Fig. 5.

Perceptual responses to centrally presented barber diamonds. Stimuli possessed 11° apertures and gratings of 0.59 cycles/°. Data were obtained from seven human subjects (RD, CL, KS, DE, BG, AV, and ROD). a–d depict responses to a particular barber-diamond condition as indicated byicons. Black arrows indicate direction of grating motion for each condition. N andF indicate crossed- and uncrossed-disparity regions that make up each depth-ordering configuration. Each barber-diamond condition consisted of a different combination of grating motion (left,a and c; right, b andd) and depth-ordering configuration (aand d, or b and c). The implied direction of surface motion (intrinsic terminator motion) that results from these combinations is indicated by gray arrows. White arrows indicate the direction of extrinsic terminator motion. For each graph, the direction of motion reported is plotted on the polar axis, and the frequency of responses for each direction is plotted on the radial axis (black bars). Left–right perceived motion is indicated on the horizontal axis, and up–down motion is represented on the vertical axis. Each subject participated in 40 trials per condition (n = 1120). Most of the reports for each condition were biased in the direction of the intrinsic terminators (89% overall). Sixty-nine percent of these reports were 45° away from the horizontal axis in the predicted direction. Each condition elicited a lesser but notable portion of reports for motion consistent with horizontal motion of the grating stripes (9% overall).