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This review appeared in Volume 4 (1) of The Semiotic Review of Books.

Evolution Of Sociality And Intelligence

by Anne E. Russon

Social Processes and Mental Abilities in NonHuman Primates: Evidences from longitudinal field studies. By Frances D. Burton, (Ed.)(1992). Lewiston, N.Y.: The Edward Mellon Press pp. iii-283. ISBN: 0-7734-9537-1.

Four main themes about nonhuman primates ribbon through this book: (1) modelling their sociality; (2) the role of intelligence in their behaviour; (3) the relative roles of immediate 'proximate' versus evolutionary 'ultimate' factors in their sociality; and (4) the importance of long-term study. Debates centre on sociality, with concerns over the prevailing theories and concepts of sociality in nonhuman primates.

Sociality and intelligence are often considered the hallmarks of the primates. Both have been studied intensely, with sociality receiving greatest attention since the rise of field research in the 1950's and 60's. While whole books have been consumed with attempts to capture the essence of their sociality (e.g., Smuts et al.,1987), perhaps the main consensus achieved is that the underlying organizing principles are neither few nor simple. The only defining qualities may be variability, complexity, and flexibility.

For the uninitiated, some of the qualities these authors highlight as important in primate sociality are sketched. Nonhuman primate societies are not simple aggregations of individuals. They are bounded in space, but much less so in time. They commonly contain a mixture of ages and sexes spanning several generations. Members actively cooperate and compete, from altruism to deception. Enduring roles and relationships form the cornerstones of many social structures. Conventional 'roles', like leader or sentry, structure and constrain individual behaviour; these can vary developmentally. Beyond basic parent-offspring and mating relationships, important interindividual relationships identified include dominance, coalitions, all mothering, and peer, sibling and non-sexual male-female 'friendships'. Resulting social structures can take a variety of forms. At base levels, they can include mother-offspring units, mating units, mixed sex adolescent groups or bachelor bands. Even these basic units involve much variability. For example, although the most common primate mating patterns are polygynous, they can range from lifelong monogamous bonds to polygyny to multiple mates for both females and males. Smaller social units can be organized, sometimes hierarchically, into larger, higher level structures. Organizing principles can centre on any of: developmental status, reproductive status, kinship (matri- or patri-focal), dominance hierarchies, age/sex associations or alliance. Social exchange occurs both within and between social units, though the two differ substantially in nature (cooperative vs. aggressive). Members of primate societies are nonetheless true individuals who acquire their social skills, relationships and status through lengthy, intense and idiosyncratic socialization experiences with the semiotic competencies this entails.

In the first chapter, Leslie Chan (1-30) is concerned with representing the great variability and complexity of nonhuman primate societies. He reviews prevailing socioecological theories modelling primate societies as the evolutionary products of a limited set of ecological pressures. His analysis of the inadequacies of these models nicely sets the stage for subsequent chapters.

Socioecological theories derive from current models of evolution which are based on the premise that behaviour is shaped by, and fits, the environment. They single out predation and resource availability as the key ecological factors that favour social living and shape its presumed key parameters, group size and composition. Two factors have importantly influenced these models: they were borrowed from research on avian societies and the focus has been on evolutionary level forces. Although many still subscribe to these models, thirty years accumulated research yields only limited support. For example, link s predicted between predation and social parameters are plausible (greater predation should lead to larger groups and a larger proportion of males as defenders) but in fact are weakly supported or even contradicted by available data. The importance of any patterns identified pales in the face of the sheer variability encountered. Resources are expected to shape cooperative defense around mating structures, since reproductive concerns are considered the raison d'être of social life. Male and female reproductive interests are considered tied to different ecological concerns -- females' to the survival of their offspring and so to food constraints, but males' to inseminating females and so to the distribution of females and to defending them against other males. Data largely confirm predictions linking mating structures to resources (e.g., males but not females tend to disperse from their natal groups). Important complexities are nonetheless neglected. For example, cooperative resource defense potentiates conflict between groups, which conflict then presses for more effective within group cooperation. This means that social organization can be directly shaped by intergroup forces, not only ecological conditions. The impact of ecological pressures on nonhuman primate sociality may not be direct but instead importantly mediated by within species social factors.

