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Laterality is defined as the occurrence of each cerebral hemisphere having asymmetric control over the different sides of the body, leading to preferences to use one side of the body over the other for various behaviors. Many types of laterality exist, but handedness is the form that is most predominantly assessed. Handedness in animals is of special interest to laterality researchers, as humans were once thought to be the only species that exhibited lateralized hand preferences. The aim of the current study was to determine if Asian small-clawed otters (Aonyx cinerea) exhibit significant paw preferences in behaviors associated with completing a specific tool-use task. Video data of the otters completing the task was analyzed for specific paw interactions with the tool-use apparatus, and the percentage of correct completion of the task was documented for each otter. Overall, no significant population level paw preference was present. However, individual differences in paw preference and differing trends in handedness on each focal behavior was present.  The results showed that paw preference (or lack thereof) did affect the tool-use task completion for some otters, and for others, the preference did not seem to have an effect. The main implications of this study are that paw preferences in Asian small-clawed otters are present on an individual level when solving a novel tool-use task.

Much discussion about large language models and language-and-vision models has focused on whether these models are intelligent agents. We present an alternative perspective. First, we argue that these artificial intelligence (AI) models are cultural technologies that enhance cultural transmission and are efficient and powerful imitation engines. Second, we explore what AI models can tell us about imitation and innovation by testing whether they can be used to discover new tools and novel causal structures and contrasting their responses with those of human children. Our work serves as a first step in determining which particular representations and competences, as well as which kinds of knowledge or skill, can be derived from particular learning techniques and data. In particular, we explore which kinds of cognitive capacities can be enabled by statistical analysis of large-scale linguistic data. Critically, our findings suggest that machines may need more than large-scale language and image data to allow the kinds of innovation that a small child can produce. [ABSTRACT FROM AUTHOR]

Tools enable humans to extend their sensing abilities beyond the natural limits of their hands, allowing them to sense objects as if they were using their hands directly. The similarities between direct hand interactions with objects (hand-based sensing) and the ability to extend sensory information processing beyond the hand (tool-mediated sensing) entail the existence of comparable processes for integrating tool- and hand-sensed information with vision, raising the question of whether tools support vision in bimanual object manipulations. Here, we investigated participants' performance while grasping objects either held with a tool or with their hand and compared these conditions with visually guided grasping (Experiment 1). By measuring reaction time, peak velocity, and peak of grip aperture, we found that actions were initiated earlier and performed with a smaller peak grip aperture when the object was seen and held with the tool or the contralateral hand compared to when it was only seen. Thus, tool-mediated sensing effectively supports vision in multisensory grasping and, even more intriguingly, resembles hand-based sensing. We excluded that results were due to the force exerted on the tool's handle (Experiment 2). Additionally, as for hand-based sensing, we found evidence that the tool supports vision by mainly providing object positional information (Experiment 3). Thus, integrating the tool-sensed position of the object with vision is sufficient to promote a multisensory advantage in grasping. Our findings indicate that multisensory integration mechanisms significantly improve grasping actions and fine-tune contralateral hand movements even when object information is only indirectly sensed through a tool. Public Significance Statement: Tools allow extending the hands' sensing capabilities beyond their anatomical limits. Here, we show that object information sensed through a tool can guide bimanual object manipulations as effectively as when directly sensed by the hand. Both tool-based and hand-mediated sensing provide relevant object positional information that is merged with vision to improve action performance. Our findings provide evidence about the interchangeable use of tools and hands for skilled actions and open new perspectives for prosthetic applications and rehabilitative plans. [ABSTRACT FROM AUTHOR]

Chimpanzee insectivory is seasonally variable, with pronounced peaks or set seasonal periods of consumption observed in most chimpanzee communities. This variation is interesting given that chimpanzees invest considerable effort into complex tool‐using behaviors to acquire insect prey. Evidence suggests this seasonal variation is related to insect behavior, but few studies have been done to empirically examine this relationship. In this study, we assessed whether a seasonal pattern of termite fishing by Nigeria‐Cameroon chimpanzees (Pan troglodytes ellioti) in Mbam & Djerem National Park, Cameroon was driven by termite behavior. We measured termite presence and termite foraging activity monthly at seven termite mounds near Ganga Research Station from April 2022 to April 2023. Macroscopic fecal analysis and camera traps placed at each mound demonstrated termite fishing in this community occurred from March to June, with a rare smaller period of termite fishing in October 2021. Average monthly rainfall, average monthly temperature, and average monthly fruit availability were used to examine potential environmental factors that could impact termite fishing seasonality. Termite presence was significantly different between months with and without chimpanzee termite fishing (t‐test, −6.569, p <.001). Termite presence was also significantly associated with average monthly rainfall (ANOVA, F = 13.9, p =.002, R2 =.775). Termites in this region appear to respond to the transition from dry to wet seasons by moving closer to the soil surface. This corresponds with greater chimpanzee termite fishing, suggesting that termite accessibility may be driving seasonal variation in this behavior. [ABSTRACT FROM AUTHOR]

