A CRITICAL APPRAISAL OF SCMs
The use of SCMs to predict health behaviour has a number of advantages and dis -
advantages. Below we outline the main advantages of a social cognition approach
before considering a range of specific and more general criticisms that have been made
of this approach.
There are four clear advantages of using SCMs to predict and understand health
behaviours. First, they provide a clear theoretical background to any research, guiding
the selection of cognitions and providing a description of the ways in which these
constructs combine in order to determine health behaviours. Second, because the
models have been repeatedly tested they provide reliable and valid measures of
selected cognitions (for example, see Ajzen’s website for guidance on developing TPB
measures at http://www.people.umass.edu/aizen/tpb.html)..) Third, SCMs provide us with a
description of the motivational and volitional processes underlying health behaviours.
As a result, they add to our understanding of the proximal determinants of health
behaviour and, because of this, they, fourth, identify key targets for interventions
designed to change motivation (see Chapter 8).
The use of SCMs could also limit our understanding of health behaviour. For
example, because SCMs provide clearly defined theoretical frameworks, their use may
lead to the neglect of other cognitions. For example, moral norms (i.e. doing what
you think is the right thing to do) are not included in the main SCMs but have been
shown to be important in behaviours such as blood donation (Godin, Conner and
Sheeran, 2005). Another limitation of SCMs is that while they usefully identify
cognition change targets, they commonly do not specify the best means to change such
cognitions. Moreover, an over-exclusive focus on SCMs may lead to the neglect of
other potentially effective behaviour change interventions, such as increased taxation
or legislation, which may not or may not have their effects through the cognitions
specified by the SCMs (see Chapter 9).
In the health psychology area there has been one widely cited critique of SCMs
written by Ogden (2003) with a response by Ajzen and Fishbein (2004) (see also
Fishbein and Ajzen, 2010; Greve, 2001; Norman and Conner, 2015; Sniehotta,
Presseau and Araujo-Soares, 2014 and associated commentaries). Ogden’s (2003)
critique is based on a review of 47 empirical studies published in four main health
psychology journals over a four-year period and focuses on the HBM, PMT and
TRA/TPB. Ogden raised four issues: use in developing interventions, interpretation
of empirical testing, analytical versus synthetic truths and mere measurement. Ogden
first concluded that SCMs were useful to researchers and ‘to inform service
development and the development of health-related interventions to promote health
behaviors’ (2003: 425). However, she also made three key criticisms. First she argued
that SCMs cannot be empirically tested, that is, confirmed or disconfirmed. She
supported this point by pointing out that researchers do not conclude that they have
disconfirmed SCMs when they find that one or more of the theory’s constructs do
not predict the outcome measure or that the findings do not explain all or most of
the variance in intentions or behaviour. Ajzen and Fishbein (2004) highlight that the
logic of this argument is unsound. For example in the case of the TPB, numerous
descriptions of the theory make clear that the extent to which each of the cognitions
predicts intentions or behaviour is a function of the population and behaviour under
156 MOTIVATION AND BEHAVIOUR