Role-differentiated Bimanual Manipulation Research Articles

The Relation between Infants’ Manual Lateralization and Their Performance of Object Manipulation and Tool Use

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

Sleight of hand: role-differentiated bimanual manipulation speed across infancy

ABSTRACT Role-differentiated bimanual manipulation (RDBM) is a complex behaviour requiring the complementary movement of two hands to achieve a common goal. We investigated the relation of RDBM speed (time to complete a successful RDBM) with a hand preference for acquiring objects (early right, late right, left, no preference), toy type (simple/difficult), age (9-14 months), and hand (right/left) used to perform the RDBM. Changes in RDBM speed across age were examined across different hand preference groups for RDBMs performed on simple toys using the right hand. The analysis revealed that early-right preference infants had a steeper slope than the no preference/left-preference infants. The same was true for right-preference infants (early- and late-) for RDBMs performed on difficult toys using the right hand. A mixed ANOVA revealed that there were decreases in RDBM times across age, therefore infants are faster at performing RDBMs over time, regardless of toy type, hand used, or hand preference. The results of the present study suggest that when exploring the development of hand preference, we should consider the influence of age, hand preference, and hand used.

Insights Into Human and Nonhuman Primate Handedness From Measuring Both Hands

Handedness is part of our everyday lives, but where does it come from? Researchers studying nonhuman primates and young children have approached this question from different perspectives—evolutionary and developmental, respectively. Their work converges on the conclusion that measurement matters in the science of handedness. Coming to a consensus on assessment will guide future research into the origins of handedness. A candidate behavior for promoting multidisciplinary comparison is role-differentiated bimanual manipulation.

Preschool language ability is predicted by toddler hand preference trajectories.

Prior work has found links between consistency in toddler handedness for the fine motor skill role-differentiated bimanual manipulation (RDBM), and language development at 2 and 3 years of age. The current study investigated whether consistency in handedness from 18 to 24 months (N = 90) for RDBM predicts receptive and expressive language abilities assessed using the Preschool Language Scales 5th edition (PLS-5) at 5 years old. Latent class growth analyses identified 3 stable RDBM hand preference trajectories: a left hand preference with moderate right hand use (left-moderate right), a right hand preference with moderate left hand use (right-moderate left), and a right hand preference with only mild left hand use (right-mild left). At 5 years of age, children with a right-mild left handedness trajectory as toddlers scored significantly higher on receptive and expressive language abilities compared to children with a left-moderate right hand preference. Children with a right-mild left hand preference for RDBM also scored significantly higher on receptive language abilities compared to children with a right-moderate left RDBM hand preference. Children with left-moderate right and children with a right-moderate left hand preference for RDBM as toddlers did not differ in receptive or expressive language abilities at 5 years. Results indicate that individual differences in hand preference consistency for fine motor skill in toddlerhood have cascading effects on language outcomes into the preschool years. (PsycINFO Database Record (c) 2020 APA, all rights reserved).

Factor analysis of the Home Handedness Questionnaire: Unimanual and role differentiated bimanual manipulation as separate dimensions of handedness

Questionnaires are commonly used to measure handedness. However, popular measures do not capture hand preference by skill type, thus reducing handedness to a single dimension. An exception is the Home Handedness Questionnaire (HHQ), an action-based measure developed initially for children, which measures skills across two dimensions of handedness: unimanual actions and role differentiated bimanual manipulation (RDBM). The goal of the current study was to confirm the factor structure of the HHQ in a large sample of adults (N = 1051). A secondary goal was to measure RDBM hand preference in adults. To further validate the HHQ, participants also completed the Edinburgh Handedness Inventory (EHI). Confirmatory factor analysis verified the two-factor structure of the HHQ, and a one-factor solution was replicated for the EHI. Individuals that were classified as consistent on the EHI had stronger preferences for unimanual and RDBM hand use on the HHQ. Right hand patterning was reduced for RDBM compared to unimanual on the HHQ, and the EHI. The HHQ was found to be reliable and valid against the EHI. The HHQ offers researchers a tool to examine individual differences across manual skills that comprise the neuropsychological phenomenon handedness, and to more broadly examine laterality patterns with respect to cognition.

