«Good intentions, bad habits, and eects of forming implementation intentions on healthy eating BAS VERPLANKEN1* and SUZANNE FAES2 1 University of ...»
European Journal of Social Psychology
Eur. J. Soc. Psychol. 29, 591±604 (1999)
Good intentions, bad habits, and eects
of forming implementation intentions
on healthy eating
BAS VERPLANKEN1* and SUZANNE FAES2
University of Tromsù, Norway
University of Nijmegen, The Netherlands
A ®eld experiment demonstrated that forming implementation intentions was eective in
changing complex everyday behavior, in this case establishing a healthier diet. Imple-
mentation intentions concerned a speci®c plan for when and how to act. The eect of implementation intentions was additive to the prediction of healthy eating by behavioral intentions to eat healthily. Implementation intentions were pitted against individual dierences in counterintentional (unhealthy) habits. The eects of implementation intentions and counterintentional habits were independent, suggesting that implementa- tion intentions did not break the negative in¯uence of unhealthy habits, and yet managed to make those with unhealthy habits eat healthier in habit-unrelated respects.
Copyright # 1999 John Wiley & Sons, Ltd.
INTRODUCTIONThe will is a powerful asset of the human mind, which enables us to reach goals and ful®l desires. Behavioral intentions represent our strivings to achieve a goal or desire.
It is not surprising then that behavioral intentions have been considered as a direct predictor of goal-directed behavior, such as is postulated in the theory of reasoned action (Ajzen & Fishbein, 1980), and the theory of planned behavior (Ajzen, 1985, 1991). The predictive value of behavioral intentions has been demonstrated in several meta-analyses and literature reviews (e.g. Ajzen, 1991; Armitage & Conner, unpublished manuscript; Godin & Kok, 1996; Sheppard, Hartwick & Warshaw, 1988; van den Putte, unpublished dissertation, University of Amsterdam). The implicit assumption underlying this model is that the likelihood of enacting a behavioral intention is a linear function of the extent to which we hold a behavioral *Correspondence to: Dr Bas Verplanken, Department of Psychology, University of Tromsù, N-9037 Tromsù, Norway. e-mail: email@example.com CCC 0046±2772/99/050591±14$17.50 Received 8 October 1997 Copyright # 1999 John Wiley & Sons, Ltd. Accepted 3 June 1998 592 B. Verplanken and S. Faes intention. Yet we all know that we don't always enact our intentions, despite the fact that an intention may be strongly held: we may postpone the onset of behaviors that are needed to achieve an intended goal, we may be distracted by other activities, or we maysimply forget an intention. Instead of enacting our intentions, we may ®nd ourselves guided by old habits that we may have wished to overcome.
Several perspectives may provide more insight in the relationship between intentions and behavior. First, there may be other variables than intentions that relate to behavior. These may be direct predictors of behavior in addition to behavioral intentions. For instance, the theory of planned behavior postulates perceived behavioral control as a potential additional predictor of behavior. Some variables have been identi®ed as moderators in the relationship of behavioral intentions and behavior, for instance the degree to which intentions are well considered (e.g. Bagozzi & Yi, 1989; Davidson, Yantis, Norwood & Montano, 1985), or the extent to which competing behavioral choice options are considered (Pieters & Verplanken, 1995). In the present study we looked at habits, and in particular habits that go against one's intentions, which we will denote as counterintentional habits, as an additional predictor of behavior.
A second perspective is to look at mechanisms that may operate in the intention± behavior relationship. Once we have an intention to achieve something, selfregulation mechanisms may be involved in the process of actual goal achievement (cf.
Scheier & Carver, 1988). Bagozzi and Warshaw (1990), for instance, postulated the process of trying as an intervening process. In the present study we focused on eects of planning, and in particular on eects of forming implementation intentions (Gollwitzer, 1993, 1996; Gollwitzer & Brandstatter, 1997; Gollwitzer & Schaal, 1998) È as an example of such a self-regulation mechanism, which is part of the model of action phases (Gollwitzer, 1990, 1996; Heckhausen & Gollwitzer, 1987). As we will argue, habits and implementation intentions have much in common, and in the case of counterintentional habits, these may act as direct competitors of implementation intentions. The joint impact of implementation intentions and counterintentional habits was studied concerning healthy eating as behavior of interest. Before turning to our hypotheses, we ®rst elaborate on the concepts of implementation intention and counterintentional habit, respectively.
In the model of action phases a distinction in the process of goal achievement is made between principles that are related to setting and committing to a goal from those that relate to the execution of actions that lead to goal achievement. In the ®rst phase a particular goal is selected on the basis of preferences, which are guided by perceptions of feasibility and desirability. Competing goals are considered, and chances of successful goal ful®llment are judged. In this phase an open orientation is needed (a `deliberative mind-set', see e.g. Gollwitzer, Heckhausen & Steller, 1990), which, for instance, promotes the comparison of utilities, attention to alternative options, and relatively objective information processing. The result of this phase is the formation of a goal intention, which is very similar to the concept of behavioral intention. A necessary condition for further actions toward actual goal achievement is Copyright # 1999 John Wiley & Sons, Ltd. Eur. J. Soc. Psychol. 29, 591±604 (1999) Implementation intentions and habits 593 a certain degree of commitment to achieve the goal. Given a goal intention and a sucient level of goal commitment, actions that should lead to goal ful®llment may be undertaken. Rather than a deliberative mind-set, an `implemental mind-set' is helpful in this phase, i.e. a cognitive orientation focused on the execution of the appropriate actions on the right time and the right place. This orientation promotes, for instance, the processing of information that directly relates to goal-directed actions, and makes the person pay less attention to distracting information. If a person is fully experienced in executing the necessary acts, situational cues will automatically draw the individual's attention and elicit the appropriate responses that lead to goal ful®llment. However, when there is no routine that guides goal ful®llment, the forming of implementation intentions may do so (Gollwitzer, 1993, 1996).
