Cognitive Ethology and the Explanation of Nonhuman Animal Behavior

 In this paper I attempt to provide a convincing case for the importance of cognitive ethological investigations for advancing our knowledge of animal cognition. Cognitive ethology is broadly defined as the evolutionary and comparative study of nonhuman animal (hereafter animal) thought processes, consciousness, beliefs, or rationality, and is an area in which research is informed by different types of investigations and explanations. After (1) a brief discussion of the agenda of cognitive ethology, in which three different views of cognitive ethology are considered as is the relationship of cognitive ethology as a science to other branches of science, I (2) argue that folk psychological explanations and empirical data both are important to cognitive ethological research and conclude that the former are not as weak and as dispensable as some claim; (3) appeal to some case studies in recent analyses of social play behavior and antipredatory behavior (vigilance against potential predators) to make the point that folk psychology works well with empirical data and to provide examples in which the cognitive ethological perspective has proven to be a good heuristic; and (4) make some suggestions for future research. Cognitive ethology is alive, has a bright future, and has much to gain from a broad interdisciplinary perspective. Comparative approaches to cognitive science are very fruitful and have much to offer.

1.1 Cognitive Ethology as a Science

Cognitive ethology, broadly defined as the evolutionary and comparative study of nonhuman animal (hereafter animal) thought processes, consciousness, beliefs, or rationality, is a rapidly growing field that is attracting the attention of researchers in numerous and diverse disciplines.¹ Because behavioral abilities have evolved in response to natural selection pressures, ethologists favor observations and experiments on animals in conditions that are as close as possible to the natural environment where the selection occurred, and because cognitive ethology is a comparative science, cognitive ethological studies emphasize broad taxonomic comparisons and do not focus on a few select representatives of limited taxa. In addition to situating the study of animal behavior in an evolutionary and comparative framework, cognitive ethologists maintain that field studies of animals that include careful observation and experimentation can inform the study of animal cognition; cognitive ethology will not necessarily have to be brought into the laboratory in order to make it respectable. Cognitive psychologists, in contrast to cognitive ethologists, typically work on related topics in laboratory settings and do not emphasize evolutionary or comparative aspects of animal cognition. When cognitive psychologists do make cross-species comparisons, they are typically interested in explaining different behavior patterns in terms of common underlying mechanisms; ethologists, in common with other biologists, are often more concerned with the diversity of solutions that living organisms have found for common problems.

Many different types of research fall under the term "cognitive ethology" and it currently is pointless to try to delimit the boundaries of cognitive ethology; because of the enormous amount of interdisciplinary interest in the area any stipulative definition of cognitive ethology is likely to become rapidly obsolete (Allen 1992a). Although cognitive ethology can trace its beginnings to the writings of Charles Darwin and some of his contemporaries and disciples, the modern era of cognitive ethology is usually thought to have begun with the appearance of Donald R. Griffin's (1976, 1981) book The question of animal awareness: Evolutionary continuity of mental experience. Thus, cognitive ethology as most of us know it is really a young science with great aspirations, and, as with many other fields in their infancy, cognitive ethology also suffers from various sorts of growing pains. While there are those who are presently willing to let cognitive ethological research take its course and wait to see how these sorts of investigations deal with current problems and inform and motivate future research, there are some who want to dispense with cognitive ethology because some of its ideas seem muddled and difficult to study, or because other minds are never fully accessible to outsiders. The latter position seems to be short-sighted and narrow minded. To claim that some of the basic tenets of cognitive ethology are unfalsifiable and thus not worthy of study is simply too cavalier an attitude (Sober 1983); there should be enough flexibility for alternative explanations, especially in developing fields. Some patience is needed. Imagine if other fields were ignored or terminated because their early thinking seemed confused or because "final answers" were not immediately available.

1.2 Three Views of Cognitive Ethology

For cognitive ethology, the major problems are those that center on methods of data collection, analysis, and on the description, interpretation, and explanation of animal behavior (Bekoff and Jamieson 1990a,b; Jamieson and Bekoff 1993; see also Purton 1978). Because cognitive ethology deals with animal minds and mental states, there is also some debate about whether or not a science of cognitive ethology is even possible (Yoerg and Kamil 1991; for discussion see Jamieson and Bekoff 1993). Based on published reviews of some of Griffin's works and other clearly stated opinions concerning animal cognition, Bekoff and Allen (1993) located different views of cognitive ethology into three major categories, slayers, skeptics, and proponents; unfortunately all views of cognitive ethology could not be covered in their survey. The views of some members of these groups can be summarized as follows.

Slayers

Slayers deny any possibility of success in cognitive ethology. They sometimes conflate the difficulty of doing rigorous cognitive ethological investigations with the impossibility of doing so. Slayers also often ignore specific details of work by cognitive ethologists and frequently mount philosophically motivated objections to the possibility of learning anything about animal cognition. They do not see that cognitive ethological approaches can lead, and have lead, to new and testable hypotheses. They often pick out the most difficult and least accessible phenomena to study (e.g. consciousness) and then conclude that because we can gain little detailed knowledge about this subject, we cannot do better in other areas. Slayers also appeal to parsimony in explanations of animal behavior, but they dismiss the possibility that cognitive explanations can be more parsimonious than noncognitive alternatives, and they deny the utility of cognitive hypotheses for directing empirical research.

Some specific examples of the slayers' position are as follows.

Zuckerman (1991, p. 46), in his review of Cheney and Seyfarth's (1990) book How Monkeys See the World: Inside the Mind of Another Species, exemplifies the unargued view of those who dismiss the field of cognitive ethology because they make little effort to consider available evidence. He writes:

 "Some of the issues they do raise sound profound as set out but, when pursued, turn out to have little intellectual or scientific significance." (Zuckerman 1991, p. 46)

Heyes (1987a), who is a laboratory psychologist, advises cognitive ethologists to hang up their field glasses and turn to laboratory research if they want to understand animal cognition. She writes:
 

"It is perhaps at this moment that the cognitive ethologist decides to hang up his field glasses, become a cognitive psychologist, and have nothing further to do with talk about consciousness or intention." (Heyes 1987a, p. 124)
 
Thus, Heyes denies that evidence gained by observing animals in natural settings, an activity that usually involves using some sort of visual aid such as field glasses, is particularly relevant to understanding animal minds. Other slayers, who claim that they need more convincing evidence from the field, rarely tell what evidence would be convincing (Colgan 1989, p. 67). Heyes and these other critics generally simply assume that no evidence that could be collected from the field would provide convincing support for attributions of mental states.

