Right-hand Preference Research Articles

Nut-cracking behaviour in wild-born, rehabilitated bonobos (Pan paniscus): a comprehensive study of hand-preference, hand grips and efficiency.

There has been an enduring interest in primate tool-use and manipulative abilities, most often with the goal of providing insight into the evolution of human manual dexterity, right-hand preference, and what behaviours make humans unique. Chimpanzees (Pan troglodytes) are arguably the most well-studied tool-users amongst non-human primates, and are particularly well-known for their complex nut-cracking behaviour, which has been documented in several West African populations. However, their sister-taxon, the bonobos (Pan paniscus), rarely engage in even simple tool-use and are not known to nut-crack in the wild. Only a few studies have reported tool-use in captive bonobos, including their ability to crack nuts, but details of this complex tool-use behaviour have not been documented before. Here, we fill this gap with the first comprehensive analysis of bonobo nut-cracking in a natural environment at the Lola ya Bonobo sanctuary, Democratic Republic of the Congo. Eighteen bonobos were studied as they cracked oil palm nuts using stone hammers. Individual bonobos showed exclusive laterality for using the hammerstone and there was a significant group-level right-hand bias. The study revealed 15 hand grips for holding differently sized and weighted hammerstones, 10 of which had not been previously described in the literature. Our findings also demonstrated that bonobos select the most effective hammerstones when nut-cracking. Bonobos are efficient nut-crackers and not that different from the renowned nut-cracking chimpanzees of Bossou, Guinea, which also crack oil palm nuts using stones.

Hand and Grasp Selection in a Preferential Reaching Task: The Effects of Object Location, Orientation, and Task Intention.

As numerous movement options are available in reaching and grasping, of particular interest are what factors influence an individual’s choice of action. In the current study a preferential reaching task was used to assess the propensity for right handers to select their preferred hand and grasp a coffee mug by the handle in both independent and joint action object manipulation contexts. Mug location (right-space, midline, and left-space) and handle orientation (toward, away, to left, and to right of the participant) varied in four tasks that differed as a function of intention: (1) pick-up (unimanual, independent); (2) pick-up and pour (bimanual, independent); (3) pick-up and pass (unimanual, joint action); and (4) pick-up, pour and pass (bimanual, joint action). In line with previous reports, a right-hand preference for unimanual tasks was observed. Furthermore, extending existing literature to a preferential reaching task, role differentiation between the hands in bimanual tasks (i.e., preferred hand mobilizing, non-preferred hand stabilizing) was displayed. Finally, right-hand selection was greatest in right space, albeit lower in bimanual tasks compared to what is typically reported in unimanual tasks. Findings are attributed to the desire to maximize biomechanical efficiency in reaching. Grasp postures were also observed to reflect consideration of efficiency. More specifically, within independent object manipulation (pick-up; pick-up and pour) participants only grasped the mug by the handle when it afforded a comfortable posture. Furthermore, in joint action (pick-up and pass; pick-up, pour and pass), the confederate was only offered the handle if the intended action of the confederate was similar or required less effort than that of the participant. Together, findings from the current study add to our knowledge of hand and grasp selection in unimanual and bimanual object manipulation, within the context of both independent and joint action tasks.

Hand Preference for a Novel Bimanual Coordinated Task During Termite Feeding in Wild Western Gorillas (Gorilla gorilla gorilla)

Although the level of handedness in humans varies cross-culturally, humans are generally described as right-handed, which has been considered a uniquely human trait. Recently, captive chimpanzees (Pan troglodytes) have been shown to exhibit right-hand preference when performing bimanual but not unimanual tasks. Less clear is whether this pattern also occurs in wild chimpanzees and other African apes. Using videos (N = 49) of six wild western gorillas (Gorilla gorilla gorilla) feeding on termites at the Mondika Research Center (Republic of Congo), we tested whether they exhibit hand preference when performing unimanual, i.e., reaching for termite mound pieces; bimanual, i.e., “termite tapping”: rhythmically shaking a piece of termite mound with the dominant hand and collecting the termites in the other hand tasks; or hand transfer prior to bimanual tasks, i.e., transferring a piece of termite mound from one hand to the other. All individuals exhibited exclusive hand preference when performing the bimanual tasks, with five of six gorillas preferring the right hand. Conversely, most individuals did not show any manual preference during the unimanual task. In addition, hand preference during hand transfer revealed clear hand dominance of similar strength and direction of those shown for the bimanual task, suggesting that this measure is as sensitive as the bimanual task itself. Thus, we propose “termite feeding” as a novel task to be considered in future hand-preference studies in wild western gorillas. Our results are in concordance with those for chimpanzees and captive gorillas showing hemispheric specialization for bimanual actions in apes.