Combinatorial behavior involves combining different elements into larger aggregates with meaning. It is generally contrasted with compositionality, which involves the combining of meaningful elements into larger constituents whose meaning is derived from its component parts. Combinatoriality is commonly considered a capacity found in primates and other animals, whereas compositionality often is considered uniquely human. Questioning the validity of this claim, this multidisciplinary special issue of the International Journal of Primatology unites papers that each study aspects of combinatoriality and compositionality found in primate and bird communication systems, tool use, skills, and human language. The majority of authors conclude that compositionality is evolutionarily preceded by combinatoriality and that neither are uniquely human. This introduction briefly introduces readers to the major findings and issues raised by the contributors. [ABSTRACT FROM AUTHOR]

Captive belugas (Delphinapterus leucas) often spit water as object play. One female beluga spit water at a ball to obtain it for play. We examined whether or not this behavior could be considered a tool-use behavior. When the ball was placed 10 cm from the poolside, the beluga poked the ball with her rostrum, while she often spit water at the ball at 50cm. This water-spitting behavior became more predominantly when the ball was placed at 30 cm or farther, corresponding to the maximum distance she could reach, suggesting her understanding of the cause-effect relationship. Next, the two balls were placed at 30 cm and 60 cm, and one was placed inside the rings, so it would not be easy to move it out by water-spitting. When the closer ball was placed in the ring, she tried to spit water at the ball farther away but without the ring, suggesting an understanding of efficiency in tool use. Furthermore, during this study, the beluga showed the behavior of throwing the ball obtained by spitting water at another one with her mouth. This generalization may be based on the causal understanding established through water-spitting.

In humans, interactions with objects are often embedded in communicative exchanges. Objects offer unique affordances to explore, carry functions and hold cultural relevance, which can shape children’s interactions and communication. Research indicates that the use of artificial objects, such as certain toys, helps promote pre-linguistic communication, consequently impacting language development. Given that chimpanzees use objects extensively compared to other great apes, and considering the differences between chimpanzees and bonobos in intrinsic motivation for tool use and the extended developmental period during which they learn to use objects, it is reasonable to expect that objects may influence chimpanzees’ communication. Here, we examined interactions of 31 immature sanctuary-living chimpanzees with non-novel artificial and natural objects and tested their vocal and facial expressions, applying methods previously designed for children. Our results showed an increase in these expressions associated with artificial objects. These findings provide the first empirical evidence that chimpanzee communicative expressions may be influenced by inherent properties of objects, potentially promoting varied communication, comparable to the impact distinctive objects have on pre-linguistic children. By exploring this connection between object-centric interactions and communication, this study reveals deep phylogenetic roots where objects may have shaped great ape communication and possibly evolutionary foundations of language.

Tool use diversity is often considered to differentiate our two closest living relatives: the chimpanzee (Pan troglodytes) and the bonobo (P. paniscus). Chimpanzees appear to have the largest repertoire of tools amongst nonhuman primates, and in this species, many forms of tool use enhance food and water acquisition. In captivity, bonobos seem as adept as chimpanzees in tool use complexity, including in the foraging context. However, in the wild, bonobos have only been observed engaging in habitual tool use in the contexts of comfort, play, self-directed behaviour and communication, whilst no tool-assisted food acquisition has been reported. Whereas captive bonobos use tools for drinking, so far, the only report from the wild populations comes down to four observations of moss sponges used at Lomako. Here, we present the first report of tool use in the form of water scooping by a wild bonobo at LuiKotale. An adult female was observed and videotaped whilst using an emptied Cola chlamydantha pod to scoop and drink water from a stream. We discuss the conditions for such observations and the importance of looking out for rare behaviours and attempt to put the observation into the context of the opportunity versus necessity hypotheses. By adding novel information on tool use, our report contributes to the ongoing efforts to differentiate population-specific traits in the behavioural ecology of the bonobo. [ABSTRACT FROM AUTHOR]

