The offensive nature of maternal aggression in mice: Effects of fluprazine hydrochloride

The phenylpiperazine fluprazine hydrochloride was used to test the hypothesis that maternal aggression in laboratory mice reflects offensive motivation. Lactating females (n = 8 per condition) tested for aggression following drug treatment (1.0 mg/kg and 5.0 mg/kg of fluprasine) were significantly less aggressive than saline controls according to all measures used. The findings support the hypothesis that maternal aggression is offensive in nature, and provide no evidence that maternal attack is a mixture of offensive and defensive tendencies.     

Fear and aggression in the rat

The effect of fear on two types of aggression in rats was investigated by adding a cat stimulus to a colony in which the dominant male was attacking an intruder (offensive aggression), or, to a tube test situation in which defensive biting was measured before and during tail shock. The cat completely abolished offense in the colony; when the cat was presented and removed before a strange rat was placed in the colony, attack on the intruder was also reduced. In contrast, defensive biting was unchanged or even slightly potentiated by the presence of the cat, demonstrating a separation of the effects of fear on offensive and defensive aggression.     

Relationship between mousekilling and conspecific aggression in the male rat

In order to investigate the relationships between mousekilling and conspecific aggression, behavioral variables of killer and nonkiller rats were compared in a “resident-intruder” paradigm, in resident as well as in intruder animals. The occurrence of offensive items (offensive sideways, attack) was significantly higher in killer rats when they were residents; their corresponding opponents displayed more defensive behaviors. No significant difference in aggressive behaviors was noted when the comparison was done in the intruders. These results and those of previous studies suggest that there is a correlation between mousekilling and intraspecific offensive behaviors. Some similarities in the situations where both behaviors are elicited–eg, introduction of an unfamiliar intruder into a familiar environment–may contribute to the existence of such a correlation and the possibility of common mechanisms underlying both behaviors is discussed.     

The persistence of attack satiation in female golden hamsters

Female hamsters were allowed to attack a series of target hamsters until they reached a criterion of attack satiation. Following delays of 0, 24, or 48 hr they were then presented with a novel “probe” target. Attacks on the probe target were reduced to 26% of baseline at 0 delay and had returned to 71% of baseline by 48 hr. The number of attacks necessary to achieve satiation criterion increased then decreased over the three test occasions, suggesting that habituationlike processes may contribute to, but cannot wholly account for, the satiation effect.     

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.     

Motivational systems of agonistic behavior in muroid rodents: A comparative review and neural model

The data on agonistic behavior of muroid rodents that have been obtained from field observations and laboratory experiments are reviewed and compared in terms of a hypothetical model of the neural organization of these behaviors. The neural model has been presented elsewhere and is used here only as a way to organize the data. The data are organized in terms of four hypothetical motivational systems: Offense, defense, submission, and patrol/marking. The various behaviors are considered as motor patterns and are compared and analyzed in terms of the proposed motivating, releasing, and directing stimuli of the motivational systems. Interactions and overlaps between the motivational systems are also considered. It is concluded that the organization of agonistic behavior may be similar across all species of muroid rodents. Generalizations are complicated by the profound effects of ontogenetic factors. Four categories of behaviors differ from species to species: Scent-marking, submissive behaviors, threat behaviors, and alarm signals. The possible phylogenetic and ontogenetic factors in these differences are considered.     

The relationship between pain tolerance and trait aggression: effects of sex and gender role

The literature on pain and aggression has indicated that pain elicits aggression. However, research has generally examined pain as a situational variable and focused less on the dispositional ability of an individual to tolerate pain. The dearth of research on pain tolerance and aggression appears to contradict the existing theory on the aggression‐eliciting effect of pain, in that studies have found a positive relationship between pain tolerance and aggression. The purpose of this study was to determine whether the relationship between pain tolerance and aggression is moderated by sex and whether the positive relationship could be explained by masculine gender role conformity. A sample of 195 collegiate men and women completed trait measures and a laboratory assessment of pain tolerance. Results indicated that correlations between pain tolerance and trait aggression were significant and positive for men but not women. However, when men's conformity to masculine gender role was controlled for, the relationship between pain tolerance and trait aggression was nil and nonsignificant. Results are discussed in reference to socialization and maintenance of masculine status. Aggr. Behav. 35:422–429, 2009. © 2009 Wiley‐Liss, Inc.     

Social dominance and individual aggressiveness

Male rats exhibiting high, moderate, or low levels of offensive aggressive behavior in interactions with intruders in their home cage were grouped in mixed-sex colonies with 1 male of each aggression-level group in each colony. Agonistic interactions measured 1, 2, 3, 7, 14, 21, and 22 days after colony formation indicated that highly aggressive males on pretests continued to be more aggressive, becoming the dominant colony male in five of seven colonies and attacking intruders more often than less aggressive males. In the two remaining colonies the moderately aggressive male became dominant. This relationship, which was consistent over a number of indices, including offensive and defensive behaviors, and wound counts and wound sites, was seen even when a substantial weight differential favored the less aggressive animal. Dominance relationships were rapidly established and within-group fighting declined significantly over the 21-day test period. Pretest offensive levels also influenced the behavior of subordinates, with high or moderately aggressive subordinates showing more defense in interactions with dominants and receiving more wounds than did low-aggression subordinates. Dominant males also showed more defense in interacting with those subordinates which had been more aggressive during pretests. This pattern of results suggests that aggression level of the subordinate as well as the dominant may be an important factor determining the intensity of agonistic interactions in male rats.     

