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Title:Insulation of Processes Across the Hemispheres Modulates Attentional Processes
Author(s):Passarotti, Alessandra
Doctoral Committee Chair(s):Banich, Marie T.
Department / Program:Psychology
Degree Granting Institution:University of Illinois at Urbana-Champaign
Subject(s):Biology, Neuroscience
Abstract:The present research provides one of the first pieces of evidence that under certain conditions each hemisphere can "insulate" its processes from conflicting processes occurring concurrently in the opposite hemisphere. We also examine some factors that may affect the efficiency of insulation. In a spatial selective attention task one of two hierarchical letters, presented one in each visual field, was to be identified at a pre-assigned level (i.e., global or local). A first experiment showed that the likelihood of insulation was directly linked to processing load demands imposed by processing the target. In fact, our findings suggest that insulation of task-irrelevant information across-fields occurs when processing demands on one hemisphere am relatively low. But as processing demands become higher (i.e., more selection is required) interchange of the irrelevant information occurs, possibly because one hemisphere tries to recruit more resources by communicating with the other hemisphere. In a second experiment we confirmed that findings from Experiment 1 are specifically due to insulation of irrelevant information across-fields, because suppression of task-irrelevant information did not occur when presented within-field (and therefore to one hemisphere). In a third experiment we found that insulation is not affected by whether the hemisphere receiving the target is cued in advance, possibly because pre-cueing is not informative in terms of the processing demands placed on one hemisphere (i.e., whether it needs interchange to recruit more resources or not) before the distracting information appears. In a fourth experiment we found that longer intervals between target and distractor presentation did not help insulation more than shorter ones, suggesting that the processes that allow for insulation occur relatively early in the stage of processing. Finally, our fifth experiment provides some evidence that strategic control may affect insulation, in that the effects of a distractor presented to the opposite hemisphere were increased, as compared to Experiment 4, by biasing participants towards a more distributed attentional focus.
Issue Date:1999
Description:188 p.
Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1999.
Other Identifier(s):(MiAaPQ)AAI9953106
Date Available in IDEALS:2015-09-25
Date Deposited:1999

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