Previous research yielded inconsistent findings regarding whether manual lateralization (e.g., a distinct and consistent hand preference) affects manual performance during infancy and early childhood. The aim of the current study was to determine whether manual lateralization, viewed as a marker of hemispheric lateralization, is associated with infants' performance in role-differentiated bimanual manipulation (RDBM) and tool use. This longitudinal study assessed 158 typically developing infants (91 males, aged 9.13 ± 0.15 months at baseline) monthly during the 9–14-month period. Developmental trajectories for manual lateralization in object acquisition were related to those for RDBM and tool use, even after accounting for potential sex differences. All statistical analyses were conducted using Hierarchical Linear Modeling software (version 6). Advanced RDBM performance was associated with a lower magnitude of manual lateralization and a higher tendency among infants to use both hands for object acquisition. No significant relation was found between the magnitude of manual lateralization and tool-use performance. Thus, the current results highlight the importance of hand coupling for enhanced RDBM performance. Moreover, across all ages, females outperformed males in sophisticated RDBMs, possibly due to their less pronounced manual lateralization and a greater inclination towards bimanual object acquisition—factors that appear to facilitate RDBM performance. [ABSTRACT FROM AUTHOR]

Over the past few decades, tool use has been described in a variety of animals across taxa. However, there are relatively limited reports and studies of tool use in marine environments. Among marine fish though, labrids have been reported to be proficient at using tools. Here, we describe the first observations of tool use in two species of tropical wrasses—Halichoeres hortulanus (checkerboard wrasse) and Thalassoma jansenii (Jansen's wrasse)—and the first report of tool use from the wild for the wrasse Thalassoma lunare (Moon wrasse). These observations were made incidentally as part of size-specific predation assays for a small burrow-dwelling sea urchin (Echinostrephus molaris) in the Lakshadweep Archipelago, Indian Ocean. We documented multiple instances of anvil use by the wrasses H. hortulanus, and T. jansenii, and one instance of anvil use by T. lunare. All three species were recorded carrying the assay urchins to a nearby coral or benthic substrate and striking them repeatedly to break off their spines and crack their tests before consuming them. The behaviour was observed multiple times in different wrasse individuals. Also, sea urchin test size was a good predictor of the size of the fish that preyed on them. As naturalists spend more time observing fish in their natural environment, records of tool use in fish are increasing. Often these observations are incidental, yet documenting them carefully is critical, so we can ask larger questions about the evolution and development of animal intelligence. This study adds to observations of predation-associated tool use by fishes expanding reports of this behaviour taxonomically as well as geographically. [ABSTRACT FROM AUTHOR]

Objectives: Current evidence suggests that flaked stone tool technologies did not emerge until ~3.3–2.6 million‐years‐ago (Ma). It is often hypothesized that early hominin (principally Ardipithecus and early Australopithecus) manual anatomy may have prevented an earlier emergence, as the forceful precision grips essential to flake tool‐use may have been ineffectively performed by these species. Marzke, Marchant, McGrew, and Reece (2015) observed potentially forceful pad‐to‐side precision grips being recruited by wild chimpanzees (Pan troglodytes) during feeding behaviors, indicating that Pan‐like manual anatomy, and therefore potentially early hominin anatomy, may be capable of effectively securing flake stone tools during their use. Materials and Methods: Here, we report on the grips recruited by four captive, human‐trained, bonobos (Pan paniscus) during the use of stone and organic tools, including flake stone tools during cutting behaviors. Results: It is revealed that pad‐to‐side precision grips are frequently recruited by these bonobos when securing stone flakes during cutting actions. In some instances, high forces could have been resisted and applied by the thumb and fingers. Discussion: While our analyzes are preliminary and limited to captive individuals, and Pan is not suggested to secure flakes with the same efficacy as Homo or Australopithecus, it points to early hominins potentially being able to perform the precision grips required to use flake stone tools. In turn, the ability to gain tangible benefits from the effective use of flake tools (i.e., gain energetic returns from processing food resources) may have been – at least anatomically – possible in early Australopithecus and other pre‐Early Stone Age hominin species. In turn, hominin manual anatomy may not be a leading restriction on the emergence of the earliest stone tool technologies. [ABSTRACT FROM AUTHOR]

Abstract Chimpanzee insectivory is seasonally variable, with pronounced peaks or set seasonal periods of consumption observed in most chimpanzee communities. This variation is interesting given that chimpanzees invest considerable effort into complex tool‐using behaviors to acquire insect prey. Evidence suggests this seasonal variation is related to insect behavior, but few studies have been done to empirically examine this relationship. In this study, we assessed whether a seasonal pattern of termite fishing by Nigeria‐Cameroon chimpanzees (Pan troglodytes ellioti) in Mbam & Djerem National Park, Cameroon was driven by termite behavior. We measured termite presence and termite foraging activity monthly at seven termite mounds near Ganga Research Station from April 2022 to April 2023. Macroscopic fecal analysis and camera traps placed at each mound demonstrated termite fishing in this community occurred from March to June, with a rare smaller period of termite fishing in October 2021. Average monthly rainfall, average monthly temperature, and average monthly fruit availability were used to examine potential environmental factors that could impact termite fishing seasonality. Termite presence was significantly different between months with and without chimpanzee termite fishing (t‐test, −6.569, p

