Whereas goal intentions specify what one wants to do or achieve (i.e., "I intend to achieve X!"), implementation intentions specify the behavior that one will perform in the service of goal attainment and the situational context in which one will enact it, in the format of an if-then plan (i.e., "If situation Y occurs, then I will initiate goal-directed response Z!"). Implementation intentions are subordinate to goal intentions because, whereas a goal intention specifies what one will do, an implementation intention only spells out the when, where, and how of what one will do.
Forming Implementation Intentions
Identifying response and critical cues. To form an implementation intention, the person must first identify a response that is instrumental for goal attainment and, second, anticipate a critical cue to initiate that response. For example, the person might specify the behavior "perform breast self-examination" and specify a situational cue "just before I leave the shower tomorrow morning" in order to enact the goal intention of detecting possible breast cancer. Implementation intention formation is the mental act of linking an anticipated critical situation with an effective goal-directed response. An association is formed between mental representations of specified cues (opportune or critical situations) and means of attaining goals (cognitive or behavioral responses) in an act of will.
Heightening accessibility of cues. The mental links created by implementation intentions facilitate goal attainment on the basis of psychological processes that relate to both the anticipated situation (the if-part of the plan) and the intended behavior (the then-part of the plan). Because forming an implementation intention implies the selection of a critical future situation, the mental representation of this situation becomes highly activated, and hence more accessible (Gollwitzer, 1999). This heightened accessibility of the if-part of the plan was demonstrated in several studies (e.g., Aarts, Dijksterhuis, & Midden, 1999; Parks-Stamm, Gollwitzer, & Oettingen, 2007; Webb & Sheeran, in press, 2007) and means that people are in a good position to identify and take notice of the critical cue when they subsequently encounter it (e.g., Webb & Sheeran, 2004). For instance, participants who formed implementation intentions to collect a coupon were faster to recognize words related to location of the coupon (e.g., corridor, red door) compared to participants who only formed the goal intentions to collect the coupon; and implementation intention participants also were more likely to collect the coupon subsequently.
Strategic automaticity of response. Studies also indicate that implementation intention formation forges a strong association between the specified opportunity and the specified response (Webb & Sheeran, in press, 2007). The upshot of these strong links is that the initiation of the goal-directed response specified in the if-then plan becomes automated, that is, exhibits features of automaticity including immediacy, efficiency, and redundancy of conscious intent (Bargh, 1994). The idea is that people do not have to deliberate anymore about when and how they should act when they have formed an implementation intention—unlike people who have formed mere goal intentions. Evidence that if-then planners act quickly (Gollwitzer & Brandstätter, 1997, Experiment 3), deal effectively with cognitive demands (Brandstätter, Lengfelder, & Gollwitzer, 2001), and do not need to consciously intend to act at the critical moment (Sheeran, Webb, & Gollwitzer, 2005, Study 2) is consistent with this idea.
These component processes of implementation intentions (enhanced cue accessibility, automatization of responding) mean that if-then planners are in a good position both to see and to seize good opportunities to move towards their goals. Fashioning an if-then plan strategically automates goal striving (Gollwitzer & Schaal, 1998) because people delegate control of goal-directed behaviors to pre-selected situational cues with the express purpose of reaching their goals—automatic action initiation originates in an act of will (if-then planning). But does the strategic automaticity in implementation intentions enable people to deal effectively with self-regulatory problems in goal striving (failing to get started, getting derailed) and increase rates of goal attainment? Findings from a recent meta-analysis (Gollwitzer & Sheeran, 2006) suggest that this is the case.
Self-regulatory Problems Related to Getting Started
Gollwitzer & Sheeran (2006) found that implementation intention formation had a medium-to-large effect on alleviating failures to get started with goal striving (d = .61). That is, if-then planning substantially increased the likelihood of initiating action compared to merely forming respective goal intentions, and this was the case for each of the three specific self-regulatory problems of getting started: remembering to act (e.g., taking vitamin pills; Sheeran & Orbell, 1999), missing opportunities (obtaining a mammography; Rutter, Steadman, & Quine, 2006), and overcoming initial reluctance (e.g., undertaking a testicular self-examination; Sheeran, Milne, Webb, & Gollwitzer, 2005). Implementation intention formation had an effect of similar magnitude on preventing derailment of goal striving (d = .77). Overall, forming implementation intentions had a medium-to-large effect on rates of goal attainment across the 94 studies included in the review (d = .65). Thus, if-then plans make an important difference to whether or not people translate their goal intentions into action.