Cultural attraction in pottery practice: Group-specific shape transformations by potters from three communities.

Pottery is a quintessential indicator of human cultural dynamics. Cultural alignment of behavioral repertoires and artifacts has been considered to rest upon two distinct dynamics: selective transmission of information and culture-specific biased transformation. In a cross-cultural field experiment, we tested whether community-specific morphological features of ceramic vessels would arise when the same unfamiliar shapes were reproduced by professional potters from three different communities who threw vessels using wheels. We analyzed the details of the underlying morphogenesis development of vessels in wheel throwing. When expert potters from three different communities of practice were instructed to faithfully reproduce common unfamiliar model shapes that were not parts of the daily repertoires, the morphometric variation in the final shape was not random; rather, different potters produced vessels with more morphometric variation among than within communities, indicating the presence of community-specific deviations of morphological features of vessels. Furthermore, this was found both in the final shape and in the underlying process of morphogenesis; there was more variation in the morphogenetic path among than within communities. These results suggest that the morphological features of ceramic vessels produced by potters reliably and nonrandomly diverge among different communities. The present study provides empirical evidence that collective alignment of morphological features of ceramic vessels can arise from the community-specific habits of fashioning clay.

Coordinating upper limbs for octave playing on the piano via neuro-musculoskeletal modeling.

Understanding the coordination of multiple biomechanical degrees of freedom in biological organisms is crucial for unraveling the neurophysiological control of sophisticated motor tasks. This study focuses on the cooperative behavior of upper-limb motor movements in the context of octave playing on the piano. While the vertebrate locomotor system has been extensively investigated, the coherence and precision timing of rhythmic movements in the upper-limb system remain incompletely understood. Inspired by the spinal cord neuronal circuits (central pattern generator, CPG), a computational neuro-musculoskeletal model is proposed to explore the coordination of upper-limb motor movements during octave playing across varying tempos and volumes. The proposed model incorporates a CPG-based nervous system, a physiologically-informed mechanical body, and a piano environment to mimic human joint coordination and expressiveness. The model integrates neural rhythm generation, spinal reflex circuits, and biomechanical muscle dynamics while considering piano playing quality and energy expenditure. Based on real-world human subject experiments, the model has been refined to study tempo transitions and volume control during piano playing. This computational approach offers insights into the neurophysiological basis of upper-limb motor coordination in piano playing and its relation to expressive features.

Relation between the kinematic synergy controlling swing foot and visual exploration during obstacle crossing.

To step over obstacles of varying heights, two distinct ongoing streams of activities-visual exploration of the environment and gait adjustment- were required to occur concurrently without interfering each other. Yet, it remains unclear whether and how the manner of embodied behavior of visual exploration is related to the synergistic control of foot trajectory to negotiate with the irregular terrain. Thus, we aimed to explore that how the synergistic control of the vertical trajectory of the swing foot (i.e., obstacle clearance) crossing an obstacle is related to the manner of visual exploration of the environment during approach. Twenty healthy young adults crossed an obstacle (depth: 1 cm, width: 60 cm, height: 8 cm) during their comfortable-speed walking. The visual exploration was evaluated as the amount of time spent in fixating the vicinity of the obstacle on the floor during the period from two to four steps prior to crossing the obstacle, and the strengths of kinematic synergy to control obstacle clearance were estimated using the uncontrolled manifold approach. We found that the participants with relatively weak synergy spent more time fixating at the vicinity of the obstacle from two to four steps prior to crossing the obstacle, and those participants exhibited greater amount of head flexion movement compared to those with stronger kinematic synergy. Taking advantage of this complex relationship between exploratory activities (e.g. looking movement) and performative activities (e.g. adjustment of ground clearance) would be crucial to adapt walking in a complex environment.

When do toddlers point during mealtime?: Pointing in the second year of life in everyday situations.