Capuchins can employ several strategies to deal with environmental challenges, such as using stone tools to access encapsulated resources. Nut-cracking is customary in several capuchin populations and can be affected by ecological and cultural factors; however, data on success and efficiency are only known for two wild populations. In this work, using camera traps, we assessed palm nut-cracking success and efficiency in two newly studied wild bearded capuchin populations (Sapajus libidinosus) and compared them with other sites. We tested the hypothesis that the overall success and efficiency of nut-cracking would be similar between sites when processing similar resources, finding partial support for it. Although using hammerstones of different sizes, capuchins had a similar success frequency. However, efficiency (number of strikes to crack a nut) was different, with one population being more efficient. We also tested whether success and efficiency varied between sexes in adults. We predict adult males would be more successful and efficient when cracking hard nuts. We found no differences between the sexes in one site but found sex differences in the other, although also for the low-resistant nut, which was unexpected. Our data add to the knowledge of capuchin nut-cracking behaviour flexibility, variance and potential cultural traits.

Observers experience visual biases in the area around handheld tools. These biases may occur when active use leads an observer to incorporate a tool into the body schema. However, the visual salience of a handheld tool may instead create an attentional prioritization that is not reliant on body-based representations. We investigated these competing explanations of near-tool visual biases in two experiments during which participants performed a target detection task. Targets could appear near or far from a tool positioned next to a display. In Experiment 1, participants showed facilitation in detecting targets that appeared near a simple handheld rake tool regardless of whether they first used the rake to retrieve objects, but participants who only viewed the tool without holding it were no faster to detect targets appearing near the rake than targets that appeared on the opposite side of the display. In a second experiment, participants who held a novel magnetic tool again showed a near-tool bias even when they refrained from using the tool. Taken together, these results suggest active use is unnecessary, but visual salience is not sufficient, to introduce visual biases in peri-tool space. [ABSTRACT FROM AUTHOR]

Objective: Semantic tool knowledge underlies the ability to perform activities of daily living. Models of apraxia have emphasized the role of functional knowledge about the action performed with tools (e.g., a hammer and a mallet allow a "hammering" action), and contextual knowledge informing individuals about where to find tools in the social space (e.g., a hammer and a mallet can be found in a workshop). The goal of this study was to test whether contextual or functional knowledge, would be central in the organization of tool knowledge. It was assumed that contextual knowledge would be more salient than functional knowledge for healthy controls and that patients with dementia would show impaired contextual knowledge. Methods: We created an original, open-ended categorization task with ambiguity, in which the same familiar tools could be matched on either contextual or functional criteria. Results: In our findings, healthy controls prioritized a contextual, over a functional criterion. Patients with dementia had normal visual categorization skills (as demonstrated by an original picture categorization task), yet they made less contextual, but more functional associations than healthy controls. Conclusion: The findings support a dissociation between functional knowledge ("what for") on the one hand, and contextual knowledge ("where") on the other hand. While functional knowledge may be distributed across semantic and action-related factors, contextual knowledge may actually be the name of higher-order social norms applied to tool knowledge. These findings may encourage researchers to test both functional and contextual knowledge to diagnose semantic deficits and to use open-ended categorization tests. [ABSTRACT FROM AUTHOR]

Tool use by animals, traditionally studied mainly in captive primates due to its relevance to human evolution, has been investigated in both free-ranging and captive mammals. Here, I present a report on tree bark and branch use behaviours by a free-ranging Japanese marten (Martes melampus). The marten put its face in a water-filled container, looking for something, and then it proceeded to make a scooping motion with a bark held in its mouth. Subsequently, it picked up a branch with its mouth and tried to scoop something from the water with it. Upon inspecting the container approximately 2 weeks later, I found a larva belonging to the family Syrphidae. While it is unclear if the marten was trying to catch this larva, its behaviour resembled reach extension behaviour seen in chimpanzees. The use of bark or branches may provide an advantage by allowing access to objects in hard-to-reach positions. [ABSTRACT FROM AUTHOR]

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Chimpanzees (Pan troglodytes) are avid tool users, although tool uses and functions vary among communities. Some chimpanzees use stones or wood in extractive foraging to crack open nuts, whereas others use long stems to consume termites or ants. Leaf sponges are versatile and widespread tools used by chimpanzees, created by crumpling leaves in the mouth and then using the hands to immerse the tool to procure liquids from difficult‐to‐access locations. Here we describe leaf sponge use by two female chimpanzees in Kibale National Park, Uganda, documenting for the first time tool use in the Buraiga chimpanzee community. [ABSTRACT FROM AUTHOR]

