A Second-Order Longitudinal Model Of Ability Structure

Area of Science:

• Psychology
• Cognitive Science
• Developmental Psychology

Background:

• Olsson and Bergman (1977) proposed a structural equation model for intellectual abilities (ages 10-13).
• Their model identified four stable, correlated factors, each developing independently.
• This prior model suggested intra-factor development was isolated from other factors.

Purpose of the Study:

• To reanalyze Olsson and Bergman's (1977) data using a different structural model.
• To investigate the role of a second-order general intelligence factor (G) in explaining correlations among primary abilities.
• To assess the stability of intellectual factors and the influence of G on their development.

Main Methods:

• Structural equation modeling reanalysis of existing longitudinal data.
• Implementation of a hierarchical model incorporating a general intelligence factor (G).
• Examination of factor stability over time and interdependencies in developmental trajectories.

Main Results:

• The general intelligence factor (G), along with verbal and spatial abilities, demonstrated stability over time.
• The initial model's findings of broad stability were largely attributable to the stability of G.
• Development within primary factors was significantly influenced by the development of G.

Conclusions:

• A hierarchical model with a general intelligence factor (G) provides a better explanation of intellectual development.
• The stability observed in primary intellectual abilities is substantially mediated by the stability of G.
• Developmental changes in specific cognitive skills are not independent but are closely linked to the growth of general intelligence.