Behavioral Biology

What is the function of cognition? On one influential account, cognition evolved to co-ordinate behaviour with environmental change or complexity. Liberal interpretations of this view ascribe cognition to an extraordinarily broad set of biological systems—even bacteria, which modulate their activity in response to salient external cues, would seem to qualify as cognitive agents. However, equating cognition with adaptive flexibility per se glosses over important distinctions in the way biological organisms deal with environmental complexity. Drawing on contemporary advances in theoretical biology (...) and computational neuroscience, we cash these distinctions out in terms of different kinds of generative models, and the representational and uncertainty-resolving capacities they afford. This analysis leads us to propose a formal criterion for delineating cognition from other, more pervasive forms of adaptive plasticity. On this view, biological cognition is rooted in a particular kind of functional organisation; namely, that which enables the agent to detach from the present and engage in counterfactual inference. (shrink)

In infancy, all primates require a caregiver who meets their physical needs, such as food and protection (among many others), and their affective, cognitive, and social needs (in some species, this requirement extends until the primate is a juvenile). The caregiver is essential for primate infant survival and social and cognitive development. For that reason, infants are greatly affected if they lose their caregivers; the effects of becoming an orphan range from being unable to survive to behavioral and physiological consequences (...) that last through adulthood. This entry provides an overview of relevant aspects of the study of primate orphans such as survival rates, adoption, variables in the adoption process, the effects of losing a mother, and orphans in sanctuaries. (shrink)

The emerging neurocomputational vision of humans as embodied, ecologically embedded, social agents—who shape and are shaped by their environment—offers a golden opportunity to revisit and revise ideas about the physical and information-theoretic underpinnings of life, mind, and consciousness itself. In particular, the active inference framework makes it possible to bridge connections from computational neuroscience and robotics/AI to ecological psychology and phenomenology, revealing common underpinnings and overcoming key limitations. AIF opposes the mechanistic to the reductive, while staying fully grounded in a (...) naturalistic and information-theoretic foundation, using the principle of free energy minimization. The latter provides a theoretical basis for a unified treatment of particles, organisms, and interactive machines, spanning from the inorganic to organic, non-life to life, and natural to artificial agents. We provide a brief introduction to AIF, then explore its implications for evolutionary theory, ecological psychology, embodied phenomenology, and robotics/AI research. We conclude the paper by considering implications for machine consciousness. (shrink)

Model organismism—the over-reliance on model organisms without sufficient attention to the adequacy of the models—continues to hobble our understanding of human brains and behaviors. I outline the problem of model organismism in contemporary biology and biomedicine, and discuss the virtues of a genuinely comparative biology for understanding ourselves, our evolutionary history, and our place in nature.

Despite an increase in research examining maternal and infant touch, and documenting its public health impact, this mode of interaction has historically been omitted from related fields of developmental research in human and non‐human primates. The broad aim of this review is to examine to what extent mother–infant touch has been included in relational paradigms and research. We argue that although theoretical and empirical scholarship on attachment and maternal sensitivity conceptualizes touch as fundamental to caregiver–infant interactions and child development more (...) broadly, touch is rarely operationalized or measured in caregiver–infant interaction paradigms or clinical interventions. Data from primarily human, but also non‐human, primates are reviewed to document the importance of touch, and clinical research is reviewed to document the formal use of touch in human attachment and sensitivity research and intervention. The review closes with recommended directions for future research and related implications. (shrink)

In this paper we take an approach in Humanoid Robots are not considered as robots who resembles human beings in a realistic way of appearance and act but as robots who act and react like human that make them more believable by people. Regarding this approach we will study robot characters in animation movies and discuss what makes some of them to be accepted just like a moving body and what makes some other robot characters to be believable as a (...) living human. The goal of this paper is to create a rule set that describes friendly, socially acceptable, kind, cute... robots and in this study we will review example robots in popular animated movies. The extracted rules and features can be used for making real robots more acceptable. (shrink)

Empirical assessments of Cognitive Behavioral Theory and theoretical considerations raise questions about the fundamental theoretical tenet that psychological disturbances are mediated by consciously accessible cognitive structures. This paper considers this situation in light of emotion theory in philosophy. We argue that the “perceptual theory” of emotions, which underlines the parallels between emotions and sensory perceptions, suggests a conception of cognitive mediation that can accommodate the observed empirical anomalies and one that is consistent with the dual-processing models dominant in cognitive psychology.

