Orientation (or reorientation) is the first step in navigation, because establishing a spatial frame of reference is essential for a sense of location and heading direction. Recent research on nonhuman animals has revealed that the vertical component of an environment provides an important source of spatial information, in both terrestrial and aquatic settings. Nonetheless, humans show large individual and sex differences in the ability to use terrain slope for reorientation. To understand why some participants-mainly women-exhibit a difficulty with slope, we tested reorientation in a richer environment than had been used previously, including both a tilted floor and a set of distinct objects that could be used as landmarks. This environment allowed for the use of two different strategies for solving the task, one based on directional cues (slope gradient) and one based on positional cues (landmarks). Overall, rather than using both cues, participants tended to focus on just one. Although men and women did not differ significantly in their encoding of or reliance on the two strategies, men showed greater confidence in solving the reorientation task. These facts suggest that one possible cause of the female difficulty with slope might be a generally lower spatial confidence during reorientation.Keywords Individual and sex differences . Spatial abilities . Reorientation . Slope . Geographical slant . Spatial confidence Few everyday cognitive abilities exhibit individual differences as marked as those seen in navigation tasks. It is apparent that some people are extremely good at finding their way, while others struggle and experience anxiety during the journey (e.g., Lawton, 1994;Schinazi, Epstein, Nardi, Newcombe, & Shipley, 2009). The complexity of the navigation process makes it difficult to understand the source of such variability in performance-after all, successful navigation depends on many component skills (e.g., perception, spatial memory, position updating, and construction of a mental map of the environment). Here we focus on the first step that any mobile animal encounters when navigating: establishing where it is and which direction it is facing. This step, often called orientation, or reorientation when orientation has been lost, is accomplished when a navigator identifies a key element of the environment (e.g., a sign, specific landmark, or familiar sound).A central question in the reorientation literature is whether any of these spatial cues has a more important role (is more salient) than others. For example, at least in small spaces, the geometric shape of the environment determined by bounding walls (e.g., in a room) seems to be a particularly strong type of reorienting cue-so strong that nonhuman animals (Cheng, 1986) and human children (Hermer & Spelke, 1994 tend to focus on this cue and disregard other, potentially more useful cues. However, the strength of geometric cues appears to wane as the space grows larger (Learmonth, Nadel, & Newcombe, 2002), for a variety of reasons that in...