Frustration as an important determinant of alcohol-related aggression

Correlation dimension of complex networks

We propose a new measure to characterize the dimension of complex networks based on the ergodic theory of dynamical systems. This measure is derived from the correlation sum of a trajectory generated by a random walker navigating the network, and extends the classical Grassberger-Procaccia algorithm to the context of complex networks. The method is validated with reliable results for both synthetic networks and real-world networks such as the world air-transportation network or urban networks, and provides a computationally fast way for estimating the dimensionality of networks which only relies on the local information provided by the walkers.

Improving risk assessment of violence among military veterans: an evidence-based approach for clinical decision-making

Increased media attention to post-deployment violence highlights the need to develop effective models to guide risk assessment among military Veterans. Ideally, a method would help identify which Veterans are most at risk for violence so that it can be determined what could be done to prevent violent behavior. This article suggests how empirical approaches to risk assessment used successfully in civilian populations can be applied to Veterans. A review was conducted of the scientific literature on Veteran populations regarding factors related to interpersonal violence generally and to domestic violence specifically. A checklist was then generated of empirically-supported risk factors for clinicians to consider in practice. To conceptualize how these known risk factors relate to a Veteran's violence potential, risk assessment scholarship was utilized to develop an evidence-based method to guide mental health professionals. The goals of this approach are to integrate science into practice, overcome logistical barriers, and permit more effective assessment, monitoring, and management of violence risk for clinicians working with Veterans, both in Department of Veteran Affairs settings and in the broader community. Research is needed to test the predictive validity of risk assessment models. Ultimately, the use of a systematic, empirical framework could lead to improved clinical decision-making in the area of risk assessment and potentially help prevent violence among Veterans.

Alcohol consumption-related antigay aggression: theoretical considerations for individual- and societal-level interventions

A substantial literature has identified risk factors for intoxicated aggression and the mechanisms by which these effects are exerted. This theoretical and empirical foundation is a valuable resource for the development of treatment inventions. In contrast, a comparable literature is not available to guide development of clinical interventions for intoxicated antigay aggression. To address this gap in the literature, the present article (1) identifies risk factors and mechanisms pertinent to alcohol consumption-related antigay aggression, (2) advances predictions regarding how alcohol will increase antigay aggression, and (3) reviews societal- and individual-level considerations for intervention based upon these hypotheses.

Acute effect of altered tryptophan levels and alcohol on aggression in normal human males

Normal males received amino acid mixtures designed to raise or lower tryptophan availability, and thus to raise or lower brain serotonin synthesis. They also received alcoholic or non-alcoholic drinks. The subjects were tested in the Taylor Competitive Reaction Time Task in which they competed against a (non-existent) partner in a reaction time task. The magnitude of electric shocks that the subjects were willing to give to their bogus partner was used as a measure of aggression. Lowered tryptophan levels and ingestion of alcohol were associated with increased aggression. Our data support the idea that low serotonin levels may be involved in the etiology of aggression. They suggest that subjects with low brain serotonin levels may be particularly susceptible to alcohol-induced violence.

Alcohol and social influences: yielding among male social drinkers to social pressure

Thirty men participated as paid volunteers in an experiment exploring whether alcohol intoxication makes a person more or less likely to yield to social pressure. Subjects were randomly assigned to either a Control, a Placebo, or an Alcohol group. The alcohol dose was 0.8 ml of 100% alcohol/kg body weight. Subjects first estimated the length of a line, then received feedback from either a male or a female reference group (social pressure), and finally made a second estimation. This procedure was repeated 30 times. The analysis indicated that the only effect of intoxication was to become more resistant in terms of number of yieldings to social pressure, provided the feedback came from a male reference group. Locus of control in terms of internality significantly predicted number of yieldings for the Alcohol group, although the analysis indicated no significant differences between groups as to mean locus of control scores.

Aggressive and nonaggressive behavior as a function of alcohol intoxication and frustration in women

An experiment tested whether alcohol increases aggression in women in a situation in which both an aggressive and a nonaggressive response alternative of equal instrumentality and of equal variability are available. Subjects were assigned to one of three groups, namely, an alcohol, a placebo, or a control group. The alcohol dose was 1.0 ml of pure alcohol/kg body weight. After drinking their respective drink, subjects were instructed to supervise a bogus partner on a visual scan test over a series of trials. Each time this partner made a mistake, subjects could either give an uncomfortable electric shock (scale 1 to 10) or a comfortable vibration (scale 1 to 10) to the partner. Aggressive and nonaggressive behavior was measured as numbers, intensities, and durations of shocks or vibrations, respectively. Neither alcohol nor frustration differentiated the groups on aggressive or nonaggressive behavior. All groups were significantly more inclined to use the nonaggressive alternative irrespective of alcohol dose and level of frustration. In conclusion it was stated that women do not increase their aggression as a function of alcohol in a situation with more than one response alternative available. The need to incorporate gender differences as to aggressive effects of alcohol was stressed.

