PSYCHOLOGICAL PERSPECTIVES IN THE GENERAL STUDY OF ANIMAL BEHAVIOR
It is much easier to characterize the ways that psychologists approach the study of animal communication, the kinds of problems they see, and the methods they use in seeking solutions than it is to delineate the subject of the study. There are some rather typical features of the perspective in which psychologists view animal behavior in general, and these are quite distinct from the points of view of zoologists concerned with behavior. These differences are, of course, due to historical differences between the two sciences, for though both have strands leading backward to common ties, especially to Darwin and his collaborators, in the history of psychology these strands have been interwoven with many others which are quite definitely not biological in color and origin. Thus psychologists, as their name clearly attests, have been concerned with such mental processes as perception, cognition, affection, and the modification of these by prior experience. These processes are clearly, within our cultural tradition, attributes of human minds. And, just as clearly, the history of the attempts to develop a scientific understanding of them has been fraught with great difficulties.
When Darwin opened evolutionary perspectives in which to regard human life, these properties of human mentality were also exposed to evolutionary consideration. The interest of psychologists in animal behavior was originally prompted by their desire, which was quite consistent with the then prevalent notions of evolution, to establish a phylogeny of human mentality by comparing the processes of animal mental activity with respect to their counterparts in human mentation. But this numerically small group of workers concerned with comparative psychological studies was eventually greatly outnumbered by those who turned their attention to animal behavior for quite different, though related reasons. On the basis of essentially orthogenetic and linear views of human evolution, it was reasoned that the supposed precursors to human psychological processes were not only literally primitive but consequently simpler than their human homologues. So when by the first few decades of this century large amounts of frustration had accumulated as the most prominent achievement of the efforts of psychologists to submit these intractably complex human processes to laboratory study, more and more psychologists turned to the standard laboratory animals, chiefly rodents and carnivores. Along with this shift in species of laboratory subjects, there was a shift in the theoretical vocabularies employed, but these verbal changes only partially obscured the identity of the newer research goals with the old. Psychologists were still intent on studying psychological, and hence human, processes, but in their presumably simpler manifestations in the laboratory rat or cat.
In the newer pattern of laboratory work and thinking an increasingly dominant motif emerged from the blending of the Darwinian notion of adaptation with the associational ideas of mental development that were inherited from the British empiricists. This trend eventuated in the supersedence of adaptive learning, the modification of behavioral dispositions in response to changes in the immediate environment, as the foremost preoccupation of most psychologists studying animal conduct that has prevailed to the present. But the features of psychological investigations of animal behavior which most distinguish them from those of zoologists do not derive from this focal emphasis on learning in itself so much as from the conceptualizations that provide the structure and motivation for this work; much of psychology’s original constitution is preserved intact, though in a much transmuted form, in these current conceptualizations. The original goal toward which psychology was launched at its inception as an independent enterprise was the development of scientific understanding of the generalized human mind, and thus it began by subjecting the presumed environmental sources of the properties of individual minds to close laboratory control in an effort to determine the general interrelations between environmental and mental events.
Nowadays the quest for general laws governing changes in behavioral dispositions has largely replaced the original goal as the stated task of psychology, though because it is supposed that, if successful, this quest would thereby furnish all that was originally sought which is scientifically feasible, it is clear that what has changed most is not the original goal but the conception of scientific methods and their limits. But the most important point for the present considerations is that the over-all strategy and even many of the tactics of psychological research have remained unchanged; namely, closely controlling the immediate environment of individual organisms in order to determine the general regularities in the relations between environmental and behavioral changes. In using nonhuman organisms, psychologists are actually pursuing the same ends, but with what they believe to be more amenable material by virtue of the presumed greater simplicity of the processes governing behavioral adaptation in nonhumans and the greater ease of imposing the required environmental controls. This is to say that in large measure the use of nonhuman research subjects is thought to be simply a matter of substituting a more suitable study medium for one more recalcitrant. And, just as the first laboratory psychologists were trying to discern the general features of all mental processes, and were not only uninterested in but even annoyed by differences in mental processes between individuals, the similar emphasis on generality in formulâting laws of behavioral modification has in the same way resulted in a lack of concern with individual and species differences, except in so far as these might be connected with the practical problems of husbandry and susceptibility to laboratory control.
