Effects of the cholinomimetic drug arecoline upon aggression: Intra- vs. inter-specific allocation of attack

Systemic injections of cholinomimetic drugs have been reported to induce both rage and predatory attack in several species. In order to assess the relative contribution of each of these two behavioral patterns in the control of cholinergically induced attack, a group of adult female cats was chemically stimulated in the simultaneous presence of both a prey object and a conspecific attack object. In this choice situation stimulated cats initially tended to engage in rage attack. When a second group of subjects was tested in a successive choice situation a significantly greater number of attacks occurred against conspecifics. The results suggest that cholmergic stimulation initially induces affective attack, with somewhat less frequent incidents of predation.     

Effects of age at differential housing and the duration of individual housing/grouping on lntermale fighting behavior and adrenocortical activity in TO strain mice

A study of the effects of the duration of individual and group housing on intermale fighting and adrenocortical activity was conducted in TO strain mice. It was found that fighting and threat increased with progressive isolation up to an asymptote at 56–58 days. ‘Basal’ adrenocortical function differed little under the 2 housing conditions, but after ‘stress,’ mice isolated for short periods, which had not fought when tested for aggression, had lower titers than group-housed counterparts. However, mice that had been isolated for longer periods, and had fought in aggression tests, had higher corticosterone titers than comparable group-housed animals. The effects of a short duration (28–30 days) of differential housing, commencing at different ages, were also studied. The shorter duration adrenocortical changes were largely confirmed. In general, the earlier the age at which the differential housing was imposed, the greater the behavioral differences between animals under each housing condition. It is suggested that this is largely a consequence of a loss of behavioral plasticity in older mice. The data provides little support for the concept of the “isolation stress syndrome,” or for the view that the characteristic fighting exhibited by individually housed mice is a consequence of “social deprivation”.     

The introduction of a group of alien mice (Mus musculus L.) into hierarchically organized groups of five male mice

Groups of 3 male or female Mus musculus were introduced into hierarchically organized colonies of 5 male mice for a period of 8 days. The colonies were of 2 kinds; high-level aggressive (HLA), which had been set up 3 days prior to the introduction of the aliens, and low-level aggressive (LLA), which had been established for 21 days before strangers were introduced. Both males and anestrous females were attacked, but males were attacked 5 times more frequently than females. In HLA colonies most of the attacks on the aliens were by the dominant; in LLA colonies there was no difference in the behavior of dominant and subordinate mice toward strangers. Both aggression toward aliens and intracolony aggression declined over the 8 day experimental period. In HLA colonies the dominant mouse mounted females 5 times more frequently than did either his subordinates or male mice in the LLA colonies. In HLA colonies aliens huddled with subordinates to form a single colony with 1 dominant and 7 subordinates. In LLA colonies alien males remained as a discrete group spatially separated in the cage. Female aliens were incorporated into the main colony. In all cases dominant male mice made more attacks on aliens as compared with familiar mice.     

Hostility in fantasy: A further test of the hypoglycemia-aggression hypothesis

In a recent investigation carried out among the Qolla Indians of Peru, Bolton (1973a) tested the hypothesis that hypoglycemia tends to produce high levels of individual aggressiveness. Glycemic condition was determined by the readings on a 4-hour glucose tolerance test performed on a sample of 54 adult males. Key informants then ranked these subjects on overt aggressiveness. A correlational analysis of the data supported the hypothesis that moderately hypoglycemic subjects would be more aggressive than the normoglycemic subjects. The present paper responds to questions raised about this study and describes the results of an additional test of the hypoglycemia-aggression hypothesis. The dependent variable in this follow-up study is fantasy aggression. Aggression scores were derived from Sentence Completion Test protocols for the same sample of subjects used in the first study. The results indicate a significant correlation between glycemic condition and aggression scores (Biserial, 0.57), thus providing further confirmation of the hypoglycemia-aggression hypothesis.     

Rank and reproduction among female langur monkeys: Aging and improvement (They're not just getting older,they're getting better)

An investigation of the social rank, reproduction, and ages of adult female Indian gray langur monkeys (Presbytis entellus) living in two colony social groups revealed that rank based on displacements is neither correlated with nor best predicted by female age or reproductive value. The hierarchy of female ranks is best conceptualized as a layered ranking system in which there are clusters of females of the same dominance rank forming layers within the structure. Statistical significance in frequencies of displacement differs between but not within these layered groups of females. Factors such as group composition, presence of uterine kin, reproductive state, and individual personality are hypothesized to predict changes in female rank far better than does reproductive value. Our data show that reproductive success increases with age. The infant survival record for the six oldest females in our colony was much better than for the five youngest adult females.     

