Social Influence / Interdependence Theory

We are interested in understanding how the health behavior of individuals can be influenced by our social environment, particularly other individuals. While SNT points out the importance of larger social networks for promoting health behaviors, a focus on social influence points to the significance of interpersonal communication. Researchers interested in the impact of social influence on health behaviors typically focus on dyadic relationships. Specifically, such researchers focus on the ways in which one individual will attempt to influence another primarily through communication. This may entail communication and influence within formal (i.e., doctor/patient) relationships and informal ones (i.e., friends, spouses).

Interdependence theory is social-psychological in nature, and focuses on how pairs of individuals affect one-another s behavior through communication and influence. In this light, health behavior is determined by a number of factors: one s own characteristics, the beliefs and values of one s partner, and the interaction between them. Interdependence theory emphasizes that within dyads, individuals affect one another. This would suggest that health interventions need to involve both members of the dyad. Health interventions should incorporate an individual s spouse or other significant individuals, rather than simply focusing on the individual himself. Health practitioners must be aware of the influence of significant others on the health behavior of the individual. For example, a smoking intervention will be more effective if the partner is a non-smoker than if the partner is a smoker who does not intend to quit as well.

Key Concepts in Interdependence Theory

Beyond the concept of interdependence itself, interdependence theory draws upon the significance of multiple different kinds / sources of power with regard to their impact on health behavior change.

Expert power: based in seeing someone as more knowledgeable; as an expert.
Legitimate power: based upon someone having the right to direct another s behavior; a characteristic of relationships in which one participant is seen as having authority.
Coercive/reward power: stem from the capacity of one participant to reward or punish another.
Informational power: based on the provision of information in a convincing manner.
Referent power: based upon one s identification with the other as a person like oneself.

Interdependence Theory in Application

These sources of power provide insight into the ways in which health care professionals may seek to influence the health behaviors of others. Health care providers can easily exert expert, legitimate and informational power simply from the basis of their professional position. However, referent power has been documented to be perhaps the most effective source of power within dyadic relationships. To that end, health professionals would be advised to share power with the patient and engage in mutual problem solving.

Not only may power-sharing with patients increase beneficial referent power, but it also serves as the basis for the form of provider-patient interaction most strongly linked to positive health outcomes. Relationships marked by mutuality, in which healthcare providers and patients work together to achieve health outcomes, are associated with better health outcomes than are other types of provider-patient relationships.

Beyond suggesting ways in which health care providers may shape their relationship with patients to influence them in positive ways, this framework also emphasizes the importance of health education for shaping health behavior. Well-educated patients are more likely to engage in this productive model of interaction. Clinical trial research has suggested that patients who receive face-to-face education sessions prior to their medical visit became more involved patients, asking questions and serving as a participant in health care decisions rather than a recipient of such decisions.

Also drawing upon insights from interdependence theory, motivational interviewing (MI) is a technique which has been used to great effect in the field of health behavior promotion. MI is a client-centered communication technique in which individuals are encouraged to work through their ambivalence about changing their health behaviors. MI has been used to help prepare people to change their substance use behaviors, improve eating habits, decrease alcohol abuse, and address eating disorders, among other health behaviors.

For a thorough discussion of MI, see Motivational Interviewing. Please watch the first video, an 8-minute interview with Dr. William Miller.

Likewise, as mentioned, the model emphasizes the importance of incorporating significant individuals into health behavior interventions. This is especially important for health interventions targeted at children and adolescents. Just as a mutual participation model seems to work best between providers and patients, a bidirectional relationship between parents and children likewise is associated with better health behaviors, such as not drinking or experimenting with tobacco.