Three actions, two groups: Looking for the origin of primate manual lateralization.

Handedness is the most evident behavioral asymmetry in humans: to study nonhuman primate hand preference could be optimal to investigate the evolutionary origin of handedness in our species, even though behavioral asymmetries are widespread among vertebrates. This study investigated hand preferences in 32 Old World monkeys and 26 great apes during 3 spontaneous actions, assessing the effect of taxonomic group, sex and age on primate handedness. Data about foraging, locomotion, and manipulation were collected and 50 bouts per behavioral category per subject were recorded. A bias toward right-hand use for starting locomotion was reported in both Old World monkeys and great apes. Furthermore, in the great apes, a group-level right-hand preference for manipulation was found. Results suggest an important role of factors such as posture and task complexity in the evolution of primate manual lateralization. The effect of taxonomic group, sex, and age on the hand preference are also discussed. (PsycINFO Database Record

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.

The association between hemispheric specialization for language production and for spatial attention depends on left-hand preference strength

Cerebral lateralization for language production and spatial attention and their relationships with manual preference strength (MPS) were assessed in a sample of 293 healthy volunteers, including 151 left-handers, using fMRI during covert sentence production (PROD) and line bisection judgment (LBJ) tasks, as compared to high- and low-level reference tasks. At the group level, we found the expected complementary hemispheric specialization (HS) with leftward asymmetries for PROD within frontal and temporal regions and rightward asymmetries for LBJ within frontal and posterior occipito–parieto-temporal regions. Individual hemispheric (HLI) and regional (frontal and occipital) lateralization indices (LI) were then calculated on the activation maps for PROD and LBJ. We found a correlation between the degree of rightward cerebral asymmetry and the leftward behavioral attentional bias recorded during LBJ task. This correlation was found when LBJ-LI was computed over the hemispheres, in the frontal lobes, but not in the occipital lobes. We then investigated whether language production and spatial attention cerebral lateralization relate to each other, and whether manual preference was a variable that impacted the complementary HS of these functions. No correlation was found between spatial and language LIs in the majority of our sample of participants, including right-handers with a strong right-hand preference (sRH, n=97) and mixed-handers (MH, n=97), indicating that these functions lateralized independently. By contrast, in the group of left-handers with a strong left-hand preference (sLH, n= 99), a negative correlation was found between language and spatial lateralization. This negative correlation was found when LBJ-LI and PROD-LI were computed over the hemispheres, in the frontal lobes and between the occipital lobes for LBJ and the frontal lobes for PROD. These findings underline the importance to include sLH in the study sample to reveal the underlying mechanisms of complementary HS.

The development of hand preference and dichotic language lateralization in males and females with congenital adrenal hyperplasia

ABSTRACTPeople with congenital adrenal hyperplasia (CAH) are exposed to elevated levels of androgens in utero due to overproduction by the adrenal cortex. In order to test whether high levels of prenatal androgens influence the development of handedness preferences and left-hemisphere language representation, we studied 39 patients with CAH (28 females, 11 males) and 25 unaffected sibling controls (17 females, 8 males). Hand preference for 15 unimanual activities was evaluated via questionnaire and pantomime, and a consonant–vowel dichotic listening test was administered. Contemporary theories disagree as to whether high testosterone is said to increase or decrease the probability of developing a typical right-hand preference. Results showed no significant differences on the handedness inventory. Relative to controls, however, patients with CAH showed a significantly larger right-ear advantage on the dichotic syllables task, indicating stronger left-hemisphere lateralization of language. These results support an emerging body of evidence suggesting that high testosterone may bias lateralized development toward the population norm, but run counter to the Geschwind–Behan–Galaburda model which associates high prenatal testosterone with a greater prevalence of left-handedness.

What Is the Role of Manual Preference in Hand-Digit Mapping During Finger Counting? A Study in a Large Sample of Right- and Left-Handers.

