ABSTRACT
The study of human information processing is concerned essentially with hypothetical capacities and mechanisms within the brain whereby external events registered by the sense organs are manipulated by the brain and give rise to observable behavior. The cognitive processes intervening between external stimulation and the response that follows can only be inferred, on the basis of theoretical assumptions about how the information processing system is organized. Because the time from the onset of a signal to the initiation of a response can be measured with high precision in a laboratory situation, a number of measures derived from reaction time (RT), together with similar “real-time” measures of mental events, have emerged as the most widely used dependent variables for investigating information processing. These measures have been central to the attempt over the past 3 decades to formulate theories of individual differences in intellectual abilities. The interested reader is referred to Welford (1980) and Jensen (1982) for accounts of these developments.
