Peripersonal (reachable) and extrapersonal (beyond reach) space is linked to hand perception. Using a tool to reach farther than normal recalibrates previously unreachable space as peripersonal, evidenced by Intraparietal Sulcus (IPS) activity related to hand perception and lateral biases during line bisection. The current study looked at the role of a visual connection between the hand and body in the ability to manipulate objects within the extended area of reach. In an immersive virtual environment, participants bisected lines using a connected hand (via arm), a disconnected hand, or a floating dot. A rightward shift in bisection was seen only for the dot condition for far lines, indicating that it was the only "tool" incapable of extending peripersonal space.

This study examines the effect fallback foods, foods eaten when other, more preferred foods are scarce, have on the tool-using behaviors of capuchin monkeys. In the arid Serra da Capivara National Park in Brazil, black-striped capuchins (Cebus libidinosus) use stone tools to dig for underground tubers, a very rare behavior among primates. I test the hypothesis that the capuchins in the Serra da Capivara exploit tubers as a fallback food because palm nuts, an important fallback resource to other groups of capuchins living in arid environments, are either rare or absent there. Studies of floristic analysis at the park and other capuchin sites show that palm nut species recorded to be consumed by capuchins are not found at the Serra da Capivara. Additionally, nutritional analysis of both palms nuts and tubers suggest that tubers could act as a replacement for palm nuts as a fallback food. This may have relevance to human evolution, as several researchers suggest tubers and other underground storage organs were important resources to early hominins. / Department of Anthropology

No description available.

<p>Tool use is an important area of research in psychology, neurophysiology, and motor behavior because it provides insights into the organization of perception, cognition, and action. Tool use research has traditionally focused on the neural structures or cognitive processes that contribute to body-tool integration, while there has been comparatively little interest in motor control. When tool use actions are studied, adaptations have mainly been examined at the level of manual control, while postural control and multi-segment coordination have received less attention. Examining these components of behavior in the context of tool use is vital for developing a better understanding of how humans integrate tools into goal-directed actions.</p><p>The goals of this dissertation were to 1) characterize adaptations to postural control over time when performing a manual task with a tool under different levels of postural constraint and determine their relation to manual task performance, 2) examine postural-manual coupling under different levels of postural constraint during tool use, and 3) determine how multi-segment coordination supports postural stability and suprapostural task performance under different levels of postural constraint during tool use. To address these questions, we adopted a sensorimotor adaptation paradigm to examine postural-manual control and multi-segment coordination before, during, and after an extended bout of tool use.</p>Tool-use adaptations were found to extend beyond the end-effector. Postural control played a crucial role in facilitating improvements in the manual control of tools. Placing constraints on posture interfered with these adaptations, disrupting the coordination of postural-manual behaviors during tool use. However, multi-segment coordination was modified to overcome this challenge and facilitate postural stability and manual performance. These results demonstrate that healthy young adults are capable of flexibly recruiting and exploiting available degrees of freedom in a task-dependent manner the potential challenges associated with integrating tools into movements. This dissertation provides preliminary support for the importance of considering postural control in tool use actions and highlights the utility of examining interactions across multiple levels of motor behavior—postural control, manual control, postural-manual coupling, and multi-segment coordination—to elucidate how tools are integrated into complex, goal-directed behaviors.

