The deformation and wear events that underlie microwear and macrowear signals commonly used for dietary reconstruction in fossil animals can be replicated and quantified by controlled laboratory tests on extracted tooth specimens in conjunction with fundamental micromechanics analysis. Key variables governing wear relations include angularity, stiffness (modulus), and size of the contacting particle, along with material properties of enamel. Both axial and sliding contacts can result in the removal of tooth enamel. The degree of removal, characterized by a “wear coefficient,” (...) varies strongly with particle content at the occlusal interface. Conditions leading to a transition from mild to severe wear are discussed. Measurements of wear traces can provide information about contact force and particle shape. The potential utility of the micromechanics methodology as an adjunct for investigating tooth durability and reconstructing diet is explored. (shrink)

Organisms are self-producing and self-maintaining, or autopoietic systems. Therefore, the course of evolution and adaptation of an organism is strongly determined by its own internal properties, whatever role external selection may play. The internal properties may either act as constraints that preclude certain changes or they open new pathways: the organism canalizes its own evolution. As an example the evolution of feeding mechanisms in salamanders, especially in the lungless salamanders of the family Plethodontidae, is discussed. In this family a (...) large variety of different feeding mechanisms is found. The authors reconstruct this evolutionary process as a series of bifurcation points of either constraints or opportunities forming a sequence of preconditions for the formation of a high-speed projectile tongue characteristic of tropical salamanders. Furthermore, it is shown how parallel evolution of seemingly unrelated domains within an organism such as respiratory physiology, life history biology and pattern of ontogeny has rather direct relevance to the feeding biology, thus demonstrating that organisms always evolve as wholes. (shrink)

The conceptual and investigative tools for the analysis of social behavior can be expanded by integrating biological theory, control systems theory, and Pavlovian conditioning. Biological theory has focused on the costs and benefits of social behavior from ecological and evolutionary perspectives. In contrast, control systems theory is concerned with how machines achieve a particular goal or purpose. The accurate operation of a system often requires feed-forward mechanisms that adjust system performance in anticipation of future inputs. Pavlovian conditioning is (...) ideally suited to subserve this function in behavioral systems. Pavlovian mechanisms have been demonstrated in various aspects of sexual behavior, maternal lactation, and infant suckling. Pavlovian conditioning of agonistic behavior has been also reported, and Pavlovian processes may likewise be involved in social play and social grooming. Several further lines of evidence indicate that Pavlovian conditioning can increase the efficiency and effectiveness of social interactions, thereby improving their cost/benefit ratio. We extend Pavlovian concepts beyond the traditional domain of discrete secretory and other physiological reflexes to complex real-world behavioral interactions and apply abstract laboratory analyses of the mechanisms of associative learning to the daily challenges animals face as they interact with one another in their natural environments. Key Words: aggression; biological theory; control theory; feed-forward mechanisms; learning theory; nursing and lactation; Pavlovian conditioning; sexual behavior; social behavior; social grooming; social play. (shrink)

Feed-forward Pavlovian conditioning can serve as a proximate mechanism for the evolution of social behavior. Feed-forward can provide the impetus for animals to associate other individuals' presence, and cooperation with them, with the acquisition of resources, whether or not the animals are genetically related. Other social behaviors such as play and grooming may develop as conditioned stimuli in feed-forward social systems.

An incoherent feed‐forward loop (FFL) is one of the most‐frequently observed motifs in biomolecular regulatory networks. It has been thought that the incoherent FFL is designed simply to induce a transient response shaped by a ‘fast activation and delayed inhibition’. We find that the dynamics of various incoherent FFLs can be further classified into two types: time‐dependent biphasic responses and dose‐dependent biphasic responses. Why do the structurally identical incoherent FFLs play such different dynamical roles? Through computational studies, we show that (...) the dynamics of the two types of incoherent FFLs are mutually exclusive. Following from further computational results and experimental observations, we hypothesize that incoherent FFLs have been optimally designed to achieve distinct biological function arising from different cellular contexts. Additional Supporting Information may be found in the online version of the article. BioEssays 30:1204–1211, 2008. © 2008 Wiley Periodicals, Inc. (shrink)