What is the distribution of cognitive ability within the animal kingdom? It would be egalitarian to assume that variation in intelligence is everywhere clinal, but examining trends among major phylogenetic groups, it becomes easy to distinguish high-performing ‘generalists’ – whose behavior exhibits domain-flexibility – from ‘specialists’ whose range of behavior is limited and ecologically specific. These generalists include mammals, birds, and, intriguingly, cephalopods. The apparent intelligence of coleoid cephalopods (squids, octopuses, and cuttlefish) is surprising – and philosophically relevant – because (...) of our independent evolutionary lineages: the most recent common ancestor between vertebrates and cephalopods would have been a small wormlike organism, without any major organizational structure to its nervous system. By identifying the cognitive similarities between these organisms and vertebrates, we can begin to derive some general principles of intelligence as a biological phenomenon. Here, I discuss trends in cephalopod behavior and surrounding theory, and suggest their significance for our understanding of domain-general cognition and its evolution. (shrink)

This article examines the presentation of humans as a subject of ecological and behavioral study in academic biology textbooks and essay collections. It aims to expand a channel of inquiry into the ways in which human relationships with other species are articulated in scientific discourse during an era of anthropogenic climate change. Both humans and nonhumans are subjects of behavioral ecology because they undergo evolutionary adaptation. However, the notion that biologists can use evolutionary adaptation to explain human behavior has been (...) much disputed. The article uses literary analysis to argue that a range of behavioral ecology publications, which all use evolutionary adaptation to explain biological processes, employ a variety of textual strategies to situate the human in relation to other species. Rather than arguing that any single approach is particularly appropriate, the focus is on variety as a sign of the complexity of contemporary human and nonhuman identities. (shrink)

In this commentary on Marino and Merskin's "Intelligence, complexity, and individuality in sheep", I argue that their literature review provides further evidence of the fundamental theoretical shift in psychology towards a non-anthropocentric psychological taxonomy, in which cognitive capacities are classified in a structure that provides an overall understanding of the place of mind (including human minds) throughout nature.

Behavioural flexibility is often treated as the gold standard of evidence for more sophisticated or complex forms of animal cognition, such as planning, metacognition and mindreading. However, the evidential link between behavioural flexibility and complex cognition has not been explicitly or systematically defended. Such a defence is particularly pressing because observed flexible behaviours can frequently be explained by putatively simpler cognitive mechanisms. This leaves complex cognition hypotheses open to ‘deflationary’ challenges that are accorded greater evidential weight precisely because they offer (...) putatively simpler explanations of equal explanatory power. This paper challenges the blanket preference for simpler explanations, and shows that once this preference is dispensed with, and the full spectrum of evidence—including evolutionary, ecological and phylogenetic data—is accorded its proper weight, an argument in support of the prevailing assumption that behavioural flexibility can serve as evidence for complex cognitive mechanisms may begin to take shape. An adaptive model of cognitive-behavioural evolution is proposed, according to which the existence of convergent trait–environment clusters in phylogenetically disparate lineages may serve as evidence for the same trait–environment clusters in other lineages. This, in turn, could permit inferences of cognitive complexity in cases of experimental underdetermination, thereby placing the common view that behavioural flexibility can serve as evidence for complex cognition on firmer grounds. (shrink)

Cognitive ecology is the study of cognitive phenomena in context. In particular, it points to the web of mutual dependence among the elements of a cognitive ecosystem. At least three fields were taking a deeply ecological approach to cognition 30 years ago: Gibson’s ecological psychology, Bateson’s ecology of mind, and Soviet cultural-historical activity theory. The ideas developed in those projects have now found a place in modern views of embodied, situated, distributed cognition. As cognitive theory continues to shift from units (...) of analysis defined by inherent properties of the elements to units defined in terms of dynamic patterns of correlation across elements, the study of cognitive ecosystems will become an increasingly important part of cognitive science. (shrink)

The chapter discusses the principle of conservatism and traces how the general principle is related to the specific one. This tracing suggests that the principle of conservatism needs to be refined. Connecting the principle in cognitive science to more general questions about scientific inference also allows us to revisit the question of realism versus instrumentalism. The framework deployed in model selection theory is very general; it is not specific to the subject matter of science. The chapter outlines some non-Bayesian ideas (...) that have been developed in model selection theory. The principle of conservatism, like C. Lloyd Morgan's canon, describes a preference concerning kinds of parameters. It says that a model that postulates only lower-level intentionality is preferable to one that postulates higher-level intentionality if both fit the data equally well. The model selection approach to parsimony helps explain why unification is a theoretical virtue. (shrink)