For this book's themes, there are further problems with these models. First they deal only with evolutionary scale patterns. First, prevailing models of evolution are themselves problematic for modelling sociality because they put the individual, not the gene or the society, as the unit on which selection pressures act; they thus focus on individual fitness assessed via reproductive success. This paints social structures as mere side-effects of individuals' encounters with the environment as they try to maximize their own reproductive success. This unidirectional view of individual-society relations is at odds with evidence that nonhuman primates have group social traditions which influence individuals -- their behaviour, reproductive success, and encounters with the environment. Individual-society relations must therefore be bidirectional. Second, socioecological theories model primate societies as simple extensions of mating systems. While this may adequately represent the avian societies for which they were developed, primate mating systems and social organization differ substantially from avian ones. For example, nonhuman primates tend to polygyny while avian species tend to monogamy and primate social structures are more complex and less closely defined by mating systems. Third, identifying social structures with mating systems leads to neglecting society-ecology relations concerning other age/sex classes (e.g., ecological access and need vary with age and social status: intrasexual relations affect access to resources) and to discounting the range and complexity of the roles typical of primate society (e.g., both pre- and post-reproductive members play key roles in societal maintenance; heterosexual 'friends' can later become either more or less preferred as mates). Secondly, other causes of social behaviour are not incorporated into these socioecological models, which tend to understate the sociosemiotic dimension of group evolution. In primates, where extensive, complex learning forms the main basis for social and ecological skills, these more immediate or 'proximate' forces are clearly key determinants of social organization whose role should be explicated.

These socioecological models also assume evolutionary convergence, that ecological conditions generate similar social structures. To the contrary, it is increasingly clear that differences in species' evolutionary histories (phylogeny) pose important constraints on the direction that evolutionary changes take. Finally the evolutionary perspective also encounters methodological problems. Reproductive success is difficult even to define in observable terms, let alone actually measure. For example, male reproductive success is a lifetime tally, not an annual or a seasonal one, and short term measures do not reliably predict the lifetime result. The short term studies typical or socioecological research are not appropriate to assess such evolutionary scale factors.

Primate social organizations represent higher levels of functioning which are not appropriately reduced to the individual and which derive from multiple causes. Chan advocates developing multidimensional theories built on hierarchical principles which accept bidirectional causation across levels.

Based on her long-term work with macaques, Frances Burton (31-60) discusses the primate group as a store and unit of information. She highlights tradition drift, one process that introduces change into the group's information store.

In monkey societies, the social group represents an information unit of the cumulative knowledge of its constituent members. This informational feature may be an essential one. In primates, with their unusually large and powerful brains, most of an individual's knowledge is acquired experientially, within its own lifespan, rather than genetically. That is, primates rely heavily on sophisticated learning. Although direct experience with the environment contributes, Burton argues that this learning is most importantly social. Primates systematically socialize their young -- they model, reinforce and shape youngsters' learning -- and learners imitate. What is acquired are then copies of knowledge already in the social store, so this store represents the body of established knowledge to be passed on to youngsters. It is semi-closed because most transmission occurs within the bounds of the social group. Social transmission of information between individuals has an advantage over genetic transmission in that change is incorporated much more rapidly and readily. It thus constitutes a mechanism for rapid adjustment to changing ecological conditions.

It should be suprising that we find group traditions in primates, endemic patterns of behaviour which arise and are sustained across generations. Monkeys make use of their group traditions when they deceive, via expectations about their own and others' conventional role behaviour. They deliberately send gestures 'belonging' to other age/sex classes, apparently relying on the predictable response. Group traditions should also be changeable rather than stable over time. Group members may alter old established patterns or even innovate completely new ones. As a true individual, each member of a primate society brings a unique interpretation to any information received as well as a unique expression to any role occupied or behaviour performed. As receivers they distort or filter messages; as senders, their messages have differential visibility in the group as well as differential acceptability. Socially transmitted copies may thus differ from the original or from other copies in idiosyncratic ways. The differences do not always represent change directed to adaptive advantage but rather nondirected 'drift' resulting from imperfections in social transmission and idiosyncracy. This sort of tradition drift results from short-term (proximate) rather than evolutionary (ultimate) forces, which does not necessarily follow adaptive routes.