There are, of course, many divergencies from the main stream of contemporary psychological research in animal behavior, some stemming uninterruptedly from the older interests in cross-specific psychological comparisons and some arising from more recent crosscurrents with various streams of biological research in the anatomy, endocrinology, genetics, and general physiology of vertebrate drive and emotional systems. But, in the main, the present intensive concentration on general processes of behavioral modification, together with its peculiar historical background, has resulted in a variety of interrelated characteristics that distinguish psychological thinking about animal behavior from that of zoologists. Some of these characteristics have already been mentioned: the location of the work in laboratories, the concentration on individual, intact animals, and the lack of attention given to species differences of all sorts. Closely connected to these are others that are less obvious but of equal importance. The urge to develop completely general laws of behavioral modification, along with the longstanding institutional value placed upon conceptual parsimony, has led to a search for the least common denominator obtaining across all processes by which behavioral dispositions of any animal are modified through changes in their environments.
As a result, psychologists have characteristically tried to simplify the environment and the kinds of behavioral dispositions as far as possible. Unfortunately, because of these enforced limitations on the kinds of environmental-behavioral interactions, and because the complexities of species, age, sex and other genetical differences are purposely avoided, the accounts provided are often as simplistic as the problems investigated. What is even more disheartening is that these restrictions promote a kind of self-perpetuating provincialism which immunizes and isolates the thinking of psychologists against the possibility of potentially valuable cross-fertilization with other scientific disciplines working within the same range of phenomena. Nevertheless, the intensive concentration on adaptive learning has provided psychologists with a body of information, analytic perspectives, and some powerful methods of manipulating certain features of vertebrate behavior that can be of considerable value in studying animal communication.
ANIMAL COMMUNICATION AND THE ANALYSIS OF SOCIAL BEHAVIOR
From what has just been said the reasons for the relatively small amount of research that psychologists have conducted on animal communication should be clear. What little that has been done is mostly due to the older concerns with essentially anthropocentric comparisons of social cooperation (Yerkes and Learned, 1925; Crawford, 1941; Wolfle and Wolfle, 1939; Mason and Hollis, 1962). Furthermore, it has been confined to very few species (mostly higher primates) and, with the very notable exceptions of the investigations of Carpenter (1964), Nissen (1931), and Hall and DeVore (1965) on free-ranging primates, it has been conducted in laboratory settings having little connection with the natural environments of these animals. As might be expected, all these studies are remarkably uniform in their concern for analyzing the social events examined on the level of the immediate environmental determinants of the particular actions of individual participants. This emphasis on the individual, when consistently held, and with full awareness that it is but one of the several required for a complete assessment, can be most helpful in clarifying some of the issues, both conceptual and substantive, arising in the study of animal communication.
Most of the difficulties besetting the efforts to develop a better understanding of animal communication are related to the strong tendency to make it conceptually more special, in one way or another, than it really is. The notion of communication can be easily extended to encompass all phenomena of life, for the basic idea of biological adaptation can be regarded as involving communication within gene pools and between them and their environments. Even on the behavioral level this broad view of animal communication seems to become more fitting as we discover previously unsuspected ways by which animals communicate with their environments, such as the echo-ranging of some bats and dolphins. But however exciting and impressive these discoveries are, they are no more (nor less) marvelous than, for example, the olfaction of carnivores or the vision of higher primates; for we are coming to appreciate more and more that the active wresting of information from the environment, rather than simply reacting to environmental changes, is characteristic of all higher modes of animal adaptation.
However, it is much more common to restrict the field of animal communication to interactions of a social nature. This restriction is surely warranted because the interactions of an animal with its social environment are most often marked by some degree of specialization and by relatively greater reciprocity of influence and concomitant fluidity than interactions with its nonsocial environment. This is not to say that the behavioral processes and mechanisms of social interactions are necessarily different in kind from those involved in interactions with nonsocial environments, but only that pressures related to social factors have participated in their evolution and ontogenetic development (Emerson, 1960; Wynne-Edwards, 1963). As far as the present discussion is concerned, it does not matter how the actions of these socially derived selection pressures are conceived, that is, whether they require augmentation of our current notions of population genetics to accommodate some sort of “group” selection (Wiens, 1966), but their clear presence in so many forms of animal social interaction justifies setting off social communication as a special part of the more general problem of animal communication.
Though this distinction is valuable and easily recognized, most theoretical statements of the domain of animal communication go further to assert or imply that it is to be considered as a subordinate part, separate and distinct, of social behavior. When examined at the level of the individual participants, this is clearly wrong; for social communication and social behavior are basically identical. At bottorn, can anything more be said of social behavior than that it is the partial, and usually reciprocal, determination of an individual animal’s actions by one or more other animal’s actions through processes shaped by social factors? But can communication between animals be considered something other than just this?
