Quantifying aphantasia through drawing: Those without visual imagery show deficits in object but not spatial memory.
Level 4 - case-series / case-control
Case-control observational study comparing individuals with congenital aphantasia to matched controls.
PubMed 33383478 · doi:10.1016/j.cortex.2020.11.014
What was done
An online experiment evaluated visual memory in 61 individuals with congenital aphantasia alongside matched controls with typical imagery. Participants studied real-world scene images and were tasked with drawing them from memory (recall condition) and copying them while visible (perceptual control condition). The drawings were objectively quantified for object details, color, and spatial accuracy by 2,795 online scorers.
What was found
The abstract reports no raw numerical values, effect sizes, or test statistics. Directionally, during memory recall, individuals with aphantasia recalled significantly fewer objects, included less color in their drawings, and showed increased reliance on verbal scaffolding compared to controls. Conversely, aphantasic participants demonstrated spatial accuracy equivalent to controls and made significantly fewer memory errors. No differences between groups were observed during the matched perceptual copying condition.
Why it matters
This study provides objective behavioral validation for congenital aphantasia and supports the dissociation of visual memory into distinct systems handling object-specific versus spatial representations.
Limits
The abstract omits exact numerical values, effect sizes, and the precise sample size of the matched control cohort. Data collection occurred entirely online rather than in a controlled laboratory setting, and the primary measurement medium was drawing, which can introduce variance related to motor skill or strategic compensation.
Cited by
- context A questionnaire given by Ed Catmull to staff at Pixar revealed that many top animators and directors have aphantasia.