Abstract: The examination of younger children’s ability to distinguish living from nonliving things in terms of essential biological properties such as growth, illness, autonomous action, inheritance and reproduction is all through the primary content of the naïve theory of biology. Past studies have shown that preschool children already can acquire understandings of these biological traits, and develop ontological distinctions and coherent causal explanatory frameworks. However, these studies focused mostly on the animal-inanimate distinction, rather than the distinction between animate objects (including both animals and plants) and inanimate objects. Interpretations of these studies may also be confounded by such methodological differences as task difficulty, scoring criteria, choice of stimuli, type of data emphasized, and number of subjects used. The present study thus tried to examine younger children’s conception of plant reproduction by varying stimulus and task types so as to map out children’s development of categorical knowledge.
A total of 152 4- to 7-year-olds from two kindergartens and two elementary schools in Yinchuan city participated in the study. The subjects were equally distributed in each of the two genders and in each of the four age groups. The stimuli used were realistic color photographs of plants (half with and half without visible fruits and seeds) and nonliving things. Interviews and a picture-choice task were both used to measure children’s concept of plant reproduction and their ability to distinguish plants from nonliving things. A 4 (age: 4, 5, 6, and 7 years) × 2 (plants vs. nonliving things) design was adopted.
Statistically significant results were obtained for the main effects associated with the two independent variables but not for the interaction effect. Children’s understanding of nonliving things was significantly better than that of plants. Also, significant difference was found between every age group except between 5- and 6-year-olds. That is, there was rapid development from 4 to 5 years, a slow development from 5 to 6 years, and a rapid development again from 6 to 7 years. Nearly two-thirds of the 7-year-olds could appreciate the reproduction of plants by pointing out the growth cycle of “plant-seed-plant.” At the same time, they could also distinguish plants from nonliving things in terms of reproduction. The result also showed that children aged 6 could appreciate the reproduction of plants with visible fruits and seeds. It seems reasonable to conclude that 6-year-olds had a mature grasp of the reproduction of plants with visible fruits and seeds.
Four conclusions may be drawn from these results. First, three levels of understanding (none, partial and good) are identifiable with 4- to 7-year-olds, with 7-year-olds being able to distinguish plants from nonliving objects in terms of reproduction. Second, it seems easier to map out the developmental potential of younger children by reducing stimulus and task difficulty, so that most of the 6-year-olds can acquire recognition of plant reproduction. Third, variations in task requirements may significantly influence the conceptual understanding in terms of plant reproduction among 5- and 6- year-olds; the same may not be true for either older or younger children. Finally, children show better cognitive performance with picture-choice tasks than interview tasks, and in plants with fruits and seeds than those without

Key words: preschoolers, naï, ve theory of biology, reproduction