Implementation intentions are concrete plans of action that specify when, where, and which actions should be taken to achieve an intended goal. In other words, implementation intentions link speci®c behavioral responses to speci®c cues within a speci®ed time and spatial frame. Implementation intentions thus take the form `I intend to do X when I encounter situation Y'. For instance, once I feel committed to adopt a healthier diet, I would help to achieve this by intending to buy lots of vegetables next time I am in the supermarket, or by taking an apple instead of chocolate when I feel hungry. Implementation intentions thus install contingencies between situational cues and goal-ful®lling responses. Once such contingencies are present, actions that lead to goal ful®llment have gained a degree of automaticity by being under the control of relevant situational cues (Bargh & Gollwitzer, 1994;
Gollwitzer, 1993, 1996).
Empirical evidence builds up that demonstrates the power of forming implementation in the process of turning a goal intention into actions to achieve that goal (e.g. Gollwitzer & Brandstatter, 1997; Orbell, Hodgkins & Sheeran, 1997; Orbell & È Sheeran, unpublished manuscript; Sheeran & Orbell, unpublished manuscript). For instance, in one study Gollwitzer and Brandstatter (1997) asked participants to write È a report on how they spent their Christmas holidays, and return it within a speci®ed period. Half of the participants were instructed to form implementation intentions, i.e. they were asked to think and specify when and where they intended to write their report, whereas the other half of the participants did not receive these instructions.
The proportions of participants who returned their report within the critical time period was higher among those who had formed implementation intentions than among control participants, which was a substantial eect in terms of eect size (r 0.39). The bene®cial eects of implementation intentions seem to be quite persistent in time. For instance, Orbell et al. (1997) demonstrated that behavioral intentions to perform breast self-examination that had been supplemented by implementation intentions (i.e. where and when to perform it) were more likely to be enacted when measured one month later than intentions without implementation plans. In addition, they also showed that the predictive power of previous behavior disappeared when implementation intentions were formed.
Implementation intentions state when, where, and which behavior should be executed in order to achieve a goal (Gollwitzer, 1993). Most studies that have been reported to date, however, have focused on implementation intentions in terms of when and where goal-directed action should be taken. The target behaviors in these studies were relatively simple. Therefore, the how of the intended actions was always unequivocal, and, unlike the when and where question, was not necessary to be Copyright # 1999 John Wiley & Sons, Ltd. Eur. J. Soc. Psychol. 29, 591±604 (1999) 594 B. Verplanken and S. Faes incorporated explicitly in implementation intentions otherwise than already had been de®ned by the goal intention. However, many goals may be achieved through a variety of dierent actions, or may only be achieved through relatively complex patterns of behavior. For instance, adopting a healthier diet can be achieved in many ways, and demands many dierent acts (e.g. concerning shopping, eating schedules, cooking, and so on), rather than executing a single act. We would argue that in such contexts implementation intentions that specify how to act are particularly helpful in goal achievement, in addition to implementation intentions that specify when and where to act. In the present study participants who formed implementation intentions thus speci®ed which actions they would take (i.e. the exact composition of their menu) on speci®c points in time. We expected that participants who formed implementation intentions would eat healthier compared to a no-implementation intentions control group.
When behavior is suciently and satisfactorily repeated, a habit may develop. Habits can be considered as automatic acts in the sense that these are operating outside our awareness and are cognitively ecient (cf. Bargh, 1994). Furthermore, habits are functional in obtaining certain goals or end states (see for a more extensive discussion, Verplanken & Aarts, 1999). Habits thus are speci®c behavioral responses to speci®c cues in the environment. Note that this formulation very much resembles the description of the mechanism of implementation intentions. Both implementation intentions and habits involve automatic cue±response links, and in both cases behavior is thus under the control of the environment in which the behavior takes place. Like implementation intentions, habits go along with a convergent cognitive orientation, which focuses attention on one behavioral option (Aarts, Verplanken & van Knippenberg, 1997; Verplanken, Aarts & van Knippenberg, 1997), and thus increases the likelihood of acting at speci®ed times and places. While such a cognitive orientation is referred to as an implemental mind-set in the case of implementation intentions, in the case of habits we might think of a habitual mind-set with very much the same properties as an implemental mind-set. The dierence between habits and implementation intentions, of course, is that implementation intentions are formed by deliberate planning, whereas habits form through (satisfactory) repetition of behavior (Gollwitzer & Brandstatter, 1997; Orbell et al., 1997; Verplanken & È Aarts, 1999).
Habits may develop that are perfectly in line with once-formed attitudes and intentions concerning a behavior (cf. Ouellette & Wood, 1998). Habits may also become the main driving force of behavior, while attitudes and intentions become unrelated to behavior (e.g. Verplanken, Aarts, van Knippenberg & Moonen, 1998;