It is widely thought that causal cognition underpins technical reasoning. Here we suggest that understanding causal cognition as a thinking system that includes theory of mind (i.e., social cognition) can be a productive theoretical tool for the field of evolutionary cognitive archaeology. With this contribution, we expand on an earlier model that distinguishes seven grades of causal cognition, explicitly presenting it together with a new analysis of the theory of mind involved in the different grades. We then suggest how such thinking may manifest in the archaeological or stone tool record and techno-behaviors of the last three million years or so. Our thesis is threefold: (a) theory of mind is an integral element of causal cognition; (b) generally speaking, the more advanced causal cognition is, the more it is dependent on theory of mind; and (c) the evolution of causal cognition depends more and more on mental representations of hidden variables. Ultimately, the final or seventh grade of causal cognition allows us to reason from a network of hidden variables that, amongst other things, enables the learning, manufacture, and use of complex technological systems. It also facilitates the seamless mapping of knowledge between personal (egocentric), physical, and social networks that allows for newly devised and innovative technical and social outcomes. [ABSTRACT FROM AUTHOR]

The aim of the study was to explore inter-rater reliability and rater experiences of applying the universal instrument Assessment of Learning Process (ALP) with persons with profound intellectual and multiple disabilities. The study used a mixed-methods design. Inter-rater reliability was tested by eight clinical raters who assessed 23 video clips of people learning to use a powered AKKA mobility platform with a line-follower system. The raters were four occupational therapists, two special education teachers, and two speech-language therapists. The qualitative Think-aloud method explored three of the raters experiences of applying the ALP instrument. The inter-rater reliability test of the universal ALP instrument showed a moderate linear weighted kappa value (0.45). All eight raters' estimated the degree of difficulty or confidence for each assessment. Content analysis of Think-aloud data elucidated three of the raters experiences of observing performance characteristics and interpreting tool-use understanding. The reported inter-rater reliability of the universal ALP instrument can be considered acceptable for an observational study involving persons with profound intellectual and multiple disabilities. Thereby, the results suggest that the ALP can be applied to this population. This is important as assessing a person's phase in the learning process guides the choice of ALP-facilitating strategies supporting progress in tool-use learning, which in turn may expand a person's activity repertoire and participation. [ABSTRACT FROM AUTHOR]

The aim of the study was to explore inter-rater reliability and rater experiences of applying the universal instrument Assessment of Learning Process (ALP) with persons with profound intellectual and multiple disabilities. The study used a mixed-methods design. Inter-rater reliability was tested by eight clinical raters who assessed 23 video clips of people learning to use a powered AKKA mobility platform with a line-follower system. The raters were four occupational therapists, two special education teachers, and two speech-language therapists. The qualitative Think-aloud method explored three of the raters experiences of applying the ALP instrument. The inter-rater reliability test of the universal ALP instrument showed a moderate linear weighted kappa value (0.45). All eight raters’ estimated the degree of difficulty or confidence for each assessment. Content analysis of Think-aloud data elucidated three of the raters experiences of observing performance characteristics and interpreting tool-use understanding. The reported inter-rater reliability of the universal ALP instrument can be considered acceptable for an observational study involving persons with profound intellectual and multiple disabilities. Thereby, the results suggest that the ALP can be applied to this population. This is important as assessing a person’s phase in the learning process guides the choice of ALP-facilitating strategies supporting progress in tool-use learning, which in turn may expand a person’s activity repertoire and participation.

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. [ABSTRACT FROM AUTHOR]

Object play is essential for infant learning, and infants spend most of their day with objects. Young infants learn about objects and their properties through multimodal exploration facilitated by caregivers. They figure out how to transport their hands to where objects are, and how to grasp objects in increasingly complex ways. Building on earlier experiences, they learn how to use their hands collaboratively to act on objects, and how to use objects to act on other objects in instrumental ways. These changes in how infants use their hands occur during the most rapid period of motor development and may have important downstream implications for other domains. Recent research findings have established the importance of effective fine motor skills for later academic skills, yet our understanding of the factors that influence the early development of hand skills is sparse at best. Latest research on reaching, grasping, object manipulation, hands collaboration, and tool use is reviewed and connections among these developments are explained from the perspective of developmental cascades. This article is categorized under:Psychology > Motor Skill and PerformancePsychology > Development and Aging [ABSTRACT FROM AUTHOR]