There are a number of reasons contributing to the widespread but mistaken thought that social communication among animals is a subject to be set apart from other social behavior, and it will be worthwhile to examine some of them at ¿¿áï point. Several of these reasons derive from rather loose analogies to certain properties of man’s linguistic actions that appear to permit them to be easily distinguished from the rest of his social interactions. But man’s linguistic activities are obviously an exceedingly specialized form of animal communication, and so it is extremely risky to apply conceptualizations growing from what are felt to be the properties of linguistic communication to nonlinguistic communication. (Caution in proceeding in the reverse direction is at least equally necessary.)
One of the most prominent sources of the strength of the inclination to separate communication from social behavior in general comes from the feeling that, along with much of human linguistic interactions, successful communication among animals involves the transmission of information or some other commodity from one participant to another. That is, it is thought that something is literally made common to both signaler and recipients that would otherwise remain the private possession of the signaler. This idea is closely associated with the notion that communication occurs only when an animal, the signaler, performs some sort of action and by this action generates the signal whose reception by others comprises the information transmission. And, to these ideas is often linked still another—that the signaler performs the act of signal emission with the intention or purpose of transmitting the information the signal is said to carry to the recipient. The question of the purpose or intention of acts of signal emission will be examined in the next section of the discussion when ecological considerations will be introduced, but for the present we will confine ourselves to consideration of the behavior of the individuals participating in social interactions. In so doing, we may hope to clarify the nature of the claim that the presence of information transfer in animal communication is what distinguishes it from social behavior in general. We can proceed by first examining the behavioral processes that we think are involved in information transmission in human linguistic communication and the evidence we have that something on that order does occur, and then seeing if the evidence that may be available for animal communication is sufficiently similar to the human case to warrant the attribution of similar processes to animals.
All conceptions of the behavioral processes involved in information transmission include a separate process of information recognition, or decoding as it is sometimes called, that is independent of whatever behavior might ensue from the recognition of that information. Or, as we often think of the process, the information is first recognized, or decoded, and then, if required, action based on it is taken. But it is important to appreciate that the action, if any, that is taken on receipt of the information is not the only indication available to us that the process of information recognition has occurred, for by itself such action would only indicate reception of a signal which was at the time effective in changing the receiver’s behavior.
Thus, for example, if a person is told that his house is on fire and his children are home, and he forthwith sets out for his home, we are justified in ascribing his departure to his acting on the information given to him because we have ready access to many different kinds of evidence of his recognition of the information in addition to, and independent from, just the fact of his leaving, which in itself would only indicate that he had heard something and that it was behaviorally effective. For instance, we could intercept him and ask why he is in such a rush or where is the fire. We can see then that the concept of information transfer, to be something beyond effective social stimulation, involves a separate process of information recognition and that this concept is warranted only when there are multiple lines of evidence leading to this separate process itself other than the action that is presumed to be its resultant.
Now, it is usually not at all difficult to meet these conceptual and evidential requirements in analyzing linguistic communication and certain human nonlinguistic communication, though it is especially valuable to notice in both cases the primary role of linguistic processes in providing the necessary evidence for information transmission. But it is at least extremely difficult, if not impossible, to adduce convincing evidence for this separate process in animal communication. If, for example, it is supposed that the response of a chicken to the alarm signal emitted by another is due to the transmission to the recipient of the information that an airborne predator is nearby, then what evidence is available for the supposed information transfer other than the flight response and other less specific indications of physiological arousal? But if the behavioral evidence that is offered in support of the idea of information transmission in animal communication is the same behavior that is supposed to result from the recipient’s acting upon the received information, then there is no way to distinguish the information the signal is supposed to carry to the receiver from its effectiveness as social stimulation, and if this is so then the distinction between animal communication and social behavior is surely quite empty and gratuitous, at least when applied to the processes governing the conduct of the animals participating in the interaction.
There is another way in which behavioral considerations might be thought to provide a conceptual distinction between animal communication and social behavior that can be considered briefly. The proposal just examined might be twisted around to make social behavior a special case of animal communication. This might seem especially appealing when considerable time or distance separates signal emission from reception as, for instance, with the pheromones of the social insects or the odiferous territorial markings of various mammals. But there are good grounds for objecting to this distinction. It rests on arbitrarily restricting the notion of social behavior to individuals in face-toÎface contact and is probably another reflection of our anthropocentric biases. Though visual and tactile channels are immensely important in the social behavior of ourselves and other higher primates, why should we think that the chemical signals in the examples mentioned provide any less direct social contact for those animals whose commerce with their environments is much more dependent on chemical sensation?
