The effect of physical flicker on visible persistence in normal and specifically disabled readers

Abstract

Howell, Smith, and Stanley (1981) found no significant differences between normal readers and specific reading‐disabled children in spatial‐frequency‐dependent visible persistence durations as previously demonstrated by Lovegrove, Heddle, and Slaghuis (1980). Howell et al. (1981) argued that the difference between these two sets of results may have been due to their use of a flicker‐free oscilloscope which reduced transient involvement whereas Lovegrove et al. (1980) used a tachistoscope which included some physical flicker. Four experiments are reported which investigate the role of physical flicker in visible persistence in controls and SRDs. The results indicate that the presence of stimulus flicker plays a role in determining visible persistence differences between the groups and are consistent with the proposal of a transient system deficit in the SRD group.