Investigating the drivers of tool use in animals has recently received great attention because of its implication in understanding animals' cognition and the evolution of tool use in hominins. The necessity hypothesis posits tool use as a necessary response to food scarcity, but its role is an ongoing debate. The largest body of literature comparing animal tool use frequencies is with regard to primates, particularly comparisons between the Pan species. This supports the hypothesis that tool use is rarer in wild bonobos because of differential manipulation abilities of chimpanzees rather than different ecological needs. In this article, I aim to enrich the discussion concerning the necessity hypothesis and the ecological drivers of tool use in apes. The higher feeding flexibility of bonobos may be a key aspect to explaining the lower use of feeding tools than that observed in chimpanzees. The diet flexibility of bonobos is similar to that of the lowest level of tool users among the wild great apes: the gorilla. Gorillas can thus help to shed further light on this debate. When fruit is scarce, Western gorillas and bonobos rely more on widely available proteinaceous herbs than chimpanzees, who remain highly frugivorous. Chimpanzees may thus face a greater necessity to search for an alternative to obtain high-quality food: toolassisted feeding. An indirect piece of evidence for this higher level of herbivory is that the prevalence of gut ciliates in bonobos is double that of chimpanzees. In each animal species, a different combination of necessity, opportunities, predisposition, and learning processes are likely to be at play in the emergence of flexible tool use in animals. [ABSTRACT FROM AUTHOR]

Introduction: Healthy aging affects several domains of cognitive and motor performance and is further associated with multiple structural and functional neural reorganization patterns. However, gap of knowledge exists, referring to the impact of these age-related alterations on the neural basis of tool use- an important, complex action involved in everyday life throughout the entire lifespan. The current fMRI study aims to investigate age-related changes of neural correlates involved in planning and executing a complex object manipulation task, further providing a better understanding of impaired tool use performance in apraxia patients. Methods: A balanced number of sixteen older and younger healthy adults repeatedly manipulated everyday tools in an event-related Go-No-Go fMRI paradigm. Results: Our data indicates that the left-lateralized network, including widely distributed frontal, temporal, parietal and occipital regions, involved in tool use performance is not subjected to age-related functional reorganization processes. However, age-related changes regarding the applied strategical procedure can be detected, indicating stronger investment into the planning, preparatory phase of such an action in older participants. [ABSTRACT FROM AUTHOR]

Object interactions play an important role in human communication but the extent to which nonhuman primates incorporate objects in their social interactions remains unknown. To better understand the evolution of object use, this study explored how objects are used in social interactions in semi-wild chimpanzees (Pan troglodytes). We used an observational approach focusing on naturally occurring object actions where we examined their use and tested whether the production of object actions was influenced by the recipients' visual attention as well as by colony membership. The results show that chimpanzees adjusted both the type of object used, and the modality of object actions to match the visual attention of the recipient, as well as colony differences in the use of targeted object actions. These results provide empirical evidence highlighting that chimpanzees use objects in diverse ways to communicate with conspecifics and that their use may be shaped by social factors, contributing to our understanding of the evolution of human nonverbal communication, language, and tool use. [ABSTRACT FROM AUTHOR]

This article, published in the Journal of Raptor Research, discusses the rare occurrence of tool use by a Peregrine Falcon for nest defense. While tool use is uncommon in non-primate animals, and particularly rare in birds, certain groups of birds are known to use tools. In this case, the Peregrine Falcon dropped rocks as a tool to strike an intruder without making direct physical contact. This is the first documented account of a projectile being dropped by a raptor to make contact with an intruder. [Extracted from the article]

Previous research yielded inconsistent findings regarding whether manual lateralization (e.g., a distinct and consistent hand preference) affects manual performance during infancy and early childhood. The aim of the current study was to determine whether manual lateralization, viewed as a marker of hemispheric lateralization, is associated with infants’ performance in role-differentiated bimanual manipulation (RDBM) and tool use. This longitudinal study assessed 158 typically developing infants (91 males, aged 9.13 ± 0.15 months at baseline) monthly during the 9–14-month period. Developmental trajectories for manual lateralization in object acquisition were related to those for RDBM and tool use, even after accounting for potential sex differences. All statistical analyses were conducted using Hierarchical Linear Modeling software (version 6). Advanced RDBM performance was associated with a lower magnitude of manual lateralization and a higher tendency among infants to use both hands for object acquisition. No significant relation was found between the magnitude of manual lateralization and tool-use performance. Thus, the current results highlight the importance of hand coupling for enhanced RDBM performance. Moreover, across all ages, females outperformed males in sophisticated RDBMs, possibly due to their less pronounced manual lateralization and a greater inclination towards bimanual object acquisition—factors that appear to facilitate RDBM performance.

Terrestrial mammals exploiting coastal resources must cope with the challenge that resource availability and accessibility fluctuate with tidal cycles. Tool use can improve foraging efficiency and provide access to structurally protected resources that are otherwise unavailable (e.g. molluscs and fruits). To understand how variable accessibility of valuable resources shapes behavioural patterns, and whether tool use aids in the efficient exploitation of intertidal resources, we compared the relationship between tidal cycles and activity patterns of tool-using versus non-tool-using groups of white-faced capuchin monkeys on Jicarón Island in Coiba National Park, Panama. Although tool use on Jicarón is localized to a small stretch of coast (approx. 1 km), all coastal groups forage on intertidal resources. Using more than 5 years of camera trap data at varying distances from the coast, we found that capuchins on Jicarón showed increased coastal activity during specific parts of the tidal cycle, and that this relationship differed between tool-using and non-tool-using groups, as well as between seasons. Activity patterns of tool-using capuchins were more strongly and consistently tied to tidal cycles compared with non-tool-users, indicating that tool use might allow for more efficient exploitation of tidal resources. Our findings highlight the potential of tool use to aid niche expansion.