"I am inclined merely to delete it [the mental realm] from biological explanation, because it is an entirely private phenomenon, and biology must deal with the publicly demonstrable."

1. Mental events are private phenomena.
2. Private phenomena cannot be studied biologically.
3. Therefore, mental events cannot be studied biologically.
4. Cognitive ethology is possible only if mental events can be studied biologically.
5. Therefore, cognitive ethology is not possible.

Other tactics used by some slayers involve grounding their criticisms on very narrow bases. Cronin thinks that Griffin, a "sentimental softy," and other cognitive ethologists are only concerned with demonstrating cleverness, and hence consciousness. In her recent review of Griffin's Animal Minds (1992) she writes:

 "A Griffin bat is a miniature physics lab. So imagine the consternation among behavioristic ethologists when Mr. Griffin came out a decade ago,with "The Question of Animal Awareness," as a sentimental softy. . . . For Mr. Griffin, all this [cleverness] suggests consciousness. He's wrong. If such cleverness were enough to demonstrate consciousness, scientists could do the job over coffee and philosophers could have packed up their scholarly apparatus years ago." (p. 14, my emphases)

 "Well, I know that I am conscious, I know a mere 500,000 generations separate me from my chimpanzee cousin, and I know that evolutionary innovations don't just spring into existence full-blown - certainly not innovations as truly momentous as our hauntingly elusive private world."

Skeptics

Skeptics are often difficult to categorize. They are a bit more open-minded than slayers, and there seems to be greater variation among skeptical views of cognitive ethology than among slayers' opinions. However, some skeptics recognize some past and present successes in cognitive ethology, and remain cautiously optimistic about future successes; in these instances they resemble moderate proponents. Many skeptics appeal to the future of neuroscience, and claim that when we know all there is to know about nervous systems, cognitive ethology will be superfluous (Griffin 1992 also makes strong appeals to neuroscience, but he does not fear that increased knowledge in neurobiology will cause cognitive ethology to disappear). Like slayers, skeptics frequently conflate the difficulty of doing rigorous cognitive ethological investigations with the impossibility of doing so, but when it is shown that some light can be shed on the nature of animal cognition, they often hedge their skepticism. Skeptics find folk psychological, anthropomorphic, anecdotal, and cognitive explanations to be off-putting, but they are not as forcefully dismissive as slayers.

Some specific examples of the skeptics' position are as follows.

With respect to the types of explanations that are offered in studies of animal cognition, many slayers and some skeptics favor noncognitive explanations because they believe them more parsimonious and more accurate than cognitive alternatives, and less off-putting to others who do not hold the field of cognitive ethology in high esteem. Snowdon (1991, p. 814) claims that:

"It is possible to explore the cognitive capacities of nonhuman animals without recourse to mentalistic concepts such as consciousness, intentionality, and deception. Studies that avoid mentalistic terminology are likely to be more effective in convincing other scientists of the significance of the abilities of nonhuman animals."

Michel (1991, p. 253) also is concerned about folk psychological explanations. He writes:

" . . . folk psychological theory pervades human thinking, remembering, and perceiving and creates a very subtle anthropomorphism that cancorrupt the formation of a science of cognitive ethology." (my emphasis)

"One must be cautious about inferring complex cognitive processes when simpler explanations will suffice."

With respect to the difficulties in studying consciousness, Alcock (1992) is a notable example in that he does not find the inaccessibility of consciousness to be grounds for dismissing the study of animal cognition (as does Cronin 1992; see also Whiten's 1993 discussion of the importance of studying observable events in studies of animal cognition). Alcock writes:

 "We need ways in which to test hypotheses in a convincing manner. In this regard Animal Minds disappoints, because it offers no practical guidance on how to test whether consciousness is an all-purpose, problem-solving device widely distributed throughout the animal kingdom. . . . And there are alternative approaches to consciousness not based on the behavioristic principle that thinking cannot be studied because it does not exist." (Alcock 1992, p. 63)

Proponents

Proponents keep an open mind about animal cognition and the utility of cognitive ethological investigations (e.g. Cheney and Seyfarth 1990, 1992; Allen and Hauser 1991; Burghardt 1991; de Waal 1991; Ristau 1991a; Allen 1992a,b; Bekoff and Allen 1992; Bekoff 1993a; Bekoff et al., 1993; Jamieson and Bekoff 1993; Whiten 1993).³ They claim that there are already many successes and they see that cognitive ethological approaches have provided new and interesting data that also can inform and motivate further study. Proponents also accept the cautious use of folk psychological and cognitive explanations to build a systematic explanatory framework in conjunction with empirical studies, and do not find anecdote or anthropomorphism to be thoroughly off-putting. While proponents recognize that Griffin has not made detailed suggestions for experimental studies, this does not discourage them from seeking ways to make ideas like Griffin's empirically rigorous (Allen and Hauser 1991; de Waal 1991; Ristau 1991a; Allen 1992a,b; Whiten 1992; Bekoff 1993a). Proponents are critical, but patient, and do not want prematurely to doom the field; if cognitive ethology is to die, it will be of natural causes and not as a result of hasty slayings.

William Mason's (1976, p. 931) quotation from his review of Griffin's (1976) The Question of Animal Awareness is a good place to start with respect to proponents' views. Mason writes:

"That animals are aware can scarcely be questioned. The hows and the whys and wherefores will occupy scientists for many years to come."

Proponents are more optimistic in their views about the contributions that the field of cognitive ethology and its reliance on field work and on comparative ecological and evolutionary studies, can make to the study of animal cognition in terms of opening up new areas of research and reconsidering old data. Ristau (1991b, p. 102) notes that in her attempts to study injury-feigning under field conditions, the cognitive ethological perspective

 " . . . led me to design experiments that I had not otherwise thought to do, that no one else had done, and that revealed complexities in the behavior of the piping plover's distraction display not heretofore appreciated."

