Familiarity with conspecific odor and isolation-induced aggressive behavior in male mice (Mus domesticus).

60 male Swiss CD-1 mice were isolated for 24 days. In the isolation group mice were exposed to their own odor; in the familiarity group mice were familiarized with pairmates' odor by daily exchange of bedding; and in the unfamiliarity group Ss (exposed) were familiarized with pairmates' odor, whereas the pairmates (nonexposed) were familiarized with odors of other isolated mice. Aggressive behavior was scored during 20-min sessions. Familiarity with the pairmate's odor (familiarity and exposed subgroups) caused an enhancement of aggressive behavior, shown by the highest frequency of tail rattling and offensive upright posture and by a decrease in latency to the 1st attack. Nonexposed Ss showed high values of submissive upright posture, screaming, fleeing, and freezing. The results suggest that dominantlike behavior, acquired in social isolation, may be directed toward a conspecific whose odor is familiar. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Cognitive level as a function of defensive isolation.

Evaluated the possibility that a failure to coordinate perspectives on the role-taking task (RTT) occurs when the TAT figures represent defensively isolated aspects of the self-structure. The Ss were given the RTT under 2 conditions: (1) Ss were assigned defensively isolated attributes, asked to tell a story built around TAT figures endowed with those attributes, and then required to take the perspectives of these figures in their role taking; (2) in the other, the assigned attributes were not defensively isolated. Ss showed more difficulty in coordinating perspectives under the defensive isolation condition than under the nonisolated condition. (17 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Role of dominance-submission relationships in shock-induced fighting of mice.

Studied 96 male DBA/2J mice. Ss were caged in pairs until dominance-submission hierarchies formed. The effects of social roles, fight training, and unfamiliarity on shock-induced biting attack and upright postures were examined under 4 levels of shock intensity. Biting attack was almost exclusively the behavior of dominant mice, and it predominated for all groups except submissive-submissive pairs, which responded to shock almost entirely with the upright posture. Fight training increased the amount of fighting response to shock. Unfamiliarity increased fighting at low shock levels and depressed fighting at high shock levels. (19 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Introverts' and extraverts' responses to nonverbal attending behavior.

Examined the different responses of 52 male undergraduate introverts and extraverts (as determined by the Extraversion scale of the Eysenck Personality Questionnaire) to 2 types of helper nonverbal attending. One half of the Ss viewed a listener intensely attending (leaning forward) and one half viewed the listener in an upright position. Results indicate that (a) introverts rated the listener higher than did extraverts, independent of his posture; (b) the listener in the forward attending posture was viewed by all participants as more attentive; and (c) the extraverts who viewed the listener in the upright position rated him as more threatening than did the introverts in either condition or the extraverts viewing the listener in the forward position. In no case was the listener in the forward attending posture rated more negatively than the listener sitting upright. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Removal of the submaxillary salivary glands first increases and then abolishes the agonistic response of male mice in repeated social encounters

Adult male mice of the CD-1 strain were sialectomized (bilateral removal of submaxillary salivary glands) under IP Nembutal anesthesia and then individually housed for 5 weeks. Control mice were sham operated. The behaviors of sialectomized and control mice towards untreated, intact, matched opponents were videotaped during the first 10 min of a 20-min social encounter repeated for 10 consecutive days (isolation days 36-46). On the first session, sialectomized mice exhibited significant increases in elements of aggression (attack, bite, offensive sideways, offensive upright, and tail rattling). These behavioral changes significantly decreased over the remaining encounters, while defensive behaviors (defensive upright, oblique, parry, and defensive sideways) and elements of arrested flight increased progressively. The results suggest that sialectomy, perhaps by removing salivary NGF, interferes with the coping response of mice towards repeated agonist challenge from a conspecific.     

Competitive fighting in the rat.

Obtained competitive fighting in 29 of 60 pairs of like-sexed DA agouti laboratory rats by placing a single piece of food into the food hopper following 48 hrs of food deprivation. The fighting was characterized by offensive sideways posture, full aggressive posture, and bite and kick attack. Tests were conducted at 110-120 days of age on pairs of Ss that had been housed together since weaning. Fighting was more frequent in pairs consisting of nonlittermates than in pairs of littermates, and it was equally frequent in male and female pairings. Probability of fighting was enhanced by prior experience with food deprivation, and attack was most often initiated by the heavier animal of the pair. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of target movement on mouse-killing attack by rats.

