Characterizing aggressive behavior

In the research literature, aggressive behavior has traditionally been classified into two distinct subtypes, impulsive or premeditated. Impulsive aggression is defined as a hair-trigger aggressive response to provocation with loss of behavioral control. Premeditated aggression is defined as a planned or conscious aggressive act, not spontaneous or related to an agitated state. The present study outlines the development of a clinically useful self-report instrument, the Impulsive/Premeditated Aggression Scales (IPAS), designed to characterize aggressive behavior as predominately impulsive or predominately premeditated in nature. The IPAS showed strong reliability and validity. Analysis of the IPASscores demonstrated thepresence of two types of aggressive behavior, impulsive and premeditated, in men referred for anger problems. The aggression of most individuals in the present sample was characterized as predominately impulsive in nature (90%).     

Predictors of aggressive behavior

A multiple factor approach was used to test additive and multiplicative models as well as to isolate a best predictive model of physical aggression. The variables of aggressive learning history, provocation, sex of target, sex of subject, sex-role orientation, and aggressive tendencies were selected. Eighty-three males and 117 females participated in the experimental session. Multiple regression analyses indicated that multiple predictor models were able to account for significantly more variance than were single predictor models; however, multiplicative models were unable to increase predictive efficacy. A model composed of sex of target, masculinity, and aggressive tendencies was established as the best predictive model for unprovoked aggression; provocation, masculinity, and aggressive tendencies made up the best predictive model of provoked aggression. © 1992 Wiley-Liss, Inc.     

Instrumental conditioning of aggressive behavior in rats

A method has been developed for bringing an aggressive response under stimulus control. It was found that the number of conditioned aggyessive responses was maximal when low-weight target rats were used. The latencies of the conditioned responses toward target animals of 124 gm were significantly lower than those toward animals of 221 and 284 gm. The application of an extinction procedure on the conditioned aggressive response substantially increased the total number of emitted aggressive responses.     

Impact of distressed and aggressive behavior

Two studies examined the hypothesis that distressed behavior induces negative emotions in others but also prompts solicitousness and deters aggression. In Study 1, 48 marital dyads rated various behaviors in terms of their feelings and reactions toward a spouse engaging in each behavior. Distressed behavior prompted both negative and solicitous emotions, but deterred hostile reactions. Aggressive behavior prompted negative feelings and hostile and argumentative reactions. In Study 2, 41 couples rated videotaped examples of a woman engaging in distressed, aggressive, or neutral behavior, with variations in verbal content and nonverbal affect. Examples of distressed behavior prompted more negative feelings and more solicitous feelings than neutral behavior. Aggressive examples prompted more negative feelings and hostile reactions. The studies indicate the importance of distinguishing between distressed and aggressive behavior.     

Intellectual ability and aggressive behavior in nonclinical-nonforensic males

The purpose of this study was to test the relationship between IQ and physical aggression in a nonclinical-nonforensic male sample in a laboratory setting. Thirty males completed an abbreviated version of the Wechsler Adult Intelligence Scale—Revised. Aggression was measured using a modified version of the Taylor reaction-time (RT) aggression paradigm in which subjects competed on a RT task and both received and delivered shocks to a fictitious opponent in provoking and nonprovoking conditions. Provocation conditions (High and Low) were defined by the intensity of shocks the subjects received. Results demonstrated strong inverse correlations between IQ and aggressive behavior under both High and Low Provocation conditions.     

Generalization of aggressive behavior in adolescent delinquent boys

The generalization of conditioned aggressive and nonaggressive responses in a group of six adolescent delinquent boys was investigated. Responses were reinforced in card games where a token reinforcement system with money as a back-up rinforcer was used. Conditioning of responses was rapid. Generalization, measured in terms of frequency of physical contact, was tested in a group game for which no reinforcement was given. Generalization occurred during aggressive contingencies. During nonaggressive contingencies, responses did not return completely to the baseline level.     

