Habitual size and projective size: the logic of spatial systems in children's drawings.

The current study analyzed figure size modification in different types of spatial context (C. Lange-Küttner, 1997, Lange-Küttner, 2004) for sequence and practice effects. Children of 7, 9, and 11 years of age, as well as 17-year-olds, drew figures in a series of ready-made spatial axes systems, which (a) logically increased in dimensional complexity as in child development, (b) were randomized in sequence, or (c) were absent, as a control condition for figure size reduction through practice. Already 7-year-olds could subtly adapt figure size in the logical sequence, but the amount of size reduction stayed within the same size range as in the other two conditions. Only at 9 years of age did children show sensitivity to spatial constraints, with smaller figures in both the logical and random sequence than in the control condition. At 11 years of age, the spatial scale of figure size was maximized, particularly so in children who could change perspective and construct a bird's-eye view, whereas this effect was attenuated in the 17-year-olds. Implications of the results for domain-specific conceptual development are discussed.