Tested 2 groups of 30 naive Long-Evans hooded rats for their reaction to motionless anesthetized mice and to active normal mice. Group 1 was tested 1st with normal mice, and Group 2 was tested 1st with anesthetized mice. More Ss in both groups killed anesthetized than normal mice, and more Ss in Group 2 than in Group 1 killed both types of mice. Normal mice were attacked faster and attacks on anesthetized mice were not stereotyped unless experience in attacking normal mice preceded. Probability of killing normal mice was increased following experience with anesthetized mice, and probability of killing anesthetized mice was decreased following experience with normal mice. (22 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Influence of upright posture on shock-elicited aggression in rats.

Conducted 2 experiments with a total of 140 male and 140 female hooded rats. In Exp. I, frequencies of upright postural responses displayed by Ss when shocked alone were predictive of upright postural response frequencies during shock-elicited aggression. These differences in upright postural frequencies were associated with differences in frequencies of aggression in male Ss only. Exp. II manipulated upright postural responses. Results suggest that the upright behavior of Ss could be controlled in the shock-elicited-aggression paradigm. Only a slight influence on the aggression of female Ss was obtained. Experimental findings suggest that the upright postural behavior is not a major variable in the provocation to attack in the shock-elicited paradigm. (19 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Fighting in mice: Dyadic escalation and what is learned.

Conducted a series of experiments to clarify the role of reciprocal reactivity in the initial elicitation of attack-fighting sequences in isolation-raised male ICR mice (N = over 300). In Exp I reactivity of the target animal was manipulated by intraperitoneal injections of chlorpromazine. As dose levels were increased (saline; 4, 8, and 16 mg/kg of chlorpromazine; lethal doses of pentobarbital) the probability that an attack would evolve in the interaction decreased monotonically from 1.0-.0. Attack behavior in isolated Ss was thus precisely controlled by diminishing the reactive characteristics of their partners and without direct manipulation of the aggressive Ss themselves. Exp II demonstrated that once attacks had been elicited in previously isolated Ss, the behavior was generalized to other conspecific partners irrespective of the reactivity-nonreactivity of the partner. Supplementary experiments confirm the importance of partner reactivity, regardless of the age of isolation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Male-female differences and the influence of neonatal and adult testosterone on intraspecies aggression in rats.

Tested Sprague-Dawley male and female albino rats for intraspecies aggression without the use of shock. In the 1st experiment, 6 male pairs showed more biting attacks, offensive sideways movements, and self-grooming than did 6 female pairs; male pairs also showed more stereotyped defensive/submissive behaviors and were wounded more frequently. The 2nd experiment with 103 Ss examined the effects of neonatal castration and testosterone propionate (TP) on fighting. Males castrated at birth attacked other males less frequently than did controls when tested with TP treatment as adults. The TP given at birth to neonatally castrated males restored attacks to control levels. Females given TP as neonates did not differ from either male or female controls. Other aggressive/defensive behaviors, however, did not show this pattern. Results suggest that while the presence of testosterone during a brief postnatal period and during adulthood is necessary for attack behavior to occur, other related behaviors may not be affected in a similar manner. (11/2 p ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Newborn stepping: An explanation for a "disappearing" reflex.

When held upright, newborns show well-coordinated walking movements that normally cannot be elicited after about 2 mo of age. In contrast, spontaneous kicking in the supine position increases in frequency during the 1st 6 mo of age. In the present study, 8 2-wk-old infants were observed with a combination of a videotaped recording and concurrent EMG of 4 muscle groups of the legs. In a single session, Ss were viewed first kicking, then stepping. Kinematic, EMG, and motivational data indicate that kicking and stepping are the same muscle synergisms. The disappearance of stepping may be a result of the biodynamic consequences of the upright posture due to asynchronous development of muscle mass and concomitant strength. It is shown how this hypothesis explains training effects on prolonging the stepping reflex. (42 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Paternal stimulation during infancy: Effects upon aggression and open-field performance of mice.

