Craving: Approaching Avoidance : Part 5

by National Institute of Health

(Page 5 of 7)

Astin proposed that the mechanism underlying this observed pattern of resolution in favor of approach was related to the timing and nature of the consequences associated with drinking. Positively reinforcing consequences of alcohol use (the euphoria of intoxication or relief from stress) tend to occur soon after consumption, whereas adverse consequences (hangover or punishment for failure to fulfill responsibilities) tend to occur later in time. Similarly, Heilizer proposed that the strengthening of approach inclinations could be attributed to the increasing salience of prospective alcohol reinforcers, relative to punishers, as one gets closer to the goal. Approach stimuli become more prevalent and gain intensity, whereas stimuli related to alcohol avoidance (punishment cues) tend to remain constant. Heilizer argued that these responses occur because approach cues are likely to involve explicit characteristics of the alcoholdrinking context and its immediate consequences. In contrast, avoidance cues are liable to be more remote and/or abstract (cognitive representations of future negative consequences) in their associations. Although neither of these theorists - Astin nor Heilizer - actually tested their hypotheses, their work has obvious relevance to the study of reactivity to alcohol cues. Moreover, data accumulated in connection with modern behavioral theories of choice as applied to drinking tend to support at least Astin's assertion regarding the importance of temporal factors.

Heather's proposal of a threelevel conceptual framework for addiction also involves both approach and avoidance components. He regards ambivalence, expressed behaviorally as repeated failures to refrain from substance use despite intentions to do so, as the basis of the definition of addiction. Briefly stated, the three components of Heather's framework are as follows: persistent desire to use the substance because of its rewarding consequences, neuroadaptation to a substance resulting from repeated use, and a pattern involving the apparent inability of addicts to curtail their indulgence despite trying to do so. The ambivalence central to Heather's framework represents conflict attributable to interplay between the neuroadaptations from repeated use and the person's history of consequences from use.

Beyond stressing the importance of the role of ambivalence and possible neural substrates involved in it, what is of particular relevance to the multidimensional framework of reactivity to alcohol cues and decisions about drinking is Heather's speculation about the cognitive-behavioral mechanisms underlying the development of conflict. Drawing from Ainslie's theory of impulsive behavior, Heather observed that when faced with a choice between "early small" and "late large" rewards, addicts repeatedly fail to implement normal cognitive compensation for their "irrational preferences." In other words, addicts appear to have difficulty basing their decisionmaking on anticipation of future outcomes, an ability that ordinarily enables humans to adjust their current behavior in order to obtain larger rewards (or avoid punishment) later.

Although the reasons for this failure are not specified, a basis for speculation does exist. For example, impaired decisionmaking may occur because the level of immediate reinforcement available provokes the brain to adapt to repeated exposures to the psychoactive substances, and the operation of neural systems underlying the inclinations of addicts ultimately begins to deviate from that evident in nonaddicts. In this connection, Heather notes that his perspective is compatible with the neuroadaptation theory of Robinson and Berridge discussed earlier. Moreover, an explanation for the development of a "desire to curtail indulgence," so central to Heather's conflict perspective, can be derived from consideration of associations linking drug cues to addicts' discomfort with their compulsion and other punishing consequences of repeated use.

Regarding these insights, the use of restraint when faced with the proximal temptations associated with indulgence requires the processing of information about consequences that are often distal and perhaps more abstract as well. Thus, the decision to not drink may be more cognitively demanding than the decision to drink, therefore rendering restraint the relatively more difficult path to follow.

In sum, craving may be best conceptualized within a broader, multidimensional perspective that incorporates the relative influence of an inclination to not drink. This involves a framework in which competing motives are evaluated. The evaluative space indicated in the figure on page 198 depicts this framework, which is described by four quadrants. Craving, in its classic form as intense and unrestrained "wanting" is synonymous with the approach quadrant, whereas strong inclination to not drink, in the absence of any significant inclination to indulge, is represented by the avoidance quadrant. If both response inclinations are balanced but at a low level of intensity, a person is characterized by indifference about drinking alcohol, whereas if both inclinations are balanced and at a high level of intensity, a person struggles with ambivalence about choices to drink or not drink.

Evidence for a Multidimensional, Ambivalence Model

A small but growing number of empirical findings support the view that an investigation of a multidimensional or ambivalence model of choices about drinking may be an important step toward better understanding the relationship between craving and substance use. Greeley and colleagues explicitly acknowledged the potential of alcoholrelated cues to elicit avoidance inclination. They used a bidirectional "craving scale" to measure alcoholics' and social drinkers' subjective reactions to alcohol cues relative to neutral cues. At one extreme of this scale was "definitely do not want a drink of alcohol," whereas at the other end of the scale was "an extreme desire for a drink of alcohol." Unfortunately, because the researchers attempted to assess approach and avoidance by means of a single scale, participants were required to collapse the two inclinations and arrive at a "sum." The authors acknowledged that this summation process obscured measurement of the true level of ambivalence that participants may have experienced. Consequently, the authors called for future studies to measure approach and avoidance inclinations independently.

About the Author

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