Studies Of Tool Use Research Articles

Human Neuroimaging Reveals Differences in Activation and Connectivity between Real and Pantomimed Tool Use.

Because the sophistication of tool use is vastly enhanced in humans compared with other species, a rich understanding of its neural substrates requires neuroscientific experiments in humans. Although functional magnetic resonance imaging (fMRI) has enabled many studies of tool-related neural processing, surprisingly few studies have examined real tool use. Rather, because of the many constraints of fMRI, past research has typically used proxies such as pantomiming despite neuropsychological dissociations between pantomimed and real tool use. We compared univariate activation levels, multivariate activation patterns, and functional connectivity when participants used real tools (a plastic knife or fork) to act on a target object (scoring or poking a piece of putty) or pantomimed the same actions with similar movements and timing. During the Execute phase, we found higher activation for real versus pantomimed tool use in sensorimotor regions and the anterior supramarginal gyrus, and higher activation for pantomimed than real tool use in classic tool-selective areas. Although no regions showed significant differences in activation magnitude during the Plan phase, activation patterns differed between real versus pantomimed tool use and motor cortex showed differential functional connectivity. These results reflect important differences between real tool use, a closed-loop process constrained by real consequences, and pantomimed tool use, a symbolic gesture that requires conceptual knowledge of tools but with limited consequences. These results highlight the feasibility and added value of employing natural tool use tasks in functional imaging, inform neuropsychological dissociations, and advance our theoretical understanding of the neural substrates of natural tool use.SIGNIFICANCE STATEMENT The study of tool use offers unique insights into how the human brain synthesizes perceptual, cognitive, and sensorimotor functions to accomplish a goal. We suggest that the reliance on proxies, such as pantomiming, for real tool use has (1) overestimated the contribution of cognitive networks, because of the indirect, symbolic nature of pantomiming; and (2) underestimated the contribution of sensorimotor networks necessary for predicting and monitoring the consequences of real interactions between hand, tool, and the target object. These results enhance our theoretical understanding of the full range of human tool functions and inform our understanding of neuropsychological dissociations between real and pantomimed tool use.

Examining the Origins of Hafting in South Asia

The appearance of hafting technologies marks a key shift in hominin behavioural evolution. Hafting first appears in Africa and Western Eurasia across the transition from Late Acheulean to Middle Palaeolithic technologies ~ 300–200 thousand years ago (ka). Hafting technology in South Asia may have emerged as a result of a local innovation, through cultural diffusion or a population dispersal. The resolution of the South Asian Palaeolithic records has improved significantly over the past decade, enabling examination of patterns of change through time in stone tool technologies. Although functional studies of tool use remain limited in the region, a range of indices of hafting appear in stone tool assemblages that offer the first means to evaluate the origins of hafting in South Asia. Rare examples appear in Middle Pleistocene contexts, but indices of hafting appear repeatedly in Middle Palaeolithic assemblages dating within the past 100 thousand years and are commonplace amongst Late Palaeolithic assemblages dating within the past 45 thousand years. This dataset remains too immature to authoritatively resolve between alternate models for the origins of hafting, whereas direct association with discrete hominin populations is hampered by the region’s scant fossil record. Nevertheless, this examination of the origin of hafting technology presents the means to reorient approaches to Late Pleistocene behavioural change in South Asia and integrate them within global debates regarding hominin innovation, demographic interaction and population expansion.

Rethinking actions: implementation and association.