From the first months of life, human infants produce “protophones,” speech-like, non-cry sounds, presumed absent, or only minimally present in other apes. But there have been no direct quantitative comparisons to support this presumption. In addition, by 2 months, human infants show sustained face-to-face interaction using protophones, a pattern thought also absent or very limited in other apes, but again, without quantitative comparison. Such comparison should provide evidence relevant to determining foundations of language, since substantially flexible vocalization, the inclination to (...) explore vocalization, and the ability to interact socially by means of vocalization are foundations for language. Here we quantitatively compare data on vocalization rates in three captive bonobo (Pan paniscus) mother–infant pairs with various sources of data from our laboratories on human infant vocalization. Both humans and bonobos produced distress sounds (cries/screams) and laughter. The bonobo infants also produced sounds that were neither screams nor laughs and that showed acoustic similarities to the human protophones. These protophone-like sounds confirm that bonobo infants share with humans the capacity to produce vocalizations that appear foundational for language. Still, there were dramatic differences between the species in both quantity and function of the protophone and protophone-like sounds. The bonobo protophone-like sounds were far less frequent than the human protophones, and the human protophones were far less likely to be interpreted as complaints and more likely as vocal play. Moreover, we found extensive vocal interaction between human infants and mothers, but no vocal interaction in the bonobo mother–infant pairs—while bonobo mothers were physically responsive to their infants, we observed no case of a bonobo mother vocalization directed to her infant. Our cross-species comparison focuses on low- and moderate-arousal circumstances because we reason the roots of language entail vocalization not triggered by excitement, for example, during fighting or intense play. Language appears to be founded in flexible vocalization, used to regulate comfortable social interaction, to share variable affective states at various levels of arousal, and to explore vocalization itself. (shrink)

Cross-species comparisons are benefited by compatible datasets; conclusions related to phylogenetic comparisons, questions on convergent and divergent evolution, or homologs versus analogs can only be made when the behaviors being measured are comparable. A direct comparison of the social function of physical contact across two disparate taxa is possible only if data collection and analyses methodologies are analogous. We identify and discuss the parameters, assumptions and measurement schemes applicable to multiple taxa and species that facilitate cross-species comparisons. To illustrate our (...) proposed guidelines for evaluating the role played by tactile contact in social behavior across disparate taxa, this paper presents data on mother-offspring relationships in the two species studied by the authors: chimpanzees (Pan troglodytes schweinfurthii) and dolphins (bottlenose and spotted, Tursiops truncatus and Stenella frontalis, respectively). Cross-species comparative studies allow for a more comprehensive assessment of the similarities and differences with respect to how animals traverse the relationships that form their social groups and societies. (shrink)

Data from a study by Savage-Rumbaugh and colleagues on comprehension of spoken English requests by a bonobo and a human infant supports Fitch's hypothesis that humans exhibit dendrophilia, or a propensity to manipulate tree structures, to a greater extent than other species. However, findings from language acquisition suggest that human infants do not show an initial preference for certain hierarchical syntactic structures. Infants are slow to acquire and generalize the structures in question, but they can eventually do so. Kanzi, in (...) contrast, is dendrophobic: even though his non-hierarchical strategy impairs comprehension, he never acquires the hierarchical structure. (shrink)

Evolutionary questions require specialized approaches, part of which are comparisons between close relatives. However, to understand the origins of human tool behavior, comparisons with solely chimpanzees are insufficient, lacking the power to identify derived traits. Moreover, tool use is unlikely a unitary phenomenon. Large-scale comparative analyses provide an alternative and suggest that tool use co-evolves with a suite of cognitive traits.

This paper summarizes the debate on human uniqueness launched by Charles Darwin’s publication of The Origin of Species in 1859. In the progress of this debate, Noam Chomsky’s introduction of the Language-Acquisition Device in the mid-1960s marked a turn to the machine model of mind that seeks human uniqueness in uniquely human components of neural circuitry. A subsequent divergence from the machine model can be traced in the short history of ape language research . In the past fifty years, the (...) focus of ALR has shifted from the search for behavioral evidence of syntax in the minds of individual apes to participant-observation of coregulated interactions between humans and nonhuman apes. Rejecting the computational machine model of mind, the laboratory methodologies of ALR scientists Tetsuro Matsuzawa and Sue Savage-Rumbaugh represent a worldview coherent with Darwin’s continuity hypothesis. (shrink)

