Cognition, action, and object manipulation

Atypical development of sequential manual motor planning and visuomotor integration in children with autism at early school-age: A longitudinal kinematic study

Sensorimotor difficulties are common in children with autism spectrum disorder, and it has been suggested that motor planning problems underlie their atypical movements. At early school-age, motor planning development typically involves changes in visuomotor integration, a function known to be affected in autism spectrum disorder. However, there is a lack of detailed characterization of typical motor planning development during this stage, and how motor planning develops in children with autism spectrum disorder is largely unknown. This longitudinal kinematic study examined goal-directed sequential manual movements in children with autism spectrum disorder and in typically developing children across ages 7, 8, and 9 years. We manipulated goal-difficulty and availability of initial visual information to investigate visuomotor integration and chaining of subparts during movement performance. The results revealed emerging group differences at older age, suggesting atypical motor planning development in children with autism spectrum disorder. Notably, unlike the typically developing group, availability of initial visual information did not facilitate motor planning for the autism spectrum disorder group. The results show that motor planning differences in autism spectrum disorder appear related to atypical visuomotor integration and global processing of sensorimotor information. The findings also emphasize the importance of considering developmental aspects in research and practice related to motor problems in children with autism spectrum disorder.Lay abstractMany children with autism struggle with movement difficulties, yet the causes of these difficulties remain unclear. One possible explanation is atypical motor planning and integration of visual and motoric information. Before performing a goal-directed movement, the brain creates a prediction of the movement based on visual and sensory information and previous experience, forming a "blueprint" of the motor steps needed to achieve the goal. This process is called motor planning. During movement, adjustments to the plan can be made through feedback mechanisms. This longitudinal study aimed to examine the development of motor planning in children with autism and typically developing children over early school-age (7-9 years). The children performed a sequential manual peg-rotation task, which involved grasping, rotating, and placing a peg, while detailed measures of movement were collected. Task end-goal difficulty varied, and the goal was either initially occluded or fully visible. The results revealed that children with autism showed atypical motor planning development compared with typically developing peers, and these differences became more pronounced as the children grew older. As the typically developing children matured, they appeared to rely more on initial visual information, which assisted them in motor planning. However, this facilitation did not occur for children with autism. These findings suggest that the differences in motor planning seen in children with autism may be linked to atypical visuomotor integration, highlighting the need for individualized interventions. Furthermore, it is crucial to consider developmental aspects to fully understand motor planning in children with autism.

Towards automatic assessment of atypical early motor development?

Atypical motor development is an early indicator for several neurodevelopmental conditions, including cerebral palsy and Rett Syndrome, prompting early diagnosis and intervention. While not currently part of the diagnostic criteria for other conditions like Autism Spectrum Disorder, the frequent retrospective diagnosis of motor impairments alongside these conditions highlights the necessity of a deeper understanding of the relations between motor and cognitive development. Traditional clinical assessments, while considered the gold standard, rely on movement characteristics discernible to the trained eye of professionals. The emergence of automated technologies, including computer vision and wearable sensors, promises more objective and scalable detections. However, these methods are not without challenges, including concerns over data quality, generalizability, interpretability, and ethics. By reviewing recent advances, we highlight the potential and the challenges of integrating automated detections into research and clinical practice. While we agree that these technologies can revolutionize pediatric care, we believe their use must be tempered with caution and supported by clinical expertise to ensure effective outcomes.

Spatially distributed biomimetic compliance enables robust anthropomorphic robotic manipulation

The impressive capabilities of humans to robustly perform manipulation stems from compliant interactions, enabled by the structure and materials distributed in the hands. We propose that mimicking this spatially distributed compliance in an anthropomorphic robotic hand enhances open-loop manipulation robustness and leads to human-like behaviors. Here we introduce the ADAPT Hand, equipped with configurable compliant elements on the skin, fingers, and wrist. After quantifying the effect of compliance on individual components against a rigid configuration, we experimentally analyze the performance of the full hand. Through automated pick-and-place tests, we show the grasping robustness mirrors the estimated geometric theoretical limit, while stress-testing the robot to perform 800+ grasps. Finally, 24 items with varying geometries are grasped in a constrained environment with a 93% success rate. We demonstrate that the hand-object self-organization behavior, driven by passive adaptation, underpins this robustness. The hand exhibits different grasp types based on object geometries, with a 68% similarity to natural human grasps.

Sharp Skills or Snipping Struggles? Qualitative Paper-Cutting Performance in 5- to 10-Year-Old Children Using Hands-On!

This study examined age-related changes in qualitative paper-cutting performance of typically developing children aged 5 to 10 years. Using the Hands-On! observation tool, we analysed 178 (85 boys; Mage 8.06 years, SD ± 1.58) children's performance on the DCDDaily paper cutting task. Paper cutting involves several intra-task components, such as grip type and cutting movements, each comprising multiple observable actions that reflect a child's qualitative performance (e.g., small or large cutting movements). We assessed the differences in the occurrence of these actions within each intra-task component across age groups, along with task duration and mistakes. Our findings revealed significant age-related differences in the qualitative performance of multiple actions within the intra-task components. Three distinct developmental patterns emerged: progression, variability in progression, and stability. Notably, these qualitative differences were observed even when quantitative measures, such as duration and mistakes, showed ceiling effects, highlighting the ability of qualitative assessments to capture nuanced developmental changes. This study provides valuable insights into the development of paper-cutting skills, emphasising the importance of incorporating qualitative analysis into motor skill assessments. Future research should explore the qualitative performance of children with both typical and atypical motor development to further understand the complex interplay of factors influencing fine motor skill performance.

Lifespan trajectories of motor control and neural oscillations: A systematic review of magnetoencephalography insights

Motor control (MC) evolves across the human lifespan, improving during childhood and adolescence, stabilizing in early adulthood, and declining in older age. These developmental and degenerative patterns are linked to neural oscillatory activity, which can be assessed via magnetoencephalography (MEG) to gain insights into motor planning, execution, termination, and command initiation. This review systematically examined age-related changes in MC and neural oscillations, centering on movement-related beta desynchronization (MRBD), post-movement beta rebound (PMBR), and movement-related gamma synchrony (MRGS). Following PRISMA guidelines, 17 cross-sectional studies were identified. The findings revealed significant enhancements in motor efficiency from childhood to adolescence, characterized by faster movement speed, shorter movement duration, weaker MRBD, and increased PMBR and MRGS. From adolescence to early adulthood, further improvements in motor performance were noted, accompanied by strengthened MRBD, PMBR, and a slight decline in MRGS. In older adults, motor performance deteriorates, presenting as slower movement and prolonged duration, alongside heightened resting beta power, elevated MRBD, and reduced PMBR. Alterations in MRGS remain insufficiently explored. Overall, MEG proves valuable for capturing neural dynamics underlying the development and decline of motor control across the lifespan. These findings underscore potential avenues for motor rehabilitation and cognitive interventions, particularly in aging populations.

