Intrafemale agonistic interactions in the domestic rabbit (oryctolagus cuniculus L.)

Agonistic interactions between adult domestic rabbit females were observed. Females were housed in groups of four in outdoor enclosures measuring 4 × 4 m. Agonistic patterns included aggression (AG), flight (FL), and submission (SB). Observations focused on 1) initial interactions between unfamiliar females, concomitant with the formation and establishment of a social structure (Phase 1); and 2) interactions between familiar females organized in a stable social structure (Phase 2). AG was frequent between unfamiliar females and appeared related to the acquisition of social dominance. When social organization was settled, there was a dramatic reduction in the number and frequency of aggressive behaviors. Similarly, FL was more frequent when females were unfamiliar, but it did not appear to be merely a response to AG. The decreased frequency of both AG and FL in Phase 2 was paralleled by an increased frequency of SB with respect to FL. Under stable social conditions, subordinate females frequently signalled submission to dominant counterparts. In contrast, the latter did not signal their social status with any consistent behavioral pattern. It follows that SB was not necessarily induced as the appropriate response to aggression given by dominant females. Thus, SB appeared relevant in social communication especially in structured groups, where it conveyed information on the actor's subordination and possibly inhibited the receiver's aggression. A further possibility is that it has an autonomous rather than secondary role in the maintenance of stable dominance/subordination relationships.     

Patterns of social preference across different social contexts in golden lion tamarins (Leontopithecus rosalia)

We investigated the role of mutual and circumstantial factors in maintaining exclusive social relationships in a New World primate. Four breeding pairs of golden lion tamarins (Leontopithecus rosalia rosalia) were allowed to interact with their mate or an unfamiliar, opposite-sex adult in each of 4 different social contexts: in view of the mate, out of the mate's view, with only the mate present, and with only the unfamiliar animal present. Males and females were in proximity to, approached, and sniffed their mates significantly more often than they did unfamiliar tamarins. These behaviors suggest a preference for the familiar mate. However, when mates were absent, tamarins demonstrated significantly higher levels of approach and sniffs toward unfamiliar animals. These patterns of behavior indicate that circumstantial factors, such as social context, may regulate social interactions between paired tamarins and unfamiliar, opposite-sex conspecifics.     

Severity of agonism of free-ranging patas monkeys differs according to the composition of dyads

Differences in the severity of behavior used in dyadic agonistic interactions of adult female and immature free-ranging patas monkeys (Erythrocebus patas) were assessed. The behaviors exhibited were rank-ordered according to severity. Analysis of data from 1,353 agonistic interactions indicated a significant difference in the severity of agonistic behaviors, based on the composition of the dyad. Interactions between two adult females contained the least severe agonism, whereas interactions between two immature monkeys contained the most severe agonistic behaviors. When adult females and immatures interacted agonistically, the severity of the behaviors emitted and received were related to the age of the immature monkey; the older the immature, the less severe were the agonistic behaviors. These results support the ideas that social stability mediates the severity of agonism, and that agonism serves a socializing function. © 1994 Wiley-Liss, Inc.     

Social organization predicts nature of infant-adult interactions in two species of wild guinea pigs (Cavia aperea and Galea monasteriensis)

The authors compared interactions of infants with mothers and unfamiliar females in a novel environment in 2 caviomorph rodent species: the harem-living Cavia aperea, the probable progenitor of the domestic guinea pig; and the pair-living Galea monasteriensis. In C. aperea, interactions with mothers and unfamiliar females were largely similar; in G. monasteriensis, interactions with the mother, but not unfamiliar female, were characterized by physical closeness and sociopositive behavior. In G. monasteriensis, plasma cortisol levels were lower when with the mother than when with the unfamiliar female. Results are consistent with the species' social organizations and suggest that behavioral interactions of pups with mothers and other females in domestic guinea pigs reflect primarily the social organization of the progenitor species rather than domestication.     

Social mediation of puberty: an adaptive female strategy?

