Abstract
"Express" saccades, named for their extremely short latencies, occur more frequently in a paradigm with a "gap" in time between the disappearance of the fixation mark and the appearance of the target to be fixated. To explain this report, it has been hypothesized that movements of the eyes are preceded by movements of attention (Posner (1980) Quarterly Journal of Experimental Psychology, 32, 3-25), and that removing the fixation mark allows attention to disengage from the fovea and to be exployed more rapidly to the peripheral target, thus diminishing saccadic latency (Fisher (1987) Reviews of Physiology, Biochemistry and Pharmacology, 105, 1-35). The authors measured attention using extra-foveal vernier acuity performance.