An event-related brain potential study of children's conservation.

To investigate the relationship between cortical activation and conservation ability, 22 children were divided into two groups based on their performance on a standard Piagetian Conservation test. Visual evoked potentials were recorded while children performed a weight conservation task. A bilateral, frontal-distributed, broad late positive component at 900 ms differed between non-conserving and conserving children, with non-conservers having a larger amplitude. The significant interaction between conservation ability and hemisphere on the amplitude of this component suggests that inferior generators gradually move from central to right frontal-central while conservation level increases. The results indicate the existence of an ERP component that reflects weight conservation ability in children and a possible relationship between conservation ability and brain activation.