Females of two hamster species with contrasting degrees of gregariousness were tested for social influences on the timing of sexual maturation. When female dwarf hamsters (Phodopus sungorus campbelli), a gregarious species, were housed with an adult male at weaning, they began estrous cycles significantly earlier than when they were housed alone or with their family. Females housed with one or two female siblings at weaning matured significantly later than did all other females. Once mature, females housed with familiar males conceived later than did females housed with unfamiliar males. Rearing conditions also affected body weight; those housed with female siblings grew more slowly and attained a lower weight at 8 weeks of age than did females in all other groups. In contrast, when weanling female golden hamsters (Mesocricetus auratus), a solitary species, were housed with either an adult male, two female siblings, or alone, they did not differ in their rate of sexual maturation or growth. It is suggested that the degree to which social factors can accelerate or delay puberty is an adaptive characteristic and may be correlated with the degree of gregariousness of a species.     

Effects of female presence on intrasexual aggression in male lizards,Podarcis hispanicus

Resource value and expected gain in reproduction may affect motivation to fight and the likelihood of winning. Previous experiments have showed that males increase their fighting effort when defending a territory that contains females. However, we hypothesized that for an intruding lizard, the value of a new territory may be lower if he already has a female in his own territory, and consequently, aggressivity should be lesser than if he has no access to any female. We staged encounters between males of the lizard Podarcis hispanicus in outdoor terraria to analyze the outcome and detailed behaviors involved in agonistic interactions in the presence or absence of a female in the terraria of resident and intruders. Our results showed that when a female was present, the level of aggressivity of the resident male was higher; the probability of winning the contest also increased, but only if the intruding male had no females in his own terraria. In contrast, when the intruding male was also the owner of another territory containing a female, residents were less aggressive. We suggest that the lack of information on the reproductive state of an unfamiliar female may be enough to decrease fighting motivation of an intruding male, if he has more expectations of success with his own familiar female. We conclude that differences in expected reproductive success with different females may help to decide the outcome of conflicts between males quicker and cheaper. Aggr. Behav. 28:491–498, 2002. © 2002 Wiley‐Liss, Inc.     

Social environment and reproduction in female European rabbits (Oryctolagus cuniculus): benefits of the presence of litter sisters

The authors investigated in an observational study the consequences of the presence of litter sisters on the social interactions and on reproductive performance of young female European rabbits (Oryctolagus cuniculus) from a population living under seminatural conditions. In early winter, when all young females were settled in a social group, they were characterized by the presence or absence of litter sisters in their groups. Females with litter sisters in their groups displayed significantly more positive social interaction with females of their social group compared to females without sisters, whereas this difference was mainly due to the high frequency of positive social interactions among the respective sisters. Such differences between the females of both categories were already apparent during the animals' juvenile phase, before the females integrated into a particular group: females which later had litter sisters in their group showed more positive social behavior than females which later no longer had litter sisters. During their first breeding season, females with litter sisters present generally started to breed earlier by an average of 14 days. A more favorable social environment might have possibly facilitated the earlier onset of breeding in females with present litter sisters by attenuating the negative consequences of stress.     

Social competence is reduced in socially deprived rhesus monkeys (Macaca mulatta)

Rhesus monkeys deprived for some period from their mother have often served as a model for the effect of adverse rearing conditions on social competence in humans. Social competence is the capacity to react in a species-specific way to social interactions. The current study assesses whether early deprivation from peers also affects the rates of behavior and social competence in rhesus monkeys. This was studied in groups of rhesus monkeys with different rearing conditions: subadult females that were mother-only reared during their first year of life and subsequently housed with peers were compared with subadult females from five naturalistic social groups. Socially deprived monkeys showed higher rates of submission and stereotypic behaviors than socially reared individuals. In addition, they show socially incompetent behavior, since they react with agonistic behavior to nonthreatening social situations. The results suggest that this socially incompetent behavior is rooted in a general feeling of anxiety toward group companions. The authors hypothesize that anxiety negatively affects social information processing, which results in socially incompetent behavior.     

