Mental rotation performance in aphantasia

Our ability to form visual images within our mind is known as visual mental imagery and enables us to draw on internal representations in the absence of external stimuli. Aphantasia, a recent condition to gain attention within the field of visual neuroscience, describes the experience of individuals who lack voluntary visual mental imagery. The majority of research in this area has stemmed from subjective reports of visual imagery, through questionnaires such as the Vividness of Visual Imagery Questionnaire (VVIQ). More recently, a few studies have investigated impairments in cognitive function; however, these studies are limited in terms of the low sample size of aphantasic individuals used within the studies. As yet, no study has explored mental rotation (MR) performance in congenital aphantasics. Using the classic Shepard and Metzler MR paradigm, here we examine MR performance in 20 individuals with congenital aphantasia, as well as measuring self-reported visual object and spatial imagery through questionnaires (VVIQ, Spontaneous Use of Imagery Scale and Object-Spatial Imagery Questionnaire). We find that aphantasic participants self-report higher scores for visual spatial imagery compared to object imagery scores, which were below average of the object imagery scores reported by controls. Furthermore, in the MR test, aphantasic individuals took longer to rotate the stimuli compared to controls, and this time increased in line with the increased level of difficulty of rotation. Despite aphantasics taking longer to mentally rotate stimuli compared to controls, aphantasic participants were more accurate then control participants across all levels of difficulty. Our results indicate that aphantasics use a different strategy when performing the MR task, leading to slower reaction times but higher accuracy. Meeting abstract presented at VSS 2018