Separate neural sites for d-amphetamine suppression of mouse killing and feeding behavior in rats

The present study was conducted to investigate several possible neural sites for d-amphetamine's effect on mouse killing and feeding behaviors. d-Amphetamine (10, 20, and 30 μg) injected into each lateral ventricle, suppressed mouse kiling, food, and water intake in a dose-dependent manner. Bilateral adminstration of d-amphetamine (20 μg) into the central amygdaloid nucleus abolished mouse killing behavior but did not affect feeding and drinking. By contrast, bilateral amphetamine injections into the substantia nigra, or into the ventral region of the caudate nucleus, did not suppress mouse killing behavior, but significantly decreased food and water intake. The lateral hypothalamus was sensitive to d-amphetamine injections, which suppressed mouse killing and food intake as well as water intake. d-Amphetamine injections into the nucleus accumbens produced inconsistent effects on mouse killing and feeding. Our observations suggest a differentiation of the neural sites that mediate feeding from those underlying mouse killing behavior.     

The effects of gormone manipulations on aggressive target-biting in mice

Aggressive biting of an inanimate target by mice was studied. Males attacked the bite-target more frequently than females, but this difference disappeared after castration when the response rate of the males approached that of the females. Ovariectomizing the females had little effect on their bite-attack frequencies. Subsequent androgen injections restored the biting-attack frequency of the castrated males to preoperative levels but had little effect on the intact males. Estrogen had little effect on the response frequency of the females, whereas androgen produced a slight increase in their bite-attack frequency. Results indicate that androgen is critical for the maintenance of this aggressive response and that the single subject paradigm utilized in this study was a sensitive measure of aggressive tendencies in mice.     

Dominance assertion in male chimpanzees (Pan troglodytes)

The social relations of three adult males in a captive chimpanzee group were evaluated for 12 months. The observations encompassed a period of transition in the dominance hierarchy providing an opportunity to assess behavioral patterns involved in the initiation of status changes. This study shows that dominance in the chimpanzee is expressed primarily through ritualized and non-contact behavior rather than by overt aggression. In particular, display behavior is important for indicating dominance rank, in communicating aggressive intent, and as a prelude to status struggles. The functional relationships between status, displays and other socio-sexual behavior patterns are presented.     

Naturalistic versus experimental approaches to aggression; theoretical and methodological issues

Various strategies to study human aggression are described, accompanied by a discussion of four major issues. It is concluded that the three major goals of research, precise measurement, realism, and generality, cannot be achieved in a single study or series of studies using only one paradigm. Investigators of a particular problem need to develop a research program that incorporates a number of strategies; hypotheses generated “in the street” need to be tested in the laboratory and vice versa.     

Effects of medial preoptic hypothalamus anterior lesions on three kinds of behavior in the rat: Intermale aggressive,male-sexual,and mouse-killing behavior

Large lesions in the medial preoptic area-anterior hypothalamus (MPOA-AH) of adult male S3 rats reduce both intermale aggressive behavior and male sexual behavior considerably, but mouse-killing behavior is not impaired. Daily treatment with high doses of testosterone propionate for 21 days does not restore these behavioral effects. Smaller lesions in the same area affect male sexual and intermale aggressive behavior differently; in the frontal part of the MPOA-AH they affect aggressive behavior, while in a more caudal part they affect sexual behavior. Indications were found that lesions in specific parts of the stria terminalis and the medial forebrain bundle inhibit aggressive and sexual behavior.     

The effects of negative reinforcement for irritable aggression on resident-intruder behavior

This experiment demonstrated that rats trained to display elevated levels of shock-induced aggression in a negative reinforcement paradigm displayed more boxing behavior than yoked control groups in a later test in which intruder rats were placed in the home cage of resident rats. Resident or intruder status did not affect the influence of the negative reinforcement procedure on the observed resident-intruder behavior of trained animals; however, naive intruders paired with trained residents displayed increased defensive behavior, suggesting that negative reinforcement for shock-induced aggression affected the behavior of these residents.     

Sexual jealousy in young women and men: Aggressive responsiveness to partner and rival

Two studies compared judgments about aggressive components of jealous reactions to the partner and to the rival, specifically, emotional (anger), cognitive (blame), and behavioral components. The first study randomly assigned 172 young women and men to two questionnaires on jealous reactions to mild (flirting) and serious (cheating) transgressions. One questionnaire assessed standards for appropriate behavior and perceptions of how people usually react. The second questionnaire asked people to report how they had reacted or, if not experienced with a sexual transgression, how they would react. The second study asked 113 people to imagine a situation in which they knew their partner had been sexually unfaithful. There were three major findings that were interpreted in the context of courtship, a time when attention is focused on the qualities of one's potential long-term partner. First, the jealous individual's anger and blame were focused more on the partner than the rival. Second, mean anger and blame scores given the partner were well matched. In contrast, the rival received more anger and blame than deemed appropriate and considerably more anger than blame. These data suggest that, in the context of courtship, a rival is not simply a competitor. Third, men were more inclined to think about aggressive action against the rival but women were more emotionally and behaviorally reactive to the rival. The latter result implies that, in the context of competition for an established romantic partner, a rival is more salient for women than for men. © 1993 Wiley-Liss, Inc.     

Showing-off behaviour of nursery children

Assertive behaviours like showing-off have an important role for a child in getting attention from other children in a class without being aggressive. This study presented the showing-off behaviour in an English nursery school, and later it was discussed in comparison with that in the German kindergartens reported by Hold-Cavell. As a result, the English children performed showing-off behaviours at only one-half the frequency of German children. No sex difference was seen in either showing-off or physical aggression in the nursery class. The frequency of showing-off did not correlate with that of physical aggression; this result is discussed in terms of Hinde's motivational postulate. Showing-off behaviour is deserving of the further studies cross-culturally and onto-genetically.     

A comparison of skill-building and desensitization strategies for intervention with aggressive children

Social skills training and desensitization interventions were conducted with 41 institutionalized aggressive children aged 7–13. Subjects were randomly assigned after blocking by aggression and cooperative play to either of the treatments. Dependent measures were direct observations of playground play and teacher ratings. Subjects in the social skills program mastered the basic cognitive skills presented to them. Observational data indicated that both groups experienced marked reduction in aggressive behavior and increases in cooperative play. The social skills training intervention engendered incremental improvement in aggression in comparison to the desensitization condition. However, none of the behavioral changes evident in the observations were reflected in teacher ratings.