Which penguin is this? Attributing false beliefs about object identity at 18 months.

Recent research has shown that infants as young as 13 months can attribute false beliefs to agents, suggesting that the psychological-reasoning subsystem necessary for attributing reality-incongruent informational states (Subsystem-2, SS2) is operational in infancy. The present research asked whether 18-month-olds' false-belief reasoning extends to false beliefs about object identity. Infants watched events involving an agent and 2 toy penguins; 1 penguin could be disassembled (2-piece penguin) and 1 could not (1-piece penguin). Infants realized that outdated contextual information could lead the agent to falsely believe she was facing the 1-piece rather than the 2-piece penguin, suggesting that 18-month-olds can attribute false beliefs about the identity of objects and providing new evidence for SS2 reasoning in the 2nd year of life.