"At this point, however, cognitive ethologists can console themselves with the knowledge that their discipline is an aspect of the broaderfield of cognitive studies and conceptually may not be in any worse shape than highly regarded, related fields such as cognitive psychology.We are a long way from understanding the natural history of the mind, but in our view this amounts to a scientific challenge rather that grounds for depression or dismissal." (Jamieson and Bekoff 1992a, p. 81)

"Cognitive ethology, rescued from both behaviorism and subjectivism, has much to say about what the life of the animal is really like. It is silent on what it is like to have that life." (Gustafson 1986, p. 182)
" . . . I have advocated use of a critical anthropomorphism in which various sources of information are used including: natural history, our perceptions, intuitions, feelings, careful behavioral descriptions, identifying with the animal, optimization models, previous studies and so forth in order to generate ideas that may prove useful in gaining understanding and the ability to predict outcomes of planned (experimental) and unplanned interventions . . . " (Burghardt 1991, p. 3)

 " . . . when a number of anecdotal examples, each with a possible alternative explanation, collectively point to the likelihood of intentional deception, and this is supported by more rigorous tests in the laboratory . . . I would argue that it adds up to a strong case." (Archer 1992, p. 224)

 "Contrary to the widespread pessimistic opinion that the content of animal thinking is hopelessly inaccessible to scientific inquiry, the communicative signals used by many animals provide empirical data on the basis of which much can reasonably be inferred about their subjective experiences." (my emphasis)

In summary, as a field of inquiry, cognitive ethology need not model itself on other scientific fields such as physics or neurobiology in order to gain some credibility or to acquire status as a respectable branch of science Physics (or hard-science) envy is what led to the loss of animal minds (Rollin 1990; Bekoff 1992a) in the early part of the twentieth century. Now, after a successful battle against those who were content to study behavior in the absence of animal minds, there are ample data that strongly support the idea that many nonhuman animals do have minds. Thus, we should continue studying animal minds and not have to begin to search for them once again. Those who believe that cognitive ethology is not worthy of being called a science seem to have an impoverished conception of science; many different types of activity fall under the umbrella "science."

1.3 Folk Psychology, Cognitive Ethology, and Beliefs About the Future of Neuroscience

 Because folk psychological explanations are so off-putting to slayers and some skeptics, a bit more needs to said about these sorts of explanations and how they are related to cognitive ethological research. Folk psychological explanations, usually referred to as the ways in which common folk talk about the world in their daily dealings with one another, can be useful parts of cognitive ethological explanations. Folk psychological explanations that appeal to belief and desires of and about things, while not necessarily true, often help to provide the best explanation (sensu Harman 1965) of observed behavior (see below and also Cling 1991). I fully agree with Mason (1986) that common sense is not a serious risk for contemporary behavioral science. Thus, while folk psychological explanations play a role in the successful prediction of animal behavior and in many cases do their explanatory work, they do not replace detailed empirical studies concerning the content of animal beliefs and desires; rather, folk psychological explanations need to be used along with these endeavors. Thinking about different levels of analysis and explanation might be useful for seeing how different sorts of explanations are related to one another (Table 1).

Beer (1992) also does not think that Stich's case against folk psychology is necessarily compelling. However, Beer is concerned with the framing and grounding of questions in cognitive ethology in folk psychology because of the weakness of some of philosophical underpinnings of folk psychology. For the reasons given above, I not think that Beer should be as troubled as he is (see also Sober 1983).

Like folk psychological explanations, "scientific" explanations also enjoy successes and failures. For example, scientists still disagree, even with hard data, over whether or not global warming has occurred and if so, whether global warming can be explained by what is called the Greenhouse Effect (e.g. Lindzen 1990). Scientists also disagree about whether or not Vitamin C is useful in treatment of the common cold. Nonetheless, folk psychological explanations of nonhuman behavior are often viewed as being scientifically weak or even ascientific. Generally, the theory of folk psychology is usually dismissed as being explanatorily weak, historically stagnating, and conceptually isolated (Churchland 1979, 1981). It usually is argued that folk psychological explanations are inexact and will be replaced in the future by a more mature and exact neuroscience, although in everyday life folk psychology can be helpful (Churchland 1981).

It is beyond the scope of this paper to consider all of the pros and cons of folk psychology in any detail (see Clark 1989; Bogdan 1991; Greenwood 1991; Heil 1992; Christensen and Turner 1993); most of the arguments, especially those against folk psychology, have very deep philosophical roots, some of which might benefit from a good watering. However, a few words can be said about the nature of the arguments that are used either to refute the utility of folk psychological explanations or to claim that while they may be of some limited use now, they will be replaced when we know all that there is to know about neuroscience. Such arguments suggest an extreme, almost religious-like faith, in the ability of science to handle difficult problems such as animal minds, and in this and other areas such faith may be wishful thinking (Heil 1992; Moussa and Shannon 1992). Indeed, arguments against folk psychology that appeal to neuroscience have their own weaknesses (Cling 1990; Gilman 1990; Saidel 1992). While it will be useful to learn more and more about nervous systems in analyses of different types of animal cognition (e.g. Howlett 1993), the hope that this knowledge will clear up all of the messy issues in cognitive ethology seems a bit lofty (Akins 1990; see also Brunjes 1992 for some worries about commonly used methods in the study of neurobiology and behavior). While it may happen that someday neuroscientists will be able to map an animal's beliefs in his nervous system, it will probably have to be in a very simple nervous system. Thus, it might be possible that this individual's beliefs are nothing like our beliefs, or even similar to those of animals toward whom we might feel comfortable in attributing beliefs.

One major problem with the arguments put forth by those who appeal to the future of neuroscience is that appeals to the future require us to wait and keep waiting for events that might never occur. Here too, personal opinions concerning just what science can do enter (not surprisingly) into how folk psychology is viewed. It is important to ask a few questions here. For example: "How patient should we be?" "Should we dispense with what we now know about the behavior of nonhumans, explanations of which rely on the careful use of folk psychology, until skeptics are satisfied that they are right and proponents of folk psychology are wrong?" "How will we know when we have a mature neuroscience?" "Will it be the time when neuroscience answers the questions that some want answers to in a way with which they feel comfortable?" "Why can't skeptics be asked to wait for a mature cognitive ethology?" Then we will be able to assess the utility of folk psychological explanations. Indeed, one convenience about future talk is that the future can always be put off until we like what it brings. We will not know what the future will bring until we get there (Akins 1990). Of course, appealing to the future of cognitive ethology is as nebulous as appealing to the future of neuroscience.