Studied aggression in random-bred albino Tuck TT strain male mice from 1st matings, reared by both parents (n = 13) and from 2nd matings, reared only by the mother (n = 15). Prolonged isolation from weaning induced more aggression in Ss from 1st matings than in Ss from a 2nd mating. In a 2nd experiment, fathers of 40 Ss were removed (a) shortly after mating, (b) at the litters' birth, or (c) at weaning. In offspring isolated from weaning, Ss in condition c were significantly more aggressive than those in a, while those in b showed an intermediate response. These differences did not occur when the period of isolation was broken by 50 days of communal housing before aggression testing, although Ss in c defecated more in the open field. It is suggested that young mice "imprint" toward the same odors of adult males which in later life elicit intermale aggression. (24 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Modifications of testosterone-dependent behaviors by estrogen receptor-alpha gene disruption in male mice

The role of the a form of estrogen receptor (ER alpha) gene expression in the regulation of testosterone-dependent male reproductive behaviors was investigated using ER knockout mice (ERKO), which are specifically deficient in functional ER alpha, but not ER beta, gene expression. Previous studies in gonadally intact ERKO mice revealed that male aggressive behavior was greatly reduced by the lack of a functional ER alpha gene. In the present study the almost complete suppression of male-typical offensive attacks was further confirmed in ERKO mice that had been singly housed since weaning. Regarding aggression, it was also found that ER alpha gene disruption virtually abolished the propensity to initiate offensive attacks, even though ERKO mice could elicit attacks from resident C57BL/6J mice as wild-type (WT) and heterozygous littermates. Daily injection of testosterone propionate (TP) was completely ineffective in inducing aggressive behavior in gonadectomized ERKO mice, whereas it successfully restored aggression in WT mice. In contrast, male sexual behaviors, mounts and intromissions, were induced by daily injection of TP in both gonadectomized ERKO and WT mice. In addition to TP, dihydrotestosterone propionate (DHTP) was also effective in restoring mounts in ERKO mice, although DHTP was much more potent in WT mice than in ERKO mice. Neither TP nor DHTP, however, ever induced ejaculation in ERKO mice. These results together with previous findings in gonadally intact ERKO mice suggest that ER alpha may be responsible for the regulation by testosterone of consummatory, but not motivational, aspects of male sexual behavior. Finally, ERKO male mice retrieved newborn pups placed in their home cage with similar latencies to males of the two other genotypes. During parental behavior tests, however, a higher percentage of ERKO mice (70%) showed infanticide compared with WT mice (35%). The latter result was interpreted as showing that ER alpha activation by testosterone during the perinatal period may exert a suppressive effect on testosterone-inducible infanticide in adulthood. With respect to three major testosterone-dependent behavioral systems reflecting masculinization, these findings demonstrate three different types of effects due to ER alpha gene disruption.     

Audience influence, social isolation, and speech.

80 children—selected as being either high or low on exhibitionism (an audience seeking tendency) and audience anxiety (a tendency to be anxious about performing before others) according to scores on 2 questionnaire scales—told stories to an adult either with or without prior exposure to a brief period of social isolation. It was found that isolated children who were high in audience anxiety told significantly shorter stories than nonisolated high anxiety children, while the stories of isolated and nonisolated low anxiety Ss did not differ in length. An analysis of length of speech according to exhibitionism level yielded no significant differences, but isolated high exhibitionism boys tended to speak at a faster rate than other groups. Boys also spoke significantly longer than girls. (17 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The roles of stimulus-response compatibility and mental rotation in mirror-image and left-right decisions.

Examined the relative roles of mental rotation and stimulus-response (SR) compatibility in mirror-image and left-right decisions. 15 Ss, aged 19–43 yrs, were shown rotated letters and asked to indicate whether the letters were normal or backward (mirror-image task). Ss were then asked whether a dot would be located to the left or right of each letter if the letter was upright (viewer-centered left-right task) or if the letter was both upright and normal (letter-centered left-right task). The functions relating reaction time (RT) to angular orientation were parallel across the 3 tasks, suggesting that SR compatibility played no role, and that the Ss mentally rotated the letters to the upright in each case. A marked increase in RT to backward letters in the letter-centered task suggested a 2nd rotation in depth to restore the letters to normal. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects on platelet aggregation and fibrinolytic activity during upright posture and exercise in healthy men

