A critical question in the study of human perception is whether information in visual working memory is stored as complete, bound-up objects, or as collections of un-bound visual features. Here I test whether the location of an object is a fundamental feature that is always stored when anything else about the object is, or if it is possible to store other features of an object even with no memory for where it was seen. New experimental paradigms and mathematical models were developed to estimate how many colors, how many locations, and how many color-location conjunctions could be stored. Results across three experiments indicate that about one color is stored with no corresponding memory for where it was seen. This memory is not due to verbal encoding, and does not simply reflect noisy location memory. This freeloating feature greatly constrains theories of how visual information is stored in memory.

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Tracking the identity of occluded objects requires binding an object’s features to its location to represent exactly which objects are located where, relying heavily on capacity-limited visual working memory. This dissertation aims to examine the capacity and stability of object working memory, and the complexity and fidelity of object working memory representations, in toddlers and young children. A series of four experiments used a novel task to examine 28- to 40-month-old toddlers’ and 5- to 6-year-old children’s visual working memory recall of specific objects in specific locations. I predicted capacity limits would vary with age, presentation/occlusion type, and complexity, and that older children would be able to monitor these limits successfully. Children observed arrays of featurally-distinct objects that were hidden from view either simultaneously (Chapter 2, Experiment 1 and Chapter 3, Experiments 1 & 2) or sequentially (Chapter 2, Experiment 2) and were asked to recall an object’s location. When objects were hidden simultaneously, toddlers showed a capacity of 3 feature-location bindings (Chapter 2, Experiment 1) and 5- to 6-year-old children showed a capacity of 4 feature-location bindings (Chapter 3, Experiment 1), and both showed capacity development, supporting the hypotheses. When objects were hidden sequentially, toddlers’ performance was impacted by whether they had the easier (set size 2) or harder (set size 3) block first, suggesting the structure of the task may have influenced how children divided attention between maintaining and encoding of representations in working memory. Additionally, in Chapter 3, the number of feature bindings that children had to maintain was varied. Children could remember more single-feature objects than multi-feature objects (limit of 4 vs. 3, respectively), suggesting that binding additional features to a representation taxes cognitive resources, as hypothesized. Finally, the study in Chapter 3 explored children’s ability to monitor the fidelity of their visual working memories by asking them to gauge their confidence by placing bets with tangible, at-risk resources. Children modulated their bets appropriately, betting more after providing correct answers and fewer after incorrect answers, as hypothesized. Together, these data help to inform our understanding of visual working memory for feature-location bound objects across early development.

People unconsciously learn spatial information about places they encounter frequently, leading them to search through familiar scenes faster than for unfamiliar scenes. We explored this phenomenon—the contextual cueing effect—in scenes containing images of different human faces. Participants searched through a series of scenes for a target among distractors, characterized as a letter T among letter L’s with each letter positioned on top of a face image (Experiment 1) or as a female face among male faces (Experiment 2). Experiment 1 showed that when the binding of identity and location was manipulated during learning, slightly greater (but not statistically significant) contextual cueing effects were found for repeated scenes with constant identity-to-location binding than those repeated scenes with constant spatial configurations but shuffled identity-to-location binding. Experiment 2 showed that if the binding of identity-to-location changed after the learning of a set of identity-to-location binding, small (but not statistically significant) costs of contextual cueing were found. The results suggest that in the contextual cueing paradigm, repeated identity-to-location binding might be learned but the learning of repeated spatial configurations alone account for a major portion of the learning. / Thesis / Master of Science (MSc)