In summary, it is important to assess continually the relationships among (1) how much we know or think we know about certain aspects of an individual's behavior, (2) how much explanatory power there is in the sentences and the data that we use to demonstrate our ability to use this knowledge to make predictions about behavior, and (3) how much tolerance we are asking for in using folk psychological explanations. Social play behavior and vigilance against intruders (potential predators) are two areas in which folk psychological explanations along with empirical data provide valuable insights into animal cognition. These areas of research will be discussed in the next section.

1.4 Social Play and Antipredatory Vigilance: What Might Individuals Know About Themselves and Others?

Space does not allow me to cover the plethora of areas of research (e.g. food caching, individual recognition and discrimination, assessments of dominance, habitat selection, mate choice, teaching, imitation, communication, tool-use, injury-feigning, observational learning) in which cognitive ethological approaches have been, or could be useful, in gaining an understanding of the behavior of nonhumans.⁴ Here I will discuss the communication of play intention and antipredatory vigilance because empirical research in both of these areas has benefited or will benefit from a cognitive approach. Furthermore, in both areas (and others) folk psychological explanations have been useful for informing and motivating further research and have also turned out to be very good predictors of behavior.

The Communication of Play Intention

Social play is a behavior that lends itself nicely to cognitive studies, and poses a great challenge to slayers, skeptics and proponents alike (de Waal 1991; but see Rosenberg 1990 and Allen and Bekoff 1993; numerous references about play can be found in Bekoff and Byers 1981; Fagen 1981; Bekoff 1989; Mitchell 1990; Bekoff and Allen 1992). Play may provide more promising evidence of animal minds than many other areas. Furthermore, understanding activities such as play is important for developing new research dealing with comparative approaches to cognition (Caudill 1992, p. 5). It would have been unfortunate if people decided that just because play was difficult to study, it was impossible to study.

When animals play, they typically use actions patterns that are also used in other contexts such as predatory behavior, antipredatory behavior, and mating. Thus, it has been argued that social play behavior cannot be studied without using a cognitive vocabulary (Jamieson and Bekoff 1993). For example, if you were merely told that Jethro and Henrietta were performing a series of movements and these movements were described with respect to anatomy, you would not know that they were playing, nor that they were engaging in an activity that they probably enjoyed; for that matter you could not know what they were doing for play is typically composed of motor patterns that are also used in a variety of other contexts (for discussion see Golani 1992; Bekoff 1992b).

Because play is typically composed of motor patterns that are also used in a variety of other contexts, an individual needs to be able to communicate to potential play partners that he is not trying to dominate them, eat them, or mate with them. Rather, he is trying to play with them. Behavioral observations of many animals who engage in social play suggest that they desire to do so and believe that their thoughts of the future - how the individuals to whom their intentions are directed would be likely to behave - would be realized if they clearly communicated their desires to play using signals that in some cases seem to have evolved specifically to communicate play intention. On this view, play is seen as a cooperative enterprise.

In most species in which play has been described, play-soliciting signals appear to foster some sort of cooperation between players so that each responds to the other in a way consistent with play and different from the responses the same actions would elicit in other contexts (Bekoff 1975, 1978); play-soliciting signals provide aid to the interpretation of other signals by the receiver (Hailman 1977, p. 266). For example, in coyotes, the response to a threat gesture after a play signal had immediately preceded the threat or a play signal had been performed in the beginning of an interaction, is different from the response to threat in the absence of any preceding play signal (Bekoff 1975). The play signal somehow altered the meaning of a threat signal by establishing (or maintaining) a "play mood." Unfortunately, there have been no other similar quantitative studies to the best of my knowledge, but observations of play in diverse species support the idea that play signals can, and do, serve to establish play moods and alter the significance of behavior patterns that are borrowed from other contexts and used in social play.

Let's consider in more detail the question of whether or not signals that appear to be used to communicate play-intention (play-soliciting signals) to other individuals (Symons 1974; Bekoff 1975, 1977, 1978; Bekoff and Byers 1981; Fagen 1981) could foster the cooperation among participants that is necessary for play to occur. It is assumed that such play-soliciting signals transmit messages such as "what follows is play," "this is still play," or "let's play again, wasn't it fun." (The latter two messages may be sent after a very short break or after rough play has occurred.) Supporting evidence concerning the importance of play signals for allowing cooperative social play to occur comes from studies in which it is shown that play-soliciting signals show little variability in form or temporal characteristics and that they are used almost solely in the context of play. For example, one action that is commonly observed in the context of social play is the "bow," during which an individual crouches (as if bowing) on her forelimbs while keeping her hindlimbs relatively straight; tail-wagging and barking may accompany the bow. In various canids, the bow is a highly stereotyped movement that seems to function to stimulate recipients to engage (or to continue to engage) in social play (Bekoff 1977). Furthermore, the first bows that very young canids have been observed to perform are highly stereotyped, and learning seems to be relatively unimportant in their development. These features of bows can be related to the fact that when engaging in social play, canids typically use action patterns that are also used in other contexts such as predatory behavior, agonistic encounters, or mating, where misinterpretation of play intention could be injurious.

Available data strongly suggest that play-soliciting actions seem to be used to communicate to others that actions such as biting, biting and shaking of the head from side-to-side, and mounting, are to be taken as play and not as aggression, predation, or reproduction (for details see Bekoff and Byers 1981 and Fagen 1981). On this view, bows are performed when the signaler wants to communicate a specific message about her desires or beliefs. How these types of intentional explanations (Dennett 1983) might be related to the communication of social play is shown as follows:
 

Some other characteristics of play bows and also some of the properties of social play support a cognitive explanation of play, and can be used to stimulate future research. For example, play bows themselves occur throughout play sequences, but usually at the beginning or towards the middle of playful encounters. In a detailed analysis of the form and duration of play bows (Bekoff 1977), it was shown that duration was more variable than form, and that play bows were always less variable when performed at the beginning, rather than in the middle of, ongoing play sequences. Recall also that the first play bows that very young canids have been observed to perform are highly stereotyped, and learning seems to be relatively unimportant in their development. One can ask why there is more variability of bows performed during play sequences when compared with bows performed at the beginning of play sequences. Right now I can only offer some possibilities that need to be pursued empirically. Thus, there may be more variability for bows performed during play bouts because of (i) fatigue, (ii) the fact that animals are performing them from a wide variety of preceding postures, and/or because (iii) there is less of a need to communicate that this is still play than there is when trying to initiate a new interaction.

