Mental Chronometry: Beyond Reaction Time

Details of response execution were examined in two classic human information processing paradigms: lexical decision and memory scanning. In the lexical decision experiment, word frequency influenced both the time of response onset and kinematic properties of the response. In the memory scanning experiment, when the probe was present in the memory set, the responses were both initiated sooner and were more forceful when the memory set consisted of two items than when it consisted of six items. When the probe was absent from the memory set, responses were initiated sooner but were less forceful when the memory set consisted of two items than when it consisted of six items. The results suggest that the amount of activation in support of a given response can modulate both the time taken to initiate the response and the force with which the response is executed. These findings bear on all models of human cognitive performance that have been developed within the mental chronometry tradition.