Open-ended categorization of chick-a-dee calls by black-capped chickadees (Poecile atricapilla)

The authors trained black-capped chickadees (Poecile atricapilla) in an operant discrimination with exemplars of black-capped and Carolina chick-a-dee calls, with the goal of determining whether the birds memorized the calls of conspecifics and heterospecifics or classified the calls by species. Black-capped calls served as both rewarded (S+) and unrewarded (S-) stimuli (the within-category discrimination), whereas Carolina chick-a-dee calls served as S-s (the between-category discrimination) in the black-capped chick-a-dee call S+ group. The Carolina call S+ group had Carolina calls as S+s and S-s (within-category) and black-capped calls as S-s (between-category). Both groups discriminated between call categories faster than within a call category. In 2 subsequent experiments, both S+ groups showed transfer to novel calls and propagation back to between-category calls. The results favor the hypothesis that the acoustically similar social calls of the 2 species constitute separate open-ended categories.     

Information theoretical approaches to chick-a-dee calls of Carolina chickadees (Poecile carolinensis)

One aim of this study was to apply information theoretical analyses to understanding the structural complexity of chick-a-dee calls of Carolina chickadees, Poecile carolinensis. A second aim of this study was to compare this structural complexity to that of the calls of black-capped chickadees, P. atricapillus, described in an earlier published report (Hailman, Ficken, & Ficken, 1985). Chick-a-dee calls were recorded from Carolina chickadees in a naturalistic observation study in eastern Tennessee. Calls were analyzed using approaches from information theory, including transition probability matrices, Zipf's rules, entropies, and information coding capacities of calls and notes of calls. As described for black-capped chickadees, calls of Carolina chickadees exhibited considerable structural complexity. Most results suggested that the call of Carolina chickadees is more structurally complex than that of black-capped chickadees. These findings add support to the growing literature on the complexity of this call system in Paridae species. Furthermore, these results point to the feasibility of detailed cross-species comparative analyses that may allow strong testing of hypotheses regarding signal evolution.     

Acoustic mechanisms of note-type perception in black-capped chickadee (Poecile atricapillus) calls

Acoustic communication in black-capped chickadees (Poecile atricapillus) has been studied intensively, the "chick-a-dee" call being among the most well described. This call consists of 4 note types; chickadees perceive these notes as open-ended categories and do so in a continuous manner, with As more similar to Bs and Bs more similar to Cs. Acoustic features contributing to the note-type differentiation are unknown. Recent analyses suggested that certain acoustic features may play a role in note-type classification. Here, the authors tested black-capped chickadees in an operant-conditioning paradigm to determine which features were controlling note-type perception. The results suggest that the note pitch and the frequency modulation in the initial portion of the note control the perception of note types.     

Social complexity can drive vocal complexity: group size influences vocal information in Carolina chickadees

One hypothesis to explain variation in vocal communication in animal species is that the complexity of the social group influences the group's vocal complexity. This social-complexity hypothesis for communication is also central to recent arguments regarding the origins of human language, but experimental tests of the hypothesis are lacking. This study investigated whether group size, a fundamental component of social complexity, influences the complexity of a call functioning in the social organization of Carolina chickadees, Poecile carolinensis. In unmanipulated field settings, calls of individuals in larger groups had greater complexity (more information) than calls of individuals in smaller groups. In aviary settings manipulating group size, individuals in larger groups used calls with greater complexity than individuals in smaller groups. These results indicate that social complexity can influence communicative complexity in this species.     

Call-note discriminations in black-capped chickadees (Poecile atricapillus)

Bioacousticians (M.S. Ficken, S. R. Ficken, & S. R. Witken, 1978) classified black-capped chickadee call notes from the chick-a-dee call complex into 4 note types (A, B, C, and D) identified from sound spectrograms. In Experiment 1, chickadees (Poecile atricapillus) learned operant auditory discriminations both within and between the 4 note types but learned the between note-type discrimination significantly faster. In Experiment 2, when the original, unrewarded between-category exemplars were replaced with novel, rewarded exemplars of these same categories, chickadees showed transfer of inhibitory stimulus control to the novel exemplars. In Experiment 3, when novel exemplars were replaced by the original exemplars, chickadees showed propagation of positive stimulus control back to the original exemplars. This evidence suggests that chickadees and bioacousticians accurately sort conspecific call notes into the same open-ended categories (R. J. Herrnstein, 1990).     