Analyses of play sequences may also inform future studies of social play. For example, in intraspecific comparisons, it has been found that sequences of social play are usually more variable than sequences of nonplay behavior (Bekoff and Byers 1981). Is it possible that animals "read" differences in behavioral sequences that are performed during play and in other contexts? Might increased (or consistent variations in) variability in sequences also (along with play signals) convey the message "this is play" and enable individuals to predict what is likely to occur or to understand what has already occurred.

Future research

A cognitive perspective will be very useful in future analyses of social play. Some of my own thoughts of the future concerning the direction of empirical research center on learning more about what a bowing (or soliciting) dog, for example, expects to happen after (or even as) she performs what is called a play-soliciting signal. Comparative observations strongly suggest that she expects that play will ensue if she performs a bow; she acts as if she wants play to occur. On what sort of grounds is this claim based? Specifically, it looks as if she is frustrated or surprised when her bow is not reciprocated in a way that is consistent with her belief about what is most likely to occur, namely, social play. Dogs and other canids are extremely persistent in their attempts to get others to play with them; their persistence suggests a strong desire to engage in some sort of activity. Frustration may be inferred from the common observation that canids and other mammals often engage in some sort of self-play such as tail-chasing, after a bow or other play invitation signal is ignored, or they rapidly run over to another potential individual and try to get them to play; play is redirected to the signaler herself or to other individuals. Surprise is more difficult to deal with, but often I and my students have agreed that a dog or coyote looked surprised when, on the very rare occasion, a bow resulted in the recipient attacking the signaler. The soliciting animal's eyes opened widely, her tail dropped, and she rapidly turned away from the noncooperating animal to whom she directed a play-soliciting, as if what happened was totally unexpected and perhaps confusing (see also Tinklepaugh's [1928] observation of surprise in monkeys when an expected and favored piece of food was replaced with lettuce). After moving away the surprised animal often looked at the other individual, cocked her head to one side, squinted, and furrowed her brow, and seemed to be saying "Are you kidding, I want to play - this is not what I wanted to happen." The concept of surprise and the having of beliefs may be closely tied together. For example, if Jethro believes that social play will occur after performing a bow (P), then he would be surprised to discover that social play does not occur after performing a bow (not P ,-P). If he is surprised to discover that -P, then he comes to believe that his original belief was false. This involves his having the second-order belief that his first-order belief was false, which involves having the concept of belief.

With respect to the solicitor's beliefs about the future, detailed analyses of movie film also show that on some occasions, a soliciting animal begins to perform another behavior before the other animal commits himself. The solicitor behaves as if she expects that something specific will happen and commits herself to this course of action. The major question, then, is how to operationalize these questions; what would be convincing data? How do we know when we have an instance of a given behavior(s)? Thus, we need to consider questions such as: what is frustrated, what is the goal, what is the belief about, and how could we study these questions? There simply is no substitute for detailed descriptions of subtle behavior patterns that might indicate surprise - facial expressions, eye movements, and body postures.

In summary, studies of social play are challenging and fascinating; I have been doing research on social play in canids for over 20 years and there are many questions to which I do not have satisfactory answers. The cognitive approach has helped me to come to terms with old data and also has raised new questions that need to be studied empirically.

Antipredatory Vigilance

Most animals are both predators and prey (Lima 1990). Thus, there is some conflict between avoiding being eaten and eating. Scanning for predators is called vigilance behavior, and in studies of vigilance it generally is assumed, for simplicity's sake, that individuals compromise their ability to detect predators when feeding with their heads down, and compromise on food intake when scanning for predators with their heads up (see Lima 1990, figure 1, p. 247). Thus, it has been argued that there are good reasons for individuals to live, or at least to forage for food, in groups, if doing so increases the probability of detecting a predator or reduces the time spent scanning for predators, thus permitting more time to be spent doing other things. Not surprisingly, there has been a lot of interest in antipredatory vigilance among those interested in the evolution of social behavior, and many different aspects of this behavior pattern have been analyzed mainly in birds and in a few mammals (Pulliam 1973; Bertram 1978; Lazarus 1979, 1990; Elgar 1989; Rasa 1989; Dehn 1990; Lima 1990; Lima and Dill 1990; Quenette 1990).

A very popular question in the comparative study of vigilance is how does the behavior of individuals vary in groups of different sizes. Generally, it has been found that there is a negative relationship between group size and rates of scanning by individuals and a positive relationship between group size and the probability of predator detection. This is because there are more eyes and perhaps other sense organs that can be used to scan for predators. In his comprehensive review, Elgar (1989) notes that although the negative relationship between group size and individual scanning rate is quite robust and is approaching the status of dogma (Lima 1990), few studies have actually controlled for confounding variables, such as variation in the density and type of food resources, group composition, ambient temperature and time of day, proximity to a safe place and to the observer, visibility within the habitat, and group composition (see also Lima 1990 and Lima and Dill 1991). There are also problems associated with the researcher really knowing whether an individual is actually scanning; behavioral data can be equivocal and attention must also be given to anatomical and physiological constraints. (The same can be said for the relationship between predator detection and escape; in the absence of any discernible response it is impossible to know whether an individual has detected a predator, and it is possible that a prey may be aware of a predator(s) before he decides to flee; Ydenberg and Dill [1986]). With respect to whether or not an individual is really being vigilant, Lazarus (1990, p. 65) notes that " . . . researchers have simply assumed that the behaviour in question is vigilant, and have then sought its function." It is important to stress that such adaptive and evolutionary tales are not necessarily any more plausible than explanations of nonhuman behavior that invoke notions such as intentionality. In both instances convincing data may still be lacking and a lot of faith in placed in folk explanations.