Children plan manual actions similarly in structured tasks and in free play

Visually guided planning is fundamental for manual actions on objects. Multi-step planning-when only the requirements for the initial action are directly visible in the scene-necessitates initial visual guidance to optimize the subsequent actions. We found that 3- to 5-year-old children (n = 23) who exhibited visually guided, multi-step planning in a structured tool-use task (hammering down a peg) also demonstrated visually guided planning during unstructured free play while interlocking Duplo bricks and Squigz pieces. Children who exhibited visually guided planning in the hammering task also spent more time looking at the to-be-grasped free-play object and at their construction during reach and transport compared with children who did not demonstrate multi-step planning in the hammering task. Moreover, visually guided planning in the Duplo and Squigz tasks was positively correlated, indicating that planning generalizes across contexts. Findings show that visually guided planning in young children generalizes across different manual actions on objects, including structured tool use and unstructured free play.

Higher order affordances

Affordances are opportunities for action for a given animal (or animals) in a given environment or situation. The concept of affordance has been widely adopted in the behavioral sciences, but important questions remain. We propose a new way of understanding the nature of affordances; in particular, how affordances are related to one another. We claim that many - perhaps most - affordances emerge from non-additive relations among other affordances, such that some affordances are of higher order relative to other affordances. That is, we propose that affordances form a continuous category of perceiveables that differ only in whether and how they relate to other affordances. We argue that: (1) opportunities for behaviors of all kinds can be described as affordances, (2) some affordances emerge from relations between animal and environment, whereas most affordances emerge from relations between other affordances, and (3) all affordances lawfully structure ambient energy arrays and, therefore, can be perceived directly. Our concept of higher order affordances provides a general account of behavioral phenomena that traditionally have been interpreted in terms of cognitive processes (e.g., remembering or imagining) as well as behavioral phenomena that have traditionally been interpreted in terms of cultural rules, such as conventions, or customs.

The Motor Melody in action Planning: The Case of Autistic Children and their Non-Autistic Siblings

Objective

it is well known that during an intentional behavior, the final goal of the action shapes the entire sequence of motor acts. This chained organization has been previously demonstrated to be altered in school-age autistic children, who modulate only the final motor act according to the action goal. Here, we investigate the temporal modulation during the intentional action in three groups of preschoolers: neurotypical, autistic, and non-autistic siblings of autistic children.

Method

the participants engaged in a simple task of reaching and grasping an object and placing it into two containers of different sizes.

Results

neurotypical children adjusted both reaching and placing times according to the width of the containers, indicating an action-chained organization. In contrast, both autistic children and non-autistic siblings adapted only the placing - but not the reaching- time according to the container size, exhibiting an unchained organization of intentional actions.

Conclusions

despite not being included among the diagnostic criteria, motor alterations are present in a large number of autistic individuals, detectable from an early age. Being motor signs also expressed by non-autistic siblings, our findings suggest a potential link between motor abnormalities and the pathogenesis of autism. Thereby, tasks similar to the one employed here could be valuable for screening children with an increased likelihood of atypical neurodevelopment.

Kinematic coding: Measuring information in naturalistic behaviour

Recent years have seen an explosion of interest in naturalistic behaviour and in machine learning tools for automatically tracking it. However, questions about what to measure, how to measure it, and how to relate naturalistic behaviour to neural activity and cognitive processes remain unresolved. In this Perspective, we propose a general experimental and computational framework - kinematic coding - for measuring how information about cognitive states is encoded in structured patterns of behaviour and how this information is read out by others during social interactions. This framework enables the design of new experiments and the generation of testable hypotheses that link behaviour, cognition, and neural activity at the single-trial level. Researchers can employ this framework to identify single-subject, single-trial encoding and readout computations and address meaningful questions about how information encoded in bodily motion is transmitted and communicated.

The role of action concepts in physical reasoning: insights from late childhood

A fundamental component of human cognition is the ability to intuitively reason about behaviours of objects and systems in the physical world without resorting to explicit scientific knowledge. This skill was traditionally considered a symbolic process. However, in the last decades, there has been a shift towards ideas of embodiment, suggesting that accessing physical knowledge and predicting physical outcomes is grounded in bodily interactions with the environment. Infants and children, who learn mainly through their embodied experiences, serve as a model to probe the link between reasoning and physical concepts. Here, we tested school-aged children (5- to 15-year-olds) in online reasoning games that involve different physical action concepts such as supporting, launching and clearing. We assessed changes in children's performance and strategies over development and their relationships with the different action concepts. Children reasoned more accurately in problems that involved supporting actions compared to launching or clearing actions. Moreover, when children failed, they were more strategic in subsequent attempts when problems involved support rather than launching or clearing. Children improved with age, but improvements differed across action concepts. Our findings suggest that accessing physical knowledge and predicting physical events are affected by action concepts, and those effects change over development. This article is part of the theme issue 'Minds in movement: embodied cognition in the age of artificial intelligence'.

High or low expectations: Expected intensity of action outcome is embedded in action kinetics

Goal-directed actions are performed in order to attain certain sensory consequences in the world. However, expected attributes of these consequences can affect the kinetics of the action. In a set of three studies (n = 120), we examined how expected attributes of stimulus outcome (intensity) shape the kinetics of the triggering action (applied force), even when the action kinetic and attribute are independent. We show that during action execution (button presses), the expected intensity of sensory outcome affects the applied force of the stimulus-producing action in an inverse fashion. Thus, participants applied more force when the expected intensity of the outcome was low (vs. high intensity outcome). In the absence of expectations or when actions were performed in response to the sensory event, no intensity-dependent force modulations were found. Thus, expectations of stimulus intensity and causality play an important role in shaping action kinetics. Finally, we examined the relationship between kinetics and perception and found no influence of applied force level on perceptual detection of low intensity (near-threshold) outcome stimuli, suggesting no causal link between the two. Taken together, our results demonstrate that action kinetics are embedded with high-level context such as the expectation of consequence intensity and the causal relationship with environmental cues.

