Inspection time in two childhood age cohorts: A constant or a developmental function?

Abstract

The development trend of inspection time (IT) was investigated by comparing performances of eleven 5–6‐year‐olds and thirteen 11–12‐year‐olds, matched for IQ using Raven's Coloured Progressive Matrices (CPM). Initial age‐related differences in IT were substantially reduced by extended practice but remained statistically significant after practice across 20 and more successive estimates had reduced IT performance to asymptotic levels. Relative rate of improvement in IT performance was not related to CPM and consideration of attentional variability and possible fatigue effects suggested that these variables could not account for the final difference between the samples in mean IT. Early 1T‐CPM correlations within cohorts were above − .5 but after eight estimates diminished steadily, eventually to negligible proportions in both age samples. This outcome was interpreted as the consequence of a shift in the type of information being processed, since a majority of children in both age samples reported learning to use post‐stimulus cues of apparent movement. Overall, results supported the hypothesis that speed of central processing increases as a function of mental age; but also highlighted methodological shortcomings in IT as an index of mental speed free from the influence of cognitive strategies.