Gardiner, Amy K.

Object use is a ubiquitous characteristic of the human species, and learning how objects function is a fundamental part of human development. This research examines the role that intentionality plays in children's understanding of causal relationships during imitation learning of object use. In Studies 1, 2, and 3, 2- to 5-year-olds observed demonstrations in which causally irrelevant and causally relevant actions were performed to achieve a desired goal of retrieving toys from within containers. Irrelevant actions were performed either intentionally ("There!") or accidentally ("Whoops! I didn't mean to do that!"). Study 1 found that 3-, 4-, and 5-year-olds, but not 2-year-olds, were less likely to imitate causally irrelevant actions performed accidentally than those performed intentionally. This suggests that older children used intentionality to guide causal inference, perceiving intentional actions as causally effective and accidental actions as causally ineffective. Study 2 foun d that the intentionality of the demonstrator's actions had an enduring effect - after watching a single demonstration, children persisted in performing intentional irrelevant actions and continued to ignore accidental irrelevant actions when given three successive opportunities to complete the task. Study 3 examined how lack of knowledge about the task goal prior to the demonstrations affected imitation and found that children without explicit verbal instruction of the toy-retrieval goal imitated irrelevant actions to a greater degree than children from Study 1, who were informed of the goal throughout the experiment. Study 4 progressed beyond irrelevant actions to investigate the effect of intentionality on 3- to 5-year-olds' imitation of relevant actions.

Two and 3 year-old children's understanding of tool affordances was investigated by measuring their tool choice decisions and tool use behaviors. Children attempted six toy retrieval tasks of three different levels of structural complexity. Children were assigned to one of four conditions in which exposure to task materials varied according to the way in which the information was presented: no experience / no observation, experience only, observation only, and experience and observation. Three year- olds consistently made more correct choices and used more working tools successfully than 2-year-olds. Tool choice was affected primarily by task difficulty and age. Tool use was influenced by task difficulty, order of task difficulty, age, and condition. The observation condition was most beneficial to children, while experience was least helpful, particularly for tasks at the hard level of difficulty.