Object Weight and Hand Dominance Impact Kinematics in a Functional Reach-to-Drink Task in School-Aged Children

This study evaluates the effects of object weight and hand dominance on the end-point kinematics of the hand-to-mouth (withdrawal) movement in a functional reach-to-drink task for typically developing school-aged children. Using 3D motion capture, speed (average velocity and peak velocity), straightness (ratio), and smoothness (number of velocity peaks and log dimensionless jerk) of hand movements were calculated for the withdrawal motion with three different bottle weights (empty, half-filled, and full). Average velocity (550.4 ± 142.0 versus 512.1 ± 145.6 mm/s) and peak velocity (916.3 ± 234 versus 842.7 ± 198.4 mm/s) were significantly higher with the empty versus half-filled bottle and with the non-dominant (average: 543.5 ± 145.2 mm/s; peak: 896.5 ± 207 mm/s) versus dominant (average: 525.2 ± 40.7 mm/s; peak: 864.2 ± 209.2 mm/s) hand. There were no differences in straightness or smoothness. These findings indicate that increasing weight in reach-to-drink task puts greater constraints on the task. The slower movements with the dominant hand might denote better precision control than the non-dominant hand. The quantitative motion capture results show average values for the kinematic variables for a functional reach-to-drink task in a typically developing population of school-aged children with changing weights of the bottles that are relevant to a real-life scenario. These results could inform the design of individualized therapeutic interventions to improve functional upper-extremity use in children with neurodevelopmental motor disorders.

Force reflections of auditory and tactile action-effect weighting in motor planning

Most voluntary actions have only few goals, which provides considerable freedom in the selection of action parameters. Recent studies showed that task-irrelevant aspects of the task context influence the motor parameters of the actions in a way which seems to reflect the relative importance of these aspects within the underlying action representation. The present study investigated how the intensity of auditory action-effects affected force exertion patterns in a self-paced action production task. Participants applied force impulses with their index finger on a force-sensitive resistor every three seconds. In four separate conditions, force impulses elicited no sound, or elicited tones with 69, 59 or 49 dB intensity. The results showed that participants applied more force when tone intensity was lower, and when tones were absent. These force differences were also present in the first 60 ms following tone onset, implying that these reflected differences in motor planning. The results are compatible with the notion that actions are represented in terms of their sensory effects, which are weighted differently-presumably to maintain an optimal level of overall auditory and tactile stimulation in the present case. These results hint at the potential usefulness of motor parameters as readouts of action intentions.

A cultural perspective of action-based learning by infants and young children

Decades of research have informed about ways in which infants and young children learn through action in connection with their sensory system. However, this research has not strongly addressed the issues of cultural diversity or taken into account everyday cultural experiences of young learners across different communities. Diversifying the scholarship of early learning calls for paradigm shifts, extending beyond the analysis at the individual level to make close connections with real-world experience while placing culture front and center. On the other hand, cultural research that specifies diversity in caregiver guidance and scaffolding, while providing insights into young learners' cultural experiences, has been conducted separately from the research of action-based cross-modal learning. Taking everyday activities as contexts for learning, in this chapter, we summarize seminal work on cross-modal learning by infants and young children that connects action and perception, review empirical evidence of cultural variations in caregiver guidance for early action-based learning, and make recommendations of research approaches for advancing the scientific understanding about cultural ways of learning across diverse communities.

Foot-dominance does not influence force variability during ankle dorsiflexion and foot adduction

The aim of our study was to compare the force steadiness and the discharge characteristics of motor units in the tibialis anterior (TA) during ankle dorsiflexion and foot adduction produced by submaximal isometric contractions with the dominant and non-dominant foot. Fifteen young men performed maximal and submaximal contractions at five target forces with both legs, and motor unit activity in TA was recorded using high-density electromyography. Maximal force and the fluctuations in force during submaximal contractions were similar between the two legs (p > 0.05). Motor unit activity was characterized by measures of mean discharge rate (MDR), coefficient of variation for interspike interval (CoV for ISI), and standard deviation of the filtered cumulative spike train (SD of fCST). There were no statistically significant differences in motor unit activity between legs during ankle dorsiflexion. In contrast, the MDR and the CoV for ISI but not the SD of fCST, were greater for the non-dominant foot compared with the dominant foot during foot adduction. Nonetheless, these differences in motor unit activity were not sufficient to influence the force fluctuations during the submaximal contractions. These results indicate that control of the force produced by TA during the two actions was not influenced by limb dominance.

Anticipation (second-order motor planning) is stored in memory - processing of grasp postures in a priming paradigm

The end-state comfort effect (ESC) describes the tendency to grasp an object with an initial uncomfortable grasp posture in order to achieve a comfortable end posture. The ESC is an example for anticipative processes in manual action. ESC planning is investigated in many studies where this effect is measured in the context of motor observation and motion capture. However, there is little evidence if the anticipative link between different action states, especially between initial grasp postures and comfortable end postures, is represented in memory. The aim of the present study was to investigate whether the perception of a grasp posture holding a bar leads to the activation of action-related representations of grasping actions. For this purpose, a priming paradigm was used in which prime images were shown depicting either a comfortable (overhand grip) or uncomfortable (underhand grip) grasp posture holding a two-colored bar. The subsequently shown target images represented either a comfortable (thumb-up) or uncomfortable (thumb-down) final grasp posture of this grasping action. Due to the different grasp postures in the prime and target, prime-target pairs represented different types of action sequences. Furthermore, physically possible, and physically impossible actions were presented. Participants were asked to react to the top color of the bar shown in the target-picture, whereby the shown grasp posture was irrelevant for this decision. Results showed that reaction times did not differ after presentation of an overhand grip to target pictures showing comfortable or uncomfortable final grasp postures. In contrast, after presentation of an underhand grip in the prime, reactions to target pictures with final comfortable grasp postures were faster compared to target pictures with uncomfortable grasp postures. The effect was only found for the physically possible action. The findings suggest that the perception of the underhand grip leads to cognitive pre-activation of a final action state. The present study suggests that the association between an initial uncomfortable underhand grip and its action effect, in form of a final action state that is consistent with the ESC, is represented in memory. Such motor representation might be important for the anticipation and control of goal-directed grasping.

