Visual persistence from brief letters and pictures

The visual persistence from briefly presented letters and pictures was assessed by the popular probe-matching procedure over a range of background and target luminance levels and for several color conditions. It was determined that the fading visible persistence measured in this way increased with increasing target luminance and with decreasing background luminance. For small foveal presentations, photopically-matched targets of differing wavelength produced equivalent persistences; but for larger, parafoveal presentations, scotopically-matched targets of differing wavelength produced equivalent persistences. This was true for both letter and picture targets. Results were discussed in terms of an early sensory locus to such persistence effects. The strong consistency of these findings to some previous work and the apparent inconsistency with other work were treated in terms of different kinds of visual persistence effects assessed by different experimental methods.