These considerations argue against any categorical conceptual distinctions at the behavioral level between animal communication and social behavior in general and for their fundamental identity, but the argument is perhaps not convincing unless we can clarify the confusion that arises quite naturally from basing our assessment of specializations in social behavior on the conspicuousness of their occurrences or the number of individuals involved. These specializations are, of course, most easily appreciated when the patterns of social stimulation and the behavioral changes they evoke are very obvious and regular in their recurrences and when there is clear indication that the form and adaptive significance of the behaviors depend primarily on their social effectiveness. In these circumstances the use of the terms signal emission and reception is especially appealing and has become quite standard. Thus, for example, in the agonistic interactions of domestic dogs there are very striking patterns of stimulation produced by the actions of the participants which are easily seen to result in consistent changes in the comportment of other antagonists without any bodily contact between them. It is easy to understand why we are inclined to regard the growls, adjustments of muzzle and postural musculature, and so forth, as threat signals and look on the social consequences of these as the outcomes of signal reception.
If this terminology is divested of the connotations of information transmission in regard to the behavioral processes involved, there surely can be no objection to this usage. However, the point is that for many animal behaviorists only such very conspicuous instances of social specialization are regarded as comprising the field of animal communication, perhaps because only in these instances is the use of signaling terminology so appealing. But what we must appreciate is that socially specialized behavior processes also occur in situations in which their detection is far more difficult. The socially effective patterns of stimulation may not be so conspicuous, either because of limits on our observational capabilities or because of the lack of stereotypy or stability in signal recurrences, or their identity may be obscured because the actions by which the signals are generated or the actions which they evoke in others may serve concurrent adaptive purposes. Returning to the example of the dogs, many workers are inclined to think that if the battle were actually joined, the participants’ actions would have to be considered as social because of there being more than one individual involved, but that there would be no communication between them as there had been in the preceding interaction. However, if we are to regard social behavior as something more than merely that at least two individuals are interacting, then the issue is concerned with whether the actions of the individuals in response to one another are specialized in their social effectiveness. Now, obviously the detection of socially specialized actions in the commotion and violence of a dog fight is a much more difficult problern than it is in the fight’s preliminaries. Yet if it were possible, experimentally or otherwise, to disentangle from the behavioral flux the strictly mechanical events, the reflexes elicited by tissue injuries, and other nonsocial parts of the participants’ actions, we would most likely discover patterns of behavioral interaction that are just as highly specialized in their social effectiveness. And to that degree we would surely say that the animals were emitting and receiving communicative signals. Thus, although we can certainly expect greater difficulties in identifying signals and the behavioral consequences of their reception when we seek to analyze more fluid or otherwise more complex social episodes, this does not provide a basis for distinguishing animal communication and social behavior, for to analyze the patterns of social interaction that occur is precisely the same as to identify the signals and their social effects.
BEHAVIORAL AND ECOLOGICAL LEVELS OF ANALYSIS
The argument that animal communication and social behavior are identical in so far as we are concerned with the processes governing the behavior of individual animals was based on demonstrating that no behavioral features could be justifiably attributed to one and not the other and that the terms referred synonymously to behavioral specialization shaped, at least in part, by social factors. But, the social specialization of behaviors, along with any other zoological specializations, is a matter of the contributions these make to the particular modes of adaptation of animal populations, and these contributions can be assessed only when they are examined within their ecological setting. Therefore, even when studying animal communication at the level of the behavior of individual animals, which is the typical approach for psychologists, this ecological perspective is required. Besides, our understanding of zoological phenomena in general is fullest and deepest to the extent that we are able to work out the details of the ways by which they participate in the adaptive modes of the animal populations exhibiting them and the ways by which they have evolved and are maintained in those populations. Because we can hope to achieve these furthest goals only when the phenomena are related to their total ecological circumstance, it is important to give the fullest possible consideration to these ecological matters whatever the level of our approach.
Now, within this ecological perspective, it is not only appropriate but essential to apply the concepts of information transmission to the phenomena of animal communication if we are to determine the particular features of their adaptive significance. But, here again the clarity of our thinking is often threatened by the intrusions of misleading analogies from human linguistic communication. One which is especially troublesome is the confusion of our notions about the biological purposes served by animal communication phenomena with our notions about the intentional purposes of human speech.