Object Exploration and Manipulation in Infants at Typical vs. Elevated Likelihood for ASD: A Review

The present review considers the growing body of literature on fine motor skills in infants at elevated genetic likelihood (EL) for autism spectrum disorder (ASD). This area of study aims to identify crucial motor markers associated with the disorder, facilitating earlier and more accurate identification of ASD, using various experimental methodologies, including standardized assessments, observational measures, and technological tools. The reviewed evidence revealed distinct developmental trajectories in EL infants, marked by differences in fine motor skills and exploratory behaviors compared to typically developing infants. We discuss the developmental trajectory of fine motor skills in infants and their predictive value for later ASD diagnosis, highlighting the significance of fine motor skills as early indicators of ASD risk in infants and emphasizing the need for further research to elucidate their predictive value and underlying mechanisms.

C-SMB 2.0: Integrating over 25 years of motor sequencing research with the Discrete Sequence Production task

An exhaustive review is reported of over 25 years of research with the Discrete Sequence Production (DSP) task as reported in well over 100 articles. In line with the increasing call for theory development, this culminates into proposing the second version of the Cognitive framework of Sequential Motor Behavior (C-SMB 2.0), which brings together known models from cognitive psychology, cognitive neuroscience, and motor learning. This processing framework accounts for the many different behavioral results obtained with the DSP task and unveils important properties of the cognitive system. C-SMB 2.0 assumes that a versatile central processor (CP) develops multimodal, central-symbolic representations of short motor segments by repeatedly storing the elements of these segments in short-term memory (STM). Independently, the repeated processing by modality-specific perceptual and motor processors (PPs and MPs) and by the CP when executing sequences gradually associates successively used representations at each processing level. The high dependency of these representations on active context information allows for the rapid serial activation of the sequence elements as well as for the executive control of tasks as a whole. Speculations are eventually offered as to how the various cognitive processes could plausibly find their neural underpinnings within the intricate networks of the brain.

Where scrollbars are clicked, and why

Scrolling is a widely used mean to interact with visual displays, usually to move content to a certain target location on the display. Understanding how user scroll might identify potentially suboptimal use and allows to infer users' intentions. In the present study, we examined where users click on a scrollbar depending on the intended scrolling action. In two online experiments, click positions were systematically adapted to the intended scrolling action. Click position selection could not be explained as strict optimization of the distance traveled with the cursor, memory load, or motor-cognitive factors. By contrast, for identical scrolling actions click positions strongly depended on the context and on previous scrolls. The behavior of our participants closely resembled behavior observed for manipulation of other physical devices and suggested a simple heuristic of movement planning. The results have implications for modeling human-computer interaction and may contribute to predicting user behavior.

Human-object interaction, connectedness with nature, and life satisfaction: a cross-sectional study

Introduction

This study aimed to elucidate the relationship between interactions with everyday objects (e.g., stationery, clothing, and tools) and one's connectedness with nature, environmentally conscious behavior, and life satisfaction. While previous research has predominantly explored the link between awareness of and behavior toward nature with direct education and experience related to the natural environment, we focused on the origins of the objects that surround us, which are inherently derived from nature.

Methods

We conducted an online survey with 1,102 Japanese participants, who completed an object-interaction measure assessing the two dimensions of care and learning, and measures of connectedness with nature, pro-environmental behavior, and life satisfaction.

Results

Interactions with everyday objects involving care and learning were significantly associated with a sense of connectedness with nature, pro-environmental behavior, and life satisfaction.

Discussion

The study highlights that interactions with everyday artifacts are not isolated experiences but are related to broader awareness of and behavior toward the natural world, and with individual life satisfaction. Hence, environmental awareness and actions can extend beyond direct environmental experiences and encompass daily interactions with objects. Future research could examine how cultural factors shape the relationship between human-object interactions, connection with nature, environmentally conscious behavior, and life satisfaction.

Motion Analysis of the Mug Transportation Task Through Upper Limb Kinematics

The task of transporting objects is a fundamental part of daily living activities. Previous kinematic studies focusing on tasks such as pointing, reach-to-grasp, and drinking have not fully captured the motor behaviors involved in object transportation, including placing a cup on a table or storing items in specific places. Hence, this study aimed to analyze the motor behavior associated with transporting a mug using upper limb kinematic variables. Fifteen healthy adults were instructed to transport an open-handle mug across a table. The kinematic metrics evaluated included object end-error for accuracy, frontal and lateral end-range for precision, movement time, peak velocity, time to peak velocity for control strategy, object path ratio for efficiency, and interjoint coordination. The stability of motor behavior was assessed through a test-retest analysis. The mug transporting task achieved accuracy with a radius <10 mm around the target, a peak velocity of ∼0.4 m/s, a control strategy where acceleration time constituted about 30% of the movement time, and a slightly curved trajectory. The test-retest analysis confirmed stable motor behavior across all kinematic metrics (ICCs > 0.75). Thus, the mug transporting task exhibited unique and stable kinematic characteristics, distinguishing it from non-transport activities and effectively mirroring transporting activities of daily living.

Grip selection without tool knowledge: end-state comfort effect in familiar and novel tool use

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.

Choice of end-state comfort is dependent upon the time spent at the beginning-state and the precision requirement of the end-state

Choice of posture while grasping an object typically depends upon several factors including the time spent in that posture, what postures were held prior to choosing that posture, and the precision required by the posture. The purpose of this study was to test choice of end-state thumb-up posture based on time spent at the beginning-state and the precision requirement of the end-state. To determine choice of thumb-up based on time or precision, we varied how long a subject had to hold the beginning state before moving an object to an end location. We made end-state precision either small or large and eliminated the precision needed to stand the object up at the end of the movement. A choice between "comfort" at the beginning or precision at the end-state would be demanded by the conditions with long beginning-state hold times and high precision demands. We aimed to determine which aspect of movement was of greater importance to individuals, overall "comfort" or precision. When the requirement was to hold the initial grasp longer, and the end-target was large, we predicted that we would see more thumb-up postures adopted at the beginning state. When the final placement was small and the initial posture was not constrained, we predicted we would see thumb-up postures adopted at the end state. On average, we found that, as beginning-state grasp time increased, more individuals chose beginning-state thumb-up postures. Perhaps, not surprisingly, we found distinct individual differences within our sample. Some individuals seemed to choose beginning-state thumb-up postures nearly 100% of the time, while other individuals chose end-state thumb-up postures nearly 100% of the time. Both the time spent in a posture and its precision requirements influenced planning, but not necessarily in a systematic way.

