Development of Intuitive Statics

Measuring preschool children's knowledge of the principle of static equilibrium in the context of building blocks: Validation of a test instrument

BACKGROUND

Preschoolers' knowledge of the principle of static equilibrium is an important research focus for understanding children's science content knowledge. Hitherto studies have mainly used behavioural observation with small samples. Thus, extending these studies with a validated test instrument is desirable.

AIMS

The aim was to validate an instrument (the Centre-of-Mass Test), which is concerned with preschoolers' knowledge of the principle of static equilibrium, using item response theory. In Study 1, the construct structure was tested, and in Study 2, its relationship with stabilities of symmetrical blocks, figural reasoning, figural perception, mental rotation, level of interest, self-concept, motivation, and language capacity was investigated.

SAMPLES

A total of 217 five- and six-year-old children participated in Study 1 and 166 five- and six-year-old children in Study 2.

METHODS

All tests were administered as paper-pencil picture tests in groups and single interviews.

RESULTS

In Study 1, the Centre-of-Mass Test's conformity with a 1PL-testlet model with an overall knowledge of static equilibrium and with two subtests, estimation of stable and unstable constructions, was confirmed. Using a 95% binomial distribution, children were categorized into three knowledge categories: geometrical-centre, centre-of-mass, and undifferentiated knowledge. In Study 2, knowledge of the principle of static equilibrium showed positive correlations with figural perception and reasoning, language capacity, and estimation of the stabilities of symmetrical objects.

CONCLUSIONS

The Centre-of-Mass Test measures knowledge of the principle of static equilibrium as a unidimensional construct and mirrors preschoolers' estimations found in previous studies. The acquisition of a more sophisticated static equilibrium knowledge is related to spatial knowledge and language capacity.

Development of basic intuitions about physical support during early childhood: Evidence from a novel eye-tracking paradigm

Using a novel eye-tracking paradigm, we assessed the development of 2- to 6-year-old children's intuitions about the physical support of symmetrical and asymmetrical objects in two experiments (Experiment 1: N = 98; Experiment 2: N = 288). Children were presented with video sequences demonstrating how two identical blocks were lowered onto a platform before being released simultaneously. In the critical test trials, both blocks remained in place although only one of them was sufficiently supported. As expected, children tended to look longer at the block, which should have fallen. Taken together, the results indicate that even 2-year-old children are sensitive to the amount of contact between symmetrical blocks and a supporting platform and even anticipate which block is going to fall. Nonetheless, we found a considerable improvement with age in this respect. Two-year-olds did not consider an object's weight distribution reliably when assessing its stability and even older preschoolers performed much more poorly with asymmetrical than symmetrical blocks. We conclude that intuitions about support are still weak and limited in toddlers and that they improve considerably during early childhood.

Contrasting preschoolers' verbal reasoning in an object-individuation task with young infants' preverbal feats

Young infants infer a second object if shown an object apparently moving on a discontinuous path (Aguiar & Baillargeon, 2002; Spelke, Kestenbaum, Simons, & Wein, 1995). In three experiments, we examined whether children aged 3-6 years and adults would do the same in their verbal explanations of an apparent continuity violation. Presenting participants with video clips (Exp. 1 and 3) as well as live events (Exp. 2) of a toy locomotive apparently passing through a tunnel without appearing in a large opening in the middle, we found virtually no evidence for generations of two-object explanations of the critical test event in preschoolers. Some of the younger children even denied a continuity violation at first. When participants were familiarized to two identical objects instead of just one, they were more likely to realize that a second object was involved in the test events but, unlike adults (Exp. 3), most children nonetheless adhered to a one-object interpretation. Analyzing 3- and 5-year-old children's and adults' eye movements (Exp. 3), we found that children's difficulties to infer a second object from an apparent continuity violation were not caused by inappropriate looking strategies. We conclude that preschoolers' physical reasoning about the numerical identity of objects is not continuous with the preverbal reasoning of infants. Rather than being exclusively constrained by the output of basic object-individuation processes, as in infants, it is also strongly influenced, in a top-down manner, by prior beliefs.