The present study aimed to gain insight into the development of the infant's awareness of others' attention that takes place in everyday contexts. We examined the relation between the toddler's pointing, the toddler's visual attention to the caregiver, and the context of the action of the caregiver in the same child-caregiver dyads at two time points (13 and 17 months of age) during lunchtime at a Japanese daycare center, in which toddlers ate lunch with the help of caregivers. Specifically, we focused on the question of whether the timing of the toddler's pointing reflected the ongoing context of the action of the caregiver, based on the analysis of what the caregiver was doing when a toddler exhibited pointing behavior. Our analysis revealed several interrelated results. First, the toddler's pointing behavior was related to the visual exploration of the face of the caregiver at 17 months of age, which was not obvious at 13 months of age. Second, toddlers were more likely to point when the caregivers were just looking at them without being engaged in other salient goal-directed activities. Third, toddlers were less likely to exhibit pointing behavior when the caregivers were manipulating objects or feeding the toddlers. Taken together, the results suggested that toddlers were increasingly aware of the dynamic context of social partner's engagement, differentiating the right time to modulate the attention of others by pointing in everyday situations. The present study supplemented the existing knowledge about pointing and the development of shared intentionality based on controlled experiments by providing a description of the context in which toddlers tend to point in the naturalistic situation of lunchtime within a specific cultural setting during the second year of life.

Activation of stance by cues, or attunement to the invariants in a populated environment?

While I agree with the distinction between expedient and proper ways of action, I find Jagiello et al.'s account of "stance switching" debatable. Fundamental to theories of cultural evolution is the fact that the shared environment is indefinitely rich, in which individuals are provided with opportunities for learning to tune themselves to specific affordances that are relevant to emerging situations.

Does the Spatial Layout of a Playground Affect the Play Activities in Young Children? A Pilot Study.

BACKGROUND: The objective of this study was to describe, through measurement of physical activity and observation of free outdoor play, the relation between children's free play and the spatial layout of the playground. To accomplish this, we altered the spatial layout of the same playground to see how the layout affects the play activity and the physical activity levels in the same children. METHODS: Participants were six young children (four girls and two boys; mean age = 5 years and 1 month, SD = 2.59 months). Participants' physical activity level and the duration of different types of action that occurred in each area and their transitions were compared before and after the alteration of the play-equipment layout using the data from accelerometers and video recordings. RESULTS: A significant increase in physical activity occurred after the spatial layout alteration, which was related to action differences. Before the alteration, children tended to play in a similar manner for a given play area; however, after the alteration, pronounced interindividual variation in play activity across children was observed. CONCLUSION: The present pilot study found that in free play situations in the outdoor playground, the spatial layout of playground affects the pattern of play activity and the physical activity levels of young children.

Structure of variability in scanning movement predicts braille reading performance in children.

Among children learning to read braille, we asked whether the quantitative kinematics of scanning movements of the reading finger would be related to the proficiency of braille reading. Over a period of 12 months, we recorded the position and orientation of the reading fingers of eight congenitally or early blind children. We found that the strength of long-range power-law temporal correlations in the velocity fluctuations increased with performance in braille reading. In addition, we found that the variability of the angular orientation of the reading finger that affects the contact region on the fingerpad was negatively related to braille reading performance. These results confirm that the quantitative kinematics of finger scanning movements were related to functional performance in braille reading. The results add to the growing body of evidence that long-range temporal correlations in exploratory behavior can predict perceptual performance, and that scanning movements that center important tactile information on the small, high resolution area contribute to the pickup of information.

Assessing the influence of culture on craft skills: A quantitative study with expert Nepalese potters.

Studies have documented that traditional motor skills (i.e. motor habits) are part of the cultural way of life that characterises each society. Yet, it is still unclear to what extent motor skills are inherited through culture. Drawing on ethnology and motor behaviour, we addressed this issue through a detailed description of traditional pottery skills. Our goal was to quantify the influence of three kinds of constraints: the transcultural constraints of wheel-throwing, the cultural constraints induced via cultural transmission, and the potters' individual constraints. Five expert Nepalese potters were invited to produce three familiar pottery types, each in five specimens. A total of 31 different fashioning hand positions were identified. Most of them (14) were cross-cultural, ten positions were cultural, five positions were individual, and two positions were unique. Statistical tests indicated that the subset of positions used by the participants in this study were distinct from those of other cultural groups. Behaviours described in terms of fashioning duration, number of gestures, and hand position repertoires size highlighted both individual and cross-cultural traits. We also analysed the time series of the successive hand positions used throughout the fashioning of each vessel. Results showed, for each pottery type, strong reproducible sequences at the individual level and a clearly higher level of variability between potters. Overall, our findings confirm the existence of a cultural transmission in craft skills but also demonstrated that the skill is not fully determined by a cultural marking. We conclude that the influence of culture on craft skills should not be overstated, even if its role is significant given the fact that it reflects the socially transmitted part of the skill. Such research offers insights into archaeological problems in providing a representative view of how cultural constraints influence the motor skills implied in artefact manufacturing.