Memory, perceptual, and motor costs affect the strength of categorical encoding during motor learning of object properties

Nearly all tasks of daily life involve skilled object manipulation, and successful manipulation requires knowledge of object dynamics. We recently developed a motor learning paradigm that reveals the categorical organization of motor memories of object dynamics. When participants repeatedly lift a constant-density "family" of cylindrical objects that vary in size, and then an outlier object with a greater density is interleaved into the sequence of lifts, they often fail to learn the weight of the outlier, persistently treating it as a family member despite repeated errors. Here we examine eight factors (Similarity, Cardinality, Frequency, History, Structure, Stochasticity, Persistence, and Time Pressure) that could influence the formation and retrieval of category representations in the outlier paradigm. In our web-based task, participants (N = 240) anticipated object weights by stretching a virtual spring attached to the top of each object. Using Bayesian t-tests, we analyze the relative impact of each manipulated factor on categorical encoding (strengthen, weaken, or no effect). Our results suggest that category representations of object weight are automatic, rigid, and linear and, as a consequence, the key determinant of whether an outlier is encoded as a member of the family is its discriminability from the family members.

Mindreading by body: incorporating mediolateral balance and mouse-tracking measures to examine the motor basis of adults' false-belief tracking

The role played by motor representations in tracking others' belief-based actions remains unclear. In experiment 1, the dynamics of adults' anticipatory mediolateral motor activity (leftwards-rightwards leaning on a balance board) as well as hand trajectories were measured as they attempted to help an agent who had a true or false belief about an object's location. Participants' leaning was influenced by the agent's belief about the target's location when the agent was free to act but not when she was motorically constrained. However, the hand trajectories participants produced to provide a response were not modulated by the other person's beliefs. Therefore, we designed a simplified second experiment in which participants were instructed to click as fast as possible on the location of a target object. In experiment 2, mouse-movements deviated from an ideal direct path to the object location, with trajectories that were influenced by the location in which the agent falsely believed the object to be located. These experiments highlight that information about an agent's false-belief can be mapped onto the motor system of a passive observer, and that there are situations in which the motor system plays an important role in accurate belief-tracking.

End-state comfort planning after explicit goal instructions in children with and without probable developmental coordination disorder

BACKGROUND

When completing grip-selection tasks, healthy adults generally plan for the most comfortable end-posture which is termed the end-state comfort (ESC) effect. Children with and without developmental coordination disorder (DCD) are less likely to plan for ESC which begs the question as to whether they are not able to perform this type of planning or whether they prioritize other aspects of the task.

AIMS

(1) Examine if children with and without probable DCD (pDCD) are able to plan for ESC if they are explicitly instructed to and (2) if this transfers to another similar task. (3) Examine if children with and without pDCD perceive the level of comfort of the grips that they use differently and if this relates to ESC planning.

METHODS

Twelve children with and 12 children without probable DCD (pDCD) (aged 5-9 years) received a 10-min training session in which children were explicitly instructed to end their movement in ESC, after which they formulated their own plan to reach this goal. The study consisted of a pre-post-test design in which changes in the proportion of ESC were analyzed on the task that was trained as well as on an untrained transfer-task. Furthermore, the perceived level of comfort was examined.

RESULTS

Both groups of children showed a higher proportion of ESC on the post-test compared with the pre-test, on the task that was trained as well as on the transfer-task. There were no group differences regarding the perceived level of comfort of the different grip postures.

CONCLUSION

The majority of the children with and without pDCD seems to be able to adjust their planning strategy and prioritize ESC if they are explicitly instructed to.

Motor invariants in action execution and perception

The nervous system is sensitive to statistical regularities of the external world and forms internal models of these regularities to predict environmental dynamics. Given the inherently social nature of human behavior, being capable of building reliable predictive models of others' actions may be essential for successful interaction. While social prediction might seem to be a daunting task, the study of human motor control has accumulated ample evidence that our movements follow a series of kinematic invariants, which can be used by observers to reduce their uncertainty during social exchanges. Here, we provide an overview of the most salient regularities that shape biological motion, examine the role of these invariants in recognizing others' actions, and speculate that anchoring socially-relevant perceptual decisions to such kinematic invariants provides a key computational advantage for inferring conspecifics' goals and intentions.

Does aging amplify the rule-based efficiency effect in action selection?

When it comes to the selection of adequate movements, people may apply varying strategies. Explicit if-then rules, compared to implicit prospective action planning, can facilitate action selection in young healthy adults. But aging alters cognitive processes. It is unknown whether older adults may similarly, profit from a rule-based approach to action selection. To investigate the potential effects of aging, the Rule/Plan Motor Cognition (RPMC) paradigm was applied to three different age groups between 31 and 90 years of age. Participants selected grips either instructed by a rule or by prospective planning. As a function of age, we found a general increase in a strategy-specific advantage as quantified by the difference in reaction time between plan- and rule-based action selection. However, in older age groups, these differences went in both directions: some participants initiated rule-based action selection faster, while for others, plan-based action selection seemed more efficient. The decomposition of reaction times into speed of the decision process, action encoding, and response caution components suggests that rule-based action selection may reduce action encoding demands in all age groups. There appears a tendency for the younger and middle age groups to have a speed advantage in the rule task when it comes to information accumulation for action selection. Thus, one influential factor determining the robustness of the rule-based efficiency effect across the lifespan may be presented by the reduced speed of information uptake. Future studies need to further specify the role of these parameters for efficient action selection.

Identification of inverse kinematic parameters in redundant systems: Towards quantification of inter-joint coordination in the human upper extremity

Understanding and quantifying inter-joint coordination is valuable in several domains such as neurorehabilitation, robot-assisted therapy, robotic prosthetic arms, and control of supernumerary arms. Inter-joint coordination is often understood as a consistent spatiotemporal relation among kinematically redundant joints performing functional and goal-oriented movements. However, most approaches in the literature to investigate inter-joint coordination are limited to analysis of the end-point trajectory or correlation analysis of the joint rotations without considering the underlying task; e.g., creating a desirable hand movement toward a goal as in reaching motions. This work goes beyond this limitation by taking a model-based approach to quantifying inter-joint coordination. More specifically, we use the weighted pseudo-inverse of the Jacobian matrix and its associated null-space to explain the human kinematics in reaching tasks. We propose a novel algorithm to estimate such Inverse Kinematics weights from observed kinematic data. These estimated weights serve as a quantification for spatial inter-joint coordination; i.e., how costly a redundant joint is in its contribution to creating an end-effector velocity. We apply our estimation algorithm to datasets obtained from two different experiments. In the first experiment, the estimated Inverse Kinematics weights pinpoint how individuals change their Inverse Kinematics strategy when exposed to the viscous field wearing an exoskeleton. The second experiment shows how the resulting Inverse Kinematics weights can quantify a robotic prosthetic arm's contribution (or the level of assistance).