Conflict and postconflict behaviour in two lemur species with different social organizations (Eulemur fulvus and Eulemur macaco): A study on captive groups

Although the brown lemur (Eulemur fulvus) and the black lemur (Eulemur macaco) share many life parameters and are genetically closed, they show considerable difference in social organization. Dominance relationships with no systematic effect of gender characterize the former, whereas the latter is based on female dominance. The present study was done on two captive groups of brown lemurs and one semi–free‐ranging group of black lemurs. To reveal links between the specific pattern of social organization and agonistic behaviors, agonistic interactions were analyzed for each species as for their context of occurrence, symmetry, initiation, and outcome. The effect of gender in the initiation of conflicts appeared as the only notable interspecific difference, aggression being mostly initiated by females in E. macaco and by males in E. fulvus. Conflict outcome was generally in favor of the initiator, regardless of gender in both species. The analysis of postconflict behaviors revealed conciliatory processes in the brown lemur, whereas reconciliation seemed to be absent in the black lemur, a characteristic shared with the ring‐tailed lemur (Lemur catta), another lemur species with female dominance. Aggr. Behav. 28:62–74, 2002. © 2002 Wiley‐Liss, Inc.     

Intrasexual interactions among female golden hamsters (Mesocricetus auratus) over the estrous cycle

Social interactions of cycling female golden hamsters paired with ovariectomized animals in large enclosures were primarily agonistic over the 4-day estrous cycle. These aggressive interactions were intense as indicated by frequent occurrences of chase and flight behavior. Dominant and subordinate social ranks were established in the majority of pairs (96%) tested, and even females in sexual heat were capable of attacking and dominating their rivals. Furthermore, cycling females exhibited significantly more aggressive acts than ovariectomized opponents 1 day prior to sexual receptivity. No differences in fighting patterns were found between animals on the other 3 days of the estrous cycle. Additional analyses revealed clear differences in agonistic elements, including flank marking, between dominant and subordinate females regardless of whether they were gonadectomized or intact. These analyses also showed that dominant individuals frequently chased and bit opponents during encounters within their nesting area. The data are examined for implications on the adaptive organization of female hamster agonistic behavior and the neuroendocrine regulation of species-typical behavior over the estrous cycle.     

Preschoolers' inhibition in their home: relation to temperament

Researchers assessed 58 preschoolers' reactions to an unfamiliar person and unfamiliar objects in their familiar home environment. Children participated in a 30-min procedure designed to elicit behavioral inhibition, including (a) a free-play period with a stranger present, (b) a structured interaction with the stranger, and (c) uncertainty-eliciting tasks. Behaviors representing the child's reactions toward the mother, stranger, and novel objects were coded. Mothers completed a temperament scale. Preschoolers exhibited behaviors indicative of inhibition toward unfamiliar social and nonsocial stimuli; behaviors remained stable across increasingly intrusive episodes. The approach/withdrawal component of temperament was related to behavioral inhibition. Individual differences in mood did not appear to be related to differences in inhibition. Parent reported temperament was related to researcher-observed behaviors.     

Preschoolers' Inhibition in Their Home: Relation to Temperament

Researchers assessed 58 preschoolers' reactions to an unfamiliar person and unfamiliar objects in their familiar home environment. Children participated in a 30-min procedure designed to elicit behavioral inhibition, including (a) a free-play period with a stranger present, (b) a structured interaction with the stranger, and (c) uncertainty-eliciting tasks. Behaviors representing the child's reactions toward the mother, stranger, and novel objects were coded. Mothers completed a temperament scale. Preschoolers exhibited behaviors indicative of inhibition toward unfamiliar social and nonsocial stimuli; behaviors remained stable across increasingly intrusive episodes. The approach/withdrawal component of temperament was related to behavioral inhibition. Individual differences in mood did not appear to be related to differences in inhibition. Parent reported temperament was related to researcher-observed behaviors.     

