سودمندی پارادایم سرکوب افکار در توضیح تکانشگری و پرخاشگری

This study investigated (1) the usefulness of the thought suppression paradigm in understanding impulsivity and aggression and (2) the relation between intrusions, suppression and other control strategies on the one hand, and psychopathology on the other. Ninety undergraduate students filled in the White Bear Suppression Inventory (WBSI), the Thought Control Questionnaire (TCQ), the Minnesota Multiphasic Personality Inventory-2 (MMPI-2), five traits from the Eysenck Personality Profiler (EPP), and the Barratt Impulsivity Scale (BIS). No relationship between intrusion and suppression, and impulsivity was found. However, significant correlations between intrusion and aggression were found. Intrusion, suppression, self-punishment, and psychopathology were all correlated positively. Implications of these findings for the dynamics between intrusion, thought control, and aggression are discussed.

The young Tolstoy, or so the story goes, was standing in the corner of a room, after his brother had challenged him to stand there until he could stop thinking of white bears (Wegner, 1989). This left him standing there, puzzled, for a considerable amount of time. From this we may conclude that we do not seem to have much control over our minds, especially when it comes to controlling thoughts that are unwanted. The experience of unwanted, so-called intrusive thoughts is a phenomenon found in both clinical and normal populations (e.g. Rachman & De Silva, 1978; Wells & Morrison, 1994). Over 80% of the individuals in the general population experience intrusions. ‘Normal’ intrusions include thinking of cigarettes when one just quit smoking, the death of a loved one, an upcoming medical appointment, and so on. Examples of pathological intrusions are obsessions, addictions, and thought patterns characteristic of depression and panic-states (see Wegner, 1989). Pathological intrusive thoughts have been described as being more frequent, more intense, longer lasting, to produce more discomfort and to invoke more resistance (Rachman & De Silva, 1978; Salkovskis & Harrison, 1984). What causes the transformation of normal unwanted thoughts into pathological ones? Wegner (1989) argued that trying not to think about an unwanted thought, that is thought suppression, is exactly the mechanism underlying the thought becoming more intrusive (also, for a competing psycho-biological model on the transformation of normal into pathological intrusions involving serotonine, see Katz, 1991). Wegner, Schneider, Carter, and White’s (1987) ‘white-bear’ experiment sought to investigate this hypothesis. In this experiment, participants in the initial suppression condition were instructed to suppress thoughts of white bears for 5 min and express these thoughts in a second period of 5 min. For participants in the initial expression condition, this order was reversed. All participants were unable to suppress thoughts of white bears when instructed to do so, which was indicated by a mean frequency of almost seven white bear thoughts during the suppression period. Moreover, white bear thoughts were more frequent after initial suppression instructions compared to initial expression instructions. This effect was named the rebound effect: an increase in thoughts (about a white bear) after first having suppressed this thought (Wegner et al., 1987). This research became known as the thought suppression paradigm and was originally proposed as an explanatory model of the persistent nature of obsessions found in Obsessive-Compulsive Disorder (OCD; American Psychiatric Association, 1994). Hence, most contemporary experimental psychologists know the thought suppression paradigm as a model of intrusions in OCD. Since then, research on intrusive thoughts has expanded and has involved many different independent variables, included some clinical samples, has included variables such as emotional valence and personal relevance of the target thought and so on (for a meta-analysis, see Abramowitz, Tolin, & Street, 2001). However, intrusions and thought suppression may be even broader concepts than already anticipated and may be worth investigating further. For instance, Abramowitz et al. (2001) suggest that individual differences in psychopathology, which was not included in their meta-analysis, might be a factor contributing significantly to suppression effects. Also, intrusive thoughts may have legal consequences: when intrusive thoughts become violent in nature, these thoughts might lead to aggression and dangerous situations. Thinking about smoking a cigarette can be harmful to one’s health, however, repeatedly thinking about killing your neighbour is an intrusive thought of a completely different level. One might think that violent intrusive thoughts or intrusive thoughts