In the future, experimental cognitive studies will help to answer many questions that have either been ignored or have risen in previous studies of antipredatory vigilance. Of course, these studies must adhere to the strictest guidelines with respect to ethical considerations (Bekoff and Jamieson 1991; Bekoff et al. 1992). Perhaps in some instances it will be the case that the coordination of vigilance among group members is not cost effective (Ward 1985), but there are not enough data now to make any sweeping generalizations. In his review, Lima (1990) notes that there seem to be no studies that have directly examined the question of whether foragers pay any attention to the behavior of other group members. He also concludes that very little is known about the perceptions of the animals being studied and that many models of vigilance reflect mainly the perceptions of the modelers themselves (p. 262).

Here, I will assume here that the negative relationship between group size and individual scanning rate is a genuine one, and ask a number of cognitive questions that bear on this general finding. Furthermore, although cooperation in vigilance is not to be expected, I will argue that although individuals do not sign binding contracts (Lima 1990) and that although cheating could occur, the evidence at hand does not refute the possibility of cooperation among at least some group members (see also Lima 1990, p. 262). Although Dehn (1990) does not suggest that any explicit reasons for individuals to cooperate in collective group vigilance, he notes that even if they live in large groups (> 10 individuals), individuals might benefit in terms so lifetime fitness if they are somewhat vigilant.

A cognitive analysis of vigilance in which we are concerned with what an individual might know about itself and others would involve asking at least the following questions, all of which are interconnected and all of which lend themselves to empirical study. One major question is "Why does the relationship between group size and scanning rates fail where it is to be expected?" Another question to which I will also return is "Is there some association between the degree of coordination or possibly cooperation among group members and the geometry of the group?" To the best of my knowledge, these questions have not been pursued rigorously. For some of the questions I am asking and for some of the analyses I am suggesting, it easier to assume that there is some stability in the composition of the groups, although some models would allow for individuals to learn about general behavior patterns of other individuals regardless of who they are. I will discuss this in more detail later on. Some are the questions that I pose here are not directly related to a cognitive inquiry, but all can inform and motivate such an approach.

(1) What is a group? To a nonhuman? To a human? What does it mean to say that an individual is a member of a group and is our conception of group the same as that of the animals? Questions that inform the conception of group membership include "What types of behavioral criteria can be used to assess if an individual thinks he is a member of a group?", "Is there a critical distance between individuals below which we can say with some degree of certainty that they are members of the same group?", and "Do individuals have to spend a certain amount of time together within a certain distance to justify calling them a group? With respect to studies of vigilance, Elgar, Burren, and Posen (1984) found that a house sparrow who was in visual contact with other house sparrows but separated by 1.2 meters scanned as if she was alone. I am presently pursuing the use of mirrors to help to answer this question.

Other questions also arise. For example, we also need to ask, how do we measure group size and how might nonhumans measure group size? This question deserves special consideration on its own because even if we can come up with a working definition of group, we also need to be able to present measures of instantaneous and long-term effective group size. In studies of vigilance (and other activities) variations in group size are often used to explain variation in other patterns of behavior, such as individual scanning rates, and precise measurements of group size are essential.

(2) Does the size of a group or the geometric distribution or orientation of individuals influence individual vigilance?

I have already mentioned the often-found relationship between group size and scanning rates above. However, it is important to keep in mind that there are confounding variables such as the geometric relationships among group members (or neighboring birds) (Figure 1) and how individuals are oriented in space that might influence scanning rates of individuals.

Answers to the question "How does the geometric distribution of individuals influence individual vigilance?" will likely have something to say about animal cognitive abilities. Thus, while it is known that the location of an individual in her group (center or periphery) can influence her pattern of vigilance, it remains to be studied how the geometry of the whole group influences the ease with which an individual is able to assess what others are doing by seeing or hearing them (and relate their behavior to her own). For example, it seems that it would be easier to see what others are doing if individuals were organized in a circle rather than in a straight line, but this is not known. Determining how each variable singly and in combination with others influences scanning is important so that we can determine the precise role of group size itself in influencing individual patterns of vigilance (Elgar 1989).

Questions such as "How does a bird or other nonhuman assess group geometry?" also need to be considered. While it is known that in some species group structure changes in response to the presence of a predator (Lima and Dill 1990, p. 627), it is not known if and how individuals actually assess the geometry of the group in which they are a member.

(3) Do changes in group size or geometry influence patterns of social interactions?

 It is possible that as group size and geometry change, either singly or together, there is also a change in how individuals interact. If this is the case, then it might be possible for an individual to gain information about these variables from changes in encounter patterns without having to read them directly (e.g. Gordon, Paul, and Thorpe

1992; Gordon, Goodwin, and Trainor 1992; see also Deneubourg and Goss 1989 and Warburton and Lazarus 1991). To the best of my knowledge, there are no data for birds or mammals that can be used to answer these questions with any degree of certainty. Of course, the problems in studying these questions are enormous, but trying to get answers to them should be an exciting venture.

Some other interesting questions that may be informed by a cognitive approach include: "Do individuals change their relative position in a group to make it more likely that they could feed more efficiently and/or detect potential predators more easily?" "Is this a cooperative endeavor?" Also, "Does one's position in a group influence influence whether he can assess changes in group size or geometry?" Here I am asking if and how the location of an individual in a group makes it easier or more difficult to know how many other individuals are there and how they are distributed in space. It might be very useful for an individual to be able to see what others are doing, for while scanning, an individual might also pick up and store information about what individuals in a particular part of the group are most likely to be doing, or she might generalize from her own previous experience in that part of the group to what others are most likely to be doing when they are in that position. If we can get answers to these sorts of questions, we might be able to assess if it possible that the inverse relationship between group size and individual scanning rate levels off or fails because of failures in individuals being able to monitor the behavior of too many other animals who might also be hard to see. Elgar et al. (1984) and Metcalfe (1984a,b) present data suggesting that in some birds there does seem to be visual inspection among individuals a flock.

