A City Guide To Battambang for van der Pligt et al n The HBM takes limited account of social influences on behaviour. For example, while young children, who take their cues about health and health behaviour from important adults in their lives, show generally good adherence to medication, adolescent adherence is poorer, reflecting a shift in influence and beliefs about health maintenance e.g. Bryon n The HBM fails to consider whether the individual feels able to initiate the behaviour or behaviour change required. Two constructs relate to this perceived behavioural control and self-efficacy, as exemplified in two of the models discussed next the theory of planned behaviour and the HAPA. Given these limitations, it is perhaps not surprising that studies employing the HBM have found that its components account for only a small proportion of variance in behaviour change see meta-analysis of adult studies by Harrison et al By initially failing to consider the interactions between its components, the role of social norms and influences, and the factors that can turn beliefs into more proximal close-up determinants of behaviour such as efficacy in carrying out the required behaviour, it provided only a limited account of human action, and more extensive models were developed and adopted. Figure The theory of reasoned action and the theory of planned behaviour TPB additions in italics. A City Guide To Battambang 2016.