Midbrain-hypothalamic interrelationships in the control of aggressive behavior

Previous studies have suggested an involvement of the midbrain ventral tegmental area in the biting attack upon a rat elicited by electrical stimulation of the lateral hypothalamus in cats. In order assess further the relationship between these two regions, 12 cats were implanted with attack-eliciting electrodes in both the lateral hypothalamus and the midbrain ventral tegmental area. Following a lesion of the midbrain attack site, attack previously elicited from hypothalamic electrodes ipsilateral to the lesion was eliminated or significantly reduced in frequency. The attack elicited from electrodes in the hypothalamus contralateral to the lesion was unaffected. Midbrain lesions made at sites from which attack was never elicited had no effect on hypothalamically elicited attack. The midbrain lesion in some cases eliminated only certain components of the total attack pattern; for example, the approach of a cat to the rat frequently remained present while the bite was absent. Additionally, it was found that the attack elicited from rostral hypothalamic electrodes was disrupted to a greater degree by a single midbrain lesion than the attack elicited from more caudal hypothalamic electrodes. These finding are discussed in terms of the neural system mediating this form of aggressive behavior in cats.     

Emotional competence and aggressive behavior in school-age children

Examined emotional competence in 87 children, aged 7–10 years, who varied with respect to reports of aggressive behavior to determine whether individual differences in emotional competence characterize children with higher levels of aggressive behavior. Emotional competence was assessed during a 1-hr lab visit that included (a) an observational period consisting of a modified disappointment paradigm, (b) assessment of cognitive and language abilities, and (c) 2 structured emotion interviews. Children with higher levels of aggressive behavior exhibited more intense and frequent expressions of anger, both as reported by mothers and as observed during the disappointment paradigm. Less sophisticated ability to identify the causes of emotion also characterized children with higher levels of aggressive behavior. Gender moderated the relation between aggressive behavior and type of emotion identified such that reports of happiness (in response to receiving a disappointing prize) were associated with lower levels of reported aggressive behavior for boys. The value of assessing children's emotional competence in the context of an emotionally arousing situation is suggested by these findings.     

Attribution of apparent arousal and proficiency of recovery from sympathetic activation affecting excitation transfer to aggressive behavior

In a pretest, subjects' proficiency to recover from sympathetic arousal induced by strenuous exercise was assessed. The results were used to determine conditions of high, intermediate, and low recovery proficiency (fitness). After an assessment of subjects' unprovoked aggressiveness, subjects were aggressively provoked. Within proficiency blocks, they were then given one of two treatments, (a) sitting followed by exercising (no decay) or (b) exercising followed by sitting (partial decay), and were there-after provided with an opportunity to retaliate against their tormentor. Under conditions of no decay, in which the high levels of arousal experienced were attributable to exertion, the provocation treatment failed to increase aggressiveness significantly, and there were no differences in aggressiveness in the various proficiency conditions in spite of differentiations in the magnitude of prevailing excitatory residues. Under partial decay, in the absence of cues linking arousal to exertion, the magnitude of residual arousal did affect aggressive behavior: In the conditions of intermediate and low recovery proficiency, aggressiveness increased significantly with provocation and was more pronounced than in the condition of high proficiency (best fitness); in the condition of low proficiency (least fitness) aggressiveness was higher than in the condition of intermediate proficiency, but not reliably so.     