Philosophers, historians of technology, and anthropologists often offer accounts of technology that include a “human clause,” some phrase to the effect that only humans use or make technologies. When these academics do consider tool use, they refer to a few cases, usually from chimpanzee studies, as special and unusual in the animal kingdom and whose similarities to human tool use can be explained through some shared evolutionary heritage. However, new observational and laboratory animal studies demonstrate that tool use and the use of learned techniques are actually more widespread than many scholars have appreciated, encompassing the behaviors of dolphins, crows, gorillas, and octopuses. Some studies have shown that even species that are not known to produce tools in the wild can, in the right contexts, produce and use tools as capably as related species that do employ tools. Some of the non-human animals' tool use and manufacture indicates learned components, shared material cultures, innovation, an understanding of 'folk' physics and causal reasoning, the standardization of tools, and the use of metatools. This dissertation involves a reflection on these new animal studies cases: what they might indicate, how they relate to concepts used in defining technology (and humanity), how they might disrupt human-centered models of technology. This dissertation also provides a framework for considering these animal cases within the context of technological knowledge, one important concept in philosophy of technology. To highlight the relationships between two different approaches to technological knowledge, this project introduces a graphical model for considering animal cases alongside human technologies; mapping individual technologies and techniques in terms of technological know-how and encapsulation of information allow for the additional consideration of animal constructions – webs, nests, dams, etc. – alongside animal tool use and human technologies. By categorizing non-human animal constructions, tool use, and technology along the same axes, we see that the individual material products of humans and non-humans are often a matter of degree, and not a matter of kind. Animal constructions and tool use can be productively incorporated into philosophy of technology. / Ph. D.

Philosophers of technology have often considered only the tools and processes used and conducted by humans, but natural structures and man-made structures are not always easily discernable from one another. The complexity of a spider web is not matched by many human-made technologies. Beaver dams, beehives, and ant hills are great creations made by non-human animals. Davis Baird has argued that our scientific instruments bear knowledge in important ways, and the idea of technological knowledge bears interestingly on discussions of natural artifacts. Baird thinks his argument for instruments bearing knowledge can be extended, but how far can it be taken? Do "natural" technologies, like spider webs, bear technological knowledge of some sort? This move to consider whether natural artifacts might bear knowledge rubs interestingly against current definitions of technology which include human agency or progression as important. If we find that some natural artifacts seem to bear knowledge in the way Baird describes, technological knowledge would not be the exclusive domain of humans. Our current definitions of technology seem incongruent with our view of knowledge and our knowledge of natural artifacts. The purpose of this paper is to sort out the inconsistencies between current philosophical literature on knowledge and on technology. In sorting out the inconsistencies we find, I recommend a spectrum approach with regard to technology based on the epistemological status of the artifact. Using observations from anthropology and biology, I suggest a scale with regard to technological behavior, tool use, and technology. / Master of Science

The chimpanzee (Pan troglodytes, Pongidae) among all other living species, is our closest relation, with whom we last shared a common ancestor less than five million years ago. These African apes make and use a rich and varied kit of tools. Of the primates, and even of the other Great Apes, they are the only consistent and habitual tool-users. Chimpanzees meet the criteria of working definitions of culture as originally devised for human beings in socio-cultural anthropology. They show sex differences in using tools to obtain and to process a variety of plant and animal foods. The technological gap between chimpanzees and human societies living by foraging (hunter-gatherers) is surprisingly narrow, at least for food-getting. Different communities of chimpanzees have different tool-kits, and not all of this regional and local variation can be explained by the varied physical and biotic environments in which they live. Some differences are likely customs based on non-functionally derived and symbolically encoded traditions. Chimpanzees serve as heuristic, referential models for the reconstruction of cultural evolution in apes and humans from an ancestral hominoid. However, chimpanzees are not humans, and key differences exist between them, though many of these apparent contrasts remain to be explored empirically and theoretically.