The goal of the present study was to test whether there is a relationship between manual preference and hand-digit mapping in 369 French adults with similar numbers of right- and left-handers. Manual laterality was evaluated with the finger tapping test to evaluate hand motor asymmetry, and the Edinburgh handedness inventory was used to assess manual preference strength (MPS) and direction. Participants were asked to spontaneously "count on their fingers from 1 to 10" without indications concerning the hand(s) to be used. The results indicated that both MPS and hand motor asymmetry affect the hand-starting preference for counting. Left-handers with a strong left-hand preference (sLH) or left-hand motor asymmetry largely started to count with their left hand (left-starter), while right-handers with a strong right-hand preference (sRH) or right-hand motor asymmetry largely started to count with their right hand (right-starter). Notably, individuals with weak MPS did not show a hand-starting preference. These findings demonstrated that manual laterality contributes to finger counting directionality. Lastly, the results showed a higher proportion of sLH left-starter individuals compared with sRH right-starters, indicating an asymmetric bias of MPS on hand-starting preference. We hypothesize that the higher proportion of sLH left-starters could be explained by the congruence between left-to-right hand-digit mapping and left-to-right mental number line representation that has been largely reported in the literature. Taken together, these results indicate that finger-counting habits integrate biological and cultural information.

Manual preferences for visually- and haptically-guided grasping

Studies have shown that individuals exhibit a right-hand preference for grasping during visually-guided tasks. Recently, we have found that when vision is occluded right-hand preference decreases dramatically. It remains unknown however, if this decrease is a result of visual occlusion or the effects of relying only on haptic feedback. Therefore, in the present study, we sought to explore the contributions of vision and haptics (separately and in conjunction) to hand preference for grasping. Right- and left-handed individuals were tested on a block building task under four different visual and haptic conditions: 1) vision/normal haptic feedback (V/H), 2) no vision/normal haptic feedback (NV/H), 3) vision/constrained haptic feedback (V/Constrained-H), and 4) no vision/constrained haptic feedback (NV/Constrained-H). Vision was occluded using a blindfold and haptic feedback was constrained by asking participants to wear textured gloves. Right-handed individuals displayed a right-hand preference when vision was available (V/H and V/Constrained-H groups), but this preference was much greater when haptic feedback was constrained (V/Constrained-H group). When vision was occluded and haptic feedback was used to complete the task (NV/H) no hand preference was found. Finally hand preference was similar between the V/H and the NV/Constrained-H groups. For left-handed individuals, no differences in hand use were found between the different sensory groups, but the NV/H group showed a clear left-hand preference for haptically-guided grasping. The results suggest that haptics plays an important role in hand preference for grasping. Furthermore, they support a left-hand/right-hemisphere specialization for haptically-guided grasping (regardless of handedness) and a right-hand/left-hemisphere specialization for visually-guided grasping (at least in right-handed individuals).

Hand preference across the lifespan: effects of end-goal, task nature, and object location.

In the present study we investigate age-related changes in hand preference for grasping and the influence of task demands on such preference. Children (2–11), young-adults (17–28) and older-adults (57–90) were examined in a grasp-to-eat and a grasp-to-construct task. The end-goal of these tasks was different (eat vs. construct) as was the nature of the task (unimanual vs. bimanual). In both tasks, ipsilateral and contralateral grasps were analyzed. Results showed a right-hand preference that did not change with age. Across the three age groups, a more robust right-hand preference was observed for the unimanual, grasp-to-eat task. To disentangle if the nature (unimanual) or the end-goal (grasp-to-eat) was the driver of the robust right-hand preference, a follow up experiment was conducted. Young-adult participants completed a unimanual grasp-to-place task. This was contrasted with the unimanual grasp-to-eat task and the bimanual grasp-to-construct task. Rates of hand preference for the grasp-to-eat task remained the highest when compared to the other two grasping tasks. Together, the results demonstrate that hand preference remains stable from childhood to older adulthood, and they suggest that a left hemisphere specialization exists for grasping, particularly when bringing food to the mouth.

Is that graspable? Let your right hand be the judge

A right-hand preference for visually-guided grasping has been shown on numerous accounts. Grasping an object requires the integration of both visual and motor components of visuomotor processing. It has been suggested that the left hemisphere plays an integral role in visuomotor functions. The present study serves to investigate whether the visual processing of graspable objects, without any actual reaching or grasping movements, yields a right-hand (left-hemisphere) advantage. Further, we aim to address whether such an advantage is automatically evoked by motor affordances. Two groups of right-handed participants were asked to categorize objects presented on a computer monitor by responding on a keypad. The first group was asked to categorize visual stimuli as graspable (e.g. apple) or non-graspable (e.g. car). A second group categorized the same stimuli but as nature-made (e.g. apple) or man-made (e.g. car). Reaction times were measured in response to the visually presented stimuli. Results showed a right-hand advantage for graspable objects only when participants were asked to respond to the graspable/non-graspable categorization. When participants were asked to categorize objects as nature-made or man-made, a right-hand advantage for graspable objects did not emerge. The results suggest that motor affordances may not always be automatic and might require conscious representations that are appropriate for object interaction.