The home handedness questionnaire: pilot data from preschoolers

ABSTRACTWhile handedness questionnaires are widely used in adults, there is no comparable measure designed specifically for children. The current study developed the Home Handedness Questionnaire (HHQ), a new measure for preschoolers administered by parents using common household items. The HHQ has two scales that distinguish action types typically combined on other measures: actions performed with only the right or left hand (i.e., unimanual, such as holding a toothbrush), and actions performed with one hand holding the object for the other hand’s action (i.e., role-differentiated bimanual manipulation or RDBM, such as unscrewing a lid from a jar). The HHQ was able to detect right preference, left preference, and no preference for unimanual and RDBM actions in a proof of concept study in 3-year-olds (N = 64). The HHQ identified a majority of children as right-handed, but was also sensitive to variability in direction across skill types. Approximately one-quarter of children in the sample had mixed preferences for the two types of manual skills, suggesting that for a subgroup of children, hand use patterns may still be undergoing change. Suggestions for refining the HHQ are discussed. Overall, the HHQ is a promising multidimensional parent-led tool for assessing preschool handedness.

Hand selection in a preferential reaching task: The effects of object location, orientation, and task intention in preadolescent children.

Introduction and MethodsHand selection was assessed in preadolescent children (ages 9–11) within a preferential reaching task to delineate the effects of object location, orientation, and task intention on the assessment procedure and compared to data previously acquired from young adults.ResultsThe observed differences support the notion that children are still in a process of refining their movements in attempt to discern the most efficient and effective patterns of behavior. Notwithstanding differences in performance, similarities between preadolescents and young adults also emerged. Greater right‐hand selection in right space and when the handle was oriented to the right indicate that object proximity and orientation influence efficiency and thus constrain hand selection in unimanual object manipulation and role‐differentiated bimanual manipulation.ConclusionsTogether, findings add to our understanding of hand preference, unimanual and bimanual object manipulation.

Toddler hand preference trajectories predict 3-year language outcome.

A growing body of work suggests that early motor experience affects development in unexpected domains. In the current study, children's hand preference for role-differentiated bimanual manipulation (RDBM) was measured at monthly intervals from 18 to 24 months of age (N = 90). At 3 years of age, children's language ability was assessed using the Preschool Language Scales 5th edition (PLS™-5). Three distinct RDBM hand preference trajectories were identified using latent class growth analysis: (1) children with a left hand preference but a moderate amount of right hand use; (2) children with a right hand preference but a moderate amount of left hand use; and (3) children with a right hand preference and only a mild amount of left hand use. Stability over time within all three trajectories indicated that children did not change hand use patterns from 18 to 24 months. Children with the greatest amount of preferred (i.e., right) hand use demonstrated higher expressive language scores compared to children in both trajectories with moderate levels of non-preferred hand use. Children with the greatest amount of right hand use also had higher scores for receptive language compared to children with a right hand preference but moderate left hand use. Results support that consistency in handedness as measured by the amount of preferred hand use is related to distal language outcomes in development.

Emerging Trends in the Multimodal Nature of Cognition: Touch and Handedness.

Advances in tactile cognition and haptics have increased our understanding of the multimodal nature of touch. Haptic data is mostly confined to human performance arising from the flexibility and dexterity of the fingers used to discriminate shapes and objects. Studies with infants indicate that recognition of objects either seen or held in the hand is possible during early periods of infancy. Evidence indicates performance differences between the hands decrease over periods of development, reflecting maturation of the cortical brain system supporting motor skills. Thus ability is not confined to the preferred hand. Tactile process and haptic cognition reflect hand ability. Studies examining manual performance must consider the relevance of haptics in research. Knowing about the evolution of the hands controlled by the cerebral hemispheres is of interest because it is a major contribution to the repertoire of human hand actions. The emergence of RDBM (role differentiated bimanual manipulation) is an important shift in the development of infant manual skills. Between 4 and 7 months of age, infants begin to manipulate objects using RDBM where one hand stabilized an object while the other hand manipulated the object. Understanding the affordance of a tool is an important cognitive milestone in early sensorimotor period that develops during the second year in full-term infants. This ability has also been demonstrated in preterm infants indicating the emergence of handedness during prenatal periods. Thus a multimodal approach that incorporates studies of tactile processes and hand actions may reveal their interactions with task demands and haptic ability.

