Aphantasia is associated with spatial memory and navigation difficulties in complex virtual environments

Visual imagery features centrally in many theories of spatial navigation, yet its contribution to wayfinding is unclear. Sea Hero Quest (SHQ), a navigation game for mobile devices that assesses spatial learning via visual maps and virtual environments, is well-suited to investigate the role of imagery in wayfinding. We examined if participants with aphantasia who report experiencing a lack of visual imagery would display greater difficulties navigating relative to controls on SHQ as demands on encoding complex visual information increase. Aphantasic participants (n = 63, Vividness of Visual Imagery Questionnaire <32) and controls (n = 99, VVIQ = 33-80) completed self-report measures of navigation, memory, and 8 SHQ levels varying in path complexity, destinations, and map characteristics. To estimate performance on the SHQ, trajectory length and completion time were normalised to thousands of controls (n = 1203 to 246,329), comparable to each participant in terms of age and gender, and group difference and correlation analyses were conducted for self-report measures and SHQ metrics. Aphantasic participants scored significantly lower on self-report spatial and memory measures and took substantially more time than both control groups to complete high-difficulty levels, but not training or low-difficulty levels, relative to controls. Imagery ability was associated with performance on difficult levels as well as self-reported spatial ability and memory. Map viewing duration was not significantly associated with any variable. The findings indicate that visual imagery plays a central role in spatial navigation when recall of complex visual information is necessary. Wayfinding difficulties observed in the aphantasic individuals appear to be robust to alternative strategies, such as verbal encoding, which is unlikely sufficient to integrate across path length and circuitousness, decision points, and visibility factors that define environmental complexity.