leading to violence would have been given much attention in psychological research. However, this is not the case. A literature search (using PsycInfo) into violence and intrusive thoughts led to a very small body of literature. The literature that was found mostly dealt with intrusive thoughts as a symptom of the victim’s trauma, not with intrusions as characteristics of the offender (e.g. McDevitt, Balboni, Garcia, & Gu, 2001; Mitchell & Hogg, 1997). In one relevant study ( Grisso, Davis, Vesselinov, Appelbaum, & Monahan, 2000) violent thoughts were significantly related to violent acts and to measures of psychopathy, anger, and impulsiveness; problems that form major threats to society and often lead to aggressive and criminal behaviour. Transferring insights from the thought suppression paradigm, one would expect suppression of (violent) intrusive thoughts to lead to an increase in the frequency of these thoughts, followed by a strengthening of and possibly compliance with the intrusion. Indeed, results from Grisso et al. (2000) suggest that violent behaviour as a response to violent intrusions could be seen as impulsive violence which is defined as violence as the result of lack of inhibition. A social-cognitive model of aggression by Grisso et al., 2000 and Huesmann, 1998 offers a theoretical model for a connection between imagined violence and violent behaviour. In this model, assumptions from social information processing theories are used to explain violent behaviour following imagination. Frequently imagined violence is considered as an elaborate rehearsal that reinforces cognitive schemata or memories through which a person evaluates social situations. Each individual creates schemata based on personal experience, which serves two goals: (1) to attribute meaning to events and (2) to guide the choice of an appropriate response. Repetitive violent thoughts are hypothesized to activate aggressive schemata, which makes them more readily available, thus increasing the likelihood of reactivating aggressive scripts in later situations. Huesmann’s model shows some similarities with the “ironic process” theory proposed by Wegner and Erber (1992). In both models the hyper-accessibility of intrusive thoughts is a central feature, although they differ in the process underlying this hyper-accessibility. In conducting our study we returned to the original paradigm by Wegner, investigating emotionally neutral thoughts. The rationale behind this is twofold. First, in Abramowitz et al.’s meta-analysis (2001) covering 28 studies into paradoxical effects of thought suppression, no differences in effect size––for neither an initial enhancement effect nor a rebound effect––for neither personal relevance nor valence of the target thought were found. Thus, participants did not differ in suppression attempts of emotionally neutral versus emotionally negative thoughts nor in suppression attempts for thoughts about personal events (e.g. the death of a loved one) versus thoughts without an emotional component (e.g. white bears). Following this finding, the authors suggest that selection of the target thought should depend on the investigator’s goals, in which a factorial design would be the ideal experimental set up (Abramowitz et al., 2001). Second, since the current research was the first to explore the relation between intrusion, suppression, aggression and impulsivity, we considered it best to use well-known and validated instruments to assess these variables rather than work with new or adjusted instruments. In summary, we argue that the thought suppression paradigm could possibly serve as an explanatory model of impulsivity and aggression and that, first of all, exploratory psychological research is called for. Especially since impulsivity and aggression are such major societal problems. We wanted to follow up on Grisso et al. (2000) and explore which, if any, aspects of impulsivity would be linked to intrusive thoughts. Our second goal was to examine the relation between intrusions, suppression and other control strategies on the one hand and psychopathology on the other, following recommendations by Abramowitz et al. (2001).

3.1. Intrusive thoughts, thought suppression, impulsivity and aggression We calculated correlations between the traditional measure of intrusions and suppression (WBSI) and concurrent measures of intrusive thoughts (MMPI-2 OBS and BIZ, and EPP Obsessiveness) and found strong relationships between the WBSI scores and both OBS and BIZ (range: r=0.42–0.52; p<0.004). Correlations between WBSI scores and EPP Obsessiveness did not reach significance, although a trend was found (range: r=0.24–0.27; p<0.02). Second, we calculated correlations between measures of intrusions and suppression and measures of impulsivity and aggression. Results are presented in Table 1.