Attack and defensive behaviors in the albino mouse

Attack by dominant male colony mice on intruders included chasing and lateral attack behaviors, while the corresponding intruder behaviors were flight, boxing, and checking. Both of these are similar to the attack and defensive behaviors of colony rats and intruders. However, mice did not show a significant constraint on bites to ventral areas, and the rat defensive behavior of lying on the back, which is effective because of this constraint, was rare; the corresponding “on-top” behavior of attackers was almost absent in mice. These findings strongly support the view that intraspecific attack and defensive behaviors, and target sites for bites, are interrelated factors facilitating effective but nonlethal agonistic interactions in muroid rodents.     

Violence and the disaggregated society

This paper reviews the evidence that social disaggregation is a major cause of destructive violence in non-human animal societies. The multifactorial theory of agonistic behavior is modified into a polysystemic theory which relates factors on each level to each other in an integrated model. As a result, it is suggested that disaggregation of systems on any level may lead to maladaptive violence. On theoretical grounds it is concluded that disaggregations of ecosystems and social systems are more probable and hence more dangerous than those of physiological and genetic systems. Applications of these findings to human affairs are discussed, both as explanations and as guides to positive action.     

Comparison of agonistic behavior in individually-housed male mice with those cohabiting with females

Videotape recordings of male mice group-housed, individually-housed and cohabiting with females, were rated for their agonistic behavior in a “standard opponent” test. Previously mated male mice showed more fighting than isolated or grouped males. Marked differences in other social and non-social behaviors, which could not be accounted for in terms of increased fighting, were not evident. These results suggest that agonistic behavior may be usefully studied by examining male mice that have cohabited with females. One obvious advantage is that such mice cannot be dismissed as being “socially deprived,” as is sometimes claimed for individually-housed mice. Other advantages are that aggressiveness is induced quickly, at high levels, and the mice appear very sensitive to hormone manipulation following castration.     

Interspecific aggression and reactivity in rats: Effects of selective raphe lesions and additional olfactory bulb ablation

Large depletion of brain 5 HT has been shown to induce mouse-killing behavior in the rat. Selective lesions of the raphe nuclei have been investigated in order to determine whether the various components of the 5 HT system exert some specific control over this aggressive behavior. Electrolytic lesions of the dorsal or the median raphe nucleus do not induce mouse killing, whereas combined lesions of these nuclei elicit this behavior in about 40% of naive rats. Consequently, it appears that serotonergic neurons originating in the dorsal and median raphe nuclei work synergistically in mediating inhibitory control over mouse-killing behavior. Loco-motor activity is increased in novel environments by each of the selective lesions and to a larger extent by combined raphe lesions; 24 hours activity in resting conditions is unchanged during the light period, and increased during the dark period of the daily cycle by the various lesions. As it has been shown previously that hyper-activity in response to novelty following raphe lesions is not directly related to the 5 HT decrease in the brain, it appears that interspecific aggression and motor responsiveness must not be dependent on the same neural substrate within the raphe nuclei. The raphe lesions do not facilitate the elicitation of mouse killing by further olfactory bulb ablations, in contrast to earlier results where bulbectomy facilitated the induction of this behavior by raphe lesions.     

Isolation-induced social pecking in domestic chicks: Contemporary correlates and sequelae

Aspects of the social pecking of domestic chicks in a free response situation were examined in a series of experiments. It was proposed that a dual pattern of responses involving (a) a preponderance of pecks at the head of a conspecific, and (b) heightened emotionality (as indicated by the emission of distress calls) might be taken to reflect an aggressive tendency, and evidence was reviewed that showed that a brief period of isolation was a sufficient condition to elicit such a pattern. The main questions asked in this paper are: (a) whether the gender of a chick had a material influence on the incidence of such social pecking, and (b) whether orders established in pecking exchanges reflected a unidimensional social ordering among chicks. In the 1st set of studies the effect of the sex of subject on rates of social pecking was tested. While an isolation procedure clearly produced the dual pattern of heightened head pecking and calling, reliable sex differences were not in evidence. In a 2nd study, concerned with the generality of social orders as observed in social pecking exchanges, the isolation procedure again was sufficient to produce apparently aggressive reactions but the resulting peck orders between chicks did not predict success in later tests when the same 2 subjects were pitted against one another in either approach or avoidance competitive tasks. These results are discussed in terms of the relationship of infant aggression to adult aggression, and suggestions are made for a revised view of the development of the aggressive behavior of fowl.