Identification of the eye-brain-hand system with point processes: A new approach to simple reaction time

By presenting a Poisson process of flashes to observers who hit a button as quickly as possible after each, the authors identified the system involved in simple reaction time (RT). The nonlinear kernels up to 2nd order were m easured from the stimulus and response point processes. The Ist-order kerne l is analogous to a histogram of simple RTs. The 2nd-order kernel shows com plex patterns of nonlinear suppression and facilitation between pairs of fl ashes. Simple RT measured as the lag of the Ist-order kernel's peak agrees with RT from conventional discrete trial experiments. RTs are shorter and l ess variable when the flashes are separated by uniform rather than exponent ial delays, which shows that observers use the stimulus hazard function to become prepared to detect and respond to the flash.