Traditional craftspeople are not copycats: Potter idiosyncrasies in vessel morphogenesis.

Ceramics are quintessential indicators of human culture and its evolution across generations of social learners. Cultural transmission and evolution theory frequently emphasizes apprentices' need for accurate imitation (high-fidelity copying) of their mentors' actions. However, the ensuing prediction of standardized fashioning patterns within communities of practice has not been directly addressed in handicraft traditions such as pottery throwing. To fill this gap, we analysed variation in vessel morphogenesis amongst and within traditional potters from culturally different workshops producing for the same market. We demonstrate that, for each vessel type studied, individual potters reliably followed distinctive routes through morphological space towards a much-less-variable common final shape. Our results indicate that mastering the pottery handicraft does not result from accurately reproducing a particular model behaviour specific to the community's cultural tradition. We provide evidence that, at the level of the elementary clay-deforming gestures, individual learning rather than simple imitation is required for the acquisition of a complex motor skill such as throwing pottery.

Social interaction in the emergence of toddler's mealtime spoon use.

The use of a spoon for eating is among the important daily skills in early development. The article provides an analysis of how caregiver-toddler interactions guides the attention of toddlers who were first learning how to use a spoon to spoon-related action opportunities that were relevant to the mealtime context. Our analysis revealed several related results. First, caregivers often manipulated objects on the table (i.e., food and dishes), and toddlers were more likely than chance to use their spoon to contact food immediately after watching these caregiver manipulations. Second, toddlers looked more often at the caregiver's hand than at their face. Third, toddlers tended to look at the caregiver's hand when the caregiver was manipulating objects on the table, and after these looks, toddlers were more likely than chance to contact food with their spoon. Finally, the toddlers' choices about when to look at the caregiver were influenced by their own behavior, as if they wanted to know how the caregiver would react to what they had done. We discuss these results in terms of the learning of socially promoted action opportunities for meal-related spoon use.

Locating the Inexhaustible: Material, Medium, and Ambient Information.

The fundamental difference between the enactive approach and Gibson's ecological approach lies in the view toward our shared environment. For Varela et al. (1991), a pregiven environment that exists "out there" is incompatible with the worlds enacted by various histories of life. For Gibson (1979/2015), the environment with its unlimited possibilities that exists out there offers many ways of life. Drawing on the recent empirical studies on the mechanical basis of information and pattern formation in a wide range of fields, this paper illustrates a principle regarding how pattern and change that are formed in an environmental medium, under certain conditions, could serve as the reservoir of information that makes available a variety of opportunities for perception. The second part of this paper offers a discussion about how the consideration of the materials that make up the terrestrial environment-the particles in the atmosphere and the textured surfaces-led Gibson to replace the concept of "space" with the notion of "medium" that allows for the open-ended activities of perception. Finally, I argue that given due consideration of the ambient information available in the medium, the apparent incompatibility between the world independent of the perceiver that exist out there and the worlds enacted by various histories of life could be resolved.

Adjusting Challenge-Skill Balance to Improve Quality of Life in Older Adults: A Randomized Controlled Trial.

OBJECTIVE: We sought to investigate whether occupational therapy that includes adjusting the challenge-skill balance improves health-related quality of life (HRQOL) for older adults in comparison with standard occupational therapy. METHOD: In this single-blind, randomized controlled trial, 56 older adults were assigned to two groups that received 10 sessions of occupational therapy with and without adjustment of challenge-skill balance. The primary outcome was change in HRQOL after 10 sessions of occupational therapy. RESULTS: Significant differences were observed in HRQOL using the EuroQol-5 Dimension score (p = .022, d = 0.76) and the eight-item Short-Form Health Survey scores for general health (p = .001, d = 0.99) and in flow experience using the Flow State Scale for Occupational Tasks (p = .008, d = 0.82). CONCLUSION: Assessment and adjustment of the challenge-skill balance of activities may effectively improve older adults' HRQOL.

