Research Description:

Development of Slope Perception: Haptic and Visual Estimates of Geographical Slope

Adults are very poor at visually estimating the slope of geographical hills. For example, when shown a 5— hill, adults typically estimate it to be 20— or more. Despite this, when asked to walk up a hill, adults properly adjust their gait to accommodate the incline. Thus, there is a discrepancy between our visual judgements of steepness and the visual guidance of movement. This suggests that separate brain pathways may be involved in these tasks.
Interestingly, the accuracy of visual judgments of slopes also depends upon an individualís behavioral potential, or one's ability to walk up slopes. Observers overestimate hill slope to a greater extent when they are exhausted following a long-distance run and when they are wearing heavy backpacks. Hills also appear steeper to the elderly compared to younger individuals. These findings indicate that oneís perception of the world depends upon one's behavioral potential.

The current research is based upon the supposition that childrenís judgments of slopes will change developmentally in relation to changes in their behavioral potential to ascend and descend slopes. Participants in the study will range in age from 5 to 22 years and will view a ramp set at varying slopes. Two techniques will be employed to estimate the slope of a ramp. First a palm board, (a small, flat board mounted on a tripod, such that the slope of the board can be adjusted to match the slope of the ramp), will be used to provide a haptic estimate. A visual estimate will be taken using a handheld disk with an angle that can be adjusted to match the cross-section of the ramp. Additionally, adult participants will provide a verbal estimate of the rampís steepness in terms of degrees. Data from older and younger population subsets will then be compared to examine age-related changes in the perceptual judgements of slopes.