Figure 7.

Pursuit and perceptual thresholds for speed discrimination depend on optic flow score. Thresholds are fractions of base speed. A, Data for subject C.S. B, Data for subject T.M. Symbol definitions: (X) coherent motion dot pattern target, 5° stationary aperture, 100 3-pixel dots that had a central speed of 6°/s; (▷) similar to (X) but its aperture also translated across the screen at the same speed as the dot pattern; (□) similar to (X) but with a circular aperture of 10° and 400 3-pixel dots; (○) 0.25° spot target with a base speed of 6°/s; (♢) same as (○), but with a base speed of 15°/s; (★) Gaussian blob (after Rasche and Gegenfurtner, 2009) with an SD of 0.5° and a base speed of 11°/s. Colors correspond to optic flow score (a.u.).