Anne Zeller (61-80) argues that one function of communication is to maintain social systems -- it evolved for this reason -- although it also promotes survival and reproduction by transmitting ecological information. Zeller too thus disputes the conventional assumption that ecological pressures as more important than social ones in primate evolution.

Communication here includes all behaviour which transmits information socially. Given primates' long lifespans and complex social systems, the communication processes which they use to establish and maintain their social units are correspondingly complex. These involve integrating sensory-motor channels (vision, audition, etc.), intra-channel modalities (facial expression, gesture, posture, etc.) and, Zeller adds, volition. ln non-volitional 'basic' communication, the information transmitted cannot be hidden and involves no intent; in volitional 'interactive' communication, choice is attributed to senders about what is sent.

Much communication in group-living primates occurs within, and is about, the social group. Group cohesiveness is managed via special roles and messages, such as sentry or leader roles and affiliative vs. aggressive messages for intra vs. inter-group exchange. Complex, lengthy communicative exchanges may be involved, as when an individual negotiates migration to a new group. Long-term relationships form the basis of many important life activities: Reproduction depends on successfully forming breeding bonds, which involves special behaviours as well as variable, lengthy courtship and relationship patterns; and individuals' actions are shaped by their dominance, coalition, and friendship relationships. These relationships directly depend on the quality of partners' communication. Failures in social functioning deriving from failures in relationships testify to the social skills needed even to survive and reproduce; for example, isolation-reared monkey infants developed aberrant nonfunctional mating and parenting patterns. Day-to-day communication about transient phenomena forms the basis of group living, maintaining group integration by assisting adjustment to fluctuations.

Communication also involves coding information into conventionalized forms and messages. In primates, this is again highly complex. For example, Zeller identified 33 different components in macaque facial expressions which can be assembled idiosyncratically. Decoding is equally complex, involving an analysis of who sent the message, what was sent, and volition. For example, identifying deception involves decoding the deliberate sending of an inappropriate message. Both coding and decoding constitute learned skills in primates. Infants are born able to send and decode only a few messages and they know little about their use. Evidence shows clearly that social learning is the main source of this knowledge and skill.

The communication of social information is then a complex and intricate process. It is fundamental to both the survival and reproductive success; it is acquired through social communication itself. This shows clearly that the evolutionary function of communication is social, not only ecological.

John Chadwick-Jones'(91-108)interest is intelligence, particularly the short-term 'proximate' processes in nonhuman primate social cognition. He suggests importing models from the human social sciences because of their greater rigor -- they have established specialized terminology with well-defined, consensual meanings while primatology suffers from casual use of ordinary, anthropomorphic terms like 'threat'. Interestingly, Chadwick-Jones is himself a recent 'import' to primatology from human social psychology. As a newcomer, he may not yet be aware of the period of primate ethology in the 70's when exhaustive behavioral repertoires and terminology were meticulously developed. He suggests two imports, social contingency analysis and social exchange theory, which, he considers, offer better analytical methods and explanations for some nonhuman primate social phenomena than those currently applied.

First, showing that cognition underlies nonhuman primate social behaviour requires demonstrating that there are plans behind their social interactions -- they act in order to achieve goals. Applying social contingency analysis from human social skills research can generate empirical bases for inferring such plans. Interactions are coded so that every signal sent by interactants is recorded in sequence; the sequence depends on previous actions, partly the actor's and partly the partner's. Consistency in an actor's sequence throughout the interaction permits inferring the presence of plans. Without statistics, this approach in fact resembles (Markov) sequential analyses used for interpreting individual and interactive primate behaviour sequences since the 60's. Chadwick Jones' qualitative reanalysis of examples from others' published long-term studies does provide evidence of such plans in baboons, and so, social cognition.