We are, most of us, willing to attribute intentions, along with personal responsibility, to the social effects of another person’s actions when we can be persuaded that the person possessed some sort of knowledge, however fragmentary, of the social consequences of his actions prior to their occurrences. In many ways the problems we face in establishing the presence of the special premeditational process that involves this knowledge aforethought are closely similar to those which we face in dealing with the question of information recognition in the reception of linguistic signals, and it is instructive to notice that the solutions we usually accept rely just as heavily on intrinsically linguistic lines of evidence. However, there are some differences that make the task of justifying the attribution of intention of a person’s actions more difficult. For example, the question usually arises only after the action has occurred, and ideally we would want some indication of the person’s appreciation of the consequences of potential actions prior to their commission.
Nevertheless, we do often have multiple lines of behavioral evidence which, though weak and indirect, permit us to justify or deny with some conviction the attribution of intentions to some human actions, because the evidence adduced is separate and independent from the action itself. But, when we attribute intention to the socially significant actions of individual animals, such lines of evidence simply do not exist. How, for example, can we justify saying that a bird in displaying a broken-wing dance is intending to lure a potential predator away from the nest area when the only behavioral evidence to which we can appeal is the dance itself and the circumstances of its occurrence?
Yet, the bird’s action when viewed within its ecological context can be clearly seen to serve adaptive purposes to the bird’s way of life, though it is purposive in exactly the same sense that any of its other specializations, such as is its mode of flight, digestion, or blood oxygenation, may be said to serve adaptive purposes. The adaptive purposes of the dance are clear to us from what we know about the situations that occasion the action and the consequences of the pattern of stimulation it produces on the actions of some other animals responsive to that stimulation. That is, to appreciate the particular contributions that these social signals make to the modes of adaptation of the populations to which the animals belong requires that the behaviors of signal emission and reception be related to their ecological contexts of occurrence. But this in turn requires that we have as full as possible analysis of the behavior of the interacting individuals, especially in regard to the actual factors involved in the initiation and organization of the actions by which the signals are emitted and which attend the reception of the signals.
It may be helpful to the analysis of animal communication on the behavioral level to provide some terms by which we can readily distinguish the conditions in the external and internal environment which provoke the behavior involved in the emission of a signal and the behavioral consequences that are evoked in others by their reception of it. We may, hopefully without prejudice, call the former the reference of the signal and the latter the significance of the signal. However, we would do well to bear in mind that, on this level, the significance of a signal is the behavioral changes it evokes in its recipients. That is, behavioral significance is not the same as adaptive significance, for that is a matter involving the interrelation of the reference and the significance of a signal within the ecological context of its occurrence. The previous discussion may now be summarized with the use of these terms by saying that we need to acquire as much information as possible about these behavioral questions of the reference and significance of animal signals in order to be able to answer the essentially ecological questions about the information transmitted and the adaptive roles played by these signals. We can also use these terms to phrase another reason why the application of the notions of information transferral to the behavioral processes involved in animal communication is strained, gratuitous, and often quite misleading because, as in the example of the broken-wing dance, there may be little or no correspondence between the reference and the significance of animal signals.
BEHAVIORAL ANALYSIS OF ANIMAL COMMUNICATION
The task of analyzing animal communicative behavior has three parts: specifying the critical features of the signals, characterizing their significance in the behavior of their recipients, and ascertaining their references. Unfortunately, each of the three sub tasks involves the others and all are equally challenging. We can only establish the occurrences of signals by determining their behavioral significance, and most often these social effects include the emission of other signals in turn, so that the significance of a signal emitted by animal A in the behavior of animal B usually involves the evocation of an answering signal referring, in part, to animal A’s original signal.
Prolonged and careful observation of the social interactions of animals ranging freely in their native habitats, which is of course essential to the ecological level of analysis, can usually delineate the major features of the nature of the signals and their reference and significance. However, experimental procedures are needed if the fine details of these behavioral processes and their anatomical and physiological substrata are sought. The use of models to determine the behaviorally critical attributes of signals is often especially valuable, as in Tinbergen’s (1963) exemplary work on visual signals and in extensions of this strategy to chemical (Wilson, 1963) and acoustic signals (Capranica, 1966).
