Figure 5. LUM motion sensitivity for pairs of pulsed L′ or M′ gratings of 1 cycle deg⁻¹ on green and orange fields.

Contrast sensitivity for pairs of pulsed L′ or M′ gratings of equated contrast, as a function of stimulus onset asynchrony (SOA) between the two pulses. Each pair was presented in spatial quadrature phase to produce motion. Negative sensitivity indicates ‘reversed’ perceived motion. The reversals occur near 60 ms for L′ patterns on the green field (left panels) and M′ patterns on the orange field (right panels); the functions are flatter and without a reversal for the other patterns. Orange field luminance was 1440 Td and green field luminance was 1040, 900 and 1100 Td for observers A.C., C.F.S. and S.K., respectively; pulse duration was 15 ms for A.C. and 10 ms for other observers.