The results of cognitive studies of vigilance would be useful not only for furthering our knowledge about antipredatory scanning but also would inform and motivate other studies (e.g. assessments of dominance) that are concerned with the question of how individuals assess what they know and what others know based either on the result of direct interactions with them, or by observing how others interact with individuals with whom they themselves have not had direct encounters (observational learning). In large groups it would probably be impossible to know about every possible paired interaction, nor might it be possible or desirable for an individual to be able to interact with every other individual. Thus, in these instances having the ability to read interaction patterns among others and then to use this information in one's own encounters would be extremely useful. How individuals glean information from their nonsocial environments also is important to consider (e.g. the location of a potential predator or safety, and how this information influences whether and how rapidly assessments of group size and group geometry and changes in group size and geometry are made). We will also learn more about how accurate are folk psychological explanations for many of the behavior patterns that are of great interest to us.

1.5 Conclusions

There are many reasons why people are interested in the study of nonhuman minds and cognition. While each does not necessarily warrant a cognitive approach, taken together they justify the current interest in cognitive ethology. These include the following (in no order of importance).

(1) Many models in ethology and behavioral ecology presuppose cognition (see Ristau 1991a, Yoerg 1991, and Griffin 1992 for examples). It would be useful to have informed ideas about the types of knowledge that nonhumans have about their social and nonsocial environments and how they use this information.

(2) It may be more economical or parsimonious to assume that not everything that an individual needs to be able to do in all situations in which he finds himself is preprogrammed. While general rules of thumb may be laid down genetically during evolution, specific rules of conduct that account for all possible contingencies are too numerous to be hard-wired (Griffin 1984). Behavioristic learning schemes can account for some flexibility in organisms, but learning at high degrees of abstraction from sensory stimulation seems less amenable to behavioristic analysis (Allen and Hauser 1991). Cognitive models of learning provide explanatory schemes for such cases.

(3) The assumption of animal minds leads to more rigorous empirical analyses of behavioral plasticity and flexibility in the many and diverse situations that many nonhumans regularly encounter. Yoerg (1991) argues that considerations of cognitive function can lead to original ideas about behavioral adaptation.

(4) By providing different perspectives on behavior, cognitive ethology can raise new questions that may be approached from different levels of analysis by people coming from different disciplines. For example, neurobiological studies would be important for informing further studies in animal cognition and might also be useful for explaining data that are already available.

(5) Animal welfare issues are tightly connected to views on the cognitive abilities of nonhumans.⁵

Of course, more comparative data dealing with animal cognition are needed, especially those that could be analyzed using rigorous methods that have been applied to other types of comparative studies(e.g. Gittleman and Luh 1993); detailed field data would be particularly welcomed, or at least enough information that could reliably inform more controlled studies of animal cognition. While some are of the opinion that advanced cognition is confined to the laboratory (e.g. Premack 1988, pp. 171-172), those who have studied animals in the wild disagree (e.g. de Waal 1991, p. 311; McGrew 1992, pp. 83ff).⁶ More concentration is also needed on individual differences in cognitive abilities; sweeping generalizations concerning the "typical" behavior of species are often misleading because of great intraspecific variation in social behavior and social organization (Lott 1991, White 1992) and in the performance of behavior patterns (e.g. tool use) that are often cited in establishing generalizations about cognition (Gibbons 1991; McGrew 1992).

Interdisciplinary efforts, despite possible pitfalls (Heil 1992, p. 235), are essential in our quest for knowledge about animal minds. In these joint efforts, open minds and pluralism would also be useful at this stage of the game (Roitblat and Weisman 1986). Philosophers need to be clear when they tell us about what they think about animal minds and those who carefully study the behavior of nonhumans need to tell philosophers what we know, what we are able to do, and how we go about doing our research. Although providing alternatives might not be a requirement in thought experiments that conclude that animals do not have beliefs for one or another reason, it would be useful for students of behavior to be presented with some viable alternatives that could be used in their empirical investigations. If it is because philosophers do not have the experience with empirical work that allows them to make realistic suggestions for experimental design, then it would be useful for philosophers to watch ethologists at work (Dennett 1987, 1988). This experience might allow philosophers to gain a better understanding of what ethology is all about. Even then, it may be the case that ethologists are ill-advised to look to philosophers for a crisp and empirically rigorous definition of intentionality (for example), even if some philosophers promise to provide one (C. Allen this volume).

Obviously, I do not think that cognitive ethologists should hang up their field glasses and have nothing to do with talk about nonhuman intentional behavior. Rather, cognitive ethologists should put their noses to the grindstone and welcome the fact that they are dealing with difficult and important questions. I expect that in the future, cognitive ethologists will be pursuing the challenging questions that confront them, rather than looking for other work.

Notes

 I thank Jean-Arcady Meyer and Herbert Roitblat for allowing me to partake in this conference and for their help in defraying some of the costs associated with traveling to France. The University of Colorado also provided financial aid for the preparation of my oral presentation and this paper. A large number of people have helped me along the way, and to them I extend many thanks. They include: Dale Jamieson, Susan Townsend, Carol Powley, Lori Gruen, Ruth Millikan, Robert Eaton, Deborah Crowell, Mark Anderson, Anderson Brown, John A Fisher, Bernard Rollin, Jack Hailman, Kim Sterelney, Deborah Gordon, Gordon Burghardt, Donald Griffin, and especially Colin Allen. To those who I have inadvertently overlooked, I extend my deepest apologies. John Heil, Andrew Whiten, and James R. Anderson graciously provided unpublished manuscripts. Herb Roitblat's, Colin Allen's, Susan Townsend's, and John Lazarus' comments on an ancestral version of this paper were especially helpful. None of these scholars necessarily agrees with what I have written.

1. See, for example, Griffin (1976, 1981, 1984, 1991, 1992); Dennett (1983, 1987); Millikan (1984); Roitblat, Bever, and Terrace (1984); Wyers (1985); Mitchell and Thompson (1986); Byrne and Whiten (1988); Cheney and Seyfarth (1990, 1992); Allen and Hauser (1991); Bekoff and Jamieson (1990a,b, 1991); Hauser and Nelson (1991); Ristau (1991a,b); Yoerg (1991); Bekoff and Allen (1992); Beer (1992); Real (1992); Roitblat and von Fersen (1992); Jamieson and Bekoff (1993).

2. Kennedy's claims about anthropomorphism are wide-ranging, but simple-minded and unargued. For more detailed and scholarly discussions of anthropomorphism as they are related to studies of animal behavior, see Fisher (1990, 1991).

