A model of the development of frontal lobe functioning: findings from a meta-analysis.

Although past research has provided an initial examination of maturational trends of frontal lobe functioning, it has not yielded a unifying developmental model. The purpose of this study was to generate a model representing the maturation of frontal lobe function as determined principally through neuropsychological tests. A meta-analytic review of the literature on the development of frontal lobe functioning was conducted. Journal articles were identified through an initial search of PsycInfo, Medline, and ERIC for the years 1984-2004 using key words executive function*, frontal function*, development*, and age. Analyses of effect size differences across age groups assisted in determining the developmental patterns for commonly used measures of frontal functioning by providing a common metric of growth. Age-related increases across the different frontal functions were averaged providing overall age-related increases in performance. A plot was made of the development of frontal lobe functioning using the mean effect size of change in performance across age groups. The model of the development of frontal lobe functioning suggests a staging of development that begins in early childhood with the maturation of frontal functioning and continues, although at a decreased rate, into adolescence and early adulthood.