Fig. 2.
Mean speed estimates for each speed and direction condition collapsed across the two distances. The interaction of stimulus speed and direction of travel was significant in (a) Experiment 1, within-subjects design (n = 77) and (b) between-subjects design (n = 200). In both studies listeners show significant speed discrimination for looming sounds but no difference in the perceived speed of receding sounds. Error bars represent 95 % confidence intervals. * p < 0.01, ** p < 0.05