Infants' Reasoning About Self-Propelled Objects, Agents, and Animals

Date of Award


Document Type


Degree Name

Doctor of Philosophy (Ph.D.)

Institution Granting Degree

University of Illinois at Urbana-Champaign

Cedarville University School or Department


First Advisor

Renée Baillargeon

Second Advisor

Cynthia Fisher

Third Advisor

John E. Hummel


Causal reasoning, self-propelled object, agent, animal, infant


In the present research, we investigated young infants’ concepts of self-propelled object, agent, and animal through three research projects. In Chapter 2, we examined infants’ concept of self-propelled object, specifically, whether 5-month-olds expect a self-propelled object to produce changes in its parts. We found that 5-month-olds understand that a self-propelled object can use its internal energy to produce orientation and position changes but not location and appearance changes in its parts. In Chapter 3, we examined infants’ concept of agent, particularly, whether infants believe that an agent can be inert. The results indicated that 14-month-olds believe that an agent can be inert, suggesting that self-propulsion is not necessary for infants to identify an object as an agent. In Chapter 4, we asked whether infants have any quasi-biological expectations about animals. The results suggest that 7-month-olds expect the inside of an animal to be full as opposed to be hollow. Together, these results support the core-concept view which states that infants divide objects into broad, abstract categories in accordance with the causal principles in specific reasoning domains.