No increased prevalence of prosopagnosia in aphantasia: Visual recognition deficits are small and not restricted to faces.

Aphantasia and prosopagnosia are both rare conditions with impairments in visual cognition. While prosopagnosia refers to a face recognition deficit, aphantasics exhibit a lack of mental imagery. Current object recognition theories propose an interplay of perception and mental representations, making an association between recognition performance and visual imagery plausible. While the literature assumes a link between aphantasia and prosopagnosia, other impairments in aphantasia have been shown to be rather global. Therefore, we assumed that aphantasics do not solely exhibit impairments in face recognition but rather in general visual recognition performance, probably moderated by stimulus complexity. To test this hypothesis, 65 aphantasics were compared to 55 controls in a face recognition task, the Cambridge Face Memory Test, and a corresponding object recognition task, the Cambridge Car Memory Test. In both tasks, aphantasics performed worse than controls, indicating mild recognition deficits without face-specificity. Additional correlations between imagery vividness and performance in both tasks were found, suggesting that visual imagery influences visual recognition not only in imagery extremes. Stimulus complexity produced the expected moderation effect but only for the whole imagery-spectrum and only with face stimuli. Overall, the results imply that aphantasia is linked to a general but mild deficit in visual recognition.

No general pathological significance of aphantasia: An evaluation based on criteria for mental disorders.

As awareness of the phenomenon of aphantasia (= lack of voluntary imagery) has increased in recent years, many psychotherapists ponder its clinical implications. The present study investigates whether aphantasia meets the criteria for mental disorders, i.e. statistical rarity, impairment in activities of daily living, violation of social norms and inappropriate behavior and personal distress. Prevalence of aphantasia was determined meta-analytically based on 3,543 participants. An international sample of 156 participants with aphantasia (58.3% male; Mage  = 35.23) and 131 controls (65.6% male; Mage  = 28.88) was assessed with the Reading the Mind in the Eyes Test, the Questionnaire for the Assessment of Everyday Memory Performance and the Aphantasia Distress Questionnaire, as well as measures of depression, anxiety and well-being. The prevalence of aphantasia was estimated at 3.5 to 4.8%. Participants with aphantasia scored significantly lower than controls on every day and autobiographical memory, but not on theory of mind. A subgroup of 34.7% of participants with aphantasia reported distress significantly associated with lower well-being and high levels of anxiety and depression. The level of distress increased with poorer performance in autobiographical memory and theory of mind. Although aphantasia meets the criterion of statistical rarity, the impact on activities of daily living and personal distress is too weak to justify a classification as a mental disorder. In a subgroup, however, distress can reach clinically relevant levels. In individual cases, it is therefore advisable to conduct a psychological assessment, for example by means of the Aphantasia Distress Questionnaire.

Memory deficits in aphantasics are not restricted to autobiographical memory - Perspectives from the Dual Coding Approach.

Scene Construction Theory suggests similar neural mechanisms for visual imagery and autobiographical memory, supporting the seeming scientific consensus that a loss of visual imagery affects autobiographical memory. Based on the Dual Coding Theory and the Reverse Hierarchy Model, we also assumed influences of visual imagery on recent visual memory and even verbal memory, although little evidence has been provided so far. Thus, in a sample of 67 congenital aphantasics (= persons without mental imagery) and 32 demographically matched controls, it was investigated whether deficits in visual imagery are associated with deficits in visual as well as verbal short-term and long-term memory. The memory tasks were theoretically selected based on task difficulty, retrieval condition, and subcategories of stimuli, as previous null findings were attributed to insensitive tasks that were solvable by aphantasics by means of non-visual alternative strategies. Significant group differences were found in all memory components, with aphantasics performing worse than non-aphantasics. Therefore, evidence was obtained for the influence of visual imagery on all memory components beyond autobiographical memory.