But, in spite of the many achievements that have been made in the analysis of communication behavior, these lines of inquiry have not advanced very far at all in considering the extremely fluid, complex, and for the psychologist, especially interesting social lives of mammals. Except perhaps for their chemical signals, mammalian signals tend to be much less stable and stereotyped than those of other fauna. Along with this, mammalian signals often occur with continuous intergradations from one type to another, and the significance of apparently the same signaling action may change depending on the interacting individuals (Schaller, 1963) or the signaler’s preceding signals (Altmann, 1962). The analysis of mammalian communicative behavior is thus an extraordinarily formidable task, and it is hard to develop any optimism that it can be carried very far. However, there is some promise that with recent developments in neurophysiological knowledge and laboratory techniques we may very well be able to advance along some very important lines of analysis. The social interactions of domestic cats and rhesus monkeys have been studied by Delgado (1964) with procedures he has developed which permit electrical excitation and recording of the activity of different structures of the brains of freely moving participants by means of miniaturized radio receivers and transmitters. Excitation of certain thalamic nuclei and parts of the limbic system differentially results in a variety of well-organized actions having obvious significance as social signals, and their experimental control in this situation provides an extremely rich opportunity to trace out many of the details of their nature, reference, and significance.
This work has special importance for psychologists, for its main emphasis is on the fundamentally emotional character of these communicative actions (Delgado, 1966). That is, it clearly indicates that the actions of signal emission are governed by shifts in the levels of arousal of the animal’s emotional states. This characterization of signal reference is, of course, flagrantly anthropocentric, and many workers, including numerous psychologists, would surely take strong objection to it, especially when applied to nonmammalian communication. Obviously, a discussion of the emotional qualities of communication in the courtship of spiders is not very meaningful. Nevertheless, our understanding of some of the features of human emotional processes has always depended very largely on results of investigations of clear homologies of these processes in other mammals; and as our ideas about these processes become more adequate and precise, the dangerous aspects of anthropocentrism can be more easily avoided.
Actually, a more forceful objection to this emphasis on the emotional character of animal communication might be made on the ground that communicative behavior is quite unexceptional in this regard, for if we could provide the concepts of emotionality with any general zoological meaning we would find that the bulk of all animal behavior, man s included, is organized and activated by emotional processes. In any event, to the degree that these concepts are applicable, it seems to be very clear that the reference of animal social signals is restricted to external and internal environmental events of an emotional character. Furthermore, the significance of the signals is largely emotional as well, for the most salient consequences of signal reception are changes in the emotional status of the recipient, usually provoking signaling actions in response. Though it is obvious that more transpires in episodes of social interaction than just the signal exchanges, the important point for the analysis of the behavioral processes involved is that the actions of the participants are steered and integrated by the emotional character of signal reference and significance. Because of the emotional restrictions on the reference and significance of animal signals, what we might call the semantics of animal communication is closed. At the ecological level required for its assessment, these behavioral limitations restrict the information transmitted by animal signals to only those circumstances of the external environment that are emotionally provocative for the signal emitters and receivers.
These semantic restrictions are thus fixed by the genetically controlled maturational processes that determine the emotional provocativeness of environmental situations and the organization of the behavioral outcomes of such provocation. The exasperating difficulties confronting the behavioral analysis of social interactions of mammalian species is due to the comparatively wider ranges of environmental situations that are emotionally provocative to them, and to the further complication that this provocativeness may vary to a comparatively great degree with quite independent changes in the emotional status of the individual (Hebb and Thompson, 1954). And in addition to these tendencies there is comparatively greater plasticity in the organization of these emotional processes in mammals such that the prior social experiences of individuals may result in the further enrichment of the range and complexity of emotionally provocative social situations and may also result in the reorganization of the behavioral components. All of these factors no doubt participate in the various other aspects of the greater emotional lability of mammals, the comparative reduction of stereotypy, “typical intensities,” discreteness, and stability of signaling actions, which make their social interactions so much more fluid and dynamic and thus so much more difficult for the observer to analyze.
These tendencies in the conduct of mammalian social life raise some psychologically interesting questions about the perceptual processes involved, for the problems of distinguishing the socially significant factors in the rapidly flowing complexity of mammalian social interactions are more demanding for the participants as well as the human observer. There is a profound difference in the perceptual capabilities required for recognizing a relatively small number of more or less discrete, categorical, and stable patterns of stimulation which stand out very clearly from their backgrounds and those required for detecting a multitude of significant changes in a rapid flow of stimulation in which there is continuous variation on several dimensions, the figure-ground relationships of critical attributes are illdefined, and the critical features are not only variable in themselves but are also dependent upon the contexts in which they occur. All of this clearly indicates that the increased complexity of patterns of mammalian communication is intimately linked with changes in the emotional organization of behavior and with changes in perceptual capabilities. These interdependent developments in mammalian social adaptations are obviously more extreme, as in the somewhat parallel developments among the social insects, when the adaptations involve social groupings in which close contacts between individuals are sustained over their life spans and in which the groups are organized by patterns of behavioral interaction that are specialized in terms of the age, sex, or other attributes of the group members. The higher primates, especially the ground-dwelling monkeys and apes, come most readily to mind as the most extreme instances of these mammalian departures in animal communication, although evidence is beginning to accumulate which indicates that the behavioral homologues in some of the toothed whales may be quite as extreme, though with very different kinds of specializations (Norris, 1966).
