Information Processing and g
Psychometric g can be studied more analytically by means of elementary cognitive tasks (ECTs) than is possible with the conventional IQ tests with items based on past acquired knowledge, reasoning, and problem solving requiring the concerted action of a number of relatively complex cognitive processes. A particular ECT is intended to measure a few relatively simple cognitive processes, independently of specific knowledge or information content. Each ECT is devised to tap a somewhat different set of cognitive processes, and performance on two or more different ECTs yields data from which individual differences in distinct processes can be measured, such as stimulus apprehension, discrimination, choice, visual search, scanning of short-term memory (STM), and retrieval of information from long-term memory (LTM).
ECTs typically involve no past-learned information content, and in those that do, the content is so familiar and overlearned as to be common to all persons taking the ECT, as can be shown on a non- speeded version of the ECT. Most ECTs are so simple that every person in the study can perform them easily, and individual differences in performance must be measured in terms of response time (RT). The theoretically most interesting ECTs are those with RTs of less than one second and with response error rates close to zero. The subject's median RT (over n number of trials) and the subject's intraindividual variability of RTs (measured as the standard deviation of RT, or RTSD, over n trials) are of particular interest. Another type of ECT, known as Inspection Time (IT), measures sheer speed of perceptual discrimination (visual or auditory) independently of RT.
Measures of RT, RTSD, and IT derived from the various ECTs