Whilst it is generally accepted that breast-feeding lowers the likelihood of conception, this relationship is not straightforward and there appears to be a wide variation in the effectiveness of the association between individual mother-infant pairs. Up to about 6 months post-partum breast-feeding probably can be used as a family planning method, with up to 98% effectiveness if behavioural guidelines are adhered to . But beyond this time significant variations appear between different countries, and even different communities within countries, (...) which make any overall recommendation impossible. To understand the reasons for variation in the duration of lactational infecundity it is necessary to understand the mechanisms involved, but knowledge of these processes is still far from complete. There are, nevertheless, enough data to indicate that suckling and maternal milk output are intimately linked with the return of fecundity. (shrink)

Urbanization affects concurrent human-animal interactions as a result of altered resource availability and land use pattern, which leads to considerable ecological consequences. While some animals have lost their habitat due to urban encroachment, few of them managed to survive within the urban ecosystem by altering their natural behavioral patterns. The feeding repertoire of folivorous colobines, such as gray langur, largely consists of plant parts. However, these free-ranging langurs tend to be attuned to the processed high-calorie food sources to attain (...) maximum benefits within the concrete jungle having insignificant greenery. Therefore, besides understanding their population dynamics, the effective management of these urbanized, free-ranging, non-human primate populations also depends on their altered feeding habits. Here, we have used a field-based experimental setup that allows gray langurs to choose between processed and unprocessed food options, being independent of any inter-specific conflicts over resources due to food scarcity. The multinomial logit model reveals the choice-based decision-making of these free-ranging gray langurs in an urban settlement of West Bengal, India, where they have not only learned to recognize the human-provisioned processed food items as an alternative food source but also shown a keen interest in it. However, such a mismatch between the generalized feeding behavior of folivorous colobines and their specialized gut physiology reminds us of Liem's paradox and demands considerable scientific attention. While urbanization imposes tremendous survival challenges to these animals, it also opens up for various alternative options for surviving in close proximity to humans which is reflected in this study, and could guide us for the establishment of a sustainable urban ecosystem in the future. (shrink)

The phenomenon of corruption as a type of crime is immanently inherent in social and political reality. Sociality as a trans-societal universal form of human community is the environment in which corruption ties are born and function. The socio-political structure is organized as a collective effort, on the one hand, it overcomes disintegration, and on the other, it generates corrupt behaviour patterns. Corruption models of behaviour have an extremely wide scale of distribution and are characterized by active institutional expansion into (...) various spheres and institutions of modern society, they feed business relations and administrative activities, covering huge masses of the population. In this sense, their study is extremely important and relevant. (shrink)

This article explores how the Slovenian women's lifestyle magazine Naša žena (Our Woman) helped the Yugoslavian socialist project construct and shape the ideal socialist woman, and argues that she became the crucial ally in implementing socialist ideas in the everyday lives of Slovenians. The article shows how texts on food preparation and consumption, as well as those touching on household management and family care, published in Naša žena from 1960 to 1991 played an important part in the ‘civilising’ process that (...) shaped behaviour, directed cultural and social practices, influenced social relations and constructed women's identities during socialism. We show how food-related texts (articles, recipes, columns, advertisements and advertorials) were never far removed from the larger political and economic socialist realities. In fact, they bore witness to changes in living standards and told stories about gender regimes, socialist ideologies and fantasies. These texts belong to a corpus of social transcripts that guide collective understandings of what it means to select, prepare, cook and eat food; what constitutes good cooking and eating; and who is responsible for preparing meals. Despite official socialist feminist rhetoric about freeing women from backward patriarchal arrangements, this article shows that texts offering food-related advice in socialist Yugoslavia contained explicit instructions for the ‘correct’ performance of the social roles of women, legitimising women's roles as worker, mother, wife and housekeeper. Above all, a woman was to be an ‘engineer’ of the private domain whose goals were to feed her family and keep the nation healthy and hence productive, and to modernise her kitchen in support of the technological and economic development of Yugoslavia. (shrink)

