Louisiana State University, 236 Audubon Hall, Baton Rouge, LA 70803, USA.
Louisiana State University, 236 Audubon Hall, Baton Rouge, LA 70803, USA; University of Nebraska at Kearney, 2504 9th Ave, Kearney, NE 68849, USA.
Biol Psychol. 2023 Mar;178:108528. doi: 10.1016/j.biopsycho.2023.108528. Epub 2023 Mar 1.
Previous research is inconclusive on when visual working memory (VWM) can be object-based or feature-based. Prior event-related potential (ERP) studies using change detection tasks have found that amplitudes of the N200-an ERP index of VWM comparison- are sensitive to changes in both relevant and irrelevant features, suggesting a bias toward object-based processing. To test whether VWM comparison processing can operate in a feature-based manner, we aimed to create circumstances that would support feature-based processing by: 1) using a strong task-relevance manipulation, and 2) repeating features within a display. Participants completed two blocks of a change detection task for four-item displays in which they were told to respond to color changes (task relevant) but not shape changes (task irrelevant). The first block contained only task-relevant changes to create a strong task-relevance manipulation. In the second block, both relevant and irrelevant changes were present. In both blocks, half of the arrays contained within-display feature repetitions (e.g. two items of the same color or shape). We found that during the second block, N200 amplitudes were sensitive to task-relevant but not irrelevant features regardless of repetition status, consistent with feature-based processing. However, analyses of behavioral data and N200 latencies suggested that object-based processing was occurring at some stages of VWM processing on task-irrelevant feature change trials. In particular, task-irrelevant changes may be processed after no task-relevant feature change is revealed. Overall, the results from the current study suggest that the VWM processing is flexible and can be either object- or feature-based.
先前的研究对于视觉工作记忆（VWM）何时可以基于对象或基于特征尚无定论。先前使用变化检测任务的事件相关电位（ERP）研究发现，N200 的振幅——VWM 比较的 ERP 指标——对相关和不相关特征的变化都敏感，这表明存在偏向于基于对象的处理。为了测试 VWM 比较处理是否可以基于特征进行，我们旨在通过以下两种情况来支持基于特征的处理：1）使用强烈的任务相关性操作，以及 2）在显示中重复特征。参与者完成了一个包含四个项目的变化检测任务的两个块，他们被告知对颜色变化做出反应（任务相关），而不对形状变化做出反应（任务不相关）。第一个块仅包含与任务相关的变化，以创建强烈的任务相关性操作。在第二个块中，同时存在相关和不相关的变化。在两个块中，一半的数组包含显示内特征重复（例如，两个相同颜色或形状的项目）。我们发现，在第二个块中，N200 振幅对任务相关但不相关的特征敏感，无论重复状态如何，这与基于特征的处理一致。然而，对行为数据和 N200 潜伏期的分析表明，在任务不相关特征变化试验的某些 VWM 处理阶段，基于对象的处理正在发生。特别是，在没有任务相关特征变化显示的情况下，可能会处理任务不相关的变化。总体而言，当前研究的结果表明，VWM 处理具有灵活性，可以是基于对象或基于特征的。
