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A longitudinal twin study of stability of components from Bayley's Infant Behavior Record
Insights
This study examined infant behavior development in twins, finding that while individual differences change over time, genetic similarity influences the pattern of these changes. Identical twins showed more consistent behavioral profiles than fraternal twins.
Area of Science:
- Developmental Psychology
- Behavioral Genetics
- Infant Studies
Background:
- Understanding the interplay between genetics and environment in shaping infant temperament is crucial.
- Longitudinal studies are essential for tracking developmental changes and continuity in early childhood.
Purpose of the Study:
- To investigate the longitudinal stability and change in infant behavior across the first two years of life.
- To examine the role of genetic similarity in the continuity of infant behavioral profiles.
- To analyze specific aspects of infant behavior including task orientation, affect-extraversion, and activity.
Main Methods:
- Utilized factor scores from Bayley's Infant Behavior Record for approximately 300-400 infant twins.
- Collected data at multiple time points: 6, 12, 18, and 24 months of age.
- Employed age-to-age correlations and comparative analyses between identical and same-sex fraternal twin pairs.
Main Results:
- Age-to-age correlations revealed a simplex pattern, indicating low to moderate stability in infant behavior scores.
- Identical twin pairs exhibited greater within-pair similarity in behavioral profiles compared to same-sex fraternal twins across developmental periods (6-18 and 12-24 months).
- Findings suggest that while infant behavior reorders over time, this sequence is influenced by genotypic similarity.
Conclusions:
- Individual differences in infant behavior undergo reordering across developmental stages.
- Genetic factors play a significant role in structuring the continuity and change of infant temperament.
- The study highlights the complex interplay of genetic predispositions and developmental processes in shaping early behavior.
Abstract:
Factor scores from Bayley's Infant Behavior Record, obtained from about 300-400 infant twins at 6, 12, 18, and 24 months, were selected to represent 3 aspects of infant behavior: task orientation, test affect-extraversion, and activity. Age-to-age correlations for the scores yielded a simplex pattern of low to moderate order. Further age-to-age analyses by twin pairs generally showed that the identical twins, as compared with same-sex fraternal twins, generated more within-pair similarities for profiles of the factor scores across 2 overlapping age ranges: 6-18 months, and 12-24 months. Overall, the findings indicated that there is reordering of individual differences for aspects of infant behavior from one age to the next, but the sequence of reordering is somewhat structured in accord with genotypic similarity. The longitudinal findings are also discussed within the context of change and continuity of the individuality of infant temperament.