Reasoning about artifacts at 24 months: the developing teleo-functional stance.

From the age of 2.5, children use social information to rapidly form enduring function-based artifact categories. The present study asked whether even younger children likewise constrain their use of objects according to teleo-functional beliefs that artifacts are "for" particular purposes, or whether they use objects as means to any desired end. Twenty-four-month-old toddlers learned about two novel tools that were physically equivalent but perceptually distinct; one tool was assigned implicit function information through a short demonstration. At test, toddlers returned to the demonstrated tool when asked to repeat the task, but, unlike older children, also used it for another task. Results imply that at 24 months, toddlers expect artifacts to have functions and proficiently use a model's intentional use to inform tool choices, suggesting cognition that differs from that of tool-using monkeys. However, their artifact representations are not yet specified enough to support exclusive patterns of tool use.