Cultural entrainment of motor skill development: Learning to write hiragana in Japanese primary school.

The aim of the present study was to examine how the social norms shared in a classroom environment influence the development of movement dynamics of handwriting of children who participate in the environment. To look into this issue, the following aspects of the entire period of classroom learning of hiragana letters in Japanese 1st graders who had just entered primary school were studied: First, the structure of classroom events and the specific types of interaction and learning within such environment were described. Second, in the experiment involving 6-year-old children who participated in the class, writing movements of children and their changes over the period of hiragana education were analyzed for each stroke composing letters. It was found that writing movement of children became differentiated in a manner specific to the different types of stroke endings, to which children were systematically encouraged to attend in the classroom. The results provide a detailed description of the process of how dynamics of fine motor movement of children is modulated by the social norms of a populated, classroom environment in a non-Latin alphabet writing system.

The utility of a care model to individualize rehabilitation in adults aged over 80 years.

OBJECTIVE: The objectives of the present study were to assess the complexity and multidimensionality of rehabilitation needs of very old stroke patients aged ≥ 80 years and report how rehabilitation interventions are customized to meet the complex needs of patients at a hospital with a majority of old patients. METHODS: The complex problems faced by 18 post-stroke patients (age, range: 80-92 years) were characterized in terms of the following multiple dimensions: (1) clinical features, (2) functional (motor/cognitive) impairment features, (3) psychological aspects, and (4) environmental aspects. We then evaluated the rehabilitation interventions designed to address the problems identified in these different dimensions in detail. RESULTS: The needs of very old stroke patients were extremely complex and unique. To cope with this complexity, rehabilitation interventions were customized in a flexible manner, considering the different dimensions of the needs of these patients. Although the interventions were customized, the complex problems experienced by patients could be divided into stroke conditions on the basis of some invariant patterns in rehabilitation intervention. CONCLUSIONS: We obtained empirical data that illustrated the necessity of considering not only clinical features, but also multiple dimensions of problems faced by very old stroke patients during rehabilitation interventions.

Movement pattern variability in stone knapping: implications for the development of percussive traditions.

The earliest direct evidence for tool-use by our ancestors are 2.6 million year old stone tools from Africa. These earliest artifacts show that, already, early hominins had developed the required advanced movement skills and cognitive capacities to manufacture stone tools. Currently, it is not well understood, however, which specific movement skills are required for successful stone knapping and accordingly it is unknown how these skills emerged during early hominin evolution. In particular, it is not clear which striking movements are indicative of skilled performance, how striking movement patterns vary with task and environmental constraints, and how movement patterns are passed on within social groups. The present study addresses these questions by investigating striking movement patterns and striking variability in 18 modern stone knappers (nine experienced and nine novices). The results suggest that no single movement pattern characterizes successful stone knapping. Participants showed large inter-individual movement variability of the elementary knapping action irrespective of knapping experience and knapping performance. Changes in task- and environmental constraints led knappers to adapt their elementary striking actions using a combination of individual and common strategies. Investigation of striking pattern similarities within social groups showed only partial overlap of striking patterns across related individuals. The results therefore suggest that striking movement patterns in modern stone knappers are largely specific to the individual and movement variability is not indicative of knapping performance. The implications of these results for the development of percussive traditions are discussed.

One month of contemporary dance modulates fractal posture in aging.

