Graduation Year


Document Type




Degree Granting Department


Major Professor

Emanuel Donchin


When responding to external stimuli, preparation reduces Reaction Time (RT). One form of preparation known as temporal preparation results from advance knowledge about when a stimulus will appear. We used Event Related Potentials to investigate how increasing temporal preparation decreases RT during a speeded, choice RT task by manipulating temporal preparation within subjects. In order to determine which cognitive processes are speeded, the latencies of the Lateralized Readiness Potential (LRP) and P300 were examined across two levels of temporal preparation. In line with previous research the stimulus locked LRP, but not the response locked LRP, was speeded when temporal preparation was high. Using Principal Component Analysis, we also found that the P300 latency was reduced by nearly the same extent as RT was reduced. These findings suggest that temporal preparation speeds stimulus evaluation processing specifically, and this explains to a large extent how temporal preparation reduces RT.