Chadwick-Jones suggests that social exchange theory may allow exploring avenues of nonhuman primate social goals in proximate versus evolutionary perspective. This theory suggests that interacting individuals are reciprocally exchanging actions in order to achieve profit or at least equity. Mutual gain appears to be the goal in nonhuman primates. Interactions where actions are exchanged for mutual gain have been discussed in terms of reciprocal altruism, individuals mutually exchanging altruistic acts (acts aiding others to the helper's disadvantage) at different times. Chadwick-Jones suggests distinguishing social exchange from reciprocal altruism: Social exchange does not involve fisk or loss while reciprocal altruism does and the benefits of social exchange lie in short term gain while those of reciprocal altruism the in reproductive success. These distinctions resemble variations of optimally theories, which model cost-benefit and profit patterns underlying animal behaviour. Empirical tests of social exchange in nonhuman primates require establishing a true contingency underlying an apparent change of favours low costs, and non-kin partners (kin partners could benefit reproductive success and so reflect reciprocal altruisism). There is evidence for such social exchange in baboons, including retaliation after delays of up to several days, female grooming males for benefits accruing from consequent male proximity, and non-kin coalitions against low-ranking (low-risk) opponents. Chadwick Jones' work again points to cases where proximate are better than ultimate explanations for social phenomena.

Susan Hornshaw (109-127) identifies this volume's theme as the view that the patterns and rules of behaviour in nonhuman primate groups are essentially vocal phenomena with transcendant properties within this frame, she presents her own research on local group traditions in captive macaques.

Much of her discussion concerns her epistemological position vis a vis traditional North American science, where tendencies are to privilege parsimony over adequacy and to treat patterns both as invariant laws vs. statistical tendencies and as prescriptive vs. descriptive rules. These tendencies have contributed to oversimplifying and even denying the richness and variability of nonhuman primate societies. Methodologically, they translate into an overreliance on stability without correspondingly appreciating that stability in findings may reflect methods rather than the objects of study. The problems are particularly intransigent for nonhuman primates because the West has vested so much interest in creating its images of human nature via nonhuman primates, especially their differences.

To address this problem complex, Hornshaw advocates a 'surface structure-deep structure' approach where patterns of behaviour are explicitly separated from rules for behaviour. The latter inevitably involve inference and so risk subjective wish fulfilment. In fact, Hornshaw advocates abandoning attempts at identifying the latter because they are ultimately unknowable. She concentrates her own empirical work on behaviour patterns 'free' of interpretive judgment at the time of data collection.

Her empirical research concerns the processes of social adaptation in captive macaques, again taking the position that social behaviour is not a direct and simple function of ecological conditions. Especially, group differences are not necessarily a function of captive versus free environments and captivity itself is not homogeneous. She has found differences in interindividual distance patterns between captive and free macaque groups contrary to predictions based on available environmental space but consistent with one facet of genealogy, matriline depth. She has also found variability rather than stability across time in social behaviour: One of her macaque groups showed relations between genealogy and behaviour at one point in time but not another.

On top of its implications concerning the importance of social vs. ecological pressures in primate sociality, her studies underline the importance of long-term research. In her concluding comments she again stresses tendencies to misattribute the causes and meanings of nonhuman primate behaviour. This final item touches on the problem of establishing patterns in inherently flexible, probabilistic systems.

James Paterson (129-181) models behaviour as a multicausal proximate strategy survival. His model is pictured as three concentric shells, each representing a different aspect of causality of khaion The generic shell is innermost surrounded successively by physiology morphology then behaviour The behaviour shell comprises subshells: learning and group traditions, cognition, and selfawareness. A capacity for flexible response is assumed in all three shells with increasing flexibility towards outer ones. Responses to pressure progress from most to less flexible shells until the pressure is met. Behaviour then constitutes the organism's first fine of defense, a common view. Behavioral change may or may not engender changes in deeper shells. Each shell acts as a buffer for deeper shells, absorbing, cushioning or redirecting pressures. Each is also influenced to some extent by deeper shells; i.e., there is communicafon between shells commonly via feedback. If pressures are sustained, several shells may change to establish new balances but only to the depth needed to resolve the pressure. This model does better represent the variability and complexity of behaviour; how it is specific to primates is unfortunately not clear.

