Mental contrasting as a behaviour change technique: a systematic review protocol paper of effects, mediators and moderators on health

Goal setting interventions, such as mental contrasting and implementation intentions, have become increasingly popular in promoting health behaviour change [1, 3‐5]. Mental contrasting involves guiding an individual to translate positive attitudes and high self-efficacy into strong goal commitment. This intervention can help guide goal pursuit behaviours, and is hypothesised to be most effective when goal attainment is challenging [3, 5]. Mental contrasting is theoretically based on the principles of fantasy realisation theory [1] (FRT). FRT posits that goal commitment is required for goal attainment, particularly when those goals are perceived as difficult to achieve [5], although this has received little empirical support. It is hypothesised that an individual’s goal commitment is founded on their high expectations of success and high incentive value held towards the goal [6], but it is possible that behaviour change could occur even when the individual’s expectation of success is not high (particularly so in the case of the difficulty of achieving long-term weight loss), but the incentive value is high.

Evidence of the effectiveness of mental contrasting as a behaviour change technique for improving motivation and performance is growing [3‐11]. Studies have assessed goal pursuit using various indicators including cognitive (e.g. making plans), affective (e.g. feelings of anticipated disappointment in case of failure), motivational (e.g. feelings of determination), physiological (e.g. energization assessed by cardiovascular measures), and behavioural (e.g. number of initiated actions) measures. Effects have been observed regardless of whether these indicators were self-reported or observed, whether they were assessed immediately after the mental exercise or weeks later, and whether mental contrasting was experimentally induced or self-generated [12‐15].

There is emerging psychophysiological evidence that mental contrasting operates by energising individuals thus providing the resources for behaviour change. This energization has been studied through changes in systolic blood pressure [15, 16]; when perceived expectation of chances of success were high, mental contrasting increased systolic blood pressure (SBP), whereas when they were low, mental contrasting decreased SBP. Moreover, changes in energization have been suggested as a mediator for the relationship between expectations and goal pursuit [17]. It is hypothesised that mentally indulging on a desired goal without performing mental contrasting uses too much energy and is then detrimental to achieving the individual’s desired behaviour change. Mental contrasting is hypothesised to mobilise sufficient energy resources to cope with obstacles in order to attain goals and facilitate goal pursuit. Importantly, mental contrasting conserves energy resources and reduces the probability of depletion and exhaustion thus permitting behavioural flexibility in responding to urgent environmental demands and accomplishing behaviour change goals [16].

In order to address this challenge and to understand the most effective active ingredients of interventions, the behaviour change taxonomy [2] aims to create a shared language. Thus, the BCT taxonomy facilitates the design and evaluation of effective interventions and is used to synthesise evidence about the effectiveness of mechanisms underlying behaviour change. Version one of the taxonomy specified 93 hierarchically clustered behaviour change techniques (BCTs). Mental contrasting most strongly relates to the goals and planning hierarchical cluster, which specifically includes the BCTs 1.1. Goal Setting (behaviour), 1.2 Problem Solving and 1.3 Goal Setting (outcome). This accords with the theory of planned behaviour study findings [18] that goal setting and forming intentions to change behaviour alone do not necessarily result in behaviour change. Mental contrasting may bridge this intention-behaviour gap (TPB) by requiring an individual to imagine a desired future or health goal, and to then contrast their goal with the reality preceding the goal state. This reflection on goals and intention requires the individual to identify potential obstacles and to form plans that increase the chances of the behaviour being performed [1].

In summary, mental contrasting shows promise as a BCT for improving health-related behaviours due to its ability to raise goal commitment and performance when perceived expectations of success are high, rather than allowing the individual to indulge and dwell [1, 7‐9, 11]. Accordingly, mental contrasting is proposed as a self-regulation strategy that translates expectancy into behaviour.

This is the first review to systematically identify and evaluate the effectiveness mental contrasting as a behaviour change technique for improving physical health-related behaviours and outcomes. The aims of this systematic review are to answer the following questions:

The results from all literature searches will be imported into the Endnote reference management software, with duplicates removed by the main reviewer.

One reviewer will screen all retrieved records by title and abstract for all inclusion and exclusion criteria. A second reviewer will also screen a random 20% of the total titles and abstracts. Any disagreements at this stage will be included for further assessment. Following initial screening, full-text versions of all potentially relevant studies will be retrieved and reviewed independently for suitability (using the inclusion and exclusion criteria to guide study selection choice) by two reviewers. Study authors will be contacted where necessary if relevant information on eligibility is missing. Reasons for inclusion and exclusion will be recorded, and a group discussion will resolve any discrepancies following a blind review by a third researcher.

Two independent reviewers (AC and DS) will complete a data extraction (using PRISMA and QUOROM guidelines) form for each selected study and will be assessed for bias against the Cochrane tool for bias. The reviewers will independently extract data from included studies into Excel using the data extraction form. Any disagreements will be resolved by discussion with a third researcher and/or by seeking further clarification from study authors.

This systematic review will provide a detailed overview of the existing evidence base for mental contrasting interventions that have been designed to improve health outcomes and health-related behaviour. It will also consider the effectiveness of the self-regulation strategy of mental contrasting as a behaviour change technique. Furthermore, examining the use of behaviour change techniques within mental contrasting interventions may provide clarity on the effective components of mental contrasting interventions. This will afford recommendations to be made about whether mental contrasting is effective as a stand-alone intervention, or whether the addition of other behaviour change techniques (such as those in implementation intentions) result to more improvement in health outcomes and health behaviours. Examining mediators may enable inferences about probable mechanisms of action to be made. Possible moderators may allow determination of those who are most likely to benefit from mental contrasting.

Our interpretation of the review studies will take into account limitations in review studies that have identified by the authors, along with any limitations identified by our review methodology. In conclusion, this is the first review to systematically identify and evaluate the effectiveness mental contrasting as a technique to change health behaviour.