Agonistic and sociable behaviors in the mound‐building mice,Mus spicilegus: A comparative study with Mus musculus domesticus

Present social organization and mating systems result from selective pressures and ecological conditions but also from proximate interactions between individuals. Many studies report on a polygynous mating system with a social group territoriality in commensal populations of Mus musculus domesticus. However, little is known about the social organization of other Mus species living in outdoor conditions, such as the mound‐building mouse Mus spicilegus. Comparative studies between M. m. domesticus and M. spicilegus have already shown behavioral differences in female sexual preferences and paternal care. To study agonistic and sociable interactions and gain insight into the social organization and the mating system of M. spicilegus, the present study compared intraspecific dyadic encounters between unfamiliar adults in these two species. Results demonstrated less tolerance between females and between the sexes in M. spicilegus than in M. m. domesticus unfamiliar mice. The consequences of those differences between M. spicilegus and M. m. domesticus on social organization and mating system are discussed. Aggr. Behav. 28:75–84, 2002. © 2002 Wiley‐Liss, Inc.     

Facial experience during the first year

Parents of 2-, 5-, 8-, and 11-month-olds used two scales we developed to provide information about their infants' facial experience with familiar and unfamiliar individuals during one week. Results showed large discrepancies in the race, sex, and age of faces that infants experience during their first year with the majority of their facial experience being with their primary caregiver, females, and other individuals of the same-race and age as their primary caregiver. The infant's age and an unfamiliar individual's sex were predictive of their time spent interacting with one another. Moreover, an unfamiliar individual's sex was predictive of the attention infants allocated during social interactions. Differences in frequency and length of interactions with certain types of faces, as well as in infant attention toward certain individuals, all likely contribute to the development of expertise in processing commonly experienced face types and deficiencies in processing less commonly experienced face types.     

Play fighting and the development of agonistic behavior in male and female rats

Two longitudinal studies were conducted to quantify the social behaviors exhibited by both male and female Long-Evans rats from the immediate postweaning period until young adulthood. In Experiment 1, male sibling pairs engaged in a high level of play fighting during the early juvenile period but such activity declined to a level significantly lower than that of female and mixed-sex pairs after 54 days of age. In Experiment 2, social exchanges during maturation were examined during the presence and absence of the piloerection response in an effort to distinguish play fighting from agonistic interactions. In male pairs, piloerection was rarely seen before 55–75 days of age but thereafter occurred with increasing frequency especially among dominant males. Furthermore, subordinate males retreated from their dominant partners and remained in an escape chamber for a significant amount of time only during encounters involving the exhibition of piloerection. This finding suggests that piloerection can be useful in identifying play and aggressive interactions. In female and heterosexual pairs, piloerection was observed infrequently during social encounters occurring throughout maturation. In addition, when given the opportunity to escape, females were less likely to retreat from play activity if their partner was another female than a male.     

Dogs’ attention towards humans depends on their relationship, not only on social familiarity

Both in humans and non-human animals, it has been shown that individuals attend more to those they have previously interacted with and/or they are more closely associated with than to unfamiliar individuals. Whether this preference is mediated by mere social familiarity based on exposure or by the specific relationship between the two individuals, however, remains unclear. The domestic dog is an interesting subject in this line of research as it lives in the human environment and regularly interacts with numerous humans, yet it often has a particularly close relationship with its owner. Therefore, we investigated how long dogs (Canis familiaris) would attend to the actions of two familiar humans and one unfamiliar experimenter, while varying whether dogs had a close relationship with only one or both familiar humans. Our data provide evidence that social familiarity by itself cannot account for dogs’ increased attention towards their owners since they only attended more to those familiar humans with whom they also had a close relationship.     