A decade ago, leptin (from the greek lepto meaning ‘thin’) was identified as the product of the ob gene.1 This adipocyte‐derived hormone was found to suppress feeding and stimulate thermogenesis, and was thus proposed as a mediator in a negative feedback loop that controls body adiposity. This discovery led to a rapid revolution in the understanding of neurobiological mechanisms regulating obesity. However, while leptin's first life was as an adipostat, it is now known to have a wide range of (...) additional neuroendocrine, metabolic and behavioural functions in the CNS and periphery. Remarkably, the pleiotropic nature of the hormone continues to be extended with the recent publication of two papers that expand on leptin's neurobiological actions in the CNS.2,3 They indicate novel regulatory roles for the hormone in both synaptic plasticity and axon guidance. Crucially, in light of the rising incidence of obesity in modern society, both of the studies reveal leptin‐mediated links between nutrition and neurodevelopment, findings that have further implications for leptin's role in the regulation of energy homeostasis. BioEssays 26:1043–1045, 2004. © 2004 Wiley Periodicals, Inc. (shrink)

Valuation consists in a positive or negative response by a subject S to an entity X. Any positive or negative response has a structure that involves a cognitive and a non-cognitive component, as well as a reason relationship between these. This structure is shown to be present in the explicit value judgement 'Hans is a kraut', and then also pointed out in the reflex-like feeding behaviour of a frog, where S treats X as providing an affordance. The conclusion is (...) that valuation need not involve mental states. The article ends with a discussion of the elusive question: what makes a response positive or negative? (shrink)

SummaryCross-sectional studies in Australia and the Philippines and a longitudinal prospective study in a selected Australian sample of breast-feeding mothers have shown that basal serum prolactin concentrations are elevated during 15–21 months of lactational amenorrhoea.A predictive model of serum PRL levels and return of cyclic ovarian activity during full breast-feeding, partial breast-feeding and weaning has been developed from the results of breast-feeding behaviour and serum PRL, gonadotrophin and oestradiol measurements in 34 mothers breast-feeding on demand (...) for a mean of 67 weeks.Breast-feeding patterns influence serum PRL levels. Important factors during full breast-feeding are the age of the baby, the longest interval between feeds at night and total 24-hr suckling time, and following the introduction of supplements, the mean interval between feeds, together with the total 24-hr suckling time and the number of solid supplements per day.The precise mechanisms whereby breast-feeding regulates cyclic ovarian activity remain unknown. Gonadotrophin secretion appears to be quantitatively normal, but qualitative changes, secondary to altered hypothalamic activity, may be the most important factor. A direct inhibitory effect of PRL on ovarian follicular development and steroidogenesis remains possible.Ovulation with a normal luteal phase is probable for 30% of breast-feeding mothers before the first menses, but is unlikely before 6 months, provided breast-feeding is frequent day and night.Measurement of serum PRL is a sensitive index of the return of menstruation and fertility during lactation in the population studied. (shrink)

An evolutionarily informed perspective on parent-infant sleep contact challenges recommendations regarding appropriate parent-infant sleep practices based on large epidemiological studies. In this study regularly bed-sharing parents and infants participated in an in-home video study of bed-sharing behavior. Ten formula-feeding and ten breast-feeding families were filmed for 3 nights for 8 hours per night. For breast-fed infants, mother-infant orientation, sleep position, frequency of feeding, arousal, and synchronous arousal were all consistent with previous sleep-lab studies of mother-infant bed-sharing (...) behavior, but significant differences were found between formula and breast-fed infants. While breast-feeding mothers shared a bed with their infants in a characteristic manner that provided several safety benefits, formula-feeding mothers shared a bed in a more variable manner with consequences for infant safety. Paternal bed-sharing behavior introduced further variability. Epidemiological case-control studies examining bed-sharing risks and benefits do not normally control for behavioral variables that an evolutionary viewpoint would deem crucial. This study demonstrates how parental behavior affects the bed-sharing experience and indicates that cases and controls in epidemiological studies should be matched for behavioral, as well as sociodemographic, variables. (shrink)

The specific mechanisms whereby Pavlovian conditioning leads to adaptive behavior need to be elaborated. There is no evidence that it is via reduction in the “destabilizing effect that time lags have on feedback control” (Domjan et al. 2000, sect. 3.3). The adaptive value of Pavlovian conditioning goes well beyond the regulation of social behavior.