16 Weeks of Physically Active Mathematics and English Language Lessons Improves Cognitive Function and Gross Motor Skills in Children Aged 8-9 Years

The aim of the present study was to examine the effects of physically active lessons, implemented through the Mathematics and English Language curriculum, on cognitive function and gross motor skill development. Following ethical approval, 192 children aged 8-9 years were randomly allocated to an intervention group (n = 98) or a control group (n = 94). The intervention consisted of 8 h.wk-1 of physically active lessons, equally split between Mathematics and English Language, for 16 weeks. Cognitive function (digit span, coding and arithmetic reasoning) and gross motor skill development (TGMD-3) were assessed at baseline and follow-up. The improvement in every domain of cognitive function was greater in the intervention group compared to the control group (group * time, p = 0.008-0.023, d = 0.34-0.42). Furthermore, total TGMD-3 score (group * time, p < 0.001, d = 1.16) and both sub-scales (locomotor, p < 0.001, d = 0.63; object control, p < 0.001, d = 1.29) also improved by a greater extent in the intervention group than in the control group. These findings suggest that 16 weeks of physically active lessons, taught in both Mathematics and English Language curriculum, synergistically improved cognitive function and gross motor skill development in primary school children aged 8-9 years.

Infants expect agents to minimize the collective cost of collaborative actions

This paper argues that human infants address the challenges of optimizing, recognizing, and interpreting collaborative behaviors by assessing their collective efficiency. This hypothesis was tested by using a looking-time study. Fourteen-month-olds (N = 32) were familiarized with agents performing a collaborative action in computer animations. During the test phase, the looking times were measured while the agents acted with various efficiency parameters. In the critical condition, the agents' actions were individually efficient, but their combination was either collectively efficient or inefficient. Infants looked longer at test events that violated expectations of collective efficiency (p = .006, d = 0.79). Thus, preverbal infants apply expectations of collective efficiency to actions involving multiple agents.

Development of Motor Imagery in School-Aged Children with Autism Spectrum Disorder: A Longitudinal Study

Autism spectrum disorder (ASD) is a diagnosis based on social communication deficits and prevalence of repetitive stereotyped behaviors, but sensorimotor disturbances are commonly exhibited. This longitudinal study aimed at exploring the development of the ability to form mental motor representations (motor imagery; MI) in 14 children with ASD and 17 typically developing (TD) children at 7, 8 and 9 years of age. MI was investigated using a hand laterality paradigm from which response times (RT) and error rates were extracted and compared with performance on a visually based mental rotation task (VI). A criterion task was used to ensure that the children could perform the task. The results showed wide performance variability in the ASD group with more failures than TD in the MI criterion task, especially at 7 years. For all age levels and both the MI and VI tasks, the error rates were significantly higher and RTs longer for the ASD group compared with TD. Signs of MI strategies were however noted in the ASD group as biomechanically constrained orientations had longer RTs than less constrained orientations, a RT pattern that differed from the VI task. The presence of MI in the ASD group was most evident at 9 years, but the error rates remained high at all ages, both in the MI and VI task. In comparison, the TD group showed stable MI strategies at all ages. These findings indicate that MI ability is delayed and/or impaired in children with ASD which may be related to difficulties performing required mental rotations.

Factors Associated with Motor Competence in Preschoolers from a Brazilian Urban Area

Background

Preschool is a crucial period for developing motor skills.

Objective

This study evaluated factors associated with motor competence in preschoolers from a Brazilian urban area.

Methods

A total of 211 preschoolers (51.2% girls and 48.8% boys) were evaluated. Body mass index was calculated; the Brazilian Economic Research Criterion, the Mini-Mental Scale (MMC) and the Early Childhood Environment Rating Scale®, Revised (ECERS-R™) were applied; the Habitual Physical Activity time was recorded; the Test of Gross Motor Development (TGMD-2) was performed. Univariate analysis was performed using simple linear regression for the independent variables, considering the motor test subscales as dependent variables. Variables with p < 0.20 in the univariate analysis were considered for the multiple linear regression model and were entered into the stepwise method.

Results

The independent variables remaining in the Standard Score Locomotor model were BMI, presence of park at school, and MMC (R2 = 0.16). The independent variables remaining in the Standard Object Control score were MMC and gender (R2 = 0.03). The variables associated with the highest scores of Gross Motor Quotient were MMC, body mass index, and presence of a park at school, respectively (R2 = 0.11).

Conclusion

Male eutrophic preschoolers who are physically active and attend schools with parks or courtyards in a Brazilian urban area have the highest scores for global cognitive function and motor competence.

Episodic Binding and Retrieval in Sequences of Discrete Movements - Evidence from Grasping Actions

In everyday life humans are confronted with changing environmental demands. In order to act successfully and achieve intended goals, action control is required. A recent approach, the Binding and Retrieval in Action Control (BRAC) framework, attempts to provide an overarching perspective on action control. Based on basic principles such as binding and retrieval, findings from several experimental paradigms could be integrated. However, the focus so far has been on rather artificial paradigms involving very simple motor response requirements, like finger lifting or button presses. We aimed to extend the BRAC framework to more complex movements consisting of a sequence of several discrete actions. Participants were asked to grasp and lift an object with an uneven mass distribution. Object features, like mass distribution and position, were either kept constant on a global level or varied in a pseudorandomized manner. When both object features were kept constant, participants were able to adjust their grasp so that it resulted in a more stable lift and less object roll. Further, with randomly mixed object features, we found best task performance when both object features were completely repeated from one trial to the other. These results suggest that tasks with more complex movements are capable of reflecting principles of action control as defined by the BRAC framework. This offers the possibility to test these principles in even more complex and ecologically relevant paradigms to improve our understanding of everyday life actions.

