Sex effects on spatial learning but not on spatial memory retrieval in healthy young adults

Objectives: Sex differences have been found in spatial learning and spatial memory, with several studies indicating that males outperform females. We tested in the virtual Morris Water Maze (vMWM) task, whether sex differences in spatial cognitive processes are attributable to differences in spatial learning or spatial memory retrieval in a large student sample. Methods: We tested 90 healthy students (45 women and 45 men) with a mean age of 23.5 years (SD = 3.5). Spatial learning and spatial memory retrieval were measured by using the vMWM task, during which participants had to search a virtual pool for a hidden platform, facilitated by visual cues surrounding the pool. Several learning trials assessed spatial learning, while a separate probe trial assessed spatial memory retrieval. Results: We found a significant sex effect during spatial learning, with males showing shorter latency and shorter path length, as compared to females (all p < 0.001). Yet, there was no significant sex effect in spatial memory retrieval (p = 0.615). Furthermore, post-hoc analyses revealed significant sex differences in spatial search strategies (p < 0.05), but no difference in the number of platform crossings (p = 0.375). Conclusion: Our results indicate that in healthy young adults, males show faster spatial learning in a virtual environment, as compared to females. Interestingly, we found no significant sex differences during spatial memory retrieval. Our study raises the question, whether men and women use different learning strategies, which nevertheless result in equal performances of spatial memory retrieval.