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The expression of pain in infants and toddlers: developmental changes in facial action
C M Lilley1, K D Craig, R E Grunau
1Department of Psychology, The University of British Columbia, Vancouver, Canada. lilley@unixg.ubc.ca
Insights
Infants
Area of Science:
- Developmental psychology
- Pain perception and expression
- Infant behavior and development
Background:
- Understanding age-related changes in infant pain expression is crucial for accurate pain assessment.
- Facial displays of pain evolve during the first 18 months of life.
- Parental responses to infant distress also change with age.
Purpose of the Study:
- To examine age-related variations in facial pain expressions in infants aged 2–18 months.
- To investigate the relationship between infant temperament and pain expression.
- To analyze parental soothing behaviors in response to infant pain.
Main Methods:
- Video recording of facial reactions during routine immunization injections in 75 infants.
- Application of two distinct facial coding systems to analyze pain displays.
- Parental questionnaires assessing child temperament and background information.
Main Results:
- Consistent and varying facial pain expressions were observed across different age groups.
- Infants at 4 months old exhibited the least pain expression.
- Infant temperament did not correlate with the intensity of pain expressed.
- Parental soothing strategies adapted systematically to the infant's age.
Conclusions:
- Facial pain expression in infants changes systematically during the first 18 months.
- Developmental factors, including inhibitory mechanisms and emotional regulation, influence pain displays.
- Parental soothing behaviors are age-dependent and crucial for managing infant distress.
Abstract:
Age-related changes in the facial expression of pain during the first 18 months of life have important implications for our understanding of pain and pain assessment. We examined facial reactions video recorded during routine immunization injections in 75 infants stratified into 2-, 4-, 6-, 12-, and 18-month age groups. Two facial coding systems differing in the amount of detail extracted were applied to the records. In addition, parents completed a brief questionnaire that assessed child temperament and provided background information. Parents' efforts to soothe the children also were described. While there were consistencies in facial displays over the age groups, there also were differences on both measures of facial activity, indicating systematic variation in the nature and severity of distress. The least pain was expressed by the 4-month age group. Temperament was not related to the degree of pain expressed. Systematic variations in parental soothing behaviour indicated accommodation to the age of the child. Reasons for the differing patterns of facial activity are examined, with attention paid to the development of inhibitory mechanisms and the role of negative emotions such as anger and anxiety.