Many health promotion educational interventions assume that increasing knowledge directly influences beliefs, intentions and behaviour, whereas research suggests that knowledge alone is insufficient for behavioural change. Social cognition frameworks such as the Theory of Reasoned Action propose a central role for beliefs and social normative influences. This Scottish study evaluates the role of knowledge and social influences (subjective norms, exposure to breast-feeding, social barriers) on beliefs and future intentions to breast-feed or bottle-feed. Social influences from family and peers are investigated.

A cross-sectional between-subjects observational design was used. A questionnaire was administered to a sample of 229 (46%) male and 267 (54%) female adolescents aged 11–18 years.

Participants completed questionnaires during lessons at three secondary schools in Central Scotland.

Knowledge about health benefits of breast-feeding was generally poor. Analyses found that perceived social barriers to breast-feeding moderated the relationship between knowledge and beliefs. More knowledge, positive beliefs and supportive subjective norms also predicted future intentions to breast-feed. Parental norms exerted greater influence than peer norms on adolescents' breast-feeding beliefs.

Knowledge and social influences are important predictors of positive breast-feeding beliefs and future intentions to breast-feed in adolescents. This has important implications for breast-feeding health promotion interventions in young people.