Paterson tests this model across physiology morphology behavioral levels via a study of thermoregulation in monkeys. Animis are here considered 'heat machines' who input compounds for conversion into energy. In homoiothermic species, some of this energy is used to maintain stable body temperatures. Outside a 'Thermal Neutral Zone', maintaining this internal thermal equilibrium requires increasing metabolism. This can be effected via behaviour like posture or activity levels because postural behaviour can influence body shape via flexion (open-close joints) and position (in-out of windsun). Shape affects surface area which itself affects thermal transfer, in Hne with Bergmann's ecogeographic rule: In warmer climatic regions smaller massed forms in a species have a survival advantage over larger ones of the same surface area or shape.

The study involved a group of Japanese macaques transferred from Japan to south Texas. Older mates born and partly raised in Japan appeared to have shorter, stockier bodies than younger males raised in Texas, who had longer, linear ones. Thermal conditions differ greatly between the two habitats, Texas being substantially hotter, suggesting that the body shape differences reflect thermal-related morphological changes; these should be balanced by differential behaviour. This was tested by comparing the two types of males' behaviour and posture across various thermal-related weather conditions during one of the hottest summers on record. More temperature factors affected posture for stocky than for long-bodied males, suggesting that the different shapes do reflect morphological adaptations which are balanced by differing behaviour. Even this short study supports the validity and utility of such multicausal and bidirectional models of behavioral causality. Fitting sociality into this model would provide a valuable contribution to the sociality-ecology conundrum presented by other contributors to this volume.

Birute Galdikas and Paul Vasey (183-224) discuss orangutan intelligence in the context of debates on the nature and evolution of human intelligence. One way that the debate over the relative importance of social versus ecological factors in primate evolution is played out is through debates over the specialization and relative sophistication of social versus ecological intelligence. The research on intelligence narrows down to those traits proposed as 'unique' to the early hominids, the 'prime movers' responsible for hominid-pongid speciation. Among others, these prime movers have included hunting and meat eating, gathering, tool use and manufacture, language, and protoculture. All have fallen by the wayside as each has been identified in living pongids, chimpanzees, gorillas and orangutans, but all are still considered crucial to hominid intelligence because all occur only infrequently in living pongids. As such, they probably constitute byproducts of some other ability in early pongids which was itself a direct adaptation to selection pressures.

Understanding pongid intelligence then requires understanding the basal adaptation allowing for the appearance of this constellation of traits. Galdikas and Vasey argue that this basal adaptation was generalized increased encephatization and concomitant increased generalized, not specific, intelligence. They discuss the extent to which advanced generalized intelligence appears in wild orangutans and how it serves important ecological and social functions. Data are from Galdikas' 20-year continuous study of wild orangutans in Tanjung Puting, Indonesian Borneo. Orangutans may be the best living models of early pongid-hominid intelligence, as the most phytogenetically conservative of the living primates.

Increased complexity in foraging problems is expected to press for greater intelligence, for handling disparate types of information. Orangutans face inordinately difficult feeding problems as large arboreal frugivorous in tropical rainforest habitats, involving food recognition, search and processing. Recognition involves over 300 different food types in Tanjung Puting, not counting the food's state of readiness. Search is highly complex given the food diversity and its unpredictably patchy distribution in both time and space-individual plants of a species tend to be widely spaced, fruiting seasonality is timed at best, and kuifing is not synchronized within species. Orangutan spatial intelligence is correspondingly sophisticated, with evidence of complex cognitive maps. Processing food adds As own complexities, especially for the numerous embedded foods. The behaviour needed to extract edible portions can involve simultaneous coordination of several complex manipulatory movements, sometimes coordinated into lengthy ordered sequences of steps. Techniques are nonetheless flexible across and within food types. Parker and Gibson (1977) have argued that needs for complex processing of embedded foods would have placed a high selective premium on intelligence; the evidence suggests this applies to orangutans.

