Psychology ETDs


Lynette Silva

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Speed of processing, theorized to be an important cognitive component of intelligence, is indexed by response speed on standardized cognitive ability tests. However, the term processing speed' is also used to refer to 'speed of information processing' during a cognitive task tapping early stages of processing, though these concepts arise from two different theoretical schools of thought. This study investigates the relationship between processing speed on higher-order cognitive tasks and information processing efficiency during early stages of processing. University of New Mexico undergraduate students (n=101) completed a widely used IQ test, the WAIS-III, and an information processing task, the visual backward masking task (VBM). The VBM consists of a computer presentation of a target and masking stimuli and is used to tap into the amount of time information is accurately processed in the sensory register. Two measures gathered during the VBM, detection accuracy, and a psychophysiological measure of mental effort, pupillary dilation response, were used to index information processing efficiency. Both VBM detection accuracy and the pupillary response to the VBM masking stimulus, which represents resources allocated to the task irrelevant stimuli, have been associated with IQ scores. Consistent with previous studies, the VBM detection accuracy scores on the 83ms and 117ms stimulus onset asynchrony conditions were associated with various components of the WAIS-III; however, the VBM pupillary dilation response had stronger relationships to WAIS-III components appears to have a stronger underlying factor of g. In addition, the shorter VBM stimulus onset asynchrony conditions were associated with WAIS-III performance measures while the longer conditions were associated with verbal measures. These results suggest that, while processing speed and information processing efficiency are similar constructs with strong relationships to IQ, they are separate constructs with different underlying factors of those relationships. The VBM physiological measure of pupillary dilation response may be a more stable measure of cognitive ability than the VBM behavioral detection accuracy responses during this early information processing task.

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First Committee Member (Chair)

Thoma, Robert

Second Committee Member

Yeo, Ron




Cognition, Human information processing, Cognition--Testing, Speed tests (Psychology), Wechsler Adult Intelligence Scale.

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