Perceptual processes and cognitive ability

We examined the contribution of perceptual processes to cognitive ability with respect to stimulus complexity, response mode, level of encoding, and attention. The participants were 124 university students. Stimulus complexity due to presenting both irrelevant and relevant information led to a substantial increase in correlation between reaction time and measures of cognitive ability. Two different response modes, correctness in brief exposures and motor response, yielded correlations of equal size. Three levels of encoding were compared. These were related to signal detection, stimulus discrimination, and stimulus identification. It was very interesting to find that the correlation of the level relating to stimulus discrimination exceeded the other correlations. The consideration of attention showed clearly that about 70% of the common variance of perceptual processes and cognitive ability were due to attentive processes and 30% to preattentive processes. (C) 2003 Elsevier Science Inc. All rights reserved.