The purpose of this paper is to define and describe the main phenomenological dimensions of the life-world of persons prone to Feeding and Eating Disorders (FEDs), within the framework of a model that considers abnormal eating behaviour an epiphenomenon of a more profound disorder of lived corporeality and identity. The core idea is that persons with FEDs experience their own body first and foremost as an object being looked at by another, rather than coenaesthetically or from a first-person perspective. (...) Alienation from one’s own body and the need to feel oneself only through the gaze of the others can be illuminated by looking at it in the light of the Sartrean concept of feeling a lived-body-for-others. (shrink)

Central question of this essay is, whether it is possible to relate specific aspects of the organization of sensorimotor systems to specific aspects of the behaviour. The role of the auditory system as part of a system for vocalization or as part of a system for prey localization and the different roles of the trigeminal system in the feeding behaviour of different birds are considered. The ascending sensory systems seem to possess a comparable organization in the various species. Also (...) the descending motor pathways from archistriatum and paleostriatal complex seem to be basically similar. Behavioural specialization may be expressed particularly in the organization of the intratelencephalic circuits and thus in the involvement of specific regions of neostriatum and hyperstriatum ventrale. In discussions on cerebralisation it will be necessary to take such differences in intratelencephalic organization into account. (shrink)

In a previous paper, we discussed a model that considers abnormal eating behaviour epiphenomena of a more profound disorder of lived corporeality and identity (Stanghellini and Mancini, this issue). The core idea is that persons with FEDs experience their own body first and foremost as an object being looked at by another, rather than coenaesthetically or from a first-person perspective. In this paper, alienation from one’s own emotions, disgust and shame for one’s body of persons with FED, will be discussed (...) in the light of the embodiment and identity model of FED. (shrink)

The first years of life mark a time of rapid development and dietary change, as children transition from an exclusive milk diet to a modified adult diet. During these early years, children's learning about food and eating plays a central role in shaping subsequent food choices, diet quality, and weight status. Parents play a powerful role in children's eating behavior, providing both genes and environment for children. For example, they influence children's developing preferences and eating behaviors by making some (...) foods available rather than others, and by acting as models of eating behavior. In addition, parents use feeding practices, which have evolved over thousands of years, to promote patterns of food intake necessary for children's growth and health. However in current eating environments, characterized by too much inexpensive palatable, energy dense food, these traditional feeding practices can promote overeating and weight gain. To meet the challenge of promoting healthy weight in children in the current eating environment, parents need guidance regarding alternatives to traditional feeding practices. (shrink)

The endocannabinoid system is the target of the main psychoactive component of the plant Cannabis sativa, the Δ9‐tetrahydrocannabinol (THC). This system is composed by the cannabinoid receptors, the endogenous ligands, and the enzymes involved in their metabolic processes, which works both centrally and peripherally to regulate a plethora of physiological functions. This review aims at explaining how the site‐specific actions of the endocannabinoid system impact on memory and feeding behavior through the cannabinoid receptors 1 (CB1R). Centrally, CB1R is (...) widely distributed in many brain regions, different cell types (e.g. neuronal or glial cells) and intracellular compartments (e.g. mitochondria). Interestingly, cellular and molecular effects are differentially mediated by CB1R according to their cell‐type localization (e.g. glutamatergic or GABAergic neurons). Thus, understanding the cellular and subcellular function of CB1R will provide new insights and aid the design of new compounds in cannabinoid‐based medicine.Also watch the Video Abstract. (shrink)

Eating behaviors evolve during the first years of life as biological and behavioral processes directed towards meeting requirements for health and growth. For the vast majority of human history, food scarcity has constituted a major threat to survival, and human eating behavior and child feeding practices have evolved in response to this threat. Because infants are born into a wide variety of cultures and cuisines, they come equipped as young omnivores with a set of behavioral predispositions that allow (...) them to learn to accept the foods made available to them. During historical conditions of scarcity, family life and resources were devoted to the procurement and preparation of foods, which are often low in energy, nutrients, and palatability. In sharp contrast, today in non-Third World countries children's eating habits develop under unprecedented conditions of dietary abundance, where palatable, inexpensive, ready-to-eat foods are readily available. (shrink)