Behavioral consistency in a changed social context in Carolina chickadees

Stable personality-like influences on behavior have been documented in nonhuman animals (S. D. Gosling, 2001), but little is known about such influences within explicitly social contexts. The authors tested whether individuals of a socially complex avian species, Carolina chickadees (Poecile carolinensis), show consistent behavioral profiles when their social context changes. Consistency was tested using 7 groups of chickadees, each group comprising 2 female-male pairs. The 2 pairs from each group were isolated from one another until the male birds were switched between the pairs. The authors made several measures before and after the male switch, including measures of affiliative and agonistic behavior, self-maintenance behavior, and vocalizations. The authors observed strong behavioral consistency despite the major change in social context, suggesting that personality can influence this fundamental social relationship.     

Statistical classification of black-capped (Poecile atricapillus) and mountain chickadee (Poecile gambeli) call notes

Both black-capped (Poecile atricapillus) and mountain chickadees (Poecile gambeli) produce a chick-a-dee call that consists of several distinct note types. In some regions, these 2 species live sympatrically, and it has been shown that 1 species will respond weakly to songs of the other. This suggests that chickadee song, and potentially other of their vocalizations, contains species-specific information. We tested the possibility that call notes were acoustically sufficient for species identification. Black-capped and mountain non-D notes were summarized as a set of 9 features and then analyzed by linear discriminant analysis. Linear discriminant analysis was able to use these notes to identify species with 100% accuracy. We repeated this approach, but with black-capped and mountain D notes that were summarized as a set of 4 features. Linear discriminant analysis was able to use these notes to identify species with 94% accuracy. This demonstrates that any of the note types in these chickadee calls possesses sufficient information for species classification.     

If Empowerment Is the Goal...: Affirmative Action and social Interaction

The goal of affirmative action policies is to empower formerly disenfranchised groups. But what if the procedures used to implement these policies activate a set of social psychological processes that prevent the occurrence of productive social interactions between target-group and non-target-group members? With that question in mind, a conceptual model is developed which focuses on the potential effects of affirmative action procedures on social interactions between members of policy target and nontarget groups. To conceptualize these potential effects of procedures, the concept of a policy schema is introduced. Special attention is paid to the conditions under which beliefs about procedures contained in policy schemas will influence patterns of interactions between target-group and non-target-group members. With that as background, a call is made for more complete analyses of the social psychology of affirmative action.     

Constructing culture in cowbirds (Molothrus ater)

In past work, the authors produced divergent patterns of courtship and communication in juvenile male cowbirds (Molothrus ater) by providing them with different social experiences during their 1st year. Here the authors determined whether these different social patterns could be transmitted to new generations of juvenile males. In Experiment 1, the authors exposed groups of juveniles to adult males who differed in the amount of male-male competition they produced. In Experiment 2, they gave groups of juveniles either social access to adult males or only visual and acoustic access to those males. In both experiments, juvenile males developed patterns of courtship and competition similar to those expressed by the adult males with whom they had social contact. The juveniles never had the opportunity to observe some of the adults' behaviors that they came to replicate. This suggests that the role of the adults was to establish the social structure in the groups, modifying juveniles' early social interactions. Juveniles were then "cultured" within these different learning environments, constructing social behavior similar to the adult males' behavior in their 1st year.     

Is self-sacrificial competitive altruism primarily a male activity?

This study explored the basis of self-sacrificial prosocial behavior in small groups. Seventy-eight undergraduates (39M, 39F) filled out a thirty-item personality scale and then participated in a "group problem-solving study" in which the monetary success of a three-person group depended upon one of its members volunteering to endure pain (a cold stressor test) and inconvenience (being soaked in a dunk tank). There were 13 groups consisting of two females and one male, and 13 groups consisting of two males and one female. Across groups, the behavior of the altruist was judged to be more costly, challenging, and important and he/she was liked better, rewarded with more money, and preferred as a future experimental partner. Groups containing two males showed more evidence of competition to become altruists than groups containing two females, and personality traits were more effective predictors of altruistic behavior in males than in females. We conclude that competition between males and "showing off" are key factors in triggering self-sacrificial altruistic behavior.     

Social processes in communication and cognition in callitrichid monkeys: a review

Studies of vocal development in nonhuman primates have found little evidence for plasticity in vocal production, somewhat more for usage of calls, with the greatest plasticity arising in response to calls of others. Generally, similar results were obtained with callitrichid monkeys, the marmosets and tamarins, but with several interesting exceptions. Infant pygmy marmosets show babbling behavior with improvement in adult call structure related to the amount and diversity of babbling. Adult marmosets alter call structure in response to changes in social partners, and wild marmosets have vocal dialects and modify call structure according to how far they are from other group members, suggesting the potential to modify call structure in different social and environmental contexts, though direct learning of novel vocalizations has not been observed. Infant cotton-top tamarins do not produce adult-like calls in appropriate contexts, at least in the first few months of life, but through food sharing from adults infants learn about appropriate foods and the appropriate contexts for food vocalizations. Tamarins modify call structure and usage with changes in social status. Tamarins, unlike other monkeys tested, can learn to avoid noxious foods through observation of other group members, and can learn about novel food locations. Recent studies provide evidence of contextual imitation in marmosets. The plasticity in vocal communication and evidence of social learning in marmosets and tamarins relative to other monkeys may be related to the cooperative breeding system of marmosets and tamarins. With a high degree of behavioral coordination among group members, there is a priority on monitoring signals and behavior of others and adjusting one's own signals and behavior. This creates the context for vocal plasticity and social learning. Accepted after revision: 23 May 2001 Electronic Publication     

