Objective: The goal of this project is to better understand the mechanisms of behavior change as they apply to smoking cessation. Such understanding requires a theory-based approach that accounts for smoking cessation and that offers direction for the development of effective interventions. Two hypotheses developed from the theory of self-control strength were tested. First, because high urge episodes are likely to utilize self-control resources, and because self-control resources need time to replenish, it was hypothesized that temptations during smoking cessation that follow high urge reports within a 4-hour time frame will be more likely to end in a lapse. And second, because frequent and prolonged resist episodes are likely to deplete self-control resources, it was also hypothesized that multiple and prolonged resist episodes will be associated with an increased risk of lapsing.
Design: A longitudinal repeated-measures design was used.
Population, Sample, Setting, Years: The target population for the study was smokers in the process of quitting. Two samples were studied: 63 smokers from the Kansas City area and 240 smokers from the Pittsburgh area. Average ages of the groups were 43 and 42 years respectively; 71% and 57% of the samples were female.
Concept or Variables Studied Together or Intervention and Outcome Variable(s): The theory of self-control strength is a new theory that posits that self-control is a limited and consumable resource much like the strength of a muscle (Muraven & Baumeister, 2000). According to this theory, self-control can be depleted and once it is depleted, time and rest are required to replenish it. Most of the support for the theory of self-control strength comes from laboratory studies. Studies typically involve asking subjects to engage in tasks that require self-control (such as solving unsolvable puzzles). Half of the subjects are randomly assigned to a group that must engage in a different self-control task (such as resisting eating chocolate candy) prior to the target self control task, while the other half engage in tasks that do not require self-control. These studies show that those who must engage in sequential self-control tasks do worse on the second task than subjects who do not engage in two consecutive self-control tasks. In other work with dieters, Heatherton and Vohs (1997) found that dieters who were presented with tempting food but did not eat it were more likely to break their diet subsequently than dieters who were not presented with tempting food. In the current study, the outcome variable was whether subjects resisted or lapsed during a tempting situation. Predictor variables indexed the amount of self-control required in preceding tempting situations within a 4-hour time frame. These variables included the urge levels, number, and duration of temptations occurring 4 hours prior to the target episodes.
Methods: Ecological momentary assessment defined as the use of monitoring strategies to assess phenomena at the moment they occur in natural settings was implemented in these studies by having participants carry palm-top computers with them during the first two to four weeks of their cessation attempt. Participants answered computer-administered questionnaires immediately after temptations that they resisted, lapses, and randomly prompted situations when they were not tempted to smoke.
Findings: Multi-level, random effects regression analyses for binary data were performed on the first data set regressing smoking status (resist or lapse) on urge level assessed within the preceding 4 hours (N=1029 pairs of assessments from 62 subjects). Results yielded support for the model. Temptation episodes occurring within 4 hours after high urge reports were more likely to end in lapses [predicted odds of lapse when prior urge=7 (75th %-ile) was 69% greater than when prior urge=2 (25th %-ile), p<.0001]. Analyses of the second data set (N=4040 pairs from 240 s's) replicated this finding (p<.0001). Tests of the second hypothesis are underway and will be available for the conference.
Conclusions: Although prior work by Shiffman and his colleagues has shown that morning urge levels predict the first lapses of a cessation attempt, this study is the first to show that urge levels of temptations predict first and later lapses in subsequent temptations. This finding is consistent with the model of self-control strength and one of the first tests of the model outside of the laboratory.
Implications: If other tests of hypotheses derived from the theory are supported, smoking cessation interventions should be aimed at helping quitters conserve their self-control resources. Related research indicates that self-control strength might be conserved by avoiding tempting situations, sleep, using coping strategies aimed at conserving self-control resources, and experiencing positive affect situations.
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