BEHAVIORAL COMPARISONS OF ANIMAL COMMUNICATION AND HUMAN LANGUAGE
Comparisons of animal species with respect to anatomy, physiology, development, ecology, behavior, etc., have provided zoology with the bulk of its most important ideas. Indeed, such comparisons furnished the basic data and the impetus to the development of the most central conception in all of biology, evolution. And beyond its necessity in studies of systematics and evolution, the comparative approach affords a perspective of immense heuristic value, even in studies confined to single species or single features thereof, not the least when indicating the lack of similarities with other taxa.
Within the human behavioral sciences comparative examinations of cultural attributes, particularly languages, have also been of inestimable value in analogous ways, i.e., in contributing to the understanding of linguistic affinities and in providing suggestive ideas about the properties of individual languages. Currently there is increasing enthusiasm for the search for detailed information about linguistic universals in the well-founded hope that these may shed light on the nature of man. Many of the present efforts to compare man’s languages with the communication of animals are simply extensions of this same desire to learn more about man’s capacity for languages and its origin. These questions about the evolution of man’s speech have challenged and frustrated us throughout most of our recorded history. But no matter how futile our efforts to answer them have been, they cannot be suppressed, for they are key parts to any query into human nature and its origins.
The difficulties we have in dealing with such questions of linguistic evolution are, of course, chiefly due to the paucity of evidence to which they can be referred, but they are also due to the lack of force carried by such evidence as we do possess in eliminating some possible answers in favor of others. Unfortunately, there is no direct and unequivocal evidence of linguistic or prelinguistic adaptations in our evolutionary history before the emergence of man in our present biological form. The meager and spotty fossil record of homonid evolution can provide a basis for only the weakest sorts of inferences about the nature and time depth of the critical events in the development and exploitation of linguistic capabilities. Similarly, the record of homonid cultural evolution in such things as the complexity of tool assemblages or the efficiency of big-game slaughter, while surely suggesting pressures which might be considered as having contributed to the dynamics of linguistic developments, does not furnish unequivocal indications of the presence of languages as the social institutions we know today. Nor does the record support any strong arguments about the character of the precursors to linguistic institutions or the nature of the capabilities subserving them. We do not currently possess any well-developed information on how much complexity a cultural tradition concerning tool manufacture or social cooperation may have and still be transmissible by nonlinguistic means, e.g., imitation, in man or other living primates. Furthermore, one may wonder if the apprenticeships required for the effective application and dispersion of Early and Middle Paleolithic technologies could have been facilitated by the possession and exploitation of linguistic capabilities. Other than simply resigning ourselves to wait patiently for decisive paleontological discoveries, which we have little reason to expect, the best we can do in our efforts to deal with these questions is to take into consideration all the lines of evidence that do become available in the hope that, however indirect and feeble may be the connection of each to the problem, when taken together they may provide some stronger restrictions on the kinds of ideas that we may entertain.
It is considerations such as these that provide the motivation for extending our interest in human linguistic communication to the study of nonlinguistic communication. Leaving aside the larger zoological importance of the study of social communication in living nonhumans and the intrinsic interest of the topic, there are quite good reasons for its relevance to the problem of linguistic evolution. It is a truism that evolutionary mechanisms can operate only on existing genetic variation in a breeding population. Consequently, whatever may be the nature of the biological specializations subserving our present linguistic institutions, we can safely assume that below some evolutionary grade some of the definitive attributes of human languages were absent in homonid communication. Therefore, if we can find properties of social communication that are common to higher nonhuman primates and perhaps other mammals as well, then we have good reason to think that they were also shared by the nonlinguistic communication of homonids before linguistic capacities evolved. We have much less assurance for the further supposition that such shared properties would stand in a direct ancestral relation to the properties of linguistic communication, that is, that the latter can be taken to be some specialized modifications of the former. What is clear is just that linguistic communication arose out of nonlinguistic signaling and that we might very well find something to aid our understanding of this evolution if we knew more about nonlinguistic communication.