Discrimination of acoustically similar conspecific and heterospecific vocalizations by black-capped chickadees (<Emphasis Type="Italic">Poecile atricapillus</Emphasis>)

Chickadees produce a multi-note chick-a-dee call in multiple socially relevant contexts. One component of this call is the D note, which is a low-frequency and acoustically complex note with a harmonic-like structure. In the current study, we tested black-capped chickadees on a between-category operant discrimination task using vocalizations with acoustic structures similar to black-capped chickadee D notes, but produced by various songbird species, in order to examine the role that phylogenetic distance plays in acoustic perception of vocal signals. We assessed the extent to which discrimination performance was influenced by the phylogenetic relatedness among the species producing the vocalizations and by the phylogenetic relatedness between the subjects’ species (black-capped chickadees) and the vocalizers’ species. We also conducted a bioacoustic analysis and discriminant function analysis in order to examine the acoustic similarities among the discrimination stimuli. A previous study has shown that neural activation in black-capped chickadee auditory and perceptual brain regions is similar following the presentation of these vocalization categories. However, we found that chickadees had difficulty discriminating between forward and reversed black-capped chickadee D notes, a result that directly corresponded to the bioacoustic analysis indicating that these stimulus categories were acoustically similar. In addition, our results suggest that the discrimination between vocalizations produced by two parid species (chestnut-backed chickadees and tufted titmice) is perceptually difficult for black-capped chickadees, a finding that is likely in part because these vocalizations contain acoustic similarities. Overall, our results provide evidence that black-capped chickadees’ perceptual abilities are influenced by both phylogenetic relatedness and acoustic structure.     

The Quality of Group Decisions,Group Verbal Behavior,and Intervention

Individuals bring beliefs and knowledge to group meetings. Group decisions arise out of the exchange of these beliefs and knowledge. Because group interactions are mainly verbal, group verbal behavior should play a central role in determining the quality of group decisions, and process interventions should change group verbal behavior. Subjects were 168 new employees in a Japanese drug company, who constituted 42 four-person groups. Treatment groups received the Consensual Conflict Resolution (CCR) intervention that emphasizes a knowledge-based logical discussion and consensual resolution of conflicts. The group task was the NASA Moon Survival problem. It was found that (1) the quality of group decisions increases to the extent that group members exchange facts and reasons (defined as a "reasoning" orientation of group verbal behavior) and decreases to the extent that group members stick to their positions (defined as a "positional" orientation), and (2) the CCR intervention increases the reasoning orientation and decreases the positional orientation, thereby improving the quality of group decisions.     

Gender and Sex Role Differences in Group Decision-Making Social Interactions: A Behavioral Analysis1

Sex role formulations assume relationships between role orientation and adjustive social behavior. However, few studies have examined behavioral differences with respect to both gender and sex role orientation in realistically complex social interactions. In the current study, groups composed of four male and four female “representatives” from each sex role category (masculine-typed, feminine-typed, androgynous, and undifferentiated) were presented with two group decision-making tasks. Group interactions were videotaped and subjects' behavior was rated on social skill variables. Analyses of variance revealed gender differences with males performing more actively than females, especially when the content of the decision-making task involved more historically male-oriented topics. However, when subjects' group behavior was examined in relation to their sex role orientation, androgynous and masculine-typed persons of both sexes performed in a more active, instrumental manner than feminine-typed or undifferentiated persons. Further, correlational analyses indicated that females' masculinity scores were substantially associated with ratings of effectiveness in the decision-making groups. Implications of these findings are discussed.     

Effects of racial diversity on complex thinking in college students

An experiment varying the racial (Black, White) and opinion composition in small-group discussions was conducted with college students (N = 357) at three universities to test for effects on the perceived novelty of group members' contributions to discussion and on participants' integrative complexity. Results showed that racial and opinion minorities were both perceived as contributing to novelty. Generally positive effects on integrative complexity were found when the groups had racial- and opinion-minority members and when members reported having racially diverse friends and classmates. The findings are discussed in the context of social psychological theories of minority influence and social policy implications for affirmative action. The research supports claims about the educational significance of race in higher education, as well as the complexity of the interaction of racial diversity with contextual and individual factors.     

