Speed of information processing, psychometric intelligence: and time estimation as an index of cognitive load

The mental speed approach to human intelligence suggests that the speed of information processing is a basic constituent of individual differences in human intelligence as indicated by consistently found negative correlations between the speed of information processing in elementary cognitive tasks (ECTs) and psychometric intelligence. A new, encouraging approach to assess the cognitive demand of a person is the method of subjective time estimation (STE) in performing cognitive tasks. The present paper describes an empirical investigation regarding the usefulness of this method as an index of cognitive load. Furthermore the relationship between mental speed, STE and psychometric intelligence was examined within one and the same experiment. Ninety-seven participants worked on two paper-and-pencil tests for the assessment of their speed of information processing and after completing a test half in each condition of both tests they were required to judge the time needed for carrying out the given tasks. For the assessment of intelligence Raven’s APM were administered. As expected, the reaction time (RT) measures correlate negatively (up to −0.62), and the STE-measures correlate positively (up to 0.48) with psychometric intelligence. Although in the expected negative direction, the correlations between RT- and STE-measures were rather low (up to −0.36). From a multiple regression analysis it can be concluded that mental speed and STE reflect different sources of intellectual variance.