Young children's recognition of commonalities between animals and plants.

In 4 experiments, we examined whether young children have grasped commonalities between animals and plants as one of the essential components of an autonomous domain of biology. Experiment 1 revealed that by age 5, children distinguished both animals and plants from nonliving things in terms of growth (i.e., changes in size over time). Experiments 2 and 2A indicated that a considerable number of 5-year-olds, when given brief vitalistic descriptions about properties of all living things, constrained inductive projections of these properties using the category of living things. They attributed not only growth but also taking food/water and being taken ill to both animals and plants only. In Experiment 3, when 5-year-old children were asked directly whether plants or nonliving things would manifest phenomena similar to those observed for animals, they responded affirmatively for plants and could offer specific phenomena for growth, feeding, and aging/dying in support of their answers (e.g., watering for plants as analogous to feeding for animals). Overall, contrary to Carey, children as young as 5 years have an integrated category of living things. The possibility that early biology is established around taking food/water and growth is discussed.