Naloxone differentially alters parental aggression by female mice towards conspecific intruders of differing sex

Lactating mice respond differently to male and female conspecific intruders, displaying defensive attack towards the former and offensive attack towards the latter. Two studies are reported in which the effects of naloxone on this differential response pattern were assessed. In the first study, lactating residents were pretreated with saline or naloxone (0.5, 2.5 mg/kg) and consecutively confronted with intruders of differing sex. Results suggested that attack (offensive) against female conspecifics is more sensitive to the inhibitory effects of opiate-receptor blockade than attack (defensive) on males. This conclusion was strengthened in a follow-up study, in which independent groups of lactating residents were used to further examine the effects of naloxone (0.5 mg/kg) on response to male and female intrusion. Analysis indicated that this low dose of naloxone significantly inhibited attack on female, but not on male, intruders. Indeed, in response to male, but not to female, intrusion, naloxone-treated residents showed a significant increase in fear-related behaviour. Findings are discussed in relation to the motivational differences in the response of lactating mice to intruders of differing sex and to possible mechanisms underlying the reported differential effects of opiate-receptor blockade.     

Offensive and defensive bite-target topographies in attacks by lactating rats

The attacks by resident lactating Wistar rats on sexually naive conspecifics of both sexes were examined. Male and female intruders were equally attacked in terms of frequency and number of bites, but the topographies of biting seen in these encounters were different. Similarly to male-male agonistic interactions, females were attacked in a fashion which avoided bites to the head and snout (“offensive” attack), whereas males were frequently bitten on such vulnerable regions (“defensive” attack). This dichotomy in bite pattern suggests that different motivations and functions underlay maternal aggression in these situations. The defensive attack on males may be a deterrent to infanticide since only male intruders counterattack lactating females and kill their pups. The attack on females may be concerned with resource competition.     

The relationship between family aggression history and expressed aggression among college males

The relationship between family of origin aggression and aggression across numerous relationship types was examined among a sample of 197 college‐aged males. Participants completed a self‐report questionnaire assessing the frequency and severity of family aggression (aggression between parents, parental aggression directed toward participants), as well as the frequency and severity of participants' aggression across a number of relationship types (dating, friends, strangers, people in bars, co‐workers, bosses, police officers). The results of the present study indicate that a substantial proportion of college‐aged males report a history of aggressive behavior, both in dating/spousal relationship and other‐relationship types. Analyses revealed that observing parental aggression and receiving aggression from parents was related to aggression in dating relationships. However, only received aggression from parents was related to more general aggressiveness in other non–dating/spousal relationship types. The pattern of findings also suggest that it is important to assess the aggressive behavior of both parents to get a better understanding of the link between family aggression and later expressed aggression. Aggr. Behav. 25:255–267, 1999. © 1999 Wiley‐Liss, Inc.     

同伴关系与攻击行为稳定性的关系研究

研究采用同伴提名法、友谊质量问卷和班级戏剧量表,对430名小学3至5年级的儿童进行了为期一年的追踪调查,在此基础上考察了攻击行为的不同发展轨迹与同伴关系之间的联系.结果表明,不同的攻击行为发展轨迹在社会喜好上的主效应显著,但是在友谊质量上的差异不显著,具体来说:(1)不同外部攻击亚组之间在社会喜好变化趋势上存在显著差异,相对于先低后高组、持续高组和持续低组,先高后低组的社会喜好存在显著的上升趋势;相对于持续低组和持续高组,先低后高组存在显著的下降趋势.(2)不同关系攻击亚组之间在社会喜好变化趋势上存在显著差异,相对于先高后低组、持续低组和持续高组,先低后高组的社会喜好得分存在显著的下降趋势.     

Aggression: Appetite or aversion?—An ethologist's viewpoint

The term “aggression” has been used to describe practically all situations in which an organism threatens, damages, or kills another-with the exception of certain predator-prey relationships. As a result, a great deal of confusion and controversy has arisen as to the causal factors and functions of aggression. The main ethological hypotheses concerning the nature of aggression are put forward. In order to illustrate the divergence in causal factors and functions, differences in motivational, physiological, and ecological bases of aggression in two closely related fish species are described. A basic division of aggression into “self-defensive” and “property-protective” behavior is suggested, together with the parameters separating these categories on behavioral, causal, and functional bases. Mechanisms which enable motivational changes from one category to another to take place during a single encounter are discussed, these being pain stimuli and physical or psychological “cornering.” The importance of learning effects on fighting behavior are emphasized, especially their negative and positive reinforcing effects in relation to self and property defense. The biological significance of aggressive conditioning for the animal and the role of aggression in species maintenance are discussed.     

