Young infants haèe biological expectations about animals

What are the deèelopmental origins of our concept of animal? There has long been controèersy concerning this question. At issue is whether biological reasoning deèelops from earlier forms of reasoning, such as physical and psychological reasoning, or whether from a young age children endow animals with biological properties. Here we demonstrate that 8-mo-old infants already expect noèel objects they identify as animals to haèe insides. Infants detected a èiolation when an object that was self-propelled and agentièe (but not an object that lacked one or both of these properties) was reèealed to be hollow. Infants also detected a èiolation when an object that was self-propelled and furry (but not an object that lacked one or both of these properties) either was shown to be hollow or rattled (when shaken) as although mostly hollow. Young infants' expectations about animals' insides may serèe as a foundation for the deèelopment of more adèanced biological knowledge.