Visual working memory (VWM) allows us to actively represent a limited amount of visual information in mind. Although its severe capacity limit is widely accepted, researchers disagree on the nature of its representational unit. Object-based theories argue that VWM organizes feature representations into integrated representations, whereas feature-based theories argue that VWM represents visual features independently. Supporting a feature-based account of VWM, recent studies have demonstrated that features comprising an object can be forgotten independently. Although evidence of feature-based forgetting invalidates a pure object-based account of VWM that assumes perfect integration of feature representations, it is possible that feature representations may be organized in a dependent manner on the basis of objects when they exist in memory. Furthermore, many previous studies prompted participants to recall object features independently by sequentially displaying a response probe for each feature (i.e., sequential estimation procedure), and this task demand might have promoted the independence of feature representations in VWM. To test these possibilities, we created a novel task to simultaneously capture the representational quality of two features of the same object (i.e., simultaneous estimation procedure) and tested their dependence across the entire spectrum of representational quality. Here, we found that the quality of feature representations within the same object covaried reliably in both sequential and simultaneous estimation procedures, but this representational dependence was statistically stronger in the simultaneous estimation procedure than in the sequential estimation procedure. Furthermore, we confirmed that neither the shared spatial location nor simultaneous estimation of two features was sufficient to induce representational dependence in VWM. Thus, our results demonstrate that feature representations in VWM are organized in a dependent manner on the basis of objects, but the degree of dependence can vary based on the current task demand.

视觉工作记忆（VWM）使我们能够主动表示脑海中有限的视觉信息。尽管其严格的容量限制已被广泛接受，但研究人员在其代表单位的性质上存在分歧。基于对象的理论认为VWM将特征表示组织为集成表示，而基于特征的理论则认为VWM独立地表示视觉特征。支持VWM的基于特征的帐户，最近的研究表明，可以独立地忘记包含对象的特征。尽管基于特征的遗忘的证据使假定特征表示完美集成的纯基于对象的VWM帐户无效，但当特征表示存在于内存中时，有可能基于对象以依赖的方式组织它们。此外，许多先前的研究提示参与者通过依次显示每个特征的响应探针（即，顺序估计过程）来独立召回对象特征，并且此任务需求可能促进了VWM中特征表示的独立性。为了测试这些可能性，我们创建了一个新颖的任务来同时捕获同一对象的两个特征的表示质量（即，同时估计过程），并测试了它们在整个表示质量范围内的依赖性。在这里，我们发现同一对象内的特征表示质量在顺序估计和同时估计过程中均可靠地协变量，但是在同步估计过程中，这种表示依赖性在统计上要比在顺序估计过程中强。此外，我们确认，共享的空间位置或两个特征的同时估计都不足以在VWM中引入表示依赖性。因此，我们的结果表明，VWM中的特征表示是基于对象的依存方式进行组织的，但是依存程度可以根据当前任务需求而变化。