What are human express saccades?

Against a role for attentional disengagement in the gap effect: A friendly amendment to Tam and Stelmach (1993)

“…Our analysis of the dual response experiment (Experiment 4), upon which this hybrid model was based, shows that manual and saccadic responses were likely compromised by a grouping or delay strategy and that subjects may not have been attending as instructed. On these grounds, we argue that Tam and Stelmach (1993), like Kingstone and Klein (1990;1993a) provide no evidence that attentional disengagement contributes to the gap effect. Analternative proposal , thatmotor preparation and oculomotor disengagement combine additively to produce the gap effect, is consistent with the data from Tam and Stelmach sExperiments 1-3, is similar to the explanation that they prefer, and has beenstrongly supported when directly tested (Kingstone, Klein, & Taylor, 1994).…”

“…We argue that the assessment of attentional allocation was compromised in that experiment, making it a weak basis for statements about attentional influence. Moreover, Kingstone and Klein (1990Klein ( , 1993a found no influence ofthe direction of covert attention on the gap effect. Thus, there is no convincing evidence to support a role for attentional disengagement in the gap effect.…”

“…Saccadic latencies are reduced when fixation offset precedes target onset (Fendrich, Hughes, & ReuterLorenz, 1991;Fischer, 1987;Fischer & Boch, 1983;Fischer & Ramsperger, 1984;Hallett & Adams, 1980;Kingstone & Klein, 1993b;Mayfrank, Mobashery, Kimmig, & Fischer, 1986;Reulen, 1984;Reuter-Lorenz, Hughes, & Fendrich, 1991 Ross, 1981;Saslow, 1967;Wenban-Smith & Findlay, 1991). Foremost among explanations of this "gap effect" are those which attribute the reduction in reaction time to the prior disengagement of covert attention that is afforded by the offset of the fixation stimulus (e.g., Braun & Breitmeyer, 1988;Fischer, 1987;Fischer & Breitmeyer, 1987;Mayfrank et al, 1986) and those which attribute the reduction in reaction time to the disengagement ofthe oculomotor system that is likely mediated by activity in the superior colliculus (e.g., Klein, 1993;Taylor, Kingstone, & Klein, 1993), Tam and Stelmach (1993; hereafter, T&S) recently reported five experiments that were intended to examine the contributions of covert attentional and oculomotor disengagement to the gap effect.…”

Manual responses to visual stimuli: early and late facilitatory effects due to the offset of a peripheral cue

“…Moreover, after training, some subjects were able to reduce or even eliminate the later peaks, thus resulting in an unimodal distribution with a single peak around 100 ms (7) -absolute latency criterion. Other researchers (10)(11)(12)(13)(14) , however, though confirming the reduction on SRTs with the gap paradigm, do not support the idea of ESs. According to their interpretation, neither the bimodality nor the latency criterion are convincing enough to propose the existence of ESs.…”

“…Based on their data, Kingstone and Klein (13) , Klein et al (23) and Reuter-Lorenz et al (11) proposed the so called two-component model to explain the gap effect. According to them, the reduction on motor responses observed in the gap paradigm would have two components: First, a warning component which follows any warning event (e.g., the offset of a visual stimuli) and is common for both saccadic and manual responses; second, a fixation offset component which is specific for saccades and is observed only when FP is turned off.…”