dc.contributor.author | Taylor, Tracy Lynn. | en_US |
dc.date.accessioned | 2014-10-21T12:37:51Z | |
dc.date.available | 1998 | |
dc.date.issued | 1998 | en_US |
dc.identifier.other | AAINQ36565 | en_US |
dc.identifier.uri | http://hdl.handle.net/10222/55577 | |
dc.description | Unpredictive visual transient cues have a biphasic effect on response times (RTs) to peripheral onset targets. At relatively short (e.g., 150 msec) cue-target stimulus onset asynchronies (SOAs), RTs to targets at cued versus uncued locations are facilitated, whereas at relatively long SOAs (e.g., beyond 300 msec), they are inhibited. The literature converges on the view that this latter, inhibitory, effect---referred to as inhibition of return (IOR; Posner & Cohen, 1984)---is a motor response bias that is generated by the activation of an oculomotor program to fixate the cue. This view is challenged by the present study, which systematically manipulated the stimulus/response conditions used to generate and measure IOR. | en_US |
dc.description | On each trial, subjects fixated the centre of three horizontally-arranged outline boxes and then were presented with a 300 msec first signal (S1) that was followed at a 1000 msec SOA by a second signal (S2). Each of these signals could be an onset in the periphery (exogenous) or else an arrow at fixation (endogenous). In different experiments, subjects made no response, a manual localization response, or a saccadic response to S1, and a manual localization or saccadic response to S2. The nature of S1 (exogenous, endogenous), S2 (exogenous, endogenous), and the relative locations signalled by S1 and S2 (different, same) were combined factorially for each of the S1-S2 response combinations that comprised Experiments 1--6, respectively: No Response-Manual, Manual-Manual, Saccadic-Manual, No Response-Saccadic, Manual-Saccadic, and Saccadic-Saccadic. IOR was measured as the difference in RT to S2 when S1 and S2 signalled the same versus different locations. | en_US |
dc.description | Two inhibitory processes were revealed. The first was a visuo-motor inhibition that operated when the saccadic system was not explicitly engaged by S1/S2 response demands. This effect appears to reflect inhibited exogenous attentional orienting to S2 due to prior covert attentional orienting to S1. The second was a motor inhibition that is revealed as a response bias that appears to be generated by the implicit or explicit activation of a motor response to S1. Despite the operation of two inhibitory processes, the present findings are consistent with the possibility that both visuo-motor and motor inhibition may be based on a common mechanism within the superior colliculus but that generating and accessing the neural representation of IOR depends on explicit engagement of the saccadic system. | en_US |
dc.description | Thesis (Ph.D.)--Dalhousie University (Canada), 1998. | en_US |
dc.language | eng | en_US |
dc.publisher | Dalhousie University | en_US |
dc.publisher | | en_US |
dc.subject | Psychology, Clinical. | en_US |
dc.subject | Psychology, Cognitive. | en_US |
dc.title | Generating and measuring inhibition of return. | en_US |
dc.type | text | en_US |
dc.contributor.degree | Ph.D. | en_US |