Putting the temporal resolution power (TRP) hypothesis to a critical test: Is the TRP-g relationship still more fundamental than an optimized relationship between speed of information processing and g?

The present study investigated whether the relationship between temporal resolution power (TRP) and general intelligence (g) is more fundamental than the relationship between speed of information processing (SIP) and g when a) TRP and SIP are assessed with an equally effective test battery, and b) when the relationship between SIP and g is strengthened by an increase of task demands. A heterogeneous sample of 110 male and 118 female participants completed a short version of the Berlin Intelligence Structure test as a measure of g. TRP was assessed with three psychophysical timing tasks and SIP with three different reaction time tasks in which cognitive task demands were systematically increased across task conditions. SIP variance was divided into a component representing speed of processing increasing cognitive task demands and a component representing processing speed independent of the experimental manipulation. The relationship between TRP and g was robust and unaffected by both SIP components. SIP caused by the enhanced cognitive task demands explained variance in g irrespective of TRP, whereas TRP completely accounted for the relationship between speed unaffected by the experimental manipulation and g. In contrast to previous findings, however, the effect of TRP on the SIP-g relationship ceases when SIP is derived from cognitively more demanding reaction time tasks.