The modern human hand is an intriguing mix of primitive morphology and derived function. Traditionally, its form and function are explained as a functional "trade‐off" between the requirements of locomotion and manipulation, but recently acquired comparative, experimental and fossil evidence suggests that this functional trade‐off is more complex than conventional wisdom suggests. Moreover, when studying hand evolution within the hominin clade, the only morphological evidence comes from the hard‐tissues, and evidence about hand function must be inferred indirectly from the archaeological record. We lack information about critical aspects of hand form (e.g., soft tissues) and function (e.g., neurology) as well as non‐lithic evidence about behavior. Thus, comparative anatomical, experimental and ethological studies of modern humans and other primates are critical to making more informed inferences about hand use in the past. We review the relevant fossil and archaeological evidence within the relevant comparative context (e.g., other extant apes and dexterous monkeys) in an attempt to reconstruct hand evolution within the hominin clade. We conclude by summarizing our current understanding—or lack thereof—of the evolutionary history of the modern human hand. [ABSTRACT FROM AUTHOR]

A well-known phenomenon for the study of movement planning is the end-state comfort (ESC) effect: When they reach and grasp tools, individuals tend to adopt uncomfortable initial hand postures if that allows a subsequent comfortable final posture. In the context of tool use, this effect is modulated by tool orientation, task goal, and cooperation. However, the cognitive bases of the ESC effect remain unclear. The goal of this study was to determine the contribution of semantic tool knowledge and technical reasoning to movement planning, by testing whether the ESC effect typically observed with familiar tools would also be observed with novel tools. Twenty-six participants were asked to reach and grasp familiar and novel tools under varying conditions (i.e., tool's handle downward vs. upward; tool transport vs. use; solo vs. cooperation). In our findings, the effects of tool orientation, task goal and cooperation were replicated with novel tools. It follows that semantic tool knowledge is not critical for the ESC effect to occur. In fact, we found an "habitual" effect: Participant adopted uncomfortable grips with familiar tools even when it was not necessary (i.e., to transport them), probably because of the interference of habitual movement programming with actual movement programming. A cognitive view of movement planning is proposed, according to which goal comprehension (1) may rely on semantic tool knowledge, technical reasoning, and/or social skills, (2) defines end-state configuration, which in turn (3) calibrates beginning-state comfort and hence the occurrence of the ESC effect. [ABSTRACT FROM AUTHOR]

Determining the cultural propensities or cultural behaviours of a species during foraging entails an investigation of underlying drivers and motivations.In this article, we propose a multicomponent approach involving behaviour, ecology, and physiology to accelerate the study of cultural propensities in the wild.We propose as the first component the use of field experiments that simulate natural contexts, such as foraging behaviours and tool use opportunities, to explore social learning and cultural tendencies in a variety of species. To further accelerate this component, we discuss and advocate for the use of modern machine learning video analysis tools.In conjunction, we examine non‐invasive methods to measure ecological influences on foraging such as phenology, fruit availability, dietary intake; and physiological influences such as stress, protein balance, energetics, and metabolism. We feature non‐invasive urine sampling to investigate urea, creatinine, ketone bodies, the thyroid hormone triiodothyronine (T3), cortisol and connecting peptides of insulin.To conclude, we highlight the benefits of combining ecological and physiological conditions with behavioural field experiments. This can be done across wild species, and provides the framework needed to test ecological hypotheses related to cultural behaviour. [ABSTRACT FROM AUTHOR]

While tool use has been widely reported in non-human animals for food acquisition, the use of tools for drinking has been largely overlooked, with primates being a notable exception. We documented tool-assisted water scooping and drinking in several Balinese long-tailed macaques (Macaca fascicularis), living in Ubud, Indonesia, over a period of four years. We observed repeated tool-assisted water scooping using leaves, nuts, pits, and stones. Our results indicate that this behaviour is associated with manual drinking and can be performed in a playful context. This population habitually engages in a cultural form of stone-assisted object play known as stone handling, and it has an overall propensity to manipulate objects in water. We discuss the relationship between instrumental and non-instrumental object-assisted actions, as well as the possibility for this behaviour to be a tradition in this population. This report offers new insights into the limited literature on tool-assisted drinking in monkeys. [ABSTRACT FROM AUTHOR]