The relationship between impulsive verbal aggression and intermittent explosive disorder

Intermittent explosive disorder (IED) is the sole psychiatric diagnostic category for which aggression is a cardinal symptom. IED focuses on physical aggression, but researchers have argued for the inclusion of verbal aggression (VA) (e.g., arguing, threatening) as a part of the IED criteria set. The utility of VA in identifying clinically relevant aggression, however, is unknown. IED participants were compared to individuals without a marked history of physical aggression, but who report frequent (two or more times a week) VA, and non-aggressive personality-disorder individuals on behavioral and self-report measures of aggression, self-report measures of related constructs (e.g., anger, affective lability), and a clinician assessment of psychosocial impairment. Both the IED and VA groups were more aggressive, angry, and clinically impaired than personality-disorder individuals, while the IED and VA groups did not differ from each other on these measures. These results support the clinical importance of frequent VA for future iterations of the IED criteria set.     

攻击性和自尊关系的元分析

以往攻击性和自尊之间关系的研究结论存在很大分歧。为了综合以往研究,明确两者之间的整体关系,分析造成分歧的原因,81项原始研究进入了元分析。结果显示:(1)攻击性和自尊呈中等程度的负相关。(2)自尊的不同结构与不同类型的攻击性呈现不同的相关模式。攻击性与外显自尊和内隐自尊呈负相关;攻击性与自尊稳定性和相倚性呈正相关(3)年级和攻击性量表类型的调节效应显著。攻击性与高自尊异质性之间的关系是将来研究的重点。     

Play-fighting differs from serious fighting in both target of attack and tactics of fighting in the laboratory rat Rattus norvegicus

Play-fighting is often difficult to differentiate from inhibited or immature serious fighting because both may utilize many of the same behavior patterns. In the rat the two behaviors involve different targets of attack. During play-fighting, snout or oral contact is directed at the opponent's nape of the neck, whereas during serious fighting, male residents mostly direct their bites at the intruder's rump. Although similar to those used in serious fighting, the behavior patterns used during play-fighting are modified to achieve the different targets of attack. Even though the tactics of attack and defense appear more adult-like with increasing age, the playful targets persist well into adulthood.     

Interpersonal violence and its relationship to some personality measures

One hundred and fifteen patients in a psychiatric hospital for criminal offenders volunteered to be tested with the overcontrolled hostility scale, the self focus sentence completion, and an emotional empathy measure. The subjects were divided into five groups on the basis of criminal offenses (murder, assault with a deadly weapon, rape, pedophilia, and nonviolent property offenses). It was also possible to divide the sample on the basis of diagnostic features (psychosis, personality disorder, and brain syndrome). The results failed to support the hypothesis that more violent (by nature of their offense) individuals would-as a group-score higher on the overcontrolled hostility scale than less aggressive counterparts. There was some evidence that psychotics showed more self focus at the expense of external focus. The empathy measure failed to reveal any meaningful differences. It is suggested that more validation data are called for to establish the generality of the overcontrolled hostility scale and that, in view of the therapeutic importance which empathy training may have for violent individuals, further effort should be expanded to find a generally valid empathy measure.     

Colony aggression in laboratory rats: A review and some recommendations

The behavioral response of established colonies of domesticated rats to the presence of an unfamiliar intruder of the same species represents one of the most effective procedures yet developed to study aggression in the laboratory. Here, the social, experiential, and environmental variables that influence attack severity are reviewed and several important methodological issues are discussed. Brief exposures of intruders to intact colonies may produce misleading results but long-term test sessions increase the likelihood that intruders will be either killed or severely injured. We describe a simple modification of the colony-intruder procedure whereby intruders can successfully defend themselves during long sessions and thus reduce serious injury. The modified procedure appears to conform more closely to what happens during aggressive encounters in free-living populations of wild rats.     

Attack and defense in conspecific fighting in tree shrews (Tupaia belangeri)

Principles of conspecific defense have been analyzed for rodents, in which specific target sites for biting by attackers on defenders serve as an important determinant of the actions involved in both attacker and defender behavior. In an effort to determine the generality of these principles, attack and defensive behaviors and target sites for biting attack were evaluated in a nonrodent species, the tree shrew (Tupaia belangeri). Brief daily and repeated conspecific dyadic encounters between adult, socially experienced males (dominants, attackers), and adult, socially naive males (subordinates, defenders) that had been transferred into the territory of the dominants, produced a polarization of attack and defense. The dominant males showed chase, chase attack, jump attack, and biting behaviors, while the subordinates displayed flight and freezing. The vast majority of bites, as well as wounds and bruises, were on the subordinates’ backs. These patterns are very similar to those previously found in rats and mice and suggest that the organization of fighting, with targets of biting (or other painful) attack serving as an important determinant of both attacker (dominant) and defender (subordinate) behavior, may show considerable generality across nonrodent as well as rodent species. Although relatively few wounds were found after 28 days of repeated and daily encounters, the subordinate tree shrews show a variety of behavioral, neuroendocrine, and central nervous changes, indicating that they are stressed by these encounters per se. Aggr. Behav. 27:139–148, 2001. © 2001 Wiley‐Liss, Inc.