Manual laterality and strategy use for a coordinated bimanual task requiring precise and power grip in guenons and mangabeys (original) (raw)
Related papers
Ethology, 2007
We assessed the manual preferences of 12 De Brazza's monkeys (Cercopithecus neglectus) in spontaneous feeding situations and in two different coordinated bimanual tasks that were not visually guided. We recorded the hand used by each subject for 22 spontaneous activities, hand and digits use while extracting peanut butter from a hollow tube (tube task) and the hand used to extract candies from hanging plastic balls (ball task). Spontaneous activities revealed individual manual preferences but no population-level biases. For both experimental tasks, all subjects were lateralized in their hand use. We found a left bias at the group level for the tube task, but no group-level asymmetry for the ball task. Experimental tasks induced greater