Belmont SURFS

Is your mind blind? How mental imagery affects visual spatial ability

Mental imagery is a reproduction of perception without environmental input (Kosslyn, 2001). Subsequently, mental rotations provide newly-oriented views of objects in space, with varying competence in the general population (Peters, 2002). One condition with mental imagery deficits is Aphantasia, revealing slower reaction times for mental rotation (Pounder, 2018) and difficulty in facial recognition (Milton, 2021). With few assessments extending beyond self-reports, the current study investigated mental imagery ability (VVIQ; Marks, 1973) and performance on imagery tasks. Participants (N=23; Age [SD]= 20.26 [2.09]) completed forced-choice assessments involving judgements of same or mirrored images in a dyad-pair, with the right image rotated along the XY-plane. Outcome variables included reaction time and accuracy. Three stimulus types comprised the mental rotation task (abstract/blocks, letters, concrete/animals) and two facial stimuli comprised the Thatcher task (normal, manipulated with eyes/mouth inversion). Results mirror the literature (Jordan, 2001), with more difficult tasks showing longer reaction times but similar accuracy (paired-samples, p<0.05). Notably, there is limited range of ability, with most showing high VVIQ scores (61.99 [12.62]) and only one within the aphantasic scope (30). No significance was shown for correlations involving imagery and mental rotation (p>0.05). For the Thatcher task, higher VVIQ scores correlated with higher accuracy on upright normal/inverted manipulated trials, (rs(23)=0.520, p=0.011). Higher imagery also correlated with increased accuracy on trials of dyads with different stimulus types, (rs(23)=0.457, p=0.028), and with the task overall (r(23)=0.447, p=0.033). This study contributes to build a systematic assessment of mental imagery ability and identify aphantasia through mechanisms extending beyond self-reports; with a novel focus on facial perception.

Keywords: mental rotation, Thatcher effect, prosopagnosia, vividness of visual imagery questionnaire, aphantasia