Autocracy bias in informal groups under need for closure

Two experiments investigated the tendency of groups with members under high (vs. low) need for cognitive closure to develop an autocratic leadership structure in which some members dominate the discussion, constitute the "hubs" of communication, and influence the group more than other members. The first experiment found that high (vs. low) need for closure groups, as assessed via dispositional measure of the need for closure, manifested greater asymmetry of conversational floor control, such that members with autocratic interactional style were more conversationally dominant and influential than less autocratic members. The second experiment manipulated the need for closure via time pressure and utilized a social network analysis. Consistent with expectation, groups under time pressure (vs. no pressure) showed a greater asymmetry of participation, of centrality, and of prestige among the group members, such that the more focal members were perceived to exert the greater influence over the groups' decisions.     

Triadic awareness predicts partner choice in male–infant–male interactions in Barbary macaques

Social knowledge beyond one’s direct relationships is a key in successfully manoeuvring the social world. Individuals gather information on the quality of social relationships between their group companions, which has been termed triadic awareness. Evidence of the use of triadic awareness in natural contexts is limited mainly to conflict management. Here we investigated triadic awareness in wild Barbary macaques (Macaca sylvanus) in the context of bridging interactions defined as male–infant–male interactions whereby a male (initiator, holder) presents an infant to another male (receiver, non-holder) in order to initiate an affiliative interaction with that male. Analyses based on 1263 h of focal observations on ten infants of one wild social group in Morocco supported the hypothesis that males use their knowledge of the relationship between infants and other adult males when choosing a male as a partner for bridging interactions. Specifically, (i) the number of bridging interactions among holder–infant–receiver triads was positively affected by the strength of the infant–receiver relationship and (ii) when two males were available as bridging partners, a male was more likely to be chosen as the receiver the stronger his social relationship with the infant relative to the other available male. This demonstrates that non-human primates establish triadic awareness of temporary infant–male relationships and use it in a naturally occurring affiliative context. Our results contribute to the discussion about the mechanism underlying the acquisition of triadic awareness and the benefits of its usage, and lend support to hypotheses linking social complexity to the evolution of complex cognition.     

Aggressive and affiliative behavior in green monkeys with differing housing complexity

Eleven green monkeys (Cercopithecus aethiops) were combined into three social groups (two heterosexual, one all-male) in enclosures with similar volume but different levels of environmental complexity (two or four compartments). Agonistic and affiliative interactions were recorded over a 21-week period. The two heterosexual groups had their environmental complexity reduced (number of compartments reduced by one-half and volume/floorspace reduced by one-third) for a 5-week period in the middle of the study. Rates of contact aggression were low throughout the study. In the group with complexity reduced to one compartment, rates of noncontact aggression and affiliative behavior increased, and remained high after complexity was restored. In the group reduced to two compartments, rates of affiliative behavior increased but rates of noncontact aggression decreased, trends which continued after complexity was restored. The all-male group exhibited low rates of affiliative behavior throughout. Two compartments appear to foster successful group formation, but any change in a group's enclosure can have long-term effects on rates of aggression. © 1992 Wiley-Liss, Inc.     

Carryover effects of feeling socially transparent or impenetrable on strategic self-presentation

The authors proposed that social orientations, such as feeling transparent or impenetrable, that are created in one context can carry over and interact with elements in a different context to influence strategic self-presentation. Participants in 2 experiments wrote narratives that made them feel transparent or impenetrable. Later, they believed they would discuss problems from a social intelligence test with other group members and believed they could do well or poorly on the problems on the basis of practice test feedback. Self-presentations of social intelligence revealed the hypothesized interactions. When transparent, participants adjusted their self-presentations to how well or poorly they expected to perform, but when impenetrable, they presented themselves positively regardless of performance expectations. These results mimic effects obtained when performance is actually made publicly accessible or inaccessible, broaden the conceptualization of strategic self-presentation, and call into question long-held assumptions surrounding public versus private manipulations.     

Social Identity and Intergroup Conflict

This paper explores why people identify with social groups and what this identification signifies for their sense of self, status in society and intergroup conflict. We describe various theories of social identity to elucidate ways in which individuals can negotiate their different social identities, and what this means for intergroup relations. We consider the implications for both majority and minority group members, and those from high and low status groups. We show that social identification is an essential part of an individual’s social existence, and that such identification is inextricably related to intergroup conflict. While overarching common identities have been hailed as a possible panacea for conflict, we demonstrate that such identities have differential effects for minority and majority group members. There is a serious tension between the assimilationist preference that the majority wishes for minority members to adopt, and the integrationist position that the minority group themselves prefer. We conclude with a call to focus research efforts on how to balance the needs of the many and the few in pluralist and unequal societies.