Abstract
When subjects make a saccade in the dark, they tend to mislocalize both a single target flash (Matin, 1972; Honda, 1990; Schlag & Schlag-Rey, 1995; Bockisch & Miller, 1999) and two successive target flashes (Matin, 1976; Sogo & Osaka, 2002). The “current view” is that this mislocalization comes from an extraretinal (exR) signal that begins changing prior to the onset of a saccade and continues to change during and following the saccade. However, a target flash produces retinal (R) signal persistence that can last for 300 msec. Pola (2004) has developed a model showing that this persistence interacting with an exR signal could have a significant influence on the features of flash mislocalization. In the present study, this model was used to explore what happens when R signal persistence interacts with three different types of exR signals: a slow, a moderately fast, and a fast exR signal. There are three main findings: (1) All three exR signals fail to yield single flash or successive flash mislocalization similar to experimental data when the exR signals begin to change in advance of a saccade. (2) The exR signals must begin at the time of, or following saccade onset, to give mislocalization similar to experimental findings. (3) As the speed of the exR signal increases, the delay of the exR signal from saccade onset must also increase to produce proper mislocalization. These results, as opposed to current psychophysics and neurophysiology, suggest that the exR signal does not begin before the saccade.