Action processing allows us to move through and interact with the world, as well as understand the movements performed by other people. In recent years, there has been increasing interest in the semantics of actions as differentiated from the semantics of objects. However, as the understanding of action semantics has evolved, it is evident that the existing literature conflates two senses of the word 'action'-one that stems from studies of tool use and the other from event representation. In this paper, we suggest that this issue can be clarified by closely examining differences in how the human parietal and temporal cortices of the brain process action-related stimuli. By contrasting the posterior parietal cortex to the posterolateral temporal cortex, we characterize two complementary action systems in the human brain, each with its own specialization of function. We suggest that these two systems be referred to as the parietal Action Implementation System, and the posterolateral temporal Action Association System. While the frontoparietal system is concerned primarily with how we perform actions, and simulate others' actions, the temporal action system is more involved with processing actions from a third-person, conceptual standpoint. Recent work in cognitive neuroscience of perception and language, as well as the neuroanatomical organization of these brain regions support this distinction. We will discuss the implications of this work for cognition-, language-, and neuroscience-based action research.

Tool use as adaptation

Tool use is a vital component of the human behavioural repertoire. The benefits of tool use have often been assumed to be self-evident: by extending control over our environment, we have increased energetic returns and buffered ourselves from potentially harmful influences. In recent decades, however, the study of tool use in both humans and non-human animals has expanded the way we think about the role of tools in the natural world. This Theme Issue is aimed at bringing together this developing body of knowledge, gathered across multiple species and from multiple research perspectives, to chart the wider evolutionary context of this phylogenetically rare behaviour.

Neural correlates of observing pretend play in which one object is represented as another

Observers were scanned while they watched a video of an actor using an object. Three conditions were contrasted in which the same object was used: (i) normally (e.g. using a tennis racket to hit a ball), (ii) in an unusual way (e.g. using a tennis racket to strain spaghetti), (iii) in a pretend play (e.g. playing a tennis racket like a banjo). Observing real and unusual uses of objects activated areas previously seen in studies of tool use including areas associated with a mirror system for action. Observing pretend play activated additional areas previously associated with theory of mind tasks and listening to narrative, including medial prefrontal cortex, posterior superior temporal sulcus and temporal poles. After presentation of each video, observers were asked to name the object as used in the preceding action video (e.g. racket, sieve or banjo). Naming the pretend object elicited activity in medial prefrontal cortex. These results are consistent with proposals that pretend play is a form of communicative narrative, associated with the ability to mentalize. However, this leaves open the question as to whether pretence or mentalizing is the more basic process.

A modular planar robotic manipulandum with end-point torque control

Robotic manipulanda are extensively used in investigation of the motor control of human arm movements. They permit the application of translational forces to the arm based on its state and can be used to probe issues ranging from mechanisms of neural control to biomechanics. However, most current designs are optimized for studying either motor learning or stiffness. Even fewer include end-point torque control which is important for the simulation of objects and the study of tool use. Here we describe a modular, general purpose, two-dimensional planar manipulandum (vBOT) primarily optimized for dynamic learning paradigms. It employs a carbon fibre arm arranged as a parallelogram which is driven by motors via timing pulleys. The design minimizes the intrinsic dynamics of the manipulandum without active compensation. A novel variant of the design (WristBOT) can apply torques at the handle using an add-on cable drive mechanism. In a second variant (StiffBOT) a more rigid arm can be substituted and zero backlash belts can be used, making the StiffBOT more suitable for the study of stiffness. The three variants can be used with custom built display rigs, mounting, and air tables. We investigated the performance of the vBOT and its variants in terms of effective end-point mass, viscosity and stiffness. Finally we present an object manipulation task using the WristBOT. This demonstrates that subjects can perceive the orientation of the principal axis of an object based on haptic feedback arising from its rotational dynamics.

Integration of use-wear with protein residue analysis – a study of tool use and function in the south Scandinavian Early Neolithic

This study presents research on how an integration of use-wear analysis with protein residue analysis can produce new results on prehistoric tool use and function. Thirty flint artefacts from an Early Neolithic TRB site in south Sweden were analysed for both use-wear and protein residues. The results show a positive correlation between the two methods. The Early Neolithic tools analysed were primarily used to process fish.

