Study Of Animal Communication Research Articles

The appropriate use of Zipf's law in animal communication studies

The appropriate use of Zipf's law in animal communication studies

Causes and consequences of song amplitude adjustment in a territorial bird: a case study in nightingales.

Vocal amplitude, one of the crucial factors for the exchange of acoustic signals, has been neglected in studies of animal communication, but recent studies on song variation in Common Nightingales Luscinia megarhynchos have revealed new insights into its importance in the singing behavior of territorial birds. In nightingales song amplitude is not maximized per se, but is individually regulated according to the level of masking background noise. Also, birds adjust their vocal intensity according to social variables, as in male-male interactions. Moreover, during such interactions, males exploited the directionality of their songs to broadcast them in the direction of the intended receivers ensuring the most effective signal transmission. Studies of the development of this typical long-range signaling suggest that sound level is highly interrelated with overall developmental progression and learning, and thus should be viewed as an integral part of song ontogeny. I conclude that song amplitude is a dynamic feature of the avian signal system, which is individually regulated according to the ecological demands of signal transmission and the social context of communication.

Anthropogenic Noise and its Effect on Animal Communication: An Interface Between Comparative Psychology and Conservation Biology

Conservation biology and comparative psychology rarely intersect, in part because conservation biology typically emphasizes populations whereas comparative psychology concentrates on individual organisms. However, both fields could benefit from their integration. Conservation biology can profit from an enhanced understanding of individual-level impacts of habitat alteration and the resulting implications for conservation mitigation strategies. Comparative psychology can gain from increased attention to the mechanisms of adjustment used by organisms to “in vivo experiments” created by anthropogenic change. In this paper, we describe a conceptual framework useful for applying our understanding of animal communication to conservation biology. We then review studies of animal communication with conservation implications, and report our own preliminary work that demonstrates our framework in action.

Timing of presentation of an audience: aggressive priming and audience effects in male displays of Siamese fighting fish (Betta splendens).

Studies of animal communication often underestimate the presence of individuals other than the signaller-receiver dyad. Signalling interactions often occur in the presence of non-participating individuals (audiences); the effect of these individuals upon the dynamics of interactions has been called the audience effect. Recent studies of fighting fish Betta splendens have shown that the presence of a male audience can increase aggression during interactions. However, in many of these studies males were allowed to see the audience prior to the interaction, thus such pre-exposure may have facilitated aggressive behaviour (aggressive priming). Here we present results of two experiments designed to examine the relative importance of priming and audience effects on the dynamics of aggressive interactions. Males that were pre-exposed showed higher levels of aggression during subsequent interactions regardless of the presence or absence of an audience. When only one of the interactants had been pre-exposed to the audience, the non-exposed male showed similar increases in aggressive behaviour, i.e. matching the level of aggression showed by his opponent. Taken together these results suggest that aggressive priming may have resulted in an over-estimation of the audience effect in previous studies. The results still highlight the importance of social environment in determining the dynamics and outcomes of aggressive contests.

Does Lateral Presentation of the Palmate Antlers During Fights by Fallow Deer (Dama damaL.) Signify Dominance or Submission?

A central aim of the study of animal communication is to identify the mode and content of information transferred between individuals. The lateral presentation of the antler palm between male fallow deer has been described as either a signal of individual quality or an attempt to avoid fighting. In the first case two phenotypic features have been proposed by which transmission of individual quality may be facilitated. These are antler size and antler symmetry. The alternative hypothesis proposes that the lateral presentation of antlers occurs as a consequence of averting a threatening posture and may signify a reluctance to fight. We examined whether mature fallow deer use lateral palm presentation as a display during fights to indicate antler size and symmetry. We found no relationship between presentation rate of the antler and antler size and symmetry. Furthermore, males did not preferentially present their larger antler to their opponent. We also investigated whether the rate at which males presented antlers laterally during a fight was related to their ability to win the fight. Our results show that the male who performed more presentations during a fight was more likely to lose it. There were behavioural differences in the way in which a bout of presentation ended; subsequent losers tended to turn their body away from their opponent and subsequent winners tended to lower their antlers to an opponent which we interpret as an invitation to continue fighting. We conclude that the lateral palm presentation serves to de‐escalate fighting between mature fallow deer. It is not a mechanism by which to communicate individual quality but rather an indication that a male is less committed to continuing investment in the current contest.