Grasping without sight: insights from the congenitally blind.

We reach for and grasp different sized objects numerous times per day. Most of these movements are visually-guided, but some are guided by the sense of touch (i.e. haptically-guided), such as reaching for your keys in a bag, or for an object in a dark room. A marked right-hand preference has been reported during visually-guided grasping, particularly for small objects. However, little is known about hand preference for haptically-guided grasping. Recently, a study has shown a reduction in right-hand use in blindfolded individuals, and an absence of hand preference if grasping was preceded by a short haptic experience. These results suggest that vision plays a major role in hand preference for grasping. If this were the case, then one might expect congenitally blind (CB) individuals, who have never had a visual experience, to exhibit no hand preference. Two novel findings emerge from the current study: first, the results showed that contrary to our expectation, CB individuals used their right hand during haptically-guided grasping to the same extent as visually-unimpaired (VU) individuals did during visually-guided grasping. And second, object size affected hand use in an opposite manner for haptically- versus visually-guided grasping. Big objects were more often picked up with the right hand during haptically-guided, but less often during visually-guided grasping. This result highlights the different demands that object features pose on the two sensory systems. Overall the results demonstrate that hand preference for grasping is independent of visual experience, and they suggest a left-hemisphere specialization for the control of grasping that goes beyond sensory modality.

Grasping with the eyes of your hands: Hapsis and vision modulate hand preference

Right-hand preference has been demonstrated for visually guided reaching and grasping. Grasping, however, requires the integration of both visual and haptic cues. To what extent does vision influence hand preference for grasping? Is there a hand preference for haptically guided grasping? Two experiments were designed to address these questions. In Experiment 1, individuals were tested in a reaching-to-grasp task with vision (sighted condition) and with hapsis (blindfolded condition). Participants were asked to put together 3D models using building blocks scattered on a tabletop. The models were simple, composed of ten blocks of three different shapes. Starting condition (Vision-First or Hapsis-First) was counterbalanced among participants. Right-hand preference was greater in visually guided grasping but only in the Vision-First group. Participants who initially built the models while blindfolded (Hapsis-First group) used their right hand significantly less for the visually guided portion of the task. To investigate whether grasping using hapsis modifies subsequent hand preference, participants received an additional haptic experience in a follow-up experiment. While blindfolded, participants manipulated the blocks in a container for 5min prior to the task. This additional experience did not affect right-hand use on visually guided grasping but had a robust effect on haptically guided grasping. Together, the results demonstrate first that hand preference for grasping is influenced by both vision and hapsis, and second, they highlight how flexible this preference could be when modulated by hapsis.

Hand preference for pointing and language development in toddlers

The aim of this study was to investigate the relationship between hand preference for communicative gestures and language during development. Hand preference for pointing gestures and level of language were assessed in 46 toddlers between 12 and 30 months of age. Results showed a right-hand preference for pointing and the use of a developmental quotient (DQ) for language revealed a significant correlation between the degree of hand preference and DQ for language in children with a quotient above 100. Thus, these children were more right-handed for pointing gestures as DQ increased. These results highlight the close association between the development of hand preference for pointing and the speed of language development, suggesting a new direction for studies of language-gesture links in toddlers.

Relationship Between Arm Usage and Instrumental Activities of Daily Living After Unilateral Stroke

Haaland KY, Mutha PK, Rinehart JK, Daniels M, Cushnyr B, Adair JC. Relationship between arm usage and instrumental activities of daily living after unilateral stroke. ObjectiveTo determine whether the preferred pattern of arm use after unilateral hemispheric damage was associated with better everyday functioning. Our previous work showed that right-handed stroke patients with right hemisphere damage (RHD) used their right, ipsilesional arm most frequently, while those with left hemisphere damage (LHD) used both arms together most frequently. This effect was explained by right-hand preference, but its relationship to functional performance is not known. DesignObservational cohort. SettingResearch laboratory. ParticipantsStroke patients (n=60; 30 RHD, 30 LHD) and healthy controls (n=52). InterventionsNot applicable. Main Outcome MeasuresThe Functional Impact Assessment was used to assess performance on instrumental activities of daily living (IADLs). ResultsThe preferred patterns of arm use were similar to those in our previous report. However, it was the greater use of both arms together that was associated with better IADL performance in both stroke groups. Ipsilesional arm use alone was not significantly associated with IADL performance in the RHD group and was associated with poorer performance in the LHD group. ConclusionsThe modal arm use pattern did not always optimize IADL functioning. Better IADL functioning in both stroke groups was associated with the use of both arms together, which is the most common arm use pattern of healthy individuals doing these same IADLs. An important practical question that arises from these findings is whether bilateral arm rehabilitation should be emphasized, because using both arms together is the best predictor of better performance on everyday tasks.