Effects of losing and testosterone upon subsequent behavior in male and female S3 (Tryon Maze Dull) rats

Attempts were made to determine whether modification of agonistic behavior by experience differs in the sexes and if so, whether testosterone is involved in this response. Gonadectomized male and female CPB-S3 (Tryon Maze Dull) rats were treated with testosterone propionate (TP, 250 μg) or vehicle and subjected to tests in which they became either winners or losers. S3 males and females were tested against Long Evans rats to become losers or against Wistar rats to become winners. Subsequently, S3 winners were tested against losers. In addition, winners and losers were tested against naive S3 opponents of the same sex. After varied agonistic experiences, all animals were tested for social preference in a situation in which they could choose between their respective opponents without the possibility of social interaction. Thereafter, they were also exposed to a two-choice passive avoidance learning procedure to see if the behavioral effects of aggressive interactions generalized to nonsocial learning. Males and females reacted differently to winning or losing, the presence of testosterone being a critical factor in the manifestation of this sex difference. Relatively permanent effects on aggressive and other behaviors were only established in TP-treated males. Losing experiences in the social-preference test generally led to a slight preference for naive, less aggressive animals. Testosterone-treated male losers, the group expected to be most vulnerable to generalized inhibition and impairment of learning, did not differ from other categories in the two-choice passive avoidance procedure, although marked differences were observed between the sexes and between testosterone and oil-treated animals.     

Infant social behavior in front of a mirror and in front of a familiar and an unfamiliar peer

In this study, we explored the differences in infant social behaviors in front of the mirror and in front of a familiar and an unfamiliar peer. We assumed that infant social behaviors in front of the mirror constitute mainly an exploration of the mirror image characteristics. Our observations were videotaped and coded according to definitions of social behavior in infant-infant situations. The results obtained indicate that 6- to 13-month-old infants display significantly more frequent social behaviors in front of a mirror than in front of a familiar or an unfamiliar peer. These behaviors are characterized by tactile contact with the mirror surface, adapting the hand to this surface, and very frequent coordinated social behaviors. This pattern of social behaviors in front of the mirror is discussed and linked to the exploration of distinctive characteristics of the self-reflected image such as perfect synchronicity of movement and two-dimensionality.     

Social and nonsocial behaviors of adult rhesus monkeys after amygdalectomy in infancy or adulthood.

At 6 yr of age six female rhesus monkeys that had sustained bilateral amygdalectomy in infancy, and five intact controls, were transferred to an observation cage where behaviors were recorded while the monkeys were (a) alone, (b) paired with unfamiliar stimulus animals, and (c) paired with familiar monkeys from the opposite experimental group. The five adult controls then underwent amygdalectomy, and all tests were repeated with the infant- and adult-operated animals. Infant-operated monkeys changed behaviors more rapidly than did intact controls in social and nonsocial situations, and their activity levels were less modified after a 24-hr period in the observation cage. They were subordinate to intact controls but expressed less fear than did controls when briefly placed with an unfamiliar aggressive animal. Adult amygdalectomy produced many changes in behavior, but these aberrations were identical to those observed in like-age monkeys that had been amygdalectomized in infancy. Infant-operated monkeys demonstrated more behavioral deficits at 6 yr than they had earlier in life.     

“Generic” and “Specific” Expertise in English: An Expert/Expert Study in Poetry Interpretation and Academic Argument

In this study, eight English professors thought aloud as they read four lyric poems and composed a short text proposing a hypothetical talk about them for a professional conference. The study used a crossed design in which participants read a poem in each of the following conditions: familiar to them and close to their professional writing, familiar and far, unfamiliar and close, unfamiliar and far. When reading familiar poems, participants produced longer protocols and more elaborate interpretations. When planning their conference talks, participants produced longer protocols for poems that were far from their professional writing as they struggled to access sufficient background knowledge. Participants attempted to say something “new” about the poems, and they closely monitored the limits of their knowledge. These results suggest that English professors, just like experts in other disciplines, develop both “generic” and “specific” expertise. Implications for expertise research, literature instruction, and academic literary scholars are considered.