Non-conscious processes and dual-process theories in health psychology

The rise of dual-process or dual-systems theories of behaviour in health psychology reflects a shift in attention from the predominant social cognitive approach in recognition of the pervasive effects that non-conscious and implicit factors have on health behaviour (Deutsch, Gawronski, & Hofmann, 2017; Sheeran, Gollwitzer, & Bargh, 2013). Dual-process theories purport that individuals’ behaviour is controlled by two processes or ‘systems’: a deliberative or reflective process which represents rational, deliberative, and conscious decision-making influences on action and an implicit or impulsive process which represents well-learned, spontaneous, and non-conscious influences (Khaneman, 2011; Hagger, 2017; Sherman, Gawronski, & Trope, 2014; Strack & Deutsch, 2004). The notion that individuals’ actions are, at least in part, determined by factors and processes that occur beyond an individual’s awareness is not new. Many theories of human behaviour have acknowledged these non-conscious influences. Behaviourism, for example, focuses exclusively on conditioning and the cues that lead to action and do not countenance any deliberation or cognitive input (Bargh & Ferguson, 2000). The rise of the cognitive approach with its information processing metaphor for action as a preeminent paradigm in psychology resulted in a concomitant shift towards the adoption social cognitive theories in to understand social behaviour, and it has come to be the dominant approach in many applied areas including health (Armitage, 2015; Biddle, Hagger, Chatzisarantis, & Lippke, 2007; Conner & Norman, 2015; Fishbein & Ajzen, 2009; Head & Noar, 2014). Nevertheless, within the social cognitive approaches, attitude theorists recognised the importance of non-conscious influences on behaviour, and that an exclusive focus on cognition and deliberation did not provide a comprehensive or realistic account for social behaviour (Aarts & Dijksterhuis, 2000; Bargh, Chaiken, Govender, & Pratto, 1992; Doll & Ajzen, 1992; Fazio, Sanbonmatsu, Powell, & Kardes, 1986). Furthermore, cognitive psychologists, particularly those conducting research and developing theory in the fields of priming, recognised the contribution of non-conscious processes to action and decisionmaking. Clear recognition of the control over mechanisms that occur beyond individuals’ awareness is illustrated in the characterisation of people as ‘cognitive misers’ (Bless & Schwarz, 1999; Petty & Cacioppo, 1986b). Automatic control over mundane actions is hypothesised to ‘free up’ cognitive space for high-priority, higher order action, and decision-making that is strategic and services survival goals, giving the development of non-conscious control over action an evolutionary function. It stands to reason, therefore, that social psychologists, whose theories are applied in health behaviour contexts with considerable regularity, developed models of behaviour that attempted to account for both conscious and non-conscious decision-making processes. Attitude theories such as the MODE (Fazio, 1990) and Elaboration Likelihood (Petty & Cacioppo, 1986a) models represent the first generation of such theories, and both outlined the potential for non-conscious attitudes and non-conscious pathways in determining behaviour alongside consciously mediated routes. A new generation of dual-process theories are currently the subject of great attention in the research literature (Bargh & Ferguson, 2000; Gibbons & Gerrard, 2016; Greenwald et al., 2002; Hofmann, Friese, & Wiers, 2011; Sherman et al., 2008; Smith & DeCoster, 2000; Strack & Deutsch, 2004). The theories have attempted to elaborate, in considerable detail, on both processes and to unify research in disciplines such as cognitive science and social neuroscience with theoretical premises from models of social cognition. The renewed interest in dual-process theories owes as much to a recognition that theories of social cognition alone are insufficient as accounts of human action