Human Infants and Baboons Show the Same Pattern of Handedness for a Communicative Gesture

To test the role of gestures in the origin of language, we studied hand preferences for grasping or pointing to objects at several spatial positions in human infants and adult baboons. If the roots of language are indeed in gestural communication, we expect that human infants and baboons will present a comparable difference in their pattern of laterality according to task: both should be more right-hand/left-hemisphere specialized when communicating by pointing than when simply grasping objects. Our study is the first to test both human infants and baboons on the same communicative task. Our results show remarkable convergence in the distribution of the two species' hand biases on the two kinds of tasks: In both human infants and baboons, right-hand preference was significantly stronger for the communicative task than for grasping objects. Our findings support the hypothesis that left-lateralized language may be derived from a gestural communication system that was present in the common ancestor of baboons and humans.

Lack of Association of Handedness With Inattention and Hyperactivity Symptoms in ADHD

Objective: Findings about the association of left-handedness and ADHD are inconsistent. While abnormal brain laterality is reported in children with ADHD, it is unclear if hand preference is associated with ADHD, severity symptoms, age, gender, comorbid psychiatric problems, or parental characteristics. Method: Subjects were 520 boys and girls with a mean age of 9.04 (2.3) years. Only four children were with mixed-handedness. ADHD was diagnosed according to clinical assessment using accepted diagnostic criteria. In addition to the demographic characteristics and hand-use preference, inattention severity, hyperactivity severity, oppositional behavior symptoms, anxiety symptoms, and developmental coordination problems were assessed. Results: A total of 87.4% were right handed. A total of 12.6% were left handed. Left- or right-hand preference was not associated with age, gender, inattentiveness score, hyperactivity-impulsivity score, comorbid psychiatric problems, developmental coordination problems score, or parental characteristics. Conclusion: Left handedness is not associated with higher parent-reported inattentiveness or hyperactivity. Hand-use preference is not gender related in ADHD.

Going beyond students: An association between mixed-hand preference and schizotypy subscales in a general population

Research on the sub-clinical condition of schizotypy suggests that it is associated with mixed handedness. To date, however, this research has focussed on undergraduate populations. If the association between schizotypy and mixed-handedness is the result of an underlying neurological trait, it is important to demonstrate that the effect extends to the general population. With this in mind, 699 participants were drawn from a wide community sample. Schizotypy was measured using the Psychosis Proneness Questionnaire and handedness was assessed using the Annett inventory. To avoid the sometimes arbitrary definitions of left-, right- and mixed-handed, regression analyses were used to explore the data. There was no evidence of a difference in schizotypy between individuals with a left- or right-hand preference. People with a mixed-hand preference, however, had higher scores on PER–MAG (Perceptual Aberration and Magical Ideation) and HYP–IMP (Hypomania and Impulsive Non-Conformity) scales (positive traits). No effect was observed for the SAN (Social Anhedonia) and PAN (Physical Anhedonia) scales (negative traits). The nature of the association between schizotypy and handedness observed in the current study is similar to that reported for student populations. The possibility that the association is related to response biases or a biological mechanism is discussed.

Handedness found in a wild group of moor monkeys in the Karaenta Nature Reserve, South Sulawesi, Indonesia

Abstract Hand preference of wild moor monkeys Macaca maurus was investigated in food reaching situations at the Karaenta Nature Reserve, South Sulawesi, Indonesia. The frequency picking up sweet-corn grains to take into the mouth by either hand of monkeys was counted directly at the feeding ground where sweet-corn grains were scattered for monkeys. Among the 20 monkeys examined, 8 were right-handed, 8 were left-handed, and 4 were ambilateral. The results indicated the prevailed hand preference on individual level but not either trends of left- or right-hand preference on population level. The trend toward a higher proportion of left-handed monkeys found in Japanese and rhesus monkeys was not found. Some other characteristics found in moor monkeys are discussed in comparison with those previous findings in Japanese and Tibetan macaques in order to evaluate variations within the genus Macaca.

Teaching Neuro Images : Confirmation of prenatal periventricular venous infarction with susceptibility-weighted MRI

Parents of a healthy child with an unremarkable perinatal history noted a right-hand preference at 4 months and left hemiparesis by 6 months. MRI was not completed until 27 months (figure), confirming periventricular venous infarction (PVI). Stroke …