prosopagnosia, clearly separating these samples,” Stantić explained. “The important thing to remember, therefore, is that there are subtle but crucial differences in experiences of people with aphantasia and prosopagnosia.”
The study also raises questions about exactly how visual imagery relates to perception. The authors note that mentally building a three-dimensional representation of a face from a two-dimensional photograph might require some level of mental imagery. It remains unknown if visual imagery is strictly necessary for face memory, or if the two functions merely rely on shared brain networks.
Future research could explore whether different subtypes of aphantasia exist. The researchers also hope to expand this work to other age groups. “In the future, we want to use this knowledge to understand how these abilities develop, or fail to develop, particularly in children of typical and atypical development,” Stantić said.
By using the new computer algorithm approach, the scientists can measure facial processing skills with greater precision. “This allows us to get a lot more targeted and precise with attempts to help those who have a hard time remembering faces,” she added. “We are hoping, in the long run, to develop programs that could help train people with difficulties.”
Gathering personal stories is a big part of that next step. “We are incredibly keen to hear from people with difficulties recognizing or remembering faces in everyday life or parents who think their children might be having a hard time with this,” Stantić said.
“First-hand accounts help us understand the range of experiences that may be missed by standard laboratory tests,” she explained. “These stories can directly inform the questions we investigate, as well as allow us to deliver targeted interventions.”
“If you want to be kept in touch with our research or potentially take part (we can come to you or often test remotely!), please contact us: mirtastantic.com.”
The study, “Individuals with aphantasia show independent impairments in face perception and face memory, but not face matching,” was authored by Zoë Pounder, Mirta Stantić, Reshanne Reeder, Caroline Catmur, and Geoffrey Bird.