Lateralized tool use in wild New Caledonian crows

Many vertebrate species exhibit sensory and motor asymmetries. Laterality studies of tool use have focused on primates, where hemispheric asymmetries, manifested behaviourally in hand preferences, are thought to be associated with complex motor tasks. Here we report strong individual lateralization for tool use in birds. New Caledonian crows, Corvus moneduloides, hold stick tools with their bills while foraging, often with the nonworking end laterally positioned on one side of the head and the working end possibly positioned in the binocular field. We observed four wild crows to determine whether tools were consistently held on one side. All crows showed a significant preference (two right, two left). This preference was independent of any asymmetry in tool manufacture and held for artificial holes similarly accessible for tools held on either side. This is the first demonstration of lateralized tool use in a nonprimate. In addition, all 173 tools used unilaterally were held only on a crow's preferred side. Such pronounced individual laterality for tool use in natural conditions has previously been reported only in humans and chimpanzees.

Primate causal understanding in the physical and psychological domains

Evidence for primates' understanding of causality is presented and discussed. Understanding causality requires the organism to understand not just that two events are associated with one another in space and time, but also that there is some `mediating force' that binds the two events to one another which may be used to predict or control those events (e.g. a physical force such as gravity or a psychological force such as an intention). In the physical domain, studies of tool use indicate that capuchin monkeys do not have a causal understanding of the functioning of tools in terms of the physical forces involved, but rather they learn to associate aspects of their own behavior with the results it produces. Apes show some possible signs of understanding the causal relations involved in tool use in the sense that they may employ various forms of foresight in approaching novel tasks, perhaps involving an understanding of physical forces—although not to the extent of human children. In the psychological domain, nonhuman primates understand conspecifics as animate beings that generate their own behavior and, thus, they appreciate that to manipulate conspecifics communicative signals, and not physical activities, are required. However, there is very little evidence that nonhuman primates of any species understand others as psychological beings with intentions and other psychological states that mediate their behavioral interactions with the world—as human children begin to do sometime during their second year of life. More research, using a wider range of problem-solving situations, is needed if we are to become more precise in our understanding of how primates understand the causal structure of the world around them.

Spoon Handling in Two-to-Four-Year-Old Children

A method for the study of tool use is presented from the perspective of an ecological approach to perception and action. It is argued that the essence of tool use lies in the maintenance of a specific relation between the organism + tool complex and the environment. Control over the tool is subordinate to this aim. It is proposed that perturbations of the tool-environment relation reveal the essential dimensions of organism + tool complex. A simple experiment is reported in which children (n = 43) from 2 to 4 years of age were asked to use (I of 6) spoons to transport rice from 1 bucket to another. Perturbation of the tool-environment relation was introduced by manipulating the geometrical configuration of the spoons. The results indicated that all children indeed controlled the relation between tool and environment. They varied their grip such that the functional act of scooping was preserved. Hence, they perceived the new spoons in terms of its functional properties, its affordances. In addition, it was found that the relative occurrence of successful and unsuccessful transport attempts was contingent upon the configuration of the spoon. The control problems posed by one spoon in particular were such that, when using this implement, five children failed to transport any rice. A highly rigid handling mode was evident during many of the transport attempts undertaken using this spoon. The results further exemplified that failures in tool use, following perturbations of the tool-environment relation, are concomitant with the adoption of rigid handling modes and the selection of maladaptive grip configurations.

Tool Use in Cebus

This paper summarizes early anecdotal information and systematic studies of tool use in capuchin monkeys (Cebus spp.). Tool use in capuchins is neither context specific nor stereotyped. The success of capuchins in using tools and in exploiting a variety of food resources in the wild derives from several factors: their manipulative abilities, interest in external objects and a tendency to explore the environment. In using tools, capuchins are similar to apes and more proficient than other monkey species. A cognitive approach indicates, however, that (in contrast with chimpanzees) they never develop an understanding of the requirements of the tool tasks presented.

Chimpanzees, Tools, and Termites: Another Example From Tanzania

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