The Umwelt and its relevance to animal communication: introduction to special issue.

This introduction applies J. von Uexküll's (1934/1957) concept of the Umwelt to the study of animal communication, particularly as it pertains to studies presented at a recent workshop on animal communication in the context of the environment. The environment is conceived broadly in the articles that follow, including the many physical and social environments in which an animal may find itself. The Umwelt concept is briefly expanded here to include also the personal microenvironment of the signaler in which the signal is embedded into the suite of concurrent nonsignaling behaviors of the individual. Other animals may even infer aspects of the signaler's own immediate Umwelt by noticing accompanying attentional cues such as the direction of eye gaze. In this way, part of the Umwelt can be accessible to companions, facilitating the communication process.

Habitats for humanity: Effects of visual affordance on the evolution of hominid antipredator communication

Habitats for humanity: Effects of visual affordance on the evolution of hominid antipredator communication

Randomization Analyses: Mimicry, Geographic Variation and Cultural Evolution of Song in Brood-Parasitic Straw-Tailed Whydahs, Vidua fischeri

Although bird song has been an important model for investigating questions of behavior development, cultural evolution and population differentiation, the quantitative methods of analysis have been problematic. Here we develop and apply quantitative randomization methods to test hypotheses about these processes in a natural population of birds. Songs of the African brood-parasitic straw-tailed whydahs (Vidua fischeri) and songs of their host species, the purple grenadier (Granatina ianthinogaster), were compared in audiospectrograms for similarity to test the following hypotheses: Whydahs mimic the songs of their host species, they have local song dialects, neighboring males match their song themes, local males match the songs of local hosts, remote populations have different songs according to their geographic distance, and songs undergo cultural evolution over time across generations. Randomization analyses were completed using (1) Mantel matrix statistics and (2) tree-based measures employing Sankoff optimization of Manhattan matrices and approximate randomizations. Our results provide evidence for song mimicry, local song dialects, matching song themes between neighboring males, song matching of local whydah mimics and grenadier song models, correspondence of song differences and geographic distance, and cultural continuity with change in song traditions within a local population. These randomization methods may be useful in other studies of animal communication, and they are sufficiently general for use both with distance matrices derived either from naturalistic impressions of song similarity as in our example or from acoustic measurements.

BIOACOUSTICS OF SOUTHERN ELEPHANT SEALS. II. INDIVIDUAL AND GEOGRAPHICAL VARIATION IN MALE AGGRESSIVE VOCALISATIONS

ABSTRACT In traditional studies of animal communication, individual variability was sometimes considered less relevant than species specific aspects, mostly because the goal was the classifications of sounds in repertories. However, individual variability seems to have a significant role in signal function and evolution. In this paper, we analyse individual variation in the structure of aggressive vocalisations of male southern elephant seals and we compare sounds from our main study population, Sea Lion Island (Falkland Islands), with sounds recorded in the nearby population of the Valdés Peninsula (Patagonia, Argentina). We firstly analysed the repeatability of acoustic parameters at vocalisation and male level. Repeatability of bouts of the same vocalisation was extremely high and this confirmed that vocalisation is the fundamental level of organisation of male acoustic communication in this species. Also repeatability of vocalisations of individual males was very high and hence sounds may effectively convey information about identity of the individual who emits the sound. Male aggressive vocalisations were categorised into a small number of types and each male emitted always the same type of vocalisation. We compared the typology of sounds emitted by Sea Lion Island males with vocalisations by Valdés Peninsula males and we found striking differences. The two populations shared none of the sound types and, although similar in fundamental acoustics, sounds from the two populations had a different macrostructure. We conclude that these two populations show dialects in male acoustic communication, although the scarcity of recordings from other populations limits the scope of this conclusion.

ANIMAL COMMUNICATION AND EVOLUTION

The study of Animal Communication is a diverse endeavor encompassing disciplines from physics and chemistry to psychology and linguistics, traversing neurobiology, behavior and evolution along the way. No one treatment of this field could be definitive. Hauser has sampled it, however, to produce a treatment that encompasses both the subject's richness and its subtleties, and that is exquisitely clear in its presentation. This work can serve as an undergraduate text, an introduction to the novice researcher and a reminder to others of us of the initial excitement that drew us to this area of study.