Understanding the human aging of postural control and how physical or motor activity improves balance and gait is challenging for both clinicians and researchers. Previous studies have evidenced that physical and sporting activity focusing on cardiovascular and strength conditioning help older adults develop their balance and gait and/or decrease their frequency of falls. Motor activity based on motor-skill learning has also been put forward as an alternative to develop balance and/or prevent falls in aging. Specifically dance has been advocated as a promising program to boost motor control. In this study, we examined the effects of contemporary dance (CD) on postural control of older adults. Upright stance posturography was performed in 38 participants aged 54-89 years before and after the intervention period, during which one half of the randomly assigned participants was trained to CD and the other half was not trained at all (no dance, ND). CD training lasted 4 weeks, 3 times a week. We performed classical statistic scores of postural signal and dynamic analyses, namely signal diffusion analysis (SDA), recurrence quantification analysis (RQA), and detrended fluctuation analysis (DFA). CD modulated postural control in older trainees, as revealed in the eyes closed condition by a decrease in fractal dimension and an increase in DFA alpha component in the mediolateral plane. The ND group showed an increase in length and mean velocity of postural signal, and the eyes open a decrease in RQA maximal diagonal line in the anteroposterior plane and an increase in DFA alpha component in the mediolateral plane. No change was found in SDA in either group. We suggest that such a massed practice of CD reduced the quantity of exchange between the subject and the environment by increasing their postural confidence. Since CD has low-physical but high-motor impact, we conclude that it may be recommended as a useful program to rehabilitate posture in aging.

Fractal dynamics in dexterous tool use: the case of hammering behavior of bead craftsmen.

Dexterous behavior exhibits exquisite context sensitivity, implying the efficacy of exploration to detect the task-relevant information. Inspired by the recent finding that fractal scaling of exploratory movements predicts how well the movements sample available perceptual information, we investigate the possibility that dexterity of craftsmen would be characterized by fractal (long-range) temporal correlation properties of fluctuations in their movement wielding a tool. A reanalysis of hammering behavior involved in stone beads production in India (Nonaka & Bril, 2012) revealed the presence of long-range, power-law correlations, as part of multiplicative cascades operating over a wide range of time scales. In the unfamiliar condition using unusual material, the wielding behavior of highly skilled experts displayed a significant increase of long-range temporal correlations, whereas that of less experts exhibited a significant loss of long-range correlations and reduced heterogeneity of scaling properties over time, which robustly discriminated the groups with different skill levels. Alterations in long-range correlation properties of movement fluctuations are apparently associated with changes in the situation differently depending on the level of expertise.

Coordination strategies used in stone knapping.

Stone tool-use and manufacture is seen as an important skill during the evolution of our species and recently there has been increased interest in the understanding of perceptual-motor abilities underlying this skill. This study provides further information with respect to the motor strategies used during stone knapping. Kinematics of the striking arm were recorded in expert and novice knappers while producing flakes of two different sizes. Using Uncontrolled Manifold Analysis, the results showed that knappers structure joint angle movements such that the hammer trajectory variability is minimized across trials, with experts displaying significantly smaller variability compared with novices. Principal component analysis further revealed that a single component captures the complexity of the strike and that the strike is governed by movements of the elbow and the wrist. Analysis of movement velocities indicated that both groups adjusted movement velocities according to flake size although experts used smaller hammer, wrist, and elbow velocities in both flake conditions compared with novices. The results suggest that while the gross striking movement is easy to replicate for a novice knapper, it requires prolonged training before a knapper becomes attuned to the finer details necessary for controlled flaking.

What exists in the environment that motivates the emergence, transmission, and sophistication of tool use?

In his attempt to find cognitive traits that set humans apart from nonhuman primates with respect to tool use, Vaesen overlooks the primacy of the environment toward the use of which behavior evolves. The occurrence of a particular behavior is a result of how that behavior has evolved in a complex and changing environment selected by a unique population.

Nesting of asymmetric functions in skilled bimanual action: dynamics of hammering behavior of bead craftsmen.

In human manual activities, the two hands are often engaged in differentiated roles while cooperating with each other to produce an integrated outcome. Using recurrence methods, we studied the asymmetric bimanual action involved in stone bead production by craftsmen of different skill levels, and examined (a) how the control of unilateral movement is embedded in that of a bimanual system, and (b) how the behavior of a bimanual system is embedded in the context of the function performed in the world. Evidence was found that the movements of the two hands of experts were functionally linked, reflecting the roles assumed by each hand. We further found that only the dynamics of bimanual coordination of experts differentiated the functional requirements of different sub-goals. These results suggest that expertise in this skilled bimanual action lies in the nesting of functionally specific adjustments at different levels of a control hierarchy.