InWhy We Cooperate, Tomasello addresses the problem of human uniqueness, which has become the focus for a lot of recent research at the frontier between the Humanities and the Life Sciences. Being both a developmental psychologist and a primatologist, Tomasello is especially well suited to tackle the subject, and the present book is the most recent one in a series of books and papers by himself and his colleagues. Tomasello’s basic position is squarely a dual-inheritance account, in which human uniqueness (...) is explained both through genetics and through culture. The main idea is that the phylogenetic specificity of humankind rests in its species-specific adaptation for sociability. The account offered by Tomasello contrasts human cooperation and altruism with nonhuman primate competition, and proposes that human altruism leads to shared intentionality. The evolutionary explanation Tomasello offers is that human ancestors were led through some kind of selection pressure to common foraging leading to collaboration and sharing. After outlining Tomasello’s position as it is described in the book, as well as the comments by Dweck, Spelke, Silk, and Skyrms which follow, I discuss Tomasello’s thesis, noting a few problems with his approach. These criticisms are based on his own work and on a number of his own other books and papers, as well as on other relevant work in the domain. (shrink)

Joint attention is the ability to intentionally co-orient towards a common focus. This ability develops in a protracted, mosaic fashion in humans. We review evidence of joint attention in humans and great apes, finding that great apes display every phenomenon described as joint attention in humans, although there is consid-erable variation among apes of different rearing histories. We conclude that there is little evidence for human species-unique cognitive adaptations in the non-verbal communication of humans in the first 18 months of (...) life. This conclusion is consistent with the Narrative Practice Hypothesis because the NPH posits training in folk psychological narratives as a basis for folk psychological competence. (shrink)

Primate vocal communication is very different from human language. Differences are most pronounced in call production. Differences in production have been overemphasized, however, and distracted attention from the information that primates acquire when they hear vocalizations. In perception and cognition, continuities with language are more apparent. We suggest that natural selection has favored nonhuman primates who, upon hearing vocalizations, form mental representations of other individuals, their relationships, and their motives. This social knowledge constitutes a discrete, combinatorial system that shares several (...) features with language. It is probably a general primate characteristic whose appearance pre-dates the evolution of spoken language in our hominid ancestors. The prior evolution of social cognition created individuals who were preadapted to develop language. Several features thought to be unique to language—like discrete combinatorics and the encoding of propositional information—were not introduced by language. They arose, instead, because understanding social life and predicting others’ behavior requires a particular style of thinking. (shrink)

To conclude that language evolved from vocalizations, through gestures, then back to vocalizations again, one must first reject the simpler hypothesis that language evolved from prelinguistic vocalizations. There is no reason to do so. Many studies – not cited by Arbib – document continuities in behavior, perception, cognition, and neurophysiology between human speech and primate vocal communication.

We propose that the crucial difference between human cognition and that of other species is the ability to participate with others in collaborative activities with shared goals and intentions: shared intentionality. Participation in such activities requires not only especially powerful forms of intention reading and cultural learning, but also a unique motivation to share psychological states with others and unique forms of cognitive representation for doing so. The result of participating in these activities is species-unique forms of cultural cognition and (...) evolution, enabling everything from the creation and use of linguistic symbols to the construction of social norms and individual beliefs to the establishment of social institutions. In support of this proposal we argue and present evidence that great apes understand the basics of intentional action, but they still do not participate in activities involving joint intentions and attention. Human children's skills of shared intentionality develop gradually during the first 14 months of life as two ontogenetic pathways intertwine: the general ape line of understanding others as animate, goal-directed, and intentional agents; and a species-unique motivation to share emotions, experience, and activities with other persons. The developmental outcome is children's ability to construct dialogic cognitive representations, which enable them to participate in earnest in the collectivity that is human cognition. Key Words: collaboration; cooperation; cultural learning; culture; evolutionary psychology; intentions; shared intentionality; social cognition; social learning; theory of mind; joint attention. (shrink)

We trace the difference between the ways in which apes and humans co–operate to differences in communicative abilities, claiming that the pressure for future–directed co–operation was a major force behind the evolution of language. Competitive co–operation concerns goals that are present in the environment and have stable values. It relies on either signalling or joint attention. Future–directed co–operation concerns new goals that lack fixed values. It requires symbolic communication and context–independent representations of means and goals. We analyse these ways of (...) co–operating in game–theoretic terms and submit that the co–operative strategy of games that involve shared representations of future goals may provide new equilibrium solutions. (shrink)

This book presents an alternative to conventional ideas about the evolution of the human intellect.

