This microgenetic experimental study examined children's spontaneous application of analogical problem solving from story problems to physical tasks. Results indicated that 4-year-olds did, with varying success, spontaneously apply analogical solutions to physical problems across sessions. A few children even gave an analogical strategy-related explanation for their own physical behavior. There was considerable inter- and intra- individual variability, suggesting that age 4 is a period of change in analogical reasoning. (Author/KB)