An approach to the ethics of cloning humans via an examination of the ethical issues pertaining to the use of any tool

Those procedures which, at some future date, could constitute the operations resulting in the cloning of a human being are defined as a tool. As humans have been using tools for some two million years, sets of rules or ethics have been devised to make sure that tools are used to promote the maximum benefit and cause the minimum harm. It would, therefore, seem appropriate to consider the human cloning process as one such tool and approach the ethical issues which might govern its use in a manner which has been informed by how we have approached similar instances of new tool development. In this we can be guided by a range of thought experiments and practical considerations. When we combine these two facilities we may conclude that there are some benefits to be gained by the use of the human cloning tool, while there are other aspects of the use of the tool that need to be carefully controlled and regulated. An outline of a pragmatic approach to the initial uses of the tool is described.     

Can object affordances impact on human social learning of tool use?

The author describes "higher" and "uniquely human" sociocognitive skills that he argues as being necessary for tool use. We propose that those skills could be based on simpler detection systems humans could share with other animal tool users. More specifically, we discuss the impact of object affordances on the understanding and the social learning of tool use.     

The role of executive control in tool use

Comparing cognitive functions between humans and nonhuman primates is helpful for understanding human tool use. We comment on the latest insights from comparative research on executive control functions. Based on our own work, we discuss how even a mental function in which non-human primates outperform humans might have played a key role in the development of tool use.     

Different social motives in the gestural communication of chimpanzees and human children

Both chimpanzees and human infants use the pointing gesture with human adults, but it is not clear if they are doing so for the same social motives. In two studies, we presented chimpanzees and human 25-month-olds with the opportunity to point for a hidden tool (in the presence of a non-functional distractor). In one condition it was clear that the tool would be used to retrieve a reward for the pointing subject (so the pointing was selfish or 'for-me'), whereas in the other condition it was clear that the tool would be used to retrieve the reward for the experimenter (so the pointing was helpful or 'for-you'). The chimpanzees pointed reliably only when they themselves benefited, whereas the human children pointed reliably no matter who benefited. These results are interpreted as evidence for the especially cooperative nature of human communication.     

Tool use and constructions

We examine tool use in relation to the capacity of animals for construction, contrasting tools and nests; place human tool use in a more general problem-solving context, revisiting the body schema in the process; and relate the evolution of language and of tool use.     

What Neuropsychology Tells us About Human Tool Use? The Four Constraints Theory (4CT): Mechanics,Space, Time,and Effort

Our understanding of human tool use comes mainly from neuropsychology, particularly from patients with apraxia or action disorganization syndrome. However, there is no integrative, theoretical framework explaining what these neuropsychological syndromes tell us about the cognitive/neural bases of human tool use. The goal of the present article is to fill this gap, by providing a theoretical framework for the study of human tool use: The Four Constraints Theory (4CT). This theory rests on two basic assumptions. First, everyday tool use activities can be formalized as multiple problem situations consisted of four distinct constraints (mechanics, space, time, and effort). Second, each of these constraints can be solved by the means of a specific process (technical reasoning, semantic reasoning, working memory, and simulation-based decision-making, respectively). Besides presenting neuropsychological evidence for 4CT, this article shall address epistemological, theoretical and methodological issues I will attempt to resolve. This article will discuss how 4CT diverges from current cognitive models about several widespread hypotheses (e.g., notion of routine, direct and automatic activation of tool knowledge, simulation-based tool knowledge).     

The cognitive bases of human tool use

This article has two goals. The first is to assess, in the face of accruing reports on the ingenuity of great ape tool use, whether and in what sense human tool use still evidences unique, higher cognitive ability. To that effect, I offer a systematic comparison between humans and nonhuman primates with respect to nine cognitive capacities deemed crucial to tool use: enhanced hand-eye coordination, body schema plasticity, causal reasoning, function representation, executive control, social learning, teaching, social intelligence, and language. Since striking differences between humans and great apes stand firm in eight out of nine of these domains, I conclude that human tool use still marks a major cognitive discontinuity between us and our closest relatives. As a second goal of the paper, I address the evolution of human technologies. In particular, I show how the cognitive traits reviewed help to explain why technological accumulation evolved so markedly in humans, and so modestly in apes.     

Unique features of human movement control predicted by the leading joint hypothesis

Vaesen suggests that motor control is not among the primary origins of the uniqueness of human tool use. However, recent findings show that cognitive processes involved in control of human limb movements may be much more sophisticated than it was believed previously. The sophistication of movement control may substantially contribute to the uniqueness of humans in tool use.     

The limits of chimpanzee-human comparisons for understanding human cognition

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.     

