Department of Experimental and Applied Psychology, Vrije Universiteit Amsterdam, Amsterdam, Netherlands.
Institute for Brain and Behavior Amsterdam, Amsterdam, Netherlands.
Elife. 2019 Aug 27;8:e49130. doi: 10.7554/eLife.49130.
The human brain recurrently prioritizes task-relevant over task-irrelevant visual information. A central question is whether multiple objects can be prioritized simultaneously. To answer this, we let observers search for two colored targets among distractors. Crucially, we independently varied the number of target colors that observers anticipated, and the number of target colors actually used to distinguish the targets in the display. This enabled us to dissociate the preparation of selection mechanisms from the actual engagement of such mechanisms. Multivariate classification of electroencephalographic activity allowed us to track selection of each target separately across time. The results revealed only small neural and behavioral costs associated with preparing for selecting two objects, but substantial costs when engaging in selection. Further analyses suggest this cost is the consequence of neural competition resulting in limited parallel processing, rather than a serial bottleneck. The findings bridge diverging theoretical perspectives on capacity limitations of feature-based attention.
人类大脑反复优先处理与任务相关的视觉信息，而不是与任务不相关的信息。一个核心问题是是否可以同时优先处理多个对象。为了回答这个问题，我们让观察者在干扰项中搜索两个颜色的目标。至关重要的是，我们独立地改变了观察者预期的目标颜色数量和用于区分显示中目标的目标颜色数量。这使我们能够将选择机制的准备与这些机制的实际参与区分开来。对脑电图活动的多元分类使我们能够在时间上分别跟踪每个目标的选择。结果显示，为选择两个对象做准备所带来的神经和行为成本很小，但在进行选择时会产生很大的成本。进一步的分析表明，这种成本是由于神经竞争导致的有限的并行处理造成的，而不是串行瓶颈造成的。这些发现弥合了基于特征的注意力容量限制的不同理论观点之间的分歧。