Variation in the durations of exclusive breastfeeding (exBF) and any breastfeeding (anyBF) is associated with socioecological factors. This plasticity in breastfeeding behavior appears adaptive, but the mechanisms involved are unclear. With this concept in mind, we investigated whether durations of exBF and anyBF in a rural Maya population covary with markers of a form of socioecological change—market integration—and whether individual factors (individual learning, physiological plasticity) and/or learning from others in the community (social learning, norm adherence) mediate these changes. Using (...) data from 419 mother-child pairs from two Guatemalan Maya villages, we fit a bivariate linear mixed model. The model compared exBF and anyBF among children from households of varying degrees of market integration whose mothers follow what we inferred to be local infant-feeding norms. It controlled for other factors expected to affect breastfeeding durations. We found evidence that exBF is associated with whether mothers follow their population’s infant feeding norms, but no evidence that exBF is associated with the household’s level of market integration. Conversely, anyBF is significantly associated with the household’s market integration, but not with the villages’ inferred norms. Because deviations from exBF norms are likely to result in infant mortality and reduced fitness, we hypothesize that the incentive to conform is relatively strong. Relatively greater individual plasticity in anyBF allows mother-child pairs to tailor it to socioecological conditions. Deviations from anyBF norms may be tolerated because they may provide later-life health/fitness payoffs, while posing few risks to infant survival. (shrink)

A motivational system approach to avoidance behavior is presented. According to this approach, a motivational state increases the probability of relevant response patterns and establishes the appropriate or “ideal” consummatory stimuli as positive reinforcers. In the case of feeding motivation, for example, hungry rats are likely to explore and gnaw, and to learn to persist in activities correlated with the reception of consummatory stimuli produced by ingestion of palatable substances. In the case of defense motivation, fearful rats are (...) likely to flee or freeze, and to learn to persist in activities correlated with consummatory stimuli produced by flight from a dangerous place. Defense system activation is distinct from alarm reactions. The latter prepare the animal for probable noxious events, involve relatively intense negative affect and extinguish rapidly in situations where the noxious event no longer occurs. In contrast, defense system activation potentiates innate and modified defense reactions, thus preparing the animal for possible, but not necessarily probable, noxious events; it involves little or no negative affect and extinguishes very slowly when the noxious event no longer occurs. With these assumptions and the resulting model we attempt to resolve several long-standing problems in avoidance learning, including the low correlation between negative affect and avoidance performance, differential rates of extinction for avoidance performance and conditioned emotional responses, and evidence that some avoidance responses are much more easily learned than others. In addition, the model has implications for the study of parallels between appetitive and aversive motivation, sign tracking in aversive conditioning, and orientation of flight responses. Historical antecedents and alternative approaches are discussed. (shrink)

The relevance of nonlinear dynamics to calcium metabolism led us to reevaluate the role of Ca-regulating hormones in Ca homeostasis. We suggest that, firstly, the main Ca metabolic functions in rat-bone and gut - are organized as dynamic entities able to generate various temporal expressions, including self-oscillating patterns and, secondly, Ca homeostasis results from interaction between both metabolic and hormonal oscillators. Following this schema, a major role for the hormonal system, with its circadian pattern, could be to act directly on (...) metabolic functions or indirectly through feeding behaviour, in order to optimize, coordinate and synchronize the Ca fluxes at ECF level. (shrink)

We applaud Domjan et al. for providing an elegant account of Pavlovian feed-forward mechanisms in social behavior that eschews the pitfall of purposivism. However, they seem to imply that they have provided a complete account without provision for operant conditioning. We argue that operant conditioning plays a central role in social behavior, giving examples from fish and infant behavior.