Infant Hand Preference and the Development of Cognitive Abilities.

Hand preference develops in the first two postnatal years with nearly half of infants exhibiting a consistent early preference for acquiring objects. Others exhibit a more variable developmental trajectory but by the end of their second postnatal year, most exhibit a consistent hand preference for role-differentiated bimanual manipulation. According to some forms of embodiment theory, these differences in hand use patterns should influence the way children interact with their environments, which, in turn, should affect the structure and function of brain development. Such early differences in brain development should result in different trajectories of psychological development. We present evidence that children with consistent early hand preferences exhibit advanced patterns of cognitive development as compared to children who develop a hand preference later. Differences in the developmental trajectory of hand preference are predictive of developmental differences in language, object management skills, and tool-use skills. As predicted by Casasanto’s body-specificity hypothesis, infants with different hand preferences proceed along different developmental pathways of cognitive functioning.

Development of role-differentiated bimanual manipulation in infancy: Part 3. Its relation to the development of bimanual object acquisition and bimanual non-differentiated manipulation.

This third paper in a series of three related developmental trajectories of bimanual object acquisition and non-differentiated bimanual manipulation (NDBM) to patterns of role-differentiated bimanual manipulation (RDBM) development to help identify the sequence of events that might predict (and potentially facilitate) the development of RDBM skill. Ninety infants were tested monthly from 6 to 14 months of age for object acquisition, and from 9 to 14 months for NDBM and RDBM. The results did not support the hypothesis proposing that the onset of RDBM would require decoupling of the hands in unimanual acquisition, but supported the prediction that coupling of the hands in bimanual acquisition would predict increasing expertise in the RDBM skill. The relation between the bimanual object acquisition and RDBM was found to be mediated by NDBM, which prompts the hypothesis that bimanual acquisition of objects facilitates the development of NDBM, which, in its turn, facilitates the development of the RDBM skill.

Development of role-differentiated bimanual manipulation in infancy: Part 1. The emergence of the skill.

This is the first paper in a series of three discussing different aspects of the development of role-differentiated bimanual manipulation (RDBM-two hands performing different but complementary actions on an object). Emergence of RDBM is an important shift in the development of infant manual skills. Trajectories of monthly changes in the number of RDBMs and RDBM hand preference were explored in a sample of 90 (57 males) normally developing infants (30 with a right preference for acquiring objects, 30 with a left preference, 30 with no preference) during the 9-14 month period. Multilevel analysis revealed that infants performed more RDBMs with age, with similar patterns of change in all hand preference groups. A hand-use preference for RDBM became more prominent with age with most right-preferring infants and those without a preference for object acquisition developing right-hand preference for RDBM. Left-preferring infants exhibited more heterogeneity in their hand-use for RDBM.

Development of role-differentiated bimanual manipulation in infancy: Part 2. Hand preferences for object acquisition and RDBM--continuity or discontinuity?

This second paper in a series of three investigated the development of hand preference for role-differentiated bimanual manipulation (RDBM) relative to the infant's hand preference for object acquisition and to the infant's hand-use for acquiring the objects used to assess RDBM. The same 90 infants (30 with a right preference, 30 with a left preference, and 30 with no preference to acquire objects) from the first paper were tested from 9 to 14 months for hand preference for acquiring those objects used to assess RDBM and for a hand preference for RDBM. Multilevel analysis revealed that infants with a hand preference for acquiring objects decreased in their use of the preferred hand for object acquisition during the 11 to 14 month interval, which coincided with the development of a hand preference for RDBM. These results are discussed in relation to the cascade theory of hand preference development.

Addressing the gap: a blueprint for studying bimanual hand preference in infants.

