Perceiving collinear, parallel, and perpendicular contours

Abstract

The orientation threshold of a single contour was estimated by using a modified Method of Constant Stimuli from responses about the configurations. The modified method was developed based on an assumption that contours composing the configurations are perceived individually. If the assumption is correct, then the threshold should be constant for all configurations. In other words, difference of the threshold represents difference of mechanisms for perceiving the configurations.The following 4 equations are used for estimating a threshold (σ) in each condition of Experiment 1 in Koshmanova & Sawada (2019). We will use Equation (D) for a parallelism configuration to estimate σ for a collinear configuration in this study.