Studying the similarities and differences in socio-communicative behavior between chimpanzees and bonobos is critical to increasing our understanding of the evolution of human sociality and communication. Both species rely heavily on the use of vocalizations during communicative interactions, although the form and function of these signals may vary between the two ape species. For example, bonobo vocalizations seem to be structurally more complex than those produced by chimpanzees, and calls seem to be directed to individuals not in immediate physical (...) proximity. Both species, however, make use of communicative signals from different modalities concurrently, particularly vocalizations and manual gestures. However, this multimodal communication is more commonly observed in chimpanzees when compared to bonobos, who more frequently use vocalizations exclusively, without signals from additional modalities. In addition, there are a number of marked differences in social characteristics between the two species. Though both species exhibit fission–fusion behavior, chimpanzees do so more often, potentially as a result of their habitat profile and foraging strategies. Differences also exist in terms of dominance and aggression. Chimpanzees live in largely patriarchal societies with strong male–male bonds, whereas bonobos tend to be matriarchal with strong female–female bonds. These differences in communicative and social characteristics are thought to be linked to the ecology of the respective habitats of the two apes and their strategies for resource exploitation. In all likelihood, similarities in feeding ecology played a crucial role in selecting for the advanced cognitive abilities of both species—e.g., producing meaningful communicative signals, regulating competition and group cohesion, and making and utilizing tools to aid in foraging. Similarly, differences in their respective habitats may have led to selection for characteristics resulting in the behavioral differences observed today between the two species. Therefore, a clearer understanding of the similarities and differences between the two species most closely related to humans will provide valuable information into our own evolution by elucidating those characteristics shared among humans and our ape ancestors and those derived in the hominin lineage. (shrink)

Recent neuroeconomic studies challenge the conventional economic logic of behavior. After an introduction to some starting points of brain research in ‘classical’ economics we discuss the final and contingent causes of rational and irrational behavior in neuroeconomics and standard economics and present the concept of expanded rationality models (ERM) which imports neuroeconomic elements like emotions, beliefs and neuroscientific constraints and exports improved testable predictions. The typical structure of neuroeconomic proof of economic models and the imprecise neuroscientific measurement let (...) us suggest a feed-back structure of economic research. We apply Hirshleifer’s conception of macro-/micro-technology and contrast it to the neuroeconomic black box critique on economic theory. Furthermore, instead of direct adjustment of preference structures we propose the auxiliary creation of neuroeconomic constraints like action-dependent or outcome-dependent neuroeconomic belief constraints (NBC) and emotion compatibility constraints (ECC). This prepares the ground for our examination of neuroeconomics and ERM as two different paths towards an analytical unification of behavioral sciences. (shrink)

Pavlovian feed-forward mechanisms represent an individual perspective that ignores how repeated interactions between the same individuals lead to social relationships. These can determine social cues, coordinated behaviors, asymmetries between partners, and physiological and emotional states associated with social interaction.

The two main theories of food-associated calls in animals propose functions either in cooperative recruitment or competitive spacing. However, not all social animals produce food calls and it is largely unclear under what circumstances this call type evolves. Sooty mangabeys do not have food calls, but they frequently produce grunts during foraging, their most common vocalisation. We found that grunt rates were significantly higher when subjects were foraging in the group’s periphery and with small audiences, in line with the cooperative (...) recruitment hypothesis. In a subsequent field experiment we presented highly desired food items and found that discovering individuals called, unless harassed by competitors, but that the calls never attracted others, confirming that the grunts do not convey any information referential to food. Our data thus suggest that the evolution of cooperative food calling is a two-step process, starting with increased motivation to vocalise in the feeding context, followed by the evolution of acoustic variants derived from context-general contact calls. This evolutionary transition may only occur in species that feed on clumped, high-quality resources where social feeding is competitive, a condition not met in sooty mangabeys. (shrink)

Understanding how biological organisms are autonomous—maintain themselves far from equilibrium through their own activities—requires understanding how they regulate those activities. In multicellular animals, such control can be exercised either via endocrine signaling through the vasculature or via neurons. In C. elegans this control is exercised by a well-delineated relatively small but distributed nervous system that relies on both chemical and electric transmission of signals. This system provides resources to integrate information from multiple sources as needed to maintain the organism. Especially (...) important for the exercise of neural control are neuromodulators, which we present as setting agendas for control through more traditional electrical signaling. To illustrate how the C. elegans nervous system integrates multiple sources of information in controlling activities important for autonomy, we focus on feeding behavior and responses to adverse conditions. We conclude by considering how a distributed nervous system without a centralized controller is nonetheless adequate for autonomy. (shrink)