3. Sometimes it is difficult to differentiate between skeptics and moderate proponents, who argue that if there is to be a science of cognitive ethology, we must develop empirical methods for applying cognitive terms and making talk about animal minds respectable (e.g. Kummer et al., 1990). Jamieson and Bekoff's (1993) differentiation between weak cognitive ethology, where a cognitive vocabulary can be used to explain, but not to describe behavior, and strong cognitive ethology, where cognitive and affective vocabularies can be used to describe and to explain behavior, may be relevant here.

4. For numerous and diverse examples see Chance and Larsen (1976); Griffin (1976, 1981, 1984, 1992); Dennett (1983, 1987); Roitblat, Bever, and Terrace (1984); Byers and Bekoff (1986); Mitchell and Thompson (1986); Schusterman, Thomas, and Wood (1986); Byrne and Whiten (1988); Bateson (1990); Blaustein and Porter (1990); Cheney and Seyfarth (1990, 1992); Pepperberg (1990); Philips and Austad (1990); Rosenzweig (1990); Smith (1990); Allen and Hauser (1991); Bekoff and Jamieson (1991); Hauser and Nelson (1991); Ristau (1991a); Yoerg (1991); Bekoff and Allen (1992); Beer (1992); Caro and Hauser (1992); Fiorito and Scotto (1992); McGrew (1992); Whiten and Ham (1992); Roitblat and von Fersen (1992).

5. For discussion see Rachels (1990), Bekoff and Jamieson (1991), Harrison (1991), Bekoff et al., (1992), Griffin (1992), G. W. Levvis (1992), M. A. Levvis (1992), and Lynch (1992). Byrne (1991, p. 47) has gone as far to claim that "If explorations of the minds of chimpanzees and other animals do nothing more than inform the debate about the ethics of animal use in research, the work will have been well worthwhile." Griffin (1992, p. 251) notes that "No one seriously advocates harming animals just for the sake of doing so, although cruelty is unfortunately prevalent in some circles." Unfortunately, Griffin does not tell us where. Despite a very large data base demonstrating highly developed cognitive skills in many animals, there are those who ignore research on animal cognition, misinterpret data from studies on humans, and base their conclusions on the moral status of animals using an intuitionistic comparison of animal and human behavior (e.g. Carruthers 1989; Leahy 1991; but see Clark 1991; Jamieson and Bekoff 1992; Singer 1992). Thus, Carruthers (1989, p. 265), who compares the behavior of animals with the behavior of humans who are driving while distracted and humans who suffer from blindsight, writes: "I shall assume that no one would seriously maintain that dogs, cats, sheep, cattle, pigs, or chickens consciously think things to themselves . . . the experiences of all these creatures [are of] the nonconscious variety." (p. 265) Furthermore, "Similarly then in the case of brutes: since their experiences, including their pains, are nonconscious ones, their pains are of no immediate moral concern. Indeed since all the mental states of brutes are nonconscious, their injuries are lacking even in indirect moral concern. Since the disappointments caused to the dog through possession of a broken leg are themselves nonconscious in their turn, they, too, are not appropriate objects of our sympathy. Hence, neither the pain of the broken leg itself, nor its further effects upon the life of the dog, have any rational claim upon our sympathy. (p. 268) And finally, " . . . it also follows that there is no moral criticism to be leveled at the majority of people who are indifferent to the pains of factory-farmed animals, which they know to exist but do not themselves observe." (p. 269) For discussion of this minority opinion, see Johnson (1991), Bekoff and Jamieson (1991), and Jamieson and Bekoff (1992). Recently, Carruthers (1992, p. xi) has come to regard " . . . the present popular concern with animal rights in our culture as a reflection of moral decadence" that distracts " . . . attention from the needs of those who certainly do have moral standing - namely, human beings." (p. 168)

Another issue that bears on studies of both animal cognition and animal welfare concerns the naming of animals, for this practice is often taken to be nonscientific. Historically, it is interesting to note the Jane Goodall's first scientific paper dealing with her research on the behavior of chimpanzees was returned by the Annals of the New York Academy of Sciences because she named, rather than numbered, the chimpanzees who she watched. This journal also wanted her to refer to the chimpanzees using "it" or "which" rather than "he" or "she" (Montgomery 1991, pp. 104-105). Goodall refused to make the requested changes but her paper was published anyway. As has been pointed out elsewhere (Bekoff 1993b), the words ""it" and "which" are typically used for inanimate objects (Random House Dictionary 1978). Given that the goal of many studies of animal cognition is to come to terms with animals' subjective experiences - the animals' points of view - making animals subjects rather than objects seems a move in the right direction.

Finally, the results of comparative approaches to cognition will raise numerous and complex ethical concerns about the moral status of androids, for example (e.g. Caudill 1992, Chapter 13). These thorny issues cannot be dismissed, but rather should be accepted as challenges for future consideration. Undoubtedly, many of these ethical concerns will be informed by the ways in which nonhumans are viewed.

6. One area in which information from the wild would be very useful concerns the question of whether animals can count (Boysen and Capaldi 1993). While I have no hard data concerning this ability in the free-living coyotes who I have studied, when pups were moved from one den to another, I never saw a mother either forget a pup or go back to a den to retrieve a pup who was not there, even when she had help from another coyote in moving the infants. McGrew (1992, p. 223) also points out that we need to know about accounting abilities in other animals to see if accounting informs decisions about reciprocity.

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(1) OBSERVATIONS AND DESCRIPTIONS OF BEHAVIOR_{Jethro (J)} inform us about the possibility of there being

(2) MENTAL STATESJ AND BELIEFS_J (cognitive ethology) that lead to attempts to ascribe

(3) CONTENT TO BELIEFS_J (folk psychological explanations) that lead to attempts to discover more about the

(4) NEURAL bases of BELIEFS_J (mature neuroscientific explanations) that lead to attempts to learn more about the

(5) MOLECULAR BIOLOGY OF BELIEFS_J (more mature explanations)

(2) Is there some sort of orderly mapping of environmental and mental events in the nervous system?

(3) Is 5 'better' than 1? Do we gain more control and increase the certainty with which we can offer more precise causal explanations as we deal with smaller pieces of the puzzle?

(4) Why should we wait for a mature neuroscience? Why can't we also expect to learn more if we wait for a mature cognitive ethology?

(1)

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