Figure 2. Social network mechanisms that influence health behaviour.

Networks affect behaviour through at least five pathways; person to person contact, social engagement, social influence, access to resources and material goods, and social support³¹. Social support comes in four forms; instrumental and financial support, informational support, appraisal support and emotional support. Appraisal support relates to how an alter can provide an ego with appropriate feedback or help with decision making. The influence of a pathway on the ego–alter relationship can change over time. Some ties operate through several pathways, while others are more specialized. The ego is the patient at the centre of the network, an alter is an individual in a network, and a tie is the connection between individuals in a network.