Adaptation to peripheral flicker: relationship to contrast detection thresholds

The time to disappearance of flicker of a temporally modulated uniform 1 degree field, steadily viewed with the temporal retina at an eccentricity of 12 degrees, was measured as a function of temporal frequency and depth of modulation (contrast). As found by others, for a fixed contrast, adaptation time declined as temporal frequency increased. To check whether this effect was genuinely temporal frequency-dependent, or reflected the amount above threshold of the adapting contrast, measurements were also made at contrasts which were multiples of the contrast threshold or matched across temporal frequencies. The results suggest that both temporal frequency and amount of adapting contrast above threshold are important in determining the speed of adaptation.