Heart Rate Reactivity of 9-and 12-Months Old Infants Showing Specific Emotions in Natural Setting

To further our understanding of the relationship between cardiovascular reactions and specific emotions, 40 9-and 12-months old infants were systematically observed in a laboratory setting. The experiment included six standardized three-minute-long situations designed to trigger one of five basic emotions: interest, anger, fear, distress and joy. During each situation, overt behaviors, cardiac reactions and judgments on emotion were recorded every five seconds. Our results revealed no fear so data on cardiovascular activity are relative to only four emotions. Heart rate associated with negative emotions is significantly different from heart rate associated with positive emotions; emotions usually considered as negative, anger and distress, evoke concurrent significant cardiac acceleration, whereas emotions usually considered as positive, interest and joy, are associated with small-non-significant deceleration. Furthermore, emotions with the same hedonic tone cannot be distinguished on the basis of their concurrent cardiac reactivity. Implications are derived from the Graham and Clifton (1966) theory as to the usefulness of heart rate measurement in developmental studies.