INFANT TEMPERAMENT AND CARDIAC VAGAL TONE - ASSESSMENTS AT 12 WEEKS OF AGE

Sixty 12-week-old infants participated in a laboratory study to explor e the relations between temperament and cardiac vagal tone. Temperamen t was evaluated via laboratory observations and maternal ratings. Card iac vagal tone, measured as the amplitude of respiratory sinus arrhyth mia, was quantified from beat-to-beat heart period data collected duri ng a resting baseline period and during the laboratory assessment of t emperament. Specific hypotheses were investigated relating temperament to both basal cardiac vagal tune and changes in cardiac vagal tone du ring social/attention challenges. Infants with higher baseline cardiac vagal tone were rated in the laboratory as showings fewer negative be haviors and were less disrupted by the experimental procedure. Infants who decreased cardiac vagal tone during the laboratory assessment wer e rated on maternal report temperament scales as having longer attenti on spans, and being more easily soothed.