The advanced use of complex tools is considered a primary characteristic of human evolution and technological advancement. However, questions remain regarding whether humans possess unique underlying brain networks that support advanced tool-using abilities. Specifically, previous studies have demonstrated the presence of a structurally and functionally unique region in the left anterior supramarginal gyrus (aSMG), that is consistently active during tool use action observation. This region has been proposed as a primary hub for integrating semantic and technical information to form action plans with tools. However, it is still largely unknown how tool use motor learning affects left aSMG activation or connectivity with other brain regions. To address this, participants with little experience using chopsticks observed an experimenter using chopsticks to perform a novel task while undergoing two functional magnetic resonance imaging (fMRI) scans. Between the scans, participants underwent four weeks of behavioral training where they learned to use chopsticks and achieve proficiency in the observed task. Results demonstrated a significant change in effective connectivity between the left aSMG and the left anterior intraparietal sulcus (aIPS), a region involved in object affordances and planning grasping actions. These findings suggest that during unfamiliar tool use, the left aSMG integrates semantic and technical information to communicate with regions involved with grasp selection, such as the aIPS. This communication then allows appropriate grasps to be planned based on the physical properties of the objects involved and their potential interactions. [ABSTRACT FROM AUTHOR]

We documented evidence of idiosyncratic but repeated twig-assisted genital stimulation by Balinese long-tailed macaques (Macaca fascicularis), living in Ubud, Indonesia. This population is known to customarily engage in genital stone-tapping/-rubbing, a behaviour expressed by males and females of different age classes as part of a broader cultural repertoire of stone-directed and overall playful actions known as stone handling. However, genital stimulation using other objects has never been reported in this population and species. We observed repeated and extensive twig-assisted genital stimulation in one adult female and one adult male. We also recorded three instances of twig-assisted genital stimulation in three additional individuals. Our results indicate that this behaviour is not accidental and may be sexually motivated; that is, it may be another form of tool-assisted masturbation in this primate population. This report provides a valuable addition to the increasing literature on tool-assisted behavioural innovations pertaining to self-care and possibly pleasure. [ABSTRACT FROM AUTHOR]

Children with autism spectrum disorder (ASD) have difficulties with tool use and pantomime actions. The current study utilized functional near-infrared spectroscopy (fNIRS) to examine the neural mechanisms underlying these gestural difficulties. Thirty-one children with and without ASD (age (mean ± SE) = 11.0 ± 0.6) completed a naturalistic peg-hammering task using an actual hammer (hammer condition), pantomiming hammering actions (pantomime condition), and performing meaningless actions with similar joint motions (meaningless condition). Children with ASD exhibited poor praxis performance (praxis error: TD = 17.9 ± 1.7; ASD = 27.0 ± 2.6, p < 0.01), which was significantly correlated with their cortical activation (R = 0.257 to 0.543). Both groups showed left-lateralized activation, but children with ASD demonstrated more bilateral activation during all gestural conditions. Compared to typically developing children, children with ASD showed hyperactivation of the inferior parietal lobe and hypoactivation of the middle/inferior frontal and middle/superior temporal regions. Our findings indicate intact technical reasoning (typical left-IPL activation) but atypical visuospatial and proprioceptive processing (hyperactivation of the right IPL) during tool use in children with ASD. These results have important implications for clinicians and researchers, who should focus on facilitating/reducing the burden of visuospatial and proprioceptive processing in children with ASD. Additionally, fNIRS-related biomarkers could be used for early identification through early object play/tool use and to examine neural effects following gesture-based interventions. [ABSTRACT FROM AUTHOR]

Upper limb exoskeletons may confer significant mechanical advantages across a range of tasks. The potential consequences of the exoskeleton upon the user's sensorimotor capacities however, remain poorly understood. The purpose of this study was to examine how the physical coupling of the user's arm to an upper limb exoskeleton influenced the perception of handheld objects. In the experimental protocol, participants were required to estimate the length of a series of bars held in their dominant right hand, in the absence of visual feedback. Their performance in conditions with an exoskeleton fixed to the forearm and upper arm was compared to conditions without the upper limb exoskeleton. Experiment 1 was designed to verify the effects of attaching an exoskeleton to the upper limb, with object handling limited to rotations of the wrist only. Experiment 2 was designed to verify the effects of the structure, and its mass, with combined movements of the wrist, elbow, and shoulder. Statistical analysis indicated that movements performed with the exoskeleton did not significantly affect perception of the handheld object in experiment 1 (BF01 = 2.3) or experiment 2 (BF01 = 4.3). These findings suggest that while the integration of an exoskeleton complexifies the architecture of the upper limb effector, this does not necessarily impede transmission of the mechanical information required for human exteroception. [ABSTRACT FROM AUTHOR]