پیش بینی سرکوب اندیشه در بزرگسالان پیر و جوان: اثر نشخوار فکری، اضطراب و سایر متغیرها

The tendency to use thought suppression in everyday life as assessed by the White Bear Suppression Inventory (WBSI) has been related to several psychopathological and personality factors. However, previous research has primarily investigated a limited set of psychopathological factors and their relation to the use of thought suppression in younger adults only. Virtually nothing is known about the relation between thought suppression and psychopathology in older adults. The present study examined a wide variety of variables that have been theoretically and empirically linked to thought suppression and used regression models to predict the tendency to suppress thoughts in everyday life, in both younger (mean age 20) and older (mean age 73) adult samples. Results demonstrated that in both samples, the use of thought suppression was best predicted by rumination and trait anxiety. In addition, young participants had significantly higher WBSI scores than older adults but this age difference disappeared when controlling for low levels of anxiety and rumination in older adults.

Most people have at times experienced disturbing or potentially distressing thoughts. One popular method by which people attempt to control these (and other) thoughts is by trying to suppress them (Wegner, 1994). However, there is ample evidence showing that thought suppression can be counter productive and produce paradoxical effects. Wegner, Schneider, Carter, and White (1987) were the first to demonstrate experimentally that prior thought suppression can lead to later preoccupation with the very same thought – a phenomenon they called the “rebound effect”. Despite numerous demonstrations of the rebound effect in the laboratory (Wenzlaff & Wegner, 2000), thought suppression continues to be used in everyday life by many people. For example, in an informal survey conducted by Erdelyi and Goldberg (1978), 99% of college students reported having tried to exclude disturbing thoughts from consciousness in an effort to avoid the associated discomfort. One widely used index of the tendency to use thought suppression in everyday life is the White Bear Suppression Inventory (WBSI) developed by Wegner and Zanakos (1994). This 15-item questionnaire had a test–retest reliability of .69 over a 3-month period leading Wegner and Zanakos (1994) to suggest that the scale measures a stable, trait-like individual difference in one’s propensity to use thought suppression. Muris, Merckelbach, and Horselenberg (1996) also examined the test–retest reliability of the WBSI and found it to be .80 over a 12-week period. Furthermore, both of these studies reported a one-factor solution when the WBSI was factor analysed (but see Blumberg, 2000, and Rassin, 2003, who report three- and two-factor solutions, respectively). An important theoretical question concerns the consequences of one’s tendency to use thought suppression. The results of several correlational studies suggest that a disposition to suppress thoughts in everyday life is linked to various forms of psychopathology. For example, several studies have shown that the WBSI correlates positively and significantly with depression and trait anxiety in both undergraduate and clinical samples (Muris et al., 1996, Spinhoven and Van der Does, 1999 and Wegner and Zanakos, 1994). Wegner and his colleagues (Erber and Wegner, 1996, Wegner, 1994 and Wegner and Zanakos, 1994) have repeatedly suggested that thought suppression itself leads to greater levels of psychopathology (see also Purdon, 1999). In contrast, other researchers have argued that pre-existing psychopathological tendencies cause one to begin to use thought suppression to avoid discomfort. For example, according to Martin and Tesser (1996) it is rumination and other linked psychopathologies that “cause” one to use thought suppression. Rumination has been defined as a type of conscious thought which revolves around one theme and is recurrent, often for extended periods of time (Martin & Tesser, 1996). Martin and Tesser suggest that rumination occurs due to a person not being able to approach or achieve goals that they have set for themselves. Under this formulation thought suppression is viewed as a consequence of rumination due to the fact that rumination can often be aversive and interfere with other tasks. As a result, thought suppression is instigated in an effort to prevent further ruminations. However, Erber and Wegner (1996) argue that rumination is a result of prior thought suppression and that the rebound effect itself may be viewed as a form of rumination. Therefore, to date, rumination has been theoretically linked with thought suppression but, to our knowledge, this link has not been tested empirically (Erber and Wegner, 1996 and Martin and Tesser, 1996). On the other hand, Rassin and colleagues (Rassin et al., 2001 and Rassin et al., 2000) have suggested that Thought Action Fusion may be an antecedent of thought suppression. Thought Action Fusion (TAF) refers to a cognitive bias whereby a person has an inflated sense of responsibility for their thoughts believing that thinking of certain acts (e.g. killing an obnoxious neighbour) is as bad as actually engaging in that act. It is therefore likely that high scorers on TAF would be inclined to avoid these disturbing cognitions by trying to suppress them. TAF is included here as one of the possible correlates of the use of thought suppression. Of particular relevance to the current study is the TAF-moral subscale that assesses how much a person views thinking of bad thoughts as being as bad as actually engaging in those behaviours (Berle & Starcevic, 2005). One further variable that we wanted to investigate is participants’ age. All previous studies have relied on young undergraduate or clinical samples. As a result, virtually nothing is known about the use of thought suppression in older adults. With respect to age, older adults may be more likely to use thought suppression as a result of health worries, the actual loss of friends and family members, and/or worries about declining cognitive functioning (cf. Teachman, 2006). However, thought suppression has been demonstrated to have negative effects on health and the immune system in young adults. For example, Petrie, Booth, and Pennebaker (1998) found that thought suppression, using both emotional and neutral thoughts, produced reductions in circulating T lymphocytes and T suppressor cells. In light of these findings, older adults may be particularly vulnerable to adverse effects of thought suppression due to their poor general health and weaker immune systems. Evidence also exists to suggest that older adults may be less able at cognitive tasks involving inhibition (Hasher & Zacks, 1988). If this is the case, it may be that older adults need to try harder to suppress their thoughts or to suppress repeatedly due to the failure of earlier suppression attempts. In summary, the current study was designed to examine the tendency to suppress thoughts in everyday life, as assessed by the White Bear Suppression Inventory, and its correlates in a sample of 84 young adults and 65 older healthy community dwelling adults. It was expected that the tendency to use thought suppression would correlate with a wide range of psychopathological variables such as trait anxiety, depression, neuroticism, rumination, and TAF in both younger and older adults. However, the present study wanted to refine the analysis of the associations between thought suppression and psychopathology by predicting the use of thought suppression from its significant correlates. Therefore, the tendency to use thought suppression as assessed by the WBSI was the main outcome variable of interest. It was hypothesised that when entered into regression models, rumination (in view of its strong theoretical links with thought suppression) would be the main significant predictor of the use of thought suppression in both young and older adults, and that rumination would remain a significant predictor when controlled for other measures of psychopathology.