Beyond 'what' and 'how many': An investigation of working memory for objects in infancy

Working memory allows us to represent information that is no longer perceptually available, such as an object that has become occluded from sight. Critically, this system supports the representation of objects throughout development, starting early in infancy. Much research has sought to characterize the architecture of working memory. Despite recent work that has addressed the question of how many objects working memory can represent---both in adults and in infants---much less work has addressed how this memory capacity is affected by the nature of the object representations themselves. The question of how the quantity and the quality of object representations interact has been particularly under-explored from a developmental perspective.;This dissertation investigates the architecture of the working memory system via three sets of experiments with infants and young children. First, Experiments 1.1-1.6 examine infants' ability to represent items other than objects in working memory---specifically, I investigate the early ability to remember collections containing multiple items. These six experiments suggest that infants can store up to three working memory representations in parallel, regardless of whether the representations are of an individual object, or a collection of multiple items defined by a common feature. Second, in Experiments 2.1-2.3, I investigate the interaction between the number of items stored in working memory and the resolution of the resulting representations. This work suggests that, for both adults and infants, there is a tradeoff between the number of objects that can be simultaneously represented and the featural resolution of the representations. Finally, in Experiments 3.1-3.3 I explore what happens to infants' memory when working memory capacity is exceeded. This work suggests that exceeding the limits of working memory can have different consequences for infants' object representations than for those of adults. Furthermore, the particular features of the objects being represented determine whether or not infants show adult-like performance.;Together, these 12 experiments illustrate the simultaneously flexible and rigid nature of working memory for objects. They show that the architecture of working memory affects object representations, and how in turn object representations affect working memory.