Individual differences in children's private speech: Consistency across tasks, timepoints, and contexts

Children often talk themselves through their activities. They produce private speech (PS), which is internalized to form inner speech (silent verbal thought). Twenty-five 8–10-year-olds completed four tasks in a laboratory context (Tower of London, digit span, and two measures of spatial IQ). PS production was recorded. Eleven months later, the same participants completed the Tower of London and academic numeracy tasks, again in a laboratory context, as well as numeracy tasks in a classroom context. Rates of PS production and its level of internalization showed large positive correlations across time, tasks, and contexts. The results are interpreted in terms of the psychometric properties of PS production and are taken as evidence for the development of a domain-general system for verbal self-regulation in childhood.