Três experimentos foram realizados sobre o uso de ferramentas para quebra de frutos encapsulados por macacos-prego (Cebus apella) em condição de semi-liberdade no Parque Ecológico do Tietê. O primeiro envolveu a introdução de um nova espécie de coco com o objetivo de estudar a disseminação do uso desse fruto no grupo e os mecanismos de transmissão social envolvidos. Essa disseminação, bastante rápida, em alguns casos deveu-se à aprendizagem inteiramente individual, mas também houve casos de consumo somente após observação de outros indivíduos quebrando cocos ou contato com restos dos cocos. Neste último caso, as eventuais influências sociais estariam restritas ao Realce de Estímulo, mas, onde houve observação direta do comportamento, Emulação ou Imitação não podem ser descartadas. Não foi detectado um padrão definido de preferências na escolha dos indivíduos alvos de observação por coespecíficos em função das características mensuradas dos animais observados. O segundo experimento examinou as preferências na escolha de “martelos" de pedra artificialmente produzidos variando de 300g a 1700g, tendo sido encontrada uma preferência pelos dois martelos mais pesados, embora tenha sido observada uma tendência dos juvenis a usar a ferramenta mais próxima, independentemente do peso. O terceiro experimento abordou o transporte das ferramentas, para determinar se este ocorria quando os “martelos" potenciais se encontravam a 5m ou 10m do seu local de uso (“bigorna"). Os resultados confirmam a ocorrência desse comportamento, o qual, no entanto, foi quase sempre acompanhado do transporte concomitante de cocos. / Three experiments were conducted about tool use to nutcracking by capuchin monkey (Cebus apella) at semi-free ranging condition in Tiete Ecological Park. The first involved the introduction of a new species of nut; the aim was to study the dissemination of the use of this new fruit in the group and the involved social transmission mechanism. The quite fast dissemination occurred by individual learning in some cases, but there were instances of consumption only after observation of other monkeys cracking the new nuts or contact with their leftovers.In the latter case, the possible social influences would be restricted to Stimulus Enhacement, but, in the cases where direct behavioral observation took place, Imitation and Emulation cannot be ruled out. There was no correlation between the choice of targets for observation and the measured traits of the targets. The second experiment examined the preferences in the choice of artificial stone hammers ranging from 300g to 1700g. We found a preference for the two heviest hammers, although the juveniles had a tendency to use the nearest tools, independently of weight. The third experiment was about the transport of tools, to determine if the transport of potential tools occurred when these were found at 5m or 10m from the use site (the “anvil"). The results confirms the occurrence of this behavior, always involving the simultaneous transport of nuts.

Existe ampla evidência do nível de seletividade exibido por macacos-prego (Sapajus sp) em situações de escolha de ferramentas para a quebra de frutos encapsulados; indicando que as características dos martelos (material, peso e distância de transporte), assim como as características físicas próprias dos indivíduos, afetam a eficiência do na quebra e determinam o processo individual de tomada de decisões no uso de ferramentas. Considerando a predição de que também é provável que a eficiência na quebra seja dependente do controle do macaco sobre a pedra e do ângulo de impacto; o presente trabalho teve como objetivo avaliar experimentalmente se a forma das ferramentas afeta a eficiência na quebra e é levada em consideração pelos macacos-prego, na hora de escolher as ferramentas a serem usadas. Para tal, testamos a escolha de pedras por cinco macacos-prego semilivres usuários de ferramentas - fazendo uso de pedras artificiais e realizando tentativas discretas de escolha com participação livre dos indivíduos - através de um delineamento fatorial de medidas repetidas com oito condições experimentais, correspondentes às possíveis combinações de três variáveis independentes em dois níveis: forma dos martelos (possibilidades de pegada e superfície potencial de contato), peso (leve e pesado) e distância de transporte exigida (perto e longe das bigornas). Avaliamos a seletividade exibida, os comportamentos manipulativos exploratórios e a proficiência natural de quebra de cada sujeito, visando elucidar os fatores determinantes do processo de escolha de ferramentas para a quebra de frutos. Os resultados apontam preferência dos macacos-prego pelos martelos que fornecem maior eficiência, pedras com maior possibilidade de pegada e maior superfície potencial de contato no golpe, aumentando os benefícios e diminuindo os custos do uso. Não encontramos um efeito evidente das variáveis de custo (peso e distância de transporte) sobre a preferência pelas características da forma, nem foi encontrada uma relação entre a preferência exibida em condições experimentais com o engajamento e proficiência natural dos indivíduos na quebra de cocos. Finalmente, verificamos que os macacos-prego baseiam suas escolhas principalmente a partir das dicas visuais, não obstante exibirem comportamentos manipulativos exploratórios que possivelmente permitem ganhar informação adicional sobre as propriedades da forma das ferramentas para realizar a escolha / Evidences point out that capuchin monkeys select stone tools for nut cracking based on the physical characteristics of tools (material, weight, transporting distance) in relation to their own physical characteristics (size, weight), and that selectivity seems to affect the efficiency of nut cracking, determining individual decision making in tool use. Considering the prediction that nut crack efficiency is affected by individual control, the stone and the impact angle; this study aimed to evaluate experimentally if the tools shape affect nut crack efficiency, and if this is considered in individual tool selection. We tested the choices of five semi-free individuals using artificial designed tools in eight different experimental conditions, manipulating hammers weight, shape and distance to the anvil, to determine the factors involved in tool selection process for nut cracking. The results shows the monkeys prefer hammers that increase cracking nut efficiency, with more holding possibility, and higher potential contact surface in the bites. There was no evidence for effect of variables related with costs (hammer weight and transporting distance) on the shape preference, and there was no relation between preferences in experimental conditions and engage or efficiency in baseline. We found that the capuchin monkeys based their tool choices in visual characteristics and exhibit manipulative exploratory behaviors that allow them to gain information about the tools shape to make choices