Between 4 and 7 months of age, infants begin to manipulate objects using role-differentiated bimanual manipulation (RDBM) where one hand stabilizes an object while the other hand manipulates the object (Rochat, 1989; Kimmerle et al., 1995, 2010). Because RDBM constrains the roles of the hands, it elicits a measurable asymmetry where the manipulating hand is considered to be the preferred hand for RDBM actions (i.e., RDBM hand preference). Initially, infants display partially differentiated roles for each hand, which is driven in part by the affordances of the object (Ramsay et al., 1979; Fagard and Jacquet, 1989; Fagard and Peze, 1997; Fagard, 1998; Fagard and Marks, 2000). Children exhibit increasing role differentiation with age (Vauclair and Imbault, 2009; Birtles et al., 2011; Cochet et al., 2011; Cochet, 2012). Only 50% of infants’ bimanual actions were characterized as fully differentiated at 12–13 months (Ramsay and Weber, 1986). At 18 months, children used a fully differentiated strategy on 71% of target RDBM actions; this figure increased to 94% by 24 months (Nelson et al., 2013). Early emerging RDBM skills (11–13 months) involve object removal and insertion, while later RDBM skills (18–24 months) include additional actions such as unscrewing and unzipping (e.g., Kimmerle et al., 2010; Nelson et al., 2013).

How the development of handedness could contribute to the development of language

We propose a developmental process which may link the development of handedness with the development of hemispheric specialization for speech processing. Using Arbib's proposed sequence of sensorimotor development of manual skills and gestures (that he considers to be the basis of speech gestures and proto-language), we show how the development of hand-use preferences in proto-reaching skills concatenate into object acquisition skills and eventually into role-differentiated bimanual manipulation skills (that reflect interhemispheric communication and coordination). These latter sensorimotor skills might facilitate the development of speech processing via their influence on the development of tool-using and object management abilities.

Unimanual to bimanual: Tracking the development of handedness from 6 to 24 months

Manual skills change dramatically over the first two years of life, creating an interesting challenge for researchers studying the development of handedness. A vast body of work to date has focused on unimanual skills during the period from the onset of reaching to walking. The current study sought to connect such early unimanual hand use to later role-differentiated bimanual manipulation (RDBM), in which one hand stabilizes the object for the other hand's action. We examined hand use in 38 children over 16 monthly visits using a validated measure for assessing hand preference for acquiring objects when children were 6–14 months old. We also developed a new measure for assessing RDBM preference presented when children were 18–24 months old. The new measure reliably elicited RDBM actions in both toddlers and an adult control group (N=15). Results revealed that some children show preferences for acquiring objects as infants; these preferences are stable and persist into their second year as new skills appear. Moreover, children with no hand preference during infancy shifted to left or right lateralized hand use as toddlers. Despite a higher incidence of left-handedness compared to adult norms, the majority of children were right-handed by 2 years of age.

Development of role‐differentiated bimanual manipulation during the infant's first year

Role-differentiated bimanual manipulation (RDBM) is a complementary movement of both hands that requires differentiation between actions of the hands. Previous research showed that RDBM can be observed in infants as early as 7 months. However, RDBM could be considered a skill only when its frequency, duration, and use is appropriate for the type of manual task, and there is some evidence of intentionality in use. Twenty-four normally developing infants were studied longitudinally at 7, 9, 11, and 13 months to assess the frequency and duration of five clearly different types of RDBM with three "single-part" and three "two-part" toys as they emerge during development. Also, the sequences of actions that lead to RDBM were examined for evidence of "intentionality." The results show that although the each type of RDBM appears early in infancy, RDBM only begins to exhibit the characters of a skill by 13 months. Moreover, the type of toy influences not only the likelihood of eliciting role differentiation, but also the type of RDBM behavior and the organization of the sequence of actions that lead to RDBM. Some useful criteria for defining an infant sensorimotor skill are provided in discussion.

Bimanual role-differentiated toy play during infancy

Role-differentiated bimanual manipulation requires each hand to perform different, but complementary, actions on one or more objects. It is usually considered to be a late-developing high-level motor and cognitive skill involving the coordination of the two hemispheres of the brain. The frequency of role-differentiated bimanual manipulations was recorded in a longitudinal sample of 24 infants tested at 7, 9, 11, and 13 months during play with 10 different toys. Role differentiation was observed as early as 7 months, and its frequency was unaffected by toy characteristics. Role-differentiated bimanual actions increased with age, and the type of toy did influence the likelihood of eliciting role differentiation between 9 and 13 months.