IMPROVED REACTION-TIME METHOD, INFORMATION-PROCESSING SPEED, AND INTELLIGENCE

Two experiments are presented which were designed to enhance the sensi tivity of RT as an information processing correlate of general ability . The first measured RT to a rapid game-like sequence of stimuli using 16 participants. Correlations with IQ in this task were negligible. T he second experiment adapted the methodology of Jensen & Munro (1979). Stimuli were presented at a constant, reduced ISI to lower uncertaint y about stimulus onset time and to decrease the session duration. Meas urement of the decision time period was enhanced in two ways. The stim ulus duration was shortened to 50 ms, thus fixing the onset of decisio n time to within 50 ms of stimulus onset. In addition, stimulus maskin g was used to restrict sampling of the stimulus to the period prior to movement onset. Finally, participants were reinforced verbally when t hey exceeded their own average performance to aid motivation. Using th is method, data recorded from 30 participants showed a correlation of 0.56 between WAIS-R Full Scale IQ and rate of information processing a s measured by the difference in the RTs recorded for two and four choi ce tasks (0.71 if corrected for restriction of range). These data are interpreted in terms of mental efficiency theories of intelligence.