What is the future for tool-specific generalized motor programs?

A key issue in cognitive sciences is to understand the cognitive bases of human tool use. Answers have been provided by two competing approaches. The manipulation-based approach assumes that humans can use tools because of the ability to store sensorimotor knowledge about how to manipulate tools. By contrast, for the reasoning-based approach, human tool use is based on the ability to reason about physical object properties. Recently, Caruana and Cuccio proposed a kind of reconciliation, based on the distinction between three types of abductive inference, involving a different contribution of motor and cognitive elements: Automatic abduction (motor + and cognitive-), abduction by selection (motor ± and cognitive±) and creative abduction (motor- and cognitive+). This perspective offers new interesting avenues. Nevertheless, it is also subject to several theoretical and epistemological limitations, which make it in its present form inappropriate for the study of the cognitive bases of human tool use. This article aims to discuss these limitations.     

How to crack nuts: acquisition process in captive chimpanzees (Pan troglodytes) observing a model

Stone tool use for nut cracking consists of placing a hard-shelled nut onto a stone anvil and then cracking the shell open by pounding it with a stone hammer to get to the kernel. We investigated the acquisition of tool use for nut cracking in a group of captive chimpanzees to clarify what kind of understanding of the tools and actions will lead to the acquisition of this type of tool use in the presence of a skilled model. A human experimenter trained a male chimpanzee until he mastered the use of a hammer and anvil stone to crack open macadamia nuts. He was then put in a nut-cracking situation together with his group mates, who were naïve to this tool use; we did not have a control group without a model. The results showed that the process of acquisition could be broken down into several steps, including recognition of applying pressure to the nut, emergence of the use of a combination of three objects, emergence of the hitting action, using a tool for hitting, and hitting the nut. The chimpanzees recognized these different components separately and practiced them one after another. They gradually united these factors in their behavior leading to their first success. Their behavior did not clearly improve immediately after observing successful nut cracking by a peer, but observation of a skilled group member seemed to have a gradual, long-term influence on the acquisition of nut cracking by naïve chimpanzees.     

Dynamic size‐change of peri‐hand space through tool‐use: Spatial extension or shift of the multi‐sensory area

Several studies in humans and non‐human primates have shown that tool‐use can expand near peripersonal space ( Farnè & Làdavas, 2000 ; Iriki, Tanaka, & Iwamura, 1996 ). In humans, the extension of the near peripersonal space is revealed by an increase in the severity of cross‐modal extinction caused by visual stimulation at the distal edge of a rake after its use as a reaching tool. The crucial question addressed here concerns whether the dynamic re‐sizing of the peri‐hand space in humans constitutes a real spatial expansion of visual‐tactile peri‐hand area along the tool axis. Alternatively, it could constitute a shift of the integrative area from the hand towards the distal edge of the tool, or the formation of a novel visual‐tactile integrative area at the same distal location ( Holmes, Calvert, & Spence, 2004 ). We contrasted the alternative predictions made by these hypotheses in a group of RBD patients by probing, at different locations along the tool axis, the changes induced by tool‐use on cross‐modal extinction. By assessing the visual‐tactile extinction near the hand, midway along the tool, and at the distal edge of the tool we found an increase in visual‐tactile extinction after tool‐use both at the middle and the distal location along the tool axis. In contrast, no change intervened at the hand proximity. These findings support the view that the tool‐use dependent re‐mapping of peri‐hand space in humans consists of a continuous elongation of visual‐tactile peri‐hand area from the hand towards the tip of the tool.     

Chimpanzee (Pan troglodytes) intentional communication is not contingent upon food

Studies of great apes have revealed that they use manual gestures and other signals to communicate about distal objects. There is also evidence that chimpanzees modify the types of communicative signals they use depending on the attentional state of a human communicative partner. The majority of previous studies have involved chimpanzees requesting food items from a human experimenter. Here, these same communicative behaviors are reported in chimpanzees requesting a tool from a human observer. In this study, captive chimpanzees were found to gesture, vocalize, and display more often when the experimenter had a tool than when she did not. It was also found that chimpanzees responded differentially based on the attentional state of a human experimenter, and when given the wrong tool persisted in their communicative efforts. Implications for the referential and intentional nature of chimpanzee communicative signaling are discussed.     

An area specifically devoted to tool use in human left inferior parietal lobule

A comparative fMRI study by Peeters et al. (2009) provided evidence that a specific sector of left inferior parietal lobule is devoted to tool use in humans, but not in monkeys. We propose that this area represents the neural substrate of the human capacity to understand tool use by using causal reasoning.     