Turtles are among the most intriguing amniotes but their communication and signaling have rarely been studied. Traditionally, they have been seen as basically just silent armored ‘walking stones’ with complex physiology but no altruism, maternal care, or aesthetic perception. Recently, however, we have witnessed a radical change in the perception of turtle behavioral and cognitive skills. In our study, we start by reviewing some recent findings pertaining to various highly developed behavioral and cognitive patterns with special emphasis on turtles. Then (...) we focus on freshwater turtles and use data about their sexual behavior and size sexual dimorphism to test whether conspicuous coloration of the head is in these animals related to sexual processes. We found that absence of aggressive mating behavior is statistically associated with the presence of conspicuous coloration on turtles’ heads. It also seems that while species with female-biased SSD are characterised by conspicuously colored head ornaments, in species with male-biased SSD conspicuous coloration is absent. Unlike large females, males thus seem to be under pressure to develop conspicuous coloration and engage in non-aggressive behavior using signaling to succeed in courtship. And finally, we discuss possible roles of head color patterns in turtle communication during mating. (shrink)

The extreme sexual size dimorphism in spiders has motivated studies for many years. In many species the male can be very small relative to the female. There are several hypotheses trying to explain this fact, most of them emphasizing the role of energy in determining spider size. The aim of this paper is to review the role of energy in sexual size dimorphism of spiders, even for those spiders that do not necessarily live in high foliage, using physical and allometric (...) principles. Here we propose that the cost of transport or equivalently energy expenditure and the speed are traits under selection pressure in male spiders, favoring those of smaller size to reduce travel costs. The morphology of the spiders responds to these selective forces depending upon the lifestyle of the spiders. Climbing and bridging spiders must overcome the force of gravity. If bridging allows faster dispersal, small males would have a selective advantage by enjoying more mating opportunities. In wandering spiders with low population density and as a consequence few male–male interactions, high speed and low energy expenditure or cost of transport should be favored by natural selection. Pendulum mechanics show the advantages of long legs in spiders and their relationship with high speed, even in climbing and bridging spiders. Thus small size, compensated by long legs should be the expected morphology for a fast and mobile male spider. (shrink)

For over two centuries, the platypus (Ornithorhynchus anatinus) has been constructed and categorized in multiple ways. An unprecedented mélange of anatomical features and physiological functions, it long remained a systematic quandary. Nevertheless, since 1797, naturalists and biologists have pursued two recurring obsessions. Investigations into platypus reproduction and lactation have focused attention largely upon females of the species. Despite its apparent admixture of avian, reptilian and mammalian characters, the platypus was soon placed as a rudimentary mammal – primitive, naïve and harmless. (...) This article pursues a different taxonomic trajectory, concentrating on a specifically male anatomical development: the crural spur and venom gland on the hind legs. Once the defining characteristic of both the platypus and echidna (Tachyglossus aculeatus), by 1830 this sexed spur had been largely dismissed as inactive and irrelevant. For a creature regularly depicted as a biological outlier, the systematic and evolutionary implications of platypus poison have remained largely overlooked. In Australia, however, sporadic cases of ‘spiking’ led to consistent homologies being remarked between the platypus crural system and the venom glands of snakes. As with its reproductive reliance upon eggs, possession of an endogenous poison suggested significant reptilian affinities, yet the platypus has rarely been classed as an advanced reptile. Indeed, ongoing uncertainty regarding the biological purpose of the male’s spur has ostensibly posed a directional puzzle. As with so many of its traits, however, platypus poison has been consistently described as a redundant remnant, rather than an emergent feature indicating evolutionary advance. (shrink)

Ethology brought some crucial insights and perspectives to the study of behavior, in particular the idea that behavior can be studied within a comparative-evolutionary framework by means of homologizing components of behavioral patterns and by causal analysis of behavior components and their integration. Early ethology is well-known for its extensive use of qualitative observations of animals under their natural conditions. These observations are combined with experiments that try to analyze behavioral patterns and establish specific claims about animal behavior. Nowadays, there (...) is still disagreement about the significance of observation and experiments and their relation. (shrink)

In 1963 Niko Tinbergen published a paper, "On Aims and Methods of Ethology," dedicated to his friend Konrad Lorenz. Here Tinbergen defines ethology as "the biological study of behavior," and seeks to demonstrate "the close affinity between Ethology and the rest of Biology." Tinbergen identifies four major areas of ethology: causation, survival value, evolution, and ontogeny. Our goal is to attempt for cognitive ethology what Tinbergen succeeded in doing for ethology: to clarify its aims and methods, to distinguish some of (...) its varieties, and to defend the fruitfulness of the research strategies that it has spawned. (shrink)

