Leibniz-Research Centre for Working Environment and Human Factors, TU Dortmund, Germany; Center for Mind/Brain Sciences (CiMeC), University of Trento, Italy.
Center for Mind/Brain Sciences (CiMeC), University of Trento, Italy.
Cortex. 2018 May;102:45-56. doi: 10.1016/j.cortex.2017.06.022. Epub 2017 Jul 13.
A cue indicating the possibility of cash reward will cause participants to perform memory-based visual search more efficiently. A recent study has suggested that this performance benefit might reflect the use of multiple memory systems: when needed, participants may maintain the to-be-remembered object in both long-term and short-term visual memory, with this redundancy benefitting target identification during search (Reinhart, McClenahan & Woodman, 2016). Here we test this compelling hypothesis. We had participants complete a memory-based visual search task involving a reward cue that either preceded presentation of the to-be-remembered target (pre-cue) or followed it (retro-cue). Following earlier work, we tracked memory representation using two components of the event-related potential (ERP): the contralateral delay activity (CDA), reflecting short-term visual memory, and the anterior P170, reflecting long-term storage. We additionally tracked attentional preparation and deployment in the contingent negative variation (CNV) and N2pc, respectively. Results show that only the reward pre-cue impacted our ERP indices of memory. However, both types of cue elicited a robust CNV, reflecting an influence on task preparation, both had equivalent impact on deployment of attention to the target, as indexed in the N2pc, and both had equivalent impact on visual search behavior. Reward prospect thus has an influence on memory-guided visual search, but this does not appear to be necessarily mediated by a change in the visual memory representations indexed by CDA. Our results demonstrate that the impact of motivation on search is not a simple product of improved memory for target templates.
提示有可能获得现金奖励会促使参与者更有效地进行基于记忆的视觉搜索。最近的一项研究表明，这种性能优势可能反映了多种记忆系统的使用：当需要时，参与者可以在长期和短期视觉记忆中保持要记住的对象，这种冗余有助于搜索过程中的目标识别（Reinhart、McClenahan 和 Woodman，2016）。在这里，我们检验了这个引人注目的假设。我们让参与者完成了一个基于记忆的视觉搜索任务，其中包括一个奖励线索，该线索要么在要记住的目标呈现之前（预线索）出现，要么在之后（回溯线索）出现。根据早期的研究，我们使用事件相关电位（ERP）的两个成分来跟踪记忆表示：反映短期视觉记忆的对侧延迟活动（CDA）和反映长期存储的前 P170。我们还分别在 contingent negative variation (CNV) 和 N2pc 中跟踪注意的准备和部署。结果表明，只有奖励预线索影响了我们的 ERP 记忆指标。然而，这两种类型的线索都引起了强大的 CNV，反映了对任务准备的影响，两者都对 N2pc 索引的注意力对目标的部署产生了同等的影响，并且都对视觉搜索行为产生了同等的影响。因此，奖励预期对记忆引导的视觉搜索有影响，但这似乎不一定是由 CDA 索引的视觉记忆表示的变化介导的。我们的结果表明，动机对搜索的影响不是对目标模板的记忆改善的简单产物。