Androgens and aggressive behavior in primates: A review

This review deals with possible central and peripheral effects of androgens upon primate aggressive behavior. One problem that clouds interpretation of experimental work is that measurements of dominance have often been employed, such as competition tests for food and water. Such measures often do not correlate with those obtained by quantifying aggressive interactions. It should be remembered that very few of the 188 primate species have been studied experimentally and that great behavioral and physiological diversity occurs within the order. Therefore, generalizations about the effects of androgens upon aggressive behavior in primates (including man) should be made with caution. Testosterone has an organizing influence upon the foetal brain of rhesus monkeys and may affect the development of neural mechanisms which govern aggression in males. More data are required on primates, however, since rhesus monkeys show some important differences from rodents as regards the effects of androgen upon sexual differentiation of the hypothalamus. In future, marmosets may provide a suitable model for such studies, because there is evidence that sexual differentiation of brain by androgen occurs postnatally in these monkeys. At puberty, male primates show a variety of behavioral changes and, during adulthood, males of seasonally breeding species may be more aggressive during the mating season, when testosterone levels are maximal. This does not indicate a causative relationship between testosterone and aggressive responses, because castration and androgen treatments have little effect upon aggression in prepubertal or adult males of several primate species. Androgens have pronounced effects on sexual responses in adult male monkeys, but their central effects upon aggression are much less important than among rodents. Elec trical stimulation of hypothalamic pathways has been employed to evoke aggressive behavior in marmosets and rhesus monkeys. In the rhesus, preliminary evidence indicates that such pathways show some sensitivity to androgens. In rodents it is known that these areas are richly supplied with monoaminergic neurons, which play an important role in aggressive behavior. There is little evidence on primates, however, and this remains a crucial topic for future research. Peripheral effects of androgens should also be considered. Many prosimians and New World monkeys use scent-marking behaviors and, in males, androgen-dependent chemical cues may be involved in sexual recognition and territorial behavior. This possibility awaits investigation. Finally, plasma testosterone levels may alter as a function of aggression itself; thus levels decrease if male rhesus monkeys are defeated by conspecifics. This might occur because neural events associated with giving (or receiving) aggression also influence pituitary function and hence alter gonadal testosterone secretion. Theoretically, it is possible that such changes in circulating testosterone might affect aggressive behavior via a feedback action on the brain, but the experimental evidence does not support such a view.     

A neurophysiologic model for aggressive behavior in the cat

A neurophysiologic model for aggessive behavior in the cat is proposed. Stimulus-bound and seizure-bound aggression was evaluated in relation to limbic and basal ganglia induced seizures (after-discharges). Electrically induced limbic and basal ganglia afterdischarges were used because they are known to implicate septohypothalamic sites from which aggression can be elicited by direct stimulation. The occurrence of behavioral aggression is correlated with the discharge characteristics of a single discharging system and with two interacting discharging systems. Aggression is composed of autonomic and somato-motor components which poses relatively low and high thresholds, respectively, for their activation. Aggression occurring during a combined septum and amygdala discharge was more intense and prolonged than with a septum discharge alone. Participation of a slow frequency discharging basal ganglia system activated seizurebound aggression in an otherwise nonaggressive limbic seizure. The limbic and basal ganglia stimulations and after-discharges lowered the excitability threshold of the aggression system and made it more vulnerable to being activated by external stimuli, such as visual and auditory stimuli. These observations are reminiscent of patients with aggressive behavior associated with psychomotor seizures.     

Stages in the development of aggressive behavior in early childhood

Primary manifestations of aggression appear in the behavior of children in the second half of the first year of life. The frequency of Occurrence of interpeer aggression increases with age, and reaches its maximum in the third year. The frequency of aggression may later decrease, but there are considerable individual differences. Changes a h Occur in the form in which aggression is manifested; its motivational background and associated elicitors; its direction, duration, timing, and other operational characteristics, and in the modes of its acquisition. A certain continuity may be traced, however, in any of these features and the development of aggression may be perhaps more adequately represented by the following sequence of developmental stage:

• 1 Stage of preaggressive behavior;
• 2 Stage of primary differentiation;
• 3 Stage of the appearance of the individual pattern of aggressive behavior;
• 4 Stage of secondary differentiation of aggression;
• 5 Stage of the beginning of the transition into covert behavior—internalization of aggression

These stages represent certain facets of the interaction between the changing behavioral performance of the child and herlhis social environment, and may be used for evaluating aggressive behavior in young children.     

The effects of humor-induced arousal upon aggressive behavior

The present experiment attempted to reconcile previous results in the area of humor and aggression. It was hypothesized that humor serves two functions, arousal and attentional shift, with regard to its influence on the relation of prior anger arousal and aggression. As a test of this assumption, subjects in the present experiment were subjected to three forms of humor (high arousing, low arousing, nonhumor) after being angered or treated in a neutral manner by a confederate. In an analysis on subsequent aggression toward the confederate, it was found that female subjects reduced their aggression after exposure to low arousing humor while maintaining aggression at a high level for high arousing stimuli. Male subjects were not influenced by humor exposure. Possible reasons for this sex difference are examined in light of the arousal and attentional shift properties of humorous stimuli.