Although stereotyped as solitary and socially rather retarded, orangutans show social intelligence worthy of the epithet "Machiavellian." Despite limited social groupings and infrequent encounters, orangutans in Tanjung Puting in fact spend substantial amounts of time in social contact (20-40%). Orangutan mating systems show the intense mate selection patterns -- male male competition and female choice-considered the most important social issues driving the evolution of higher intelligence. For orangutans, simply finding mates is extremely complex given the wide dispersal of individuals, females' lengthy sterile periods between births (up to 7-8 years) and their opportunities to exercise choice by hiding in their arboreal environment. Subadult males and adolescent females must negotiate mating acceptance from positions of least favoured mates; especially for males, this may involve triadic encounters. Orangutans recognize themselves, others as individuals, the nature of their relationships with others, and most importantly, the nature of the relationships between others. They also form coalitions and practice deception. All have been cited as indicative of the most sophisticated social intelligence.

Both critical ecological and social pressures fit well with the advanced intelligence of orangutans. Others attempt to assign priority to one or the other pressure in shaping primate intelligence; Galdikas and Vasey consider, to the contrary, that the two are inextricably wound together and that intelligence may be integrated in the pongids. Finally, clearly only long-term studies make such findings possible.

Comments will centre on the four central themes in this book in an effort to situate the work and suggest where it might lead.

Sociality. Appreciation for the significance and complexity of nonhuman primate sociality has waxed steadily sine the 1960's when primatologists such as Jolly (1966) and later Humphrey (1976) began arguing that sociality, not only physical world ecological pressures, must have been a central driving force in primate evolution. This position recently broke into mainstream theoretical importance with Byrne and Whiten's (1988) work on nonhuman primate social intelligence, where they coined the phrase "Machiavellian intelligence" to capture the sophistication of nonhuman primate social manoeuvring. Contributors to Burton's book clearly subscribe to this view.

These authors, like others, advance this view of sociality by pointing out examples apparently contradictory to ecological predictions; for example, where social forces affect behaviour more directly than ecological ones or where social structures affect individual behaviour rather than the reverse. They go beyond identifying theoretical injustice to offer suggestions for conceptualizing phenomena unique to sociality (e.g.,tradition drift; social contingency and social exchange; volitional communication) and for better models of the relationships between individual, social, and ecological forces in nonhuman primate behaviour (a shell model; a generalized intelligence evolving with the pongids). Importantly, the theoretical resolutions treat social and ecological pressures as complementary and integrated rather than as opposing and contradictory forces.

Mental abilities. Discussions of mental abilities tie directly with issue of proximate causes of social organization because of the essential role of intelligence in nonhuman primate behaviour. Intelligence, in the sense of highly flexible and sophisticated learning abilities, is acknowledged to be a prime factor underlying the acquisition and quality of nonhuman primate behaviour. Burton, Zeller, Paterson, Galdikas and Vasey all emphasize that behavioral management of both social and ecological pressures is importantly mediated by individual mental processes. Like Byrne and Whiten, these authors contribute to conceptualizations about how nonhuman primate intelligence is manifested socially -- what problems characterize the social versus the physical world (competition, cooperation, negotiation, exchange), what is the nature of solutions to social problems (coalitions, reciprocal exchange), what processes are involved (socialization, social learning like imitation, conventionalization) and how these various processes are organized mentally (integrated versus domain-specific intelligence; individual-society-enviroment buffering shells).

Given the importance these authors attribute to intelligence in nonhuman primate sociality, especially as a proximate cause, a more scholarly treatment of issues surrounding intelligence would have been appropriate. There is a wealth of material. Psychological researchers have focused on nonhuman primate intelligence, especially in pongids, for over 60 years via laboratory studies of memory, learning, problem solving, and imitation; primate intelligence has currently taken a central and vibrant role in both primatology and animal cognition; and in human psychology, the issue of social cognition has been seriously examined for the last two decades. Central issues that should be discussed, but are only hinted at in Galdikas' and Vasey's chapter, are: whether nonhuman primate social intelligence is in fact substantially different from 'ecological' intelligence, if so how, and how do they interrelate; and whether the nature of intelligence itself differs substantially across the primates, especially between monkeys and pongids. Currently, there are strong arguments to the effect that social and ecological intelligence in monkeys are not integrated -- principles applied to social problems are not accessible to ecological problems (e.g., Antinucci, 1989; Cheney & Seyfarth, 1991) -- and that the levels of intellectual sophistication attained by monkeys are importantly lower than those attained by the pongids or humans (e.g., although monkeys may imitate in the sense that they reproduce behaviour they observe performed by others, current evidence suggests they cannot imitate in the sense of learning new behaviour by observation alone, whereas humans and probably the pongids can). Any such differences in intellectual capacities must have important implications for how nonhuman primate sociality is established and maintained. These are clearly critical issues for discussions of intelligence as a proximate mechanism underlying nonhuman primate sociality.

