Abstract
Large biases in the perception of orientation and distance may indicate efficient coding of angular variables. Deviations of surface orientation from horizontal are exaggerated by about 1.5 in perceptual experience: For example, a surface only 34° from horizontal appears to be midway between vertical and horizontal (VH bisection). Perceptual matching of egocentric distance along the ground with vertical height of tall objects also implies a 1.5 gain in perceived angular direction relative to straight ahead. How do these spatial biases develop? We compared young children (4–8 years old; N = 18) and adults (18-21 years old; N = 31) on standard tasks measuring angular expansion: outdoors height/distance matching tasks (pole heights of 5 and 7m), indoors 3D surface VH bisection task, and a similar 2D line orientation VH bisection task. For the indoor orientation tasks, children showed a similar bias as adults in the perception of both surface orientation (~34° = VH bisection) and 2D line orientation (~38° = VH bisection). Similarly, on the outdoor task in which egocentric distance was matched to pole height, the overall mean bias for children was similar to that observed for adults. Interestingly, there was a reliable trend in the data for younger children to show less bias for the 7m pole, r(16) = .61, p = .007, and a non-reliable trend for the 5m pole, r(16) = .23, p = .356. Consistent with this trend, for the 7m pole, children 5.5 years or younger showed a smaller bias (M = 1.36) than those older than 5.5 years (M = 1.7), t(16) = 3.6, p = .002, although neither bias differed from adults (M = 1.5). Overall, perceptual biases in children and adults are consistent with angular expansion suggesting that this form of efficient coding is present early in childhood and is fairly stable into adulthood.
Meeting abstract presented at VSS 2016