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Title: Intelligence, inspection time, and cognitive strategies
Author: Egan, Vincent
Awarding Body: University of Edinburgh
Current Institution: University of Edinburgh
Date of Award: 1991
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It has been argued that the negative correlation between IQ scores and perceptual intake speed (as measured by Inspection Time (IT)), is not due to common variance between mental speed and IQ, but because of differential strategy use during IT. This thesis examined the effect of IQ and reported cognitive strategies on experimental measurements of IT to test strategic theories of intelligence. Experiments 1 and 2 considered the general claims made by strategy theorists about performance on experimental tasks; that performance strategies are driven by an executive 'metacognitive' process; that higher-IQ subjects are more likely to report strategies; that individuals who use strategies have general advantages on all tasks due to this conceptual approach; and that developing effective strategies for tasks requires a period of practice and feedback during which techniques can be refined. It was found that strategy users were not advantaged on all IT tasks, and that the IQs for subjects who reported IT performance strategies (or not) were the same. An IT task which limited practice and gave false feedback did not affect strategy reporters more than those who did not report strategies. These studies suggested that strategic effects were specific to particular IT tasks, rather than generalised to all IT measures, and were not due to metacognitive processes. Experiments 3 and 4 investigated whether the perception and use of apparent motion cues seen after an IT stimulus was due to metacognitive processes directing the use of specific cues, or whether these cues were epiphenomenal to more basic mental processes. Both studies demonstrated that individuals who report apparent motion cues during IT tasks have shorter ITs than individuals who do not report these cues. When IT was performed in conjunction with a parallel, attention-demanding task, ITs tended to be shorter for apparent motion reporters compared to non-reporters, despite previously defined motion reporters not being able to report them during the dual-task condition. This suggested that the perception of apparent motion cues was not dependent on focussed attention to the IT task. These results were discussed in relation to theories of attentional resources. Experiment 4 looked at the response latencies (RT) of IT and IT-like tasks, in order to measure the time taken for the assumed subcomponents of strategic processing to occur. Subtraction of the tasks from one another did not isolate a specific strategy processing stage associated with using apparent motion to guide IT discriminations. Though static measures of RT within IT did not discriminate strategy users from non-users, dynamic measures of RT within IT, based on the rate of change of RT with increasing difficulty of IT, tended to be faster for apparent motion reporters. These individuals were not faster on an unmasked version of IT. As the experiment could not identify a specific processing stage associated with the use of apparent motion, it was concluded that the perception and response to IT-related apparent motion cues were preconscious in origin. Pooled results from experiments 3 and 4 provided a sample of 75 subjects for whom the same IT and IQ measures have been taken. The overall IT/IQ correlation (Pearson's r) was -0.39 (P&60 .01); when the sample was divided according to the reported use of apparent motion cues to guide IT discriminations or not, IT/IQ correlations were the same for both groups; r = -0.44 (P< .01). There was no difference in IQ between the two groups (t&61 -0/72, n.s.). The IT/IQ correlation is therefore not because of the inclusion or exclusion of individuals reporting apparent motion; nor does IQ account for the difference between these groups, despite IT being faster among apparent motion reporters (t = 2.97, P< .005). This thesis has thus shown that perception of apparent motion cues from two-line visual IT stimuli does not reflect metacognitive processes directing the use of these cues.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available