Exploring temperamental differences in infants from the United States of America (US) and the Netherlands.

This longitudinal study employed the Infant Behavior Questionnaire-Revised in assessing temperamental differences between infants at 6 months (n = 114 US, 184 Dutch) and 12 months (n = 92 US, 172 Dutch) from the United States of America and The Netherlands. Main effects indicated that Dutch infants were rated higher on the Orienting/Regulatory Capacity factor and fine-grained dimensions of Smiling and Laughter, Falling Reactivity, Cuddliness, Low-Intensity Pleasure, and Soothability; whereas US infants received higher ratings on the Negative Affectivity factor and on dimensions of Activity Level, Vocal Reactivity, Fear, Frustration, and Sadness. Cultural differences for Orienting/Regulatory Capacity were more pronounced in early infancy, cultural differences for Fear were stronger in late infancy, and US infants demonstrated higher Duration of Orienting at 12 months only. Culture also appeared to impact the pace of consolidation of temperamental characteristics, with greater stability exhibited by US than Dutch infants in Smiling and Laughter and Vocal Reactivity.