Experimentos realizados com grupos de macacos-prego (Sapajus sp) cativos, semilivres e livres em tarefas de escolha de ferramentas para a quebra de frutos encapsulados parecem indicar que esses primatas possuem a capacidade de distinguir ferramentas funcionais de não-funcionais e que também sejam capazes de escolher, dentre as funcionais, a ferramenta mais eficiente. Neste estudo buscamos examinar estas escolhas num grupo semi-livre de macacos-prego através de experimentos que tiveram como objetivos gerais analisar possíveis preferências por martelos de determinados pesos e os efeitos de custos e benefícios associados ao seu transporte e manejo, verificando se essas preferências se modificam em função da distância de transporte até o local de uso (as bigornas) ou do grau de dureza dos cocos oferecidos. Encontramos uma preferência dos juvenis por martelos mais pesados que os escolhidos pelos adultos, o que pode refletir uma compensação daqueles, menores e mais fracos, já que com um martelo mais pesado, menos golpes são necessários para romper o coco. As escolhas individuais parecem vii indicar a influência de fatores, como tamanho corporal e experiência na quebra de cocos, na escolha dos martelos em função do peso. Depois do peso, o custo do transporte da ferramenta até o local de uso parece ter sido a variável de maior importância, dentre as que investigamos, na escolha do peso médio dos martelos: quando estes tinham que ser transportados até as bigornas, os indivíduos escolheram martelos mais leves em comparação com a situação onde os martelos eram oferecidos junto às bigornas; entretanto esse custo não parece ser levado em conta de forma precisa, uma vez que a distância de transporte (5m x 10m) não afetou as escolhas. As escolhas por martelos de determinada faixa de peso também não variaram significativamente em função das espécies de cocos oferecidas, jerivá, Syagrus Romanzoffiana (menor) e indaiá, Atallea dubia (maior) / Experiments with captive, semi-free and wild tufted capuchin (Sapajus sp) groups in tasks involving the selection of tools to crack encapsulated fruit seem to show that these primates can distinguish functional from non-functional tools, and also choose, among functional tools, the most efficient ones. In the present study, we investigate these choices in a semi-free group by means of experiments analyzing the potential preferences for hammer stones of a particular weight and the effects of costs and benefits associated with their transport and handling, to verify whether these preferences are modified as a function of the transport distance to their place of utilization (the anvils) or of the toughness of the available nuts. We found a preference by juveniles for heavier hammers than the ones chosen by adults, which may point to a compensation by the former, since they are smaller and weaker, and heavier hammers require less strikes to crack nuts open. Individual choices seem to indicate the influence of factor such as body size and nut cracking experience on hammer choice. ix Besides weight, the costs of transporting the tools to their utilization sites seem to be the most relevant variable examined affecting the average weight of the chosen hammers: when these had to be carried to the anvils, the subjects selected lighter hammers, as compared to when hammers were made available near the anvils. The precise transport costs did not seem to be taken into account, though, since the transport distance (5m x 10m) did not affect choices. The choice of hammers of a given weight were also not significantly affected by the palm nut species made available, either Syagrus Romanzoffiana (smaller), or Atallea dubia (bigger)