The impact of intervening tasks on response preparation

Response preparation usually facilitates performance, but it may also interfere with other concurrent tasks. In this article, the authors used event-related brain potentials to study how intervening tasks affect response preparation. In 3 experiments, participants performed intervening tasks during the preparation of a precued hand choice response. Intervening tasks were simple or choice foot responses to tones with different probabilities or at different times during the preparation period. The contingent negative variation component indicated that the intervening task led to an increased recruitment of processing resources, whereas behavioral data and the lateralized readiness potential indicated a deliberately reduced level of preparedness. Two factors seem to be responsible for this result pattern, a bottleneck-like postponement of the prepared response and a reluctance of participants to prepare prior to expected interference.