Perception of hill slant is exaggerated in explicit awareness. Proffitt (Perspectives on Psychological Science 1:110–122, 2006) argued that explicit perception of the slant of a climb allows individuals to plan locomotion in keeping with their available locomotor resources, yet no behavioral evidence supports this contention. Pedestrians in a built environment can often avoid climbing stairs, the man-made equivalent of steep hills, by choosing an adjacent escalator. Stair climbing is avoided more by women, the old, and the overweight than by their comparators. Two studies tested perceived steepness of the stairs as a cue that promotes this avoidance. In the first study, participants estimated the steepness of a staircase in a train station (n = 269). Sex, age, height, and weight were recorded. Women, older individuals, and those who were heavier and shorter reported the staircase as steeper than did their comparison groups. In a follow-up study in a shopping mall, pedestrians were recruited from those who chose the stairs and those who avoided them, with the samples stratified for sex, age, and weight status. Participants (n = 229) estimated the steepness of a life-sized image of the stairs they had just encountered, presented on the wall of a vacant shop in the mall. Pedestrians who avoided stair climbing by choosing the escalator reported the stairs as steeper even when demographic differences were controlled. Perceived steepness may to be a contextual cue that pedestrians use to avoid stair climbing when an alternative is available.

The apparent steepness of hills and stairs is overestimated in explicit perception. These overestimations are malleable in that when physiological resources are compromised, apparent steepness is further overestimated. An alternative explanation of these experimental findings attributes them to demand characteristics. This article tests the relationship between estimated steepness and naturally occurring differences in body composition. A quasi-experimental field study revealed more exaggerated reports of staircase steepness in overweight than in healthy-weight participants in a situation where experimental demand would be an implausible explanation for any differences. A longitudinal follow-up study used dual X-ray absorptiometry to objectively measure participants' body composition at the beginning and end of a weight-loss program (N = 52). At baseline, higher levels of body fat were associated with steeper explicit estimates of staircase steepness. At follow-up, changes in body fat were associated with changes in estimated steepness such that a loss of fat mass co-occurred with shallower estimates. Discussion focuses on the malleability of perceived steepness at an individual level and the implication of these findings for the debate surrounding "embodied" models of perception. (PsycINFO Database Record

The apparent slope of a hill or staircase, termed geographical slant perception, is exaggerated in explicit awareness. Across two experiments this paper tests the use of a laboratory environment to study geographical slant perception. First, using a student-aged sample (N = 166), we examine the similarity of slant estimates in the field with those made in the laboratory using life-sized images of the built environment as stimuli. Results reveal no differences in slant estimates between the two test environments. Furthermore, three traditional measures of perceived geographical slant (verbal, visual, and haptic) appear sensitive to a difference in slant of only 3.4 degrees in both the field and laboratory environments. In a follow-up experiment we test the effect of fatigue on slant estimates in the laboratory. In line with previous research with outdoor stimuli, fatigued participants provided more exaggerated explicit reports of slant relative to those in a control group, and females gave more exaggerated slant estimates than males across both experiments. The current set of findings open the door to future studies of geographical slant perception that may be more suited to laboratory conditions.

In two recent issues of Acta, the widely accepted view of Proffitt (2006), that 'haptic' measures of perceived geographical slant are generally accurate, and dissociated from explicit overestimates, came under intense scrutiny (Durgin, Hajnal, Li, Tonge, and Stigliani, 2010; 2011). Durgin and colleagues' challenge to this account centred on the claim that Proffitt's haptic' measure of geographical slant, the palm-board, may be accidently accurate due to restricted movements available at the wrist. Two experiments reported here compare the accuracy of Proffitt's palm-board with an alternative measure of geographical slant perception, the Palm-Controlled Inclinometer (PCI), which allows participants to use wrist, elbow and shoulder movements to match slant with their hand. Participants (N=320) made slant judgements using both measures, across five hills and five staircases with 32 participants for each stimulus angle (4.5°-31°). Results for the palm-board replicated those of Proffitt and co-workers, overestimation at shallow angles (≤14°), contrasted with underestimation at steeper angles (≥23°), whereas estimates made using the PCI had a greater degree of accuracy for steeper slopes. A follow-up experiment tested the accuracy of the palm-board and PCI for surfaces in near space to repeat the design of Durgin et al. (2010, experiment 1). Participants (N=20) used the palm-board and PCI to judge the angle of slanted blocks (25°, 30°). As with traversable slopes, PCI judgements did not differ from the actual angle of the blocks whereas the palm-board measure underestimated. 'Haptic' measures of geographical slant perception can be accurate for relatively steep slopes, in both near and far space.

The apparent steepness of the locomotor challenge presented by hills and staircases is overestimated in explicit awareness. Experimental evidence suggests the visual system may rescale our conscious experience of steepness in line with available energy resources. Skeptics of this "embodied" view argue that such findings reflect experimental demand. This article tested whether perceived steepness was related to resource choices in the built environment. Travelers in a station estimated the slant angle of a 6.45 m staircase (23.4°) either before (N = 302) or after (N = 109) choosing from a selection of consumable items containing differing levels of energetic resources. Participants unknowingly allocated themselves to a quasi-experimental group based on the energetic resources provided by the item they chose. Consistent with a resource based model, individuals that chose items with a greater energy density, or more rapidly available energy, estimated the staircase as steeper than those opting for items that provided less energetic resources.