Charting the Unknown : Sex Differences in Spatial Exploration Across the Lifespan.

Previous work has suggested that males and females adopt different exploration styles, with females often taking a more secure, or cautious exploration approach. However, exploration behavior is multi-faceted, and previous studies often investigated only specific aspects of it. As a result, sex differences in exploration remain vaguely defined, and it currently remains unclear when differences develop. In the current study, females (n = 206) and males (n = 218) aged 7-77 years explored a 3D virtual environment. First, we computed a series of exploration measures that are commonly used in the animal literature (including roaming entropy, distance traveled, shape of exploration and exploratory efficiency). Taking a fine-grained approach, based on a hierarchical cluster analysis we identified three distinct measures of exploration: (1) Exploratory activity; (2) Exploratory efficiency; (3) Shape of exploration. We investigated whether these distinct aspects capture individual differences- between sexes and across the lifespan- in exploration behavior. Males were found to explore more than females, as evidenced by higher exploratory activity and a more complex shape of exploration. Interestingly, however, females explored more efficiently than males. No interaction between age and sex was observed, suggesting that the effect remains stable across the lifespan. These findings suggest that even though women show more caution when exploring an unknown environment, they are more efficient in charting it. Our novel fine-grained exploratory behavior analyses further suggested that older individuals had a simpler exploration shape- as defined by lower sinuosity/tortuosity in their path- than younger individuals, while other exploration measures were not affected by age. The current novel findings thus suggest that specific characteristics of exploration behavior depend on individual differences, including sex and age. Previous work has suggested that exploration behavior is affected in several neuropsychiatric disorders (e.g., in schizophrenia), and our measures of exploration could potentially be used to characterize unique aspects of these disorders, and serve as cognitive markers.