DIRECTED ACTION AND ANIMAL COMMUNICATION

AbstractHuman action theory, with its emphasis on intentions and reasons, does little to enhance our understanding of the actions of nonhuman animals. Many animal (and human) actions are directed to objects in the world, including other animals. The notion of directedness can be analysed without attributing intentions or reasons to the agent. An action is directed to object X if and only if: (1) the agent singles out X, either by orientation or by selective performance of the action in the presence of X; (2) the agent recognizes X as a suitable object; and (3) the goal of the action is that X should be in a certain relation to the agent or to some other object. The goal of an action is not necessarily attributable to the agent as the agent's goal in acting. Moreover, an agent can have a goal in acting without understanding how the action achieves the goal. The usefulness of the concept of directed action in the study of animal communication is illustrated with examples from the recent ethological literature.

A Quantitative Technique to Compare and Classify Humpback Whale (Megaptera novaeangliae) Sounds

AbstractIn an attempt to minimize observer bias, numerical taxonomy methods were used to describe and classify humpback whale sounds. The spectrograms (N = 1255) were digitized into a 16 × 21 binary matrix. The rows were 16 frequencies selected on a logarithmic scale (0.12–8 kHz). The columns were 21 time samples taken every 0.1 s. Each point of the matrix was coded 1 if it lay over part of the sound. Other binary variables were added to code for relative intensity within a sound, frequency modulation and amplitude modulation. The sounds were then compared using the Jaccard similarity coefficient for binary data, and classified with average linkage cluster analysis. This technique produced 115 clusters, which were compared with my aural and visual impressions of the sounds. I agreed with most major categories identified by cluster analysis, but many small clusters had to be fused to other categories. This was partially due to the technique used, and to the complexity of the repertoire under study. Improvements are proposed to further reduce observer bias in classification of sounds, and thus make studies of animal communication performed by different researchers or on different species more easily comparable.

Ethology, Zoosemiotic and Sociobiology

Synopsis. Current research reveals that the somewhat separate subdisciplines ethology, zoosemiotic and sociobiology function together in clarifying animal behavior. Ethology is taken as the study of individual behavioral patterns, zoosemiotic as the study of animal communication, and sociobiology as the study of social organization. The explosive pro? gress in all research areas cannot be summarized briefly but examples are drawn to provide the flavor of each subdiscipline and their interactions. Among the illustrative topics selected are behavioral development, animal orientation, signal structure, the context of com? munication, language, mating systems and cooperative breeding. At junctures some possible paths toward future study are identified, but the concluding examples point to the principal theme and prediction: the integrated study of behavior combining historically distinct approaches?which promises to help clarify not only the lives of our fellow earthly inhabitants but our own lives as well.

Information measures: Statistical confidence limits and inference

This paper presents tested statistical methods for reducing sampling bias in, for assigning approximate confidence bounds to, and for testing hypotheses about information-theoretic measures used in the study of animal communication and in behavioral sequence analysis. These procedures are also applicable in fields other than animal behavior, including psychology and ecology. Results of a Monte Carlo evaluation of the methods, including comparison of these techniques with possible alternative procedures, are presented.