Male physical aggression as a function of alcohol intoxication and frustration: experimental results and methodological considerations

Forty-five undergraduate students were assigned to either an Alcohol, a Placebo, or a Control group. The alcohol dose was 0.80 g of 100% alcohol/kg body weight. Subjects were informed that they could win a sum of money depending on the performance of a partner. They then supervised the partner over a series of trials on a visual scan test and could influence the partner by either giving an uncomfortable electric shock (aggressive alternative) or a comfortable vibration (nonaggressive alternative) at each incorrect response from the partner. Both alternatives were said to be equally instrumental in reaching the goal of winning the money and both could be varied in intensity on a 10-point scale and without limits in terms of duration. Aggression was measured as number of aggressive responses chosen, and in terms of intensity and duration. Nonaggression was measured in terms of intensity and duration. Intoxicated subjects did not increase their aggression but all groups chose significantly more nonaggressive responses and did so with higher intensity and duration. Frustration did not significantly affect these types of responding. Results are discussed in terms of methodological considerations and the importance of using realistic experimental paradigms is stressed. Also, theoretical implications are discussed.

Male physical aggression as a function of alcohol, frustration, and subjective mood

An experiment tested the hypothesis that alcohol intoxication will increase aggression only if the subject is experiencing the intoxicated state as displeasing. Forty males drank either 0.8 mL of pure alcohol/kg body weight or a placebo drink and were then exposed to either a pleasant or an unpleasant mood manipulation. Following this, they were given the chance to aggress in a modified version of the Buss "aggression machine" paradigm. All subjects were observed under varying levels of frustration. Results indicated that alcohol-drinking subjects were more aggressive than placebo-drinking subjects, and that both intoxicated and sober subjects increased their aggression when frustrated. Intoxicated subjects in a pleasant mood were most aggressive under both provocative and nonprovocative conditions. The hypothesis was not supported and results are discussed in relation to different theoretical models and in relation to results from other similar studies.

Alcohol and the validation of experimental aggression paradigms: the Taylor reaction time procedure

The aim was to find out whether intoxicated and sober subjects would calibrate a shock scale to the same objective level and whether shocks received would be subjectively experienced in the same way in terms of pain and discomfort. The intention was also to replicate previous studies attributing an aggression enhancing effect to alcohol. The subjective ratings were made within the Taylor reaction time 'aggression machine'. Twenty-four subjects were randomly assigned to either an alcohol or a control group. The former drank 0.8 ml of pure alcohol/kg body wt. Results indicated no differences among groups on a shock setting measure of aggression under unprovoked or provoked conditions and no differences in level of calibration of shocks or in subjective ratings of pain and discomfort. These results were contrary to all predictions and are discussed as indirectly supportive of an hypothesis stating that this version of the 'aggression machine' may not generate a valid measure of aggression when used in alcohol research.

Beer intoxication and physical aggression in males

Twenty subjects participated in an experiment testing the effects of a moderate dose of beer on physical aggression. Subjects were randomly assigned to a beer drinking group or a control group. Aggression was measured in terms of number of shocks given, shock intensity, and shock duration in a modified version of the Buss' aggression machine. There were no differences among groups and there was no interaction of beer by frustration on aggression. The results are explained in terms of expectancies held by subjects as to the effects of beer intoxication on behaviour.

Effects of beer and wine on male aggression as measured by a paper-and-pen test

Two experiments were performed testing whether alcohol in the form of beer and wine would increase aggression measured on a self-rating aggression inventory. No significant differences among sober and intoxicated subjects were obtained either for beer or wine. This result was discussed in terms of specific beverage-type effects on aggression, in terms of blood alcohol level, and in terms of the response measure used.

Human physical aggression as a function of frustration: role of aggressive cues

An experiment was performed testing whether aggressive cues are necessary or only facilitative in increasing aggression to a frustration and whether their role is to “pull out” aggression directly or to add to the experience of displeasure. 20 subjects participated and a modified version of the Buss' “aggression machine” was used in which frustration was manipulated within subjects and aggressive cues between subjects. Frustration was of an arbitrary kind and aggression was defined to subjects to have instrumental value in overcoming the frustrative event Results indicated that (1) frustration alone is a weak antecedent of aggression, (2) at low frustration aggressive cues seem to be necessary for aggression to increase, and (3) aggressive cues apparently elicit aggression directly. Results were discussed in terms of Berkowitz' reformulation of the frustration-aggression hypothesis.