Proximate causes. In 1951 Niko Tinbergen, one of the fathers of modern ethology, argued that it is necessary to answer four questions about behaviour to understand it thoroughly: its function or 'ultimate' cause (its original evolutionary scale purpose, its adaptive significance or raison d'etre); its proximate causes (the short term, immediate circumstances and internal mechanisms that underlie behaviour); its ontogeny (development or age-related causes, or how behaviour emerges and changes through an individual's lifespan); and its phylogeny (how it evolved in the scope of evolutionary forces and time).

Most accept this view today, including the present authors, who single out the neglect of proximate for ultimate causes. For primates, with their long lifespans and extended dependency periods, ontogeny is clearly a key determinant of behaviour -- including semiotic behaviour -- and deserves equally explicit incorporation into theoretical models (e.g.,Gould, 1977; Parker & Gibson, 1991; Antinucci, 1989). Phylogeny somehow always disappears into the background; only Chan points out that sometimes "you can't get there from here". Although arguing the importance of proximate causes is a major project alone, it is still unfortunate that the theoretical importance of phylogeny and ontogeny are not equally acknowledged.

As with sociality and ecology, researchers have argued for the importance of proximate causes by opposing them to ultimate ones, identifying examples supporting proximate while contradicting ultimate predictions; again, it is more likely that these factors act in conjunction. It would hardly make sense, after all, for proximate mechanisms to consistently undermine ultimate goals. Although some consider that how ultimate and proximate forces interact in causing behaviour is anybody's guess, clearly an important further step is articulating the nature of this interaction. There is in fact a substantial body of relevant research from comparative psychology and general animal behaviour.

Traditional North American animal behaviour research, via comparative psychology, has analyzed proximate mechanisms since the 1920's. One version of history has it that the emphasis on evolutionary 'adaptive' processes began in the 1960's when European ethology, emphasising the study of animal behaviour under natural field conditions precisely because behaviour does have adaptive significance, was introduced into North American comparative psychology. Probably because primate field studies blossomed in this period, primatology was caught up in this wave of evolutionary fervour, especially within anthropology and biology. Psychologists kept researching proximate causes in their labs. In this context, it is interesting that two of this book's contributors emphasizing proximate causes have psychology backgrounds, and others argue the need to address proximate questions when they encounter the psychological mechanisms (e.g., learning, memory, imitation, communication) that underlie social behaviour.

Extant research on proximate mechanisms does suggest how proximate and ultimate forces interrelate. As a social example, genealogical kinship is considered an essential social dimension because aiding kin contributes to the evolutionary goal of reproductive success. Altruism, in the classic sense of aiding another to one's own disadvantage, is most commonly directed towards kin. However, few believe that nonhuman primates appreciate kinship in the way of sophisticated humans or that they have direct knowledge of genetic relatedness. One proximate mechanism for identifying kin or relatedness may be familiarity. This works because one tends to spend more time with kin than non-kin and with closely rather than distantly related kin -- although only on average. At the individual level 'failures' can occur (e.g.,Burton observed two old Bear macaque females looking after long-tail macaque infants), in that the behaviour generated by proximate mechanisms does not appear to coincide with ultimate goals. Some of these 'failures' do harm a few individuals, but commonly the same approach is successful for the majority. Other 'failures' turn out to be errors in interpretation, often concerning time scales. For example, in some avian species, young help non-kin raise their nestlings; this looks like a mistake in the short run, but in the long run it improves later opportunities for mating and establishing territories. Many proximate mechanisms seem to work this way: They extract snippets of information and apply simplistic "Rube Goldberg" rules of thumb to generate understanding and behaviour which, more often than not and in the long run, serve associated ultimate goals. The fact that they 'fail', in the sense of sometimes producing individual results which are counterproductive in achieving ultimate purposes, may in fact be important. As Burton points out, variability in the behaviour created by proximate mechanisms may constitute one major source of the variability needed to cope with unpredictable environmental change. In Paterson's terms, behaviour constitutes a multicausal proximate strategy for achieving ultimate goals. From this perspective, proximate mechanisms may relate to ultimate ones probabilistically, not absolutely. Single proximate examples don't, in and of themselves, contradict ultimate goals. It may be necessary to consider the distribution of proximate outcomes in order to appropriately assess the relationship of proximate to ultimate goals. Again, this means long-term study.