The circadian variation of acute myocardial infarction suggests that daily activities such as assuming the upright posture and performing different daily activities may trigger the onset of coronary thrombosis. Such triggering may result from unfavorable alterations in the balance between the prothrombotic and antithrombotic properties of the blood. The present study compares the effects of 2 common daily activities, assuming the upright posture and exercise, on platelet aggregation and fibrinolytic activity. In healthy male subjects, assuming the upright posture in the morning significantly increased platelet aggregation and produced only a moderate increase in fibrinolytic activity within 10 minutes. These changes were still present after 90 minutes in the upright posture. Supine posture for 45 minutes resulted in levels of fibrinolytic activity and platelet aggregation comparable to that observed before initially assuming the upright posture in the morning. Return to the supine posture for 45 minutes resulted in levels of fibrinolytic activity and platelet aggregation comparable to that observed before the initial assumption of upright posture. The changes recurred when upright posture was taken later in the day. Exercise did not increase platelet aggregation to levels beyond that produced by the upright posture, but was associated with a marked increase in fibrinolytic activity. Thus, exercise and upright posture produce distinctive alterations in the thrombogenic potential of the blood that may influence the timing of clinical vascular events.     

Serial position and isolation effects in a classroom lecture simulation.

Laboratory investigations of serial learning have demonstrated superior mastery by Ss of initially presented and final material over centrally located material. Isolating an item in the sequence tends to increase the probability that that item will be learned. Both effects were examined using meaningful discourse with 108 graduate students as stimulus material. Two counterbalanced forms of a tape-recorded lecture resulted in significant serial section and isolation effects favoring initial over middle and final material, final over middle material, and isolated over nonisolated material. Item counterbalancing coupled with nonsignificant forms and interaction effects indicate that results are not due to spurious inherent item difficulty differences. (21 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Hand preferences in unimanual and coordinated-bimanual tasks by tufted capuchin monkeys (Cebus apella).

Hand preferences in 26 capuchin monkeys (Cebus apella) were examined in 2 reaching-for-food tasks under 2 postural conditions. In the 1st task (unimanual), monkeys were required to reach for food from both a quadrupedal and an upright posture. A right-hand bias was found for the upright but not for the quadrupedal condition. In the 2nd task (coordinated bimanual), monkeys were required to extract the food from a hanging Plexiglas tube from both a crouched and an upright posture. A right-hand bias was found for both conditions. A significant increase in right-hand use was noted from the unimanual, quadrupedal, reaching task to the coordinated-bimanual task, with females exhibiting a greater right-hand preference than males. In addition, a significant effect of task complexity on strength in laterality was found. Results are discussed in the context of recent theories on primate laterality. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A violation of pure insertion: Mental rotation and choice reaction time.

Six experiments tested the assumption that the mental rotation process is purely inserted into a mirror–normal discrimination task. In Exp 1, Ss took significantly longer to respond to upright characters in blocks containing rotated stimuli than in blocks containing only upright stimuli. Exps 2 and 3 showed that this rotational uncertainty effect was not caused by the need to determine stimulus orientation, and Exp 4 showed that it was independent of the visual quality of the stimulus. Exp 5 showed that the effect was greatly reduced when Ss performed a go–no-go task rather than choice reaction time (RT), and Exp 6 showed that it was independent of the complexity of the response required in the choice task. Results suggest that response selection in a choice RT mirror–normal discrimination task is altered when mental rotation is added, violating the assumption of pure insertion. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Nonverbal interaction of patients and therapists during psychiatric interviews.

Videotaped interviews of 50 psychiatric inpatients and 25 control Ss with 5 psychiatrists and analyzed the nonverbal behavior, which was coded and recorded every 10 sec for 2 5-min segments per interview. After the interview the therapists rated the Ss on the Brief Psychiatric Rating Scale (BPRS). Results show that the psychiatric patients held their legs symmetrically, groomed themselves, shifted posture, and frowned more than the control Ss did, and smiled and looked toward the therapist less. Nonverbal behavior of patients varied according to BPRS factor scores: Withdrawal was positively associated with turning the head away and negatively associated with smiling. Thought Disorder was positively correlated with grooming. Anxiety–Depression was associated with holding the head even and with hand tapping; and Mania was correlated with sitting upright and smiling. In interviews with patients vs controls, therapists' behavior differed in head orientation, smiling, hand tapping, and foot movements. It also differed according to the patients' ratings on the BPRS. Results are discussed in terms of affiliative–conflict theory and the construct of the therapeutic role. (40 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)