Alcohol, frustration, and aggression: an experiment using the balanced placebo design

In a balanced placebo experiment it was hypothesized that pharmacological effects of alcohol would override expectancy effects and that alcohol would increase aggression only under frustrative conditions by a process of an exaggerated subjective experience of frustration. In a modified “aggression-machine” frustration was defined as arbitrary and manipulated in a within-subjects fashion. Manipulation checks indicated difficulties in deceiving subjects as to the content of the drink, and it was not possible to evaluate pure pharmacological effects. Ratings of subjective frustration did not differentiate experimental groups. Only during frustrative conditions did intoxicated subjects increase their aggression regardless of information about drink's content. Frustration per se and expectancy factors did not lead to increased aggression. This was explained in terms of a more narrow focusing on outstanding available response alternatives and as opposed to the 1983 Taylor and Leonard explanation of alcohol-increased aggression.

Threat as a determinant of alcohol-related aggression

An experimental study was performed within a modified version of the Buss “aggression-machine” paradigm testing the hypothesis that threat will inhibit aggression in intoxicated subjects given that threat is not unavoidable. 40 males were randomly assigned to either an alcohol group, drinking .08 ml of pure alcohol per kg body weight, or a placebo group, drinking only tonic. Half of the subjects in each group were exposed to a threat and the other half to no threat. At 10 opportunities subjects could choose between a nonaggressive response or an aggressive response in the form of an electric shock given to a bogus partner. Aggression was estimated in terms of number of aggressive responses, the intensity and duration of these responses, and response latency. Results clearly confirmed the hypothesis and were discussed theoretically in a model combining pharmacological and psychological factors.

A possible confounding variable in different versions of the "aggression machine" when used in research on alcohol

When various versions of the Buss aggression paradigm are used in research concerning alcohol-related aggression, different information about the confederate's degree of intoxication is given to the subject. Sober subjects get the impression that the confederate is sober, whereas intoxicated subjects believe that the confederate is intoxicated. This constitutes a confounding variable making it impossible to attribute conclusively differences among alcohol and control groups on measures of aggression to consumed alcohol. An experiment tested whether this difference in information affects subjects' conception concerning expected level of aggression directed towards them from an opponent and their own level of aggression towards the opponent within the Taylor version of the “aggression machine”. Results clearly indicate that subjects expect intoxicated opponents to be more aggressive. Subjects are also more aggressive toward intoxicated opponents than sober ones. This confirms the importance of holding constant information about the confederate; this has not been done in many relevant studies.

Alcohol and aggression: pharmacological versus expectancy effects

An expectancy hypothesis has been put forward to explain the relationship between alcohol intoxication and aggressive behavior. An experiment tested this hypothesis using a balanced placebo design. The experiment was performed within a modified version of the Buss “shock-machine” procedure. Subjects were randomly assigned to either an alcohol-drinking group or a tonic-drinking group. Each group was further subdivided into one informed that the drink contained alcohol and one informed that the drink contained only tonic. Subjects' expectancies concerning the effects of alcohol on aggression were actively manipulated. Aggressive behavior was measured both in an absolute and a relative way. Given difficulties with the procedural deception about the drink, it was not possible to evaluate pure pharmacological effects. Results did not support an expectancy interpretation in that the two alcohol-drinking groups were more aggressive than the two tonic-drinking groups. Results were discussed in terms of methodology explaining the difference in results between the present study and a similar study by Lang, et al. in 1975.

Alcohol-related aggression: a further study of the importance of frustration

This experiment investigated aggression as an interactive effect of alcohol and frustration in a situation where frustration was defined as strong and arbitrary and aggression as instrumental. 40 male subjects were randomly assigned to either an alcohol or a placebo group, each group further divided into an aggressive-cue group and a no-aggressive-cue group. Subjects either consumed an alcohol dose of 0.8 ml of pure alcohol per kg body weight or a placebo drink. Intensity and duration of shocks administered by subjects to a bogus partner in a supervision “cover task” were measures of relative aggression and absolute aggression was defined as number of shocks given. The aggressive cue manipulation had no effect, and both absolute and relative aggression increased only when intoxicated subjects were frustrated. Aggression was clearly of an instrumental kind with no ingredients of emotional aggression. The different dependent measures were highly intercorrelated and not associated with different types of aggression. The results were discussed as supportive of a model proposing a shift in attentional processes under alcohol to salient external features.