Long-term studies. Almost all these authors emphasize and illustrate the importance of longterm field work in the study of nonhuman primate behaviour. Given their arguments, the need is hardly disputable. Don't we wish that funding agencies would get the picture. Of further importance is articulating long-term designs to address questions that cannot be handled via the short term designs commonly used .

As a notable fifth dimension, this book represents a first collection of Canadian contributions to primatology. In typically Canadian fashion, the book is modest and understated. It would be hard to be otherwise, given that the number of Canadian primatologists almost fits on the fingers of two hands. This may be because, like wine grapes, nonhuman primates themselves find the Canadian climate inhospitable. What primatologists we do manage to generate tend to pick up and leave, taking root instead with their subjects. That this book should even appear is then encouraging. Its attempts to tackle two major themes in primatology, sociality and intelligence, marks it as a serious move to influence current thought about nonhuman primates. A scan of the list of authors shows new blood: several newly graduating (Chan, Vasey) and two 'converts' from neighbouring human psychology (Chadwick-Jones, Hornshaw) . Given the limited (viz. nonexistent) opportunities for nonhuman primate study in Canada, the fact that primatology is managing to grow speaks to the fascination and importance of nonhuman primate work in these days of environmental and biodiversity concern. The fact that several internationally respected primatologists have developed out of this diminutive Canadian community adds hope for solid Canadian contributions to an important field.

Criticisms. What would a review be without its criticisms? Aside from the differences of viewpoint or interpretation discussed above, one worth mentioning is the consistently poor quality of the book's production. I sympathize with the embarrassment that the authors must feel over the poor editing and layout given their work. It is a shame that this volume, making one sort of entree of Canadian primatology even if it is published in the United States, should be so noticeably marred by such readily avoidable superficial flaws. But even this cloud has a silver lining -- the hardback is reportedly much better produced than the soft cover copy I received.


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Anne E. Russon is an associate professor of Psychology at Glendon College of York University in Toronto. Her research interests centre on social and cognitive development in nonhuman primates, especially the great apes. For the last four years she has collaborated extensively with Birute Galdikas on observational (ethologically correct) studies of imitation and tool use in rehabilitant orangutans in central Indonesian Borneo. Recent publications include: Russon, A.E. & Galdikas, Birute M.F. (under review). Model and action selectivity in rehabilitant orangutan imitation, Proceedings of the XlVth Congress of the International Primatological Society. Russon, A.E. & Galdikas, Birute M.F. (in press). "Imitation in free-ranging rehabilitant orangutans." Journal of Comparative Psychology. Russon, A.E. (1991). "Deconstructing primatology." Semiotic Review of Books. Russon, A.E. and Waite, B.E. (1991). "Patterns of dominance and imitation in an infant peer group." Ethology and Sociobiology, 12(1), 55-73.Russon, Anne E. (1990). "The development of social interaction in infant chimpanzees: A description and comparative analysis" in S.T. Parker and K.R. Gibson (Eds), Language and Intelligence in Monkeys and Apes, Cambridge: Cambridge University Press. Russon, A.E., Bard, K. and Parker, S.T. (Eds). (in prep). Reaching into Thought: New views on the Minds of the Great Apes.

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