Infants' Understanding of Object Weight: Relations with Action Experience and Strength

Thesis (Ph.D.)--University of Washington, 2016-06

Our ability to plan actions, interpret other people’s behavior, and predict the outcomes of physical events is profoundly influenced by our understanding of object weight and the ability to recognize its consequences. Given its importance, it is perhaps unsurprising that an understanding of object weight begins in infancy. Prior work demonstrates that infants’ understanding of object weight is primarily garnered through their interactions with objects and that they can apply this understanding in order to guide their actions. However, we know far less about other applications of this knowledge in infancy and whether bodily factors that influence the acquisition of experience interacting with objects play a role. This dissertation demonstrates that infants can apply an understanding of object weight in order to guide action in novel contexts (Chapter 2), interpret and predict the outcome of physical events (Chapter 3), and understand another person’s actions (Chapter 4). In addition, this dissertation demonstrates that strength, a bodily factor that gates the acquisition of experience interacting with objects, influences infants’ understanding of object weight when observing another person’s actions but not when reasoning about physical events. Altogether, these studies demonstrate that by the end of their first year, infants’ understanding of object weight is already flexible (i.e., applied in areas outside of action production in familiar contexts) and sophisticated (i.e., used to reason abstractly about the outcome of physical events).