Possible Continuity Theories of Language

Serious difficulties with existing continuity theories of the relationship between human language and systems of communication in other animals have caused many linguists to reject the possibility of investigating this relationship. Some of the difficulties seem to be inherent in the assumption that continuity theories must be theories of comparative intellect. These difficulties can be avoided, however, by theories which place their major emphasis on the adaptive functions of communication systems in their ecological context. Recent work on the ontogeny of bird song provides a basis for such a theory, within which a new evaluation may be made of the significance of recent experiments on language abilities in chimpanzees. Theories on the origin of human language and its relationship to the communication systems of other animals have been grouped by Lenneberg 1967 into two types: continuity theories, which suggest that human language can be derived evolutionarily by well-understood processes operating on the kind of communicative display system general in the vertebrates; and discontinuity theories, which hold that human language is completely different from any known kind of communicative display system in other animals, that its evolutionary origins are not at all obvious, and that the study of animal communication probably will be of little use in increasing our understanding of human languages. To Lenneberg's dichotomy I should like to add another, between comparative-intelligence theories and ecological theories. Comparative-intelligence theories of the origins of language exist in both continuity and discontinuity guises. They emphasize that the crucial differences between human language and other communicative display systems lie in the structures of cognitive skills or 'forms of cerebration' (Lenneberg 1971:1), which are graded in phylogeny and which underlie the communicative system. Ecological theories, on the other hand, emphasize the adaptive properties of human language over other types of display systems in the particular selective contexts which were probably involved in the evolution of man. An emphasis on the role of intelligence or intellect is not necessarily central to their content. Further, they need not limit themselves to consideration only of man's close phylogenetic relatives. In the present paper, I review some properties of the comparative-intelligence kinds of theory, and show that a kind of theory based more closely in the ecological context of human evolution, and less in comparative intelligence, may make the beginnings of a continuity theory possible, in the sense that known processes of natural selection may be invoked to account for some aspects of human language. A careful investigation of the possibility of some form of continuity theory is

Electrical stimulation of the brain as a tool for study of animal communication. Behavior evoked in Mallard ducks (Anas platyrhynchos).

Electrical Stimulation of the brains (ESB) of 63 Mallard ducks (Anas platyrhynchos) that were free to move about in a 1.5 X 1.5 X 1.5 m chamber yielded detectable responses from 416

Electrical Stimulation of the Brain as a Tool for Study of Animal Communication; pp. 270–286

Electrical Stimulation of the brains (ESB) of 63 Mallard ducks (Anas platyrhynchos) that were free to move about in a 1.5 X 1.5 X 1.5 m chamber yielded detectable responses from 416 of the 515 sites tested (286 in males, 130 in females). Responses ranged from relatively simple acts such as feather-tract movements or rapid opening and closing of the bill through prolonged oiling-preening sequences to complex attack and escape activities. Plots of histologically verified electrode locations indicated that most responses were elicited from fairly extensive and widely (but not completely) overlapping regions. All attack points were from di- and telencephalic sites while escape responses were evoked from many mesencephalic points as well. Threat sites overlapped both of these response sets and threat accompanied all attack more intense than occasional nipsor jabs at a companion. Stimulus control of the evoked responses varied from questionable increases in probability of some acts to highly repeatable actions, that commenced with latencies of a second or less, at stimulus onset and terminated promptly at the end of stimulation. In attack and escape behavior variable actions were sometimes taken to achieve similar ends. Hunger, thirst and nonagonistic social behavior were not evoked.

Some social aspects of paralanguage

The term ‘paralanguage’ and the corresponding adjective ‘paralinguistic’ are less than ten years old but already they loom large in the study of animal communication. In one sense all non-language communications (kinesics, haptics, as well as “vocalization”) are paralinguistic but this term is now almost exclusively applied to significant, non-linguistic noises made with the vocal tract. Observations of these phenomena are of course quite old. Demosthenes undoubtedly studied “delivery” and “tone of voice.” There are pre-Christian statements on phonology also, but no systematic study of that subject antedates that of Grimm in 1819, and that was a lucky forerunner. Actual investigation of phonology as structure, as patterns in a system, began with Ferdinand De Saussure late in the nineteenth and early in the twentieth century. The first systematic study of paralanguage was by Henry Lee Smith, Jr. in a paper called “The Communication Situation,” mimeographed for the Foreign Service Institute of the United States Department of State in 1950. This was later expanded into “An Outline of Metalinguistic Analysis” in the 1952 Georgetown Round Table Conference on Linguistics and Language Study. Smith did not use the term ‘paralanguage,’ however, but ‘vocalization,’ subdivided into ‘vocal qualifiers’ and ‘vocal modifiers.’ Paralanguage became established with the most complete study to date, the 1958 article by George L. Trager “Paralanguage: A Preliminary Statement.” Other writers in the field are Norman A. McQuown and Charles F. Hockett. This study is more systematic than that of Smith and less complex than that of Trager. The infancy of the field, I think, warrants various approaches.