Despite being excellent observers' of each others' behavior, vervet monkeys (Cercopithecus aethiops) appear to be surprisingly ignorant about the behavior of the species that prey upon them. In particular, they fail to attend to many of the visual cues created by their predators. One explanation for this lack of attentiveness is that natural selection has favored skills in the social domain that cannot be extended to non-social contexts. In this paper, we review the ways that the term "domain" has been (...) used in studies of children's cognitive development. We then examine the extent to which hypotheses based on domain-specific adaptations satisfactorily account for patterns of predator detection in vervet monkeys. We contrast domain-specific explanations with more general explanations based on classical conditioning and the relative salience of visual and auditory cues. Finally, we examine vervets' perception of causality and contrast their recognition of cause-effect relations in social and nonsocial contexts. (shrink)

Heat sensitive pit organs in different species of snakes show various shapes. The relation between form characters and functions were analysed by means of two different research programs. This paper presents the methodological steps involved in these research programs. The first approach is called a qualitative explanation because it connects experimental data by means of qualitative statements in order to give a functional morphological explanation for the construction of the pits in respect to the behaviour of the snake. The second (...) approach is called a quantitative explanation because the core of the explanation is a mathematical model which in its consequences explaines the construction of the pits in respect to image formation. (shrink)

There is something important about the way human primates use touch in social encounters; for example, consider greetings in airports (hugs vs. handshakes) and the way children push each other in a playground (a quick push to warn, a really hard one when it is serious!). Human primates use touch as a way of conveying a wide range of social information. In this chapter I will argue that one of the best ways of understanding social cognition in non-human primates is (...) through touch. Moreover, I will argue that if we would like to describe the evolutionary history of social cognition, touch is one of the ideal modes to operationalize social interaction across different kinds of primates. (shrink)

This paper provides a theoretical exploration of how comparative research on the expression of emotions has traditionally focused on the visual mode and argues that, given the neurophysiological, developmental, and behavioral evidence that links touch with social interactions, focusing on touch can become an ideal mode to understand the communication of emotions in human and nonhuman primates. This evidence shows that touch is intrinsically linked with social cognition because it motivates human and nonhuman animals from birth to form social bonds. (...) It will be shown that touch is one of the modes of interaction used by the mother-infant or caregiver- infant dyad that facilitates the expression of emotions by the infant (and later the expression of emotions by the adult that the infant has become) in ways that are understood by other members of the group. (shrink)

All methodologies used to characterize mother-infant interaction in non-human primates includes mother, infant, and other social factors. The chief difference is their understanding of how this interaction takes place. Using chimpanzees as a model, I will compare the different methodologies used to describe mother-infant interaction and show how implicit notions of communication and social interaction shape descriptions of this kind of interaction. I will examine the limitations and advantages of different approaches used in mother-infant studies and I will sketch an (...) alternative approach to studying mother-infant interaction in non-human primates that adopts Jerome Bruner’s developmental studies on human infant communication. (shrink)

Whenever humans have a good idea, zoologists have grown accustomed to finding it anticipated in the animal kingdom.. Why not the wheel? Bats and dolphins perfected sophisticated echo-ranging systems millions of years before human engineers gave us sonar and..

The paper gives an overview of primate research and the economic-ethical 'lessons' we can derive from it. In particular, it examines the complex, multi-faceted and partially conflicting nature of human primates. Our closest living relatives, the chimpanzees and bonobos, apparently walk on two legs: a selfish and a groupish leg. Given evolutionary continuity and gradualism between monkeys, apes and humans, human primates seem to be bipolar apes as well. They, too, tend to display a dual structure: there seems to be (...) a pro-social and a self-interested side to our species and a bipolar tension seems to exist between competition and cooperation respectively between self-interest and the common good. We are apparently at the same time Homines oeconomici and Homines culturali. Our inner ape tries to combine self-interested and common good motives. Based on de Waal's Russian doll model, the essay investigates the evolutionary origins of morality and 'eusociality'. With the help of selected case studies stemming from behavioural sciences/economics, the paper illustrates examples of empathy, altruism, reciprocal fairness, pro-social and other-regarding preferences, inequity aversion and altruistic punishment in human primates. Beside this selfless and groupish side, the paper also reflects on the self-interest and egoistic nature of human primates and the behavioural and cognitive differences between monkeys, apes and humans. (shrink)