engleski

Capturing how G is expressed in successive Developmental Phases: A longitudinal study from 8 to 17 years of age

This is a longitudinal study that examined how G is expressed in each of three developmental phases, i.e. 8-10, 11-13 and 14-17 years. We tested the model proposed by Demetriou and colleagues that intellectual development advances in four cycles, with two phases in each, such that Gf changes coalesce with speed in the first phase and with working memory in the second phase. In the present study we predicted that changes in time in G would be better predicted by working memory, speeded performance, and inferential power in the 8-10, 11-13, and 14-17 years phase. Method: A total of 478 participants were involved, about equally sampled among 8-10, 11- 13 and 14-17 years old children and adolescents. Participants were examined by a battery of speeded performance tasks addressed to speed and divided attention, working memory, fluid intelligence (Raven's SPM), and to mathematical reasoning (i.e., arithmetic operations, algebra, mathematical proportions). Participants were examined twice separated by a year. Results and conclusions: Structural equation modeling revealed that there always was a strong general factor driving change in time (G accounted for more of 70% of the change in process). Cross-lagged causal interactions revealed three levels of mental organization (i.e., processing efficiency, representational, and inferential) hierarchically intertwined, with systematic changes across the three phases. To test the prediction above G at second testing was regressed on speed, control, working memory, and Raven based Gf at first testing. G at second was exclusively predicted by working memory, control of attention, and inference in the 8-10, 13-13, and 14-17 years phase, respectively. Discussion: Implications for psychometric and developmental theories are discussed. In concern to the dispute between theories emphasizing G and theories emphasizing specific processes, we showed that this apparent rather than real contradiction. G-based values show how much of the change in each process derives from processes shared by all, in the way that the sun influences the movement of all planets. Auto-regressions show how each process constrains itself over time, given its relations with others, and cross-lagged correlations reflect how a particular process at a particular point in time is influenced by others. In concern to developmental theories, this study suggests that G prefers different process to express itself at different phases, depending upon its state of organization.

developmental phases; processing speed; selective and divided attention; aspects of working memory; relation to fluid intelligence and mathematical thought; g-factor

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