Department of Psychology, University of Tübingen, Tübingen, Germany.
Department of Psychology, University of Otago, Dunedin, New Zealand.
Psychophysiology. 2022 Jan;59(1):e13951. doi: 10.1111/psyp.13951. Epub 2021 Oct 10.
We combined behavioral measures with electrophysiological measures of motor activation (i.e., lateralized readiness potentials, LRPs) to disentangle the relative contribution of premotor and motor processes to multitasking interference in the prioritized processing paradigm. Specifically, we presented stimuli of two tasks (primary and background task) in each trial, but participants were instructed to perform the background task only if the primary task required no response. As expected, task performance was substantially influenced by a task probability manipulation: Background task responses were faster, psychological refractory period effects were smaller, and interference from the second task (i.e., backward compatibility effects) was larger when there was a larger probability that this task required a response. Critically, stimulus-locked and response-locked LRP analyses indicate that these behavioral effects of parallel processing were not driven by background task motor processing (e.g., motoric response activation) taking place during primary task processing. Instead, the LRP results suggest that these effects were exclusively localized during premotor stages of processing (e.g., response selection). Thus, the present results generally provide evidence for multitasking accounts allowing parallel task processing during response selection, whereas the task-specific motor responses are activated in a serial manner. One plausible account is that multiple task information sources can be processed in parallel, with sharing of limited cognitive resources depending on task relevance, but a primary and still active task goal prevents motor activation related to the goals of other tasks in order to avoid outcome conflict.
我们结合运动激活的行为测量和电生理测量（即，偏侧准备电位，LRPs），以区分在优先级处理范式中多任务干扰的前运动和运动过程的相对贡献。具体来说，我们在每个试验中呈现两个任务（主要任务和背景任务）的刺激，但如果主要任务不需要响应，则指示参与者仅执行背景任务。如预期的那样，任务表现受到任务概率操纵的极大影响：当需要响应的任务的概率较大时，背景任务的响应更快，心理不应期效应更小，并且第二个任务（即反向兼容性效应）的干扰更大。至关重要的是，刺激锁定和响应锁定的 LRP 分析表明，这些并行处理的行为效应不是由主要任务处理期间的背景任务运动处理（例如，运动响应激活）驱动的。相反，LRP 结果表明，这些效应仅在处理的前运动阶段局部化（例如，响应选择）。因此，目前的结果普遍为允许在响应选择期间并行处理多个任务的多任务解释提供了证据，而特定于任务的运动反应则以串行方式激活。一种合理的解释是，多个任务信息源可以并行处理，根据任务相关性共享有限的认知资源，但主要的且仍然活跃的任务目标可以防止与其他任务的目标相关的运动激活，以避免结果冲突。