Language lateralization to the dominant hemisphere: Tool use, gesture and language in hominid evolution

Shared tool use in our hominid ancestry is perhaps the most satisfactory explanation for human dextrality and left-hemisphere language lateralization. Recent palaeoarchaeological evidence suggests that brachiation preceded bipedalism, which in turn preceded advanced tool use, with all three preceding any dramatic increase in brain size and/or the development of speech-related neural structures. Shared tool use probably led to population dextrality, and then to the development of left-hemisphere centres for fine motor coordination and the mediation of serial, segmental, time-dependent and syntactic processes at sensory and more particularly motor levels, including the control of limbs, fingers and articulators. Such centres, initially developed for tool construction and use, would have occupied an intermediate position in the evolutionary sequence. Thus cortically-driven facial gestures may possibly have accompanied manual signing, modulating limbic vocalizations of affect, though a cortical-limbic distinction with respect to communication may be unwarranted. However, the uniqueness of human language is still a matter of debate both with respect to other primates and our own evolutionary ancestors.     

Young children's rapid learning about artifacts

Tool use is central to interdisciplinary debates about the evolution and distinctiveness of human intelligence, yet little is actually known about how human conceptions of artifacts develop. Results across these two studies show that even 2-year-olds approach artifacts in ways distinct from captive tool-using monkeys. Contrary to adult intuition, children do not treat all objects with appropriate properties as equally good means to an end. Instead, they use social information to rapidly form enduring artifact categories. After only one exposure to an artifact's functional use, children will construe the tool as 'for' that particular purpose and, furthermore, avoid using it for another feasible purpose. This teleo-functional tendency to categorize tools by intentional use represents a precursor to the design stance - the adult-like tendency to understand objects in terms of intended function - and provides an early foundation for apparently distinctive human abilities in efficient long-term tool use and design.     

Look, no hands!

Contrary to Vaesen's argument that humans are unique with respect to nine cognitive capacities essential for tool use, we suggest that although such cognitive processes contribute to variation in tool use, it does not follow that these capacities are necessary for tool use, nor that tool use shaped cognition per se, given the available data in cognitive neuroscience and behavioral biology.     

Childhood and advances in human tool use

Human life history incorporates childhood, a lengthy post-weaning period of dependency. This species-specific period provides an opportunity for extensive learning and for sophisticated cultural behaviors to develop, including crucial tool use skills. Although I agree that no individual cognitive trait singularly differentiates humans from other animals, I suggest here that without childhood, the traits that are key to human tool use would not emerge.     

An era of webs: Technique,technology and the new cognitive (r)evolution

This paper explores the relationship between technology and technique in the use of computers as tools and how it is leading cognitive sciences into to an era of “webs.” Ernst Kapp suggested that it is humans who determine the “appropriate form” of any tool through the way they use and think about it; Douglas Engelbart, a pioneering computer researcher suggested that tools change to meet our expectations pushing us to understand the world in different ways. These two interrelated observations about technology are especially salient for our burgeoning information age. The current intersection of technologies leads to two competing visions of the computer – both deeply influenced by the concept of human–computer symbiosis – and to very different conceptions of human thinking. The vision of computer as recreation of human thinking, heavily influenced by the development of tools such as the personal computer and object-oriented programming, leads to viewing ideal human thinking as efficiently designed, well organized, and locally regulated by executive functions. The second vision of computers, as augmenting the human mind by extending brain activity out into the information universe, leads to web or trails related themes that focus on non-linear, non-hierarchical inter-linking of information into cohesive patterns. This paper suggests that because of the pace of tool development in these two computer capabilities the theme of the central processing unit dominated early, but we are now entering a new, more complex “age of webs.”     

A claw is like my hand: comparison supports goal analysis in infants

Understanding the intentional relations in others' actions is critical to human social life. Origins of this knowledge exist in the first year and are a function of both acting as an intentional agent and observing movement cues in actions. We explore a new mechanism we believe plays an important role in infants' understanding of new actions: comparison. We examine how the opportunity to compare a familiar action with a novel, tool use action helps 7- and 10-month-old infants extract and imitate the goal of a tool use action. Infants given the chance to compare their own reach for a toy with an experimenter's reach using a claw later imitated the goal of an experimenter's tool use action. Infants who engaged with the claw, were familiarized with the claw's causal properties, or learned the associations between claw and toys (but did not align their reaches with the claw's) did not imitate. Further, active participation in the familiar action to be compared was more beneficial than observing a familiar and novel action aligned for 10-month-olds. Infants' ability to extract the goal-relation of a novel action through comparison with a familiar action could have a broad impact on the development of action knowledge and social learning more generally.