This same reasoning applies even if we consider that some of these attributes might have arisen from specific courses of cultural, and not biological, evolution, though this possibility poses conceptual difficulties because of the clear indication of reciprocal interaction between cultural and biological evolutionary processes from the very inception of the homonid line. But basically what this possibility involves is only that the biological provisions for man’s linguistic capacities might be considered as specializations which, though evolving in response to culturally mediated selective pressures, might not have been associated with some incipient form of linguistic, or perhaps any, communication. In the light of this possibility some of the generic attributes of man’s languages could be regarded as emerging as cultural innovations exploiting these traits whose primary adaptation was not connected with any linguistic function as such, and thus the maintenance and dispersion of these innovations would not involve any additional genetic changes. If this were so, then the ubiquity of these linguistic features, though with local modifications, would be akin to those associated with other cultural innovations, such as core toolor firemaker traditions, in being determined by processes of cultural diffusion, prior cultural developments, and ecological constraints. And though they would be only partly, weakly, and indirectly determined by the genetic status of their possessors, such possession would be no less a unique characteristic of the species. There would then be no basis for the ascription of linguistic universals to the evolution of specific linguistic Anlagen in homonids, or for the supposition that specifically linguistic specializations are responsible for the linguistic competencies of humans, and especially not for conjectures about a single Anlage underlying them.
Whatever the strength of this possibility that some of the generic properties of linguistic communication may have arisen as social inventions, there are few who seriously doubt that social forces have been solely responsible for shaping the specific features of all known languages in all of their diversity. It is exactly this that is the basis for asserting that all of the particular properties of the phonology, lexicon, and grammar of any language are arbitrary conventions, and why we regard languages as cultural institutions. And this is what prohibits comparing man’s languages and animal communication. Mans languages have objective status as internally organized systems that are independent of the people who speak them, whereas animal communication is precisely the social interactions of the animals. Notice that this difference is not just a matter of the cultural rather than genetical transmission of human languages, for many animal signaling actions, references, or significances may be culturally acquired either separately or together.
There are some very strong and valid reasons why languages and their parts can be considered as objects such as tools and vehicles quite apart from the actions of those who use them, e.g., there are no more Hittites, but their language continues to be studied just as their axes and methods of transportation continue to be studied. Because languages are, as such, not behaviors, their properties cannot be compared with the properties of animal communication. But the reasons why languages have this objective status cannot be found in their formal properties. They will have to be sought in the properties of man, in what it is in his nature that permits him to be in some degree objective about anything, including his languages and, we hope, animal communication. If we exercise some of these objective capabilities, perhaps we can use a different class of human cultural institutions, his religions, as an even more extreme illustration of the problems involved in comparisons with animals and what we can hope to gain from them. We would all surely be in agreement that man s religions are uniquely his and nothing resembling them can be found in any other fauna. We would also all agree that comparative study of human religions in history and prehistory is a valuable endeavor, and most of us would continue to agree that questions about their further evolution and origin in the life of man are valid, if immensely difficult, problems. Now is there any prospect that the study of animals would provide us with information that would contribute to our understanding of these evolutionary developments?
It is immediately apparent that, because there is nothing comparable to religious institutions among animals, we would have to shift our level of analysis to the actions of people engaged in the practices of their religion, so that the human side of the possible comparisons would be commensurate with what can be observed in animals. But can any relevant similarities or common elements be found in the conduct of animals and the religious actions of humans? Any examination that is serious enough to pass over the resting postures of the praying mantis as irrelevant would surely indicate that there are no biologically pertinent points of comparison in the actions as such. But if we were to consider what kinds of processes are capable of organizing and directing the religious practices of man in all their present and historical diversity, we would be led to consider the perceptual, emotional, and cognitive properties of these capabilities. Now these are clearly theoretical considerations, for the capacity for religious conduct is not apparent in the conduct itself. However, they are also theoretical considerations which are cogent to the analysis of the behavior of any animal. It is at this level of consideration that we can expect the effort of behavioral comparisons to be helpful. Comparative behavioral considerations of this sort can provide some useful indications of what can be appropriately called the psychological pre-adaptations for religious development in the species and in the individual.
Although this illustration is a rather extreme example of the great difficulties that are involved in trying to obtain a stereoscopic view of the phenomena of human cultural institutions through the lens systems of both psychology and zoology, it does serve to indicate what can and cannot be expected from these comparative efforts when they are focused on human languages. There is not enough space available to discuss the results of such an effort here, but elsewhere another one has been presented in almost dreary detail and length (Bastian, 1965).
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