Selective effects of psychosocial stress on plan based movement selection

Efficient movement selection is crucial in everyday activities. Whether this function is governed by our stress system is so far unknown. In the current study, data from thirty-six young male adults were analyzed. They performed rule- and plan-based movement selection tasks before (session 1) and after (session 2) a psychosocial stressor, or after a control condition without additional social stressor. Results showed that the rule-based efficiency advantage which was observed prior to the psychosocial stressor was significantly reduced afterwards in the whole sample, as well as in the stress group. Regression analyses revealed that this effect was due to a modulation of the plan-based approach. Especially variations-both increase and decrease-in the parasympathetic activity (reflected by the heart rate variability measure RMSSD) appeared to be disadvantageous for plan-based movement selection improvement. In contrast, performance in the rule-based movement selection tasks appeared to be rather invariant to external influences. The current results suggest that autonomic nervous system activity might modulate motor-cognitive performance. This modulatory capability might be selective for plan-based approaches, hence the applied strategy to movement selection could be decisive when it comes to the vulnerability of motor-cognitive processes towards psychosocial stress.

Same Action, Different Meaning: Neural Substrates of Action Semantic Meaning

Voluntary actions are shaped by desired goals and internal intentions. Multiple factors, including the planning of subsequent actions and the expectation of sensory outcome, were shown to modulate kinetics and neural activity patterns associated with similar goal-directed actions. Notably, in many real-world tasks, actions can also vary across the semantic meaning they convey, although little is known about how semantic meaning modulates associated neurobehavioral measures. Here, we examined how behavioral and functional magnetic resonance imaging measures are modulated when subjects execute similar actions (button presses) for two different semantic meanings-to answer "yes" or "no" to a binary question. Our findings reveal that, when subjects answer using their right hand, the two semantic meanings are differentiated based on voxel patterns in the frontoparietal cortex and lateral-occipital complex bilaterally. When using their left hand, similar regions were found, albeit only with a more liberal threshold. Although subjects were faster to answer "yes" versus "no" when using their right hand, the neural differences cannot be explained by these kinetic differences. To the best of our knowledge, this is the first evidence showing that semantic meaning is embedded in the neural representation of actions, independent of alternative modulating factors such as kinetic and sensory features.

The ontogeny of efficient second-order action planning: The developing interplay of controlled and habitual processes in goal-directed actions

The ability to act efficiently plays an important role in everyday human life. The current study investigated efficient motor planning in 2- to 14-year-old children and adults (N = 246) in two different object manipulation tasks that involved everyday objects (a cup and a spoon). Importantly, we manipulated whether or not the efficient controlled grasp was incongruent with the habitual use of the object. We assessed to what extent participants planned their grasping action in an anticipatory controlled manner or relied on the habitual use of an object. We found the ability of efficient movement planning to be correlated between the two conceptually different tasks. Furthermore, the interplay of controlled and habitual processes of action control showed different developmental patterns for the two tasks and does not indicate a simple linear developmental trend. Thus, this study expands our knowledge on the ontogeny of efficient motor planning and highlights the developmental dynamics of the interplay of controlled and habitual processes in goal-directed action control.

Shared Representations in Athletes: Segmenting Action Sequences From Taekwondo Reveals Implicit Agreement

How do athletes represent actions from their sport? How are these representations structured and which knowledge is shared among experts in the same discipline? To address these questions, the event segmentation task was used. Experts in Taekwondo and novices indicated how they would subjectively split videos of Taekwondo form sequences into meaningful units. In previous research, this procedure was shown to unveil the structure of internal action representations and to be affected by sensorimotor knowledge. Without specific instructions on the grain size of segmentation, experts tended to integrate over longer episodes which resulted in a lower number of single units. Moreover, in accordance with studies in figure-skating and basketball, we expected higher agreement among experts on where to place segmentation marks, i.e., boundaries. In line with this hypothesis, significantly more overlap of boundaries was found within the expert group as compared to the control group. This was observed even though the interindividual differences in the selected grain size were huge and expertise had no systematic influence here. The absence of obvious goals or objects to structure Taekwondo forms underlines the importance of shared expert knowledge. Further, experts might have benefited from sensorimotor skills which allowed to simulate the observed actions more precisely. Both aspects may explain stronger agreement among experts even in unfamiliar Taekwondo forms. These interpretations are descriptively supported by the participants’ statements about features which guided segmentation and by an overlap of the group’s agreed boundaries with those of an experienced referee. The study shows that action segmentation can be used to provide insights into structure and content of action representations specific to experts. The mechanisms underlying shared knowledge among Taekwondoists and among experts in general are discussed on the background of current theoretic frameworks.

Real-time processes in the development of action planning

Across species and ages, planning multi-step actions is a hallmark of intelligence and critical for survival. Traditionally, researchers adopt a "top-down" approach to action planning by focusing on the ability to create an internal representation of the world that guides the next step in a multi-step action. However, a top-down approach does not inform on underlying mechanisms, so researchers can only speculate about how and why improvements in planning occur. The current study takes a "bottom-up" approach by testing developmental changes in the real-time, moment-to-moment interplay among perceptual, neural, and motor components of action planning using simultaneous video, motion-tracking, head-mounted eye tracking, and electroencephalography (EEG). Preschoolers (n = 32) and adults (n = 22) grasped a hammer with their dominant hand to pound a peg when the hammer handle pointed in different directions. When the handle pointed toward their non-dominant hand, younger children ("nonadaptive planners") used a habitual overhand grip that interfered with wielding the hammer, whereas adults and older children ("adaptive planners") used an adaptive underhand grip. Adaptive and nonadaptive children differed in when and where they directed their gaze to obtain visual information, neural activation of the motor system before reaching, and straightness of their reach trajectories. Nonadaptive children immediately used a habitual overhand grip before gathering visual information, leaving insufficient time to form a plan before acting. Our novel bottom-up approach transcends mere speculation by providing converging evidence that the development of action planning depends on a real-time "tug of war" between habits and information gathering and processing.

Sowing the seeds of intentionality: Motor intentions in plants

Motor intention/intentionality has been investigated from a wide variety of perspectives: some researchers have, for example, been focusing on the purely physical and mechanical aspects underlying the control of action, while others have been concentrating on subjective intentionality. Basically, all approaches ranging from the neuroscientific to phenomenological-inspired ones have been used to investigate motor intentions. The current study set out to examine motor intentions in connection to plant behavior utilizing the final goal of plant action as the definition of its motor intention. Taking a wide-angle approach, the first part of the review is dedicated to examining philosophical and psychological studies on motor intentions. Recent data demonstrating that plant behavior does indeed seem goal-directed will then be reviewed as we ponder the possibility of purposeful or intentional plant responses to stimuli and stress conditions in their environment. The article will draw to a close as we examine current theories attempting to explain plants' overt behavior and corresponding covert representations.

