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Sex differences in 6-month-old infants' affect and behavior: Impact on maternal caregiving

Marta Katherine Weinberg, University of Massachusetts Amherst


Previous studies of gender differences in emotional and behavioral expressivity have generally found few differences between male and female infants despite persistent reports by parents to the contrary. This study presents striking sex differences in infants' behavior and affect during face-to-face interactions with their mother. 81 infants (43 females and 38 males) and their mothers were videotaped in Tronick's Still-Face Paradigm at 6 and 6 1/2 months. The Still-Face Paradigm consists of three two-minute episodes: normal age-appropriate interaction, mother acting unresponsive by holding a still-face (a stressful event), and a reunion of normal interaction. The infants' behavior (e.g., gaze, self-regulatory coping behaviors, gestural and vocal signals, and withdrawal/ escape behaviors) was coded using the Infant Regulatory Scoring System and their affective expressions with the AFFEX system. The mothers' behavior (e.g., facilitative or disruptive behaviors, gaze, gestural and vocal signals) was coded with the Maternal Regulatory Scoring System and their affect with Emde's Maternal Hedonic Tone Scale. The videotapes were coded second by second and reliability was maintained at over 75% for each behavior and facial expression. Boys showed significantly more joy and anger, more positive vocalizations, fussiness, and crying, more gestural signals directed towards the mother, and more escape behaviors than girls. Girls were significantly more likely to show interest, to gaze at objects, and to use self-regulatory behaviors such as diverting their attention to objects and to thumbsuck than boys. Several of these sex differences were stable over time and none could be accounted for in terms of maternal behavior and affect. Finally, significant between-session stability in both sexes' behavioral and affective displays was found particularly in the first play suggesting that stress does not highlight individual differences at this age. These data indicate that boys are more affectively reactive and socially directed than girls, and that girls are more object oriented and use more self-regulatory behaviors than boys. Thus 6-month-old infants show gender based affective, behavioral, and self-regulatory differences that appear independent of maternal behavior and affect.

Subject Area

Developmental psychology

Recommended Citation

Weinberg, Marta Katherine, "Sex differences in 6-month-old infants' affect and behavior: Impact on maternal caregiving" (1992). Doctoral Dissertations Available from Proquest. AAI9219513.