Children's planning of efficient tool use in a social context

Efficient joint action requires that we anticipate situational demands both regarding our own and another person's perspective, and adapt our actions accordingly. Accordingly, when handing over a tool somebody else, it is advantageous to anticipate our future hand orientation (motor imagery), as well as the future orientation of the tool (mental rotation) relative to the other person, in order to make the transfer as smooth and efficient as possible. Furthermore, familiarity with specific tools might facilitate planning. We tested thirty-two 5.5- to 7-year-old children on a tool transfer task, asking if they consider another person's comfort when handing over different tools, and whether tool familiarity, motor imagery, and mental rotation are related to their grip choices. We compared the children's performance to that of an adult control group. Besides a rather low performance on the transfer task, we found differences in children's consideration of another person's comfort related to the specific tools they interacted with. Specifically, the unfamiliar tool (a bar) was transferred more efficiently than the familiar tools (hammer/brush). In addition, the results suggest a relation between children's consideration of another person's comfort and their mental rotation score, but no relation with their motor imagery score.

100 years after Liepmann-Lesion correlates of diminished selection and application of familiar versus novel tools

100 years ago, Liepmann highlighted the role of left ventro-dorsal lesions for impairments in conceptual (rather ventral) and motor (more dorsal) related aspects of apraxia. Many studies thereafter attributed to an extended left fronto-temporo-parietal network. Yet, to date there are only few studies that looked at apraxic performance in the selection and application of familiar versus novel tools. In the current study we applied modern voxel-based lesion-symptom mapping (VLSM) to analyze neural correlates of impaired selection and application of familiar versus novel tools. 58 left (LBD) and 51 right brain damaged (RBD) stroke patients participated in the Novel Tools Test (NTT) and the Familiar Tools Test (FTT) of the Diagnostic Instrument for Limb Apraxia (DILA-S). We further assessed performance in control tasks, namely semantic knowledge (BOSU), visuo-spatial working memory (Corsi Block Tapping) and meaningless imitation of gestures (IML). Impaired tool use was most pronounced after LBD. Our VLSM results in the LBD group suggested that selection- versus application-related aspects of praxis and semantics of familiar versus novel tool use can be behaviorally and neuro-anatomically differentiated. For impairments in familiar tool tasks, the major focus of lesion maps was rather ventral while deficiencies in novel tool tasks went along with rather dorsal lesions. Affected selection processes were linked to rather anterior lesions, while impacted application processes went along with rather posterior lesion maps. In our study, particular tool selection processes were rather specific for familiar versus novel tools. Foci for lesion overlaps of experimental and control tasks were noticed ventrally for semantic knowledge and FTT, in fronto-parietal regions for working memory and NTT, and ventro-dorsally for imitation of meaningless gestures and the application of NTT and FTT. We visualized our current interpretation within a neuroanatomical model for apraxia of tool use.

The effects of an object's height and weight on force calibration and kinematics when post-stroke and healthy individuals reach and grasp

Impairment in force regulation and motor control impedes the independence of individuals with stroke by limiting their ability to perform daily activities. There is, at present, incomplete information about how individuals with stroke regulate the application of force and control their movement when reaching, grasping, and lifting objects of different weights, located at different heights. In this study, we assess force regulation and kinematics when reaching, grasping, and lifting a cup of two different weights (empty and full), located at three different heights, in a total of 46 participants: 30 sub-acute stroke participants, and 16 healthy individuals. We found that the height of the reached target affects both force calibration and kinematics, while its weight affects only the force calibration when post-stroke and healthy individuals perform a reach-to-grasp task. There was no difference between the two groups in the mean and peak force values. The individuals with stroke had slower, jerkier, less efficient, and more variable movements compared to the control group. This difference was more pronounced with increasing stroke severity. With increasing stroke severity, post-stroke individuals demonstrated altered anticipation and preparation for lifting, which was evident for either cortical lesion side.

Hand preference for unimanual and bimanual tasks: Evidence from questionnaires and preferential reaching

The current research compared hand selection in a preferential reaching paradigm with unimanual (i.e., pick-up cup) and bimanual (pick-up cup and pour from pitcher) tasks. In addition, relationships between self-report, questionnaire-based hand preference (unimanual and bimanual) and patterns of hand selection were assessed. Data offer support for a division of labour between the hands in at the midline; however, bimanual selection otherwise reflects consideration of object proximity (i.e., location) and comfort (i.e., biomechanical constraints). When grasping cups in right space, the right-hand was used to stabilize the cup and left-hand to mobilize the pitcher, whereas the opposite pattern was observed in left-space. Unimanual hand selection was also driven by object location. Subsequent analyses revealed a relationship between unimanual measures, but not bimanual measures of hand preference. Overall, findings support the notion that questionnaire data are associated with hand preference for grasping to a certain extent; however, use of a comprehensive battery of assessments is recommended when assessing and/or predicting handedness.

The road towards understanding embodied decisions

Most current decision-making research focuses on classical economic scenarios, where choice offers are prespecified and where action dynamics play no role in the decision. However, our brains evolved to deal with different choice situations: "embodied decisions". As examples of embodied decisions, consider a lion that has to decide which gazelle to chase in the savannah or a person who has to select the next stone to jump on when crossing a river. Embodied decision settings raise novel questions, such as how people select from time-varying choice options and how they track the most relevant choice attributes; but they have long remained challenging to study empirically. Here, we summarize recent progress in the study of embodied decisions in sports analytics and experimental psychology. Furthermore, we introduce a formal methodology to identify the relevant dimensions of embodied choices (present and future affordances) and to map them into the attributes of classical economic decisions (probabilities and utilities), hence aligning them. Studying embodied decisions will greatly expand our understanding of what decision-making is.

Children do not distinguish efficient from inefficient actions during observation

Observation is a powerful way to learn efficient actions from others. However, the role of observers' motor skill in assessing efficiency of others is unknown. Preschoolers are notoriously poor at performing multi-step actions like grasping the handle of a tool. Preschoolers (N = 22) and adults (N = 22) watched video-recorded actors perform efficient and inefficient tool use. Eye tracking showed that preschoolers and adults looked equally long at the videos, but adults looked longer than children at how actors grasped the tool. Deep learning analyses of participants' eye gaze distinguished efficient from inefficient grasps for adults, but not for children. Moreover, only adults showed differential action-related pupil dilation and neural activity (suppressed oscillation power in the mu frequency) while observing efficient vs. inefficient grasps. Thus, children observe multi-step actions without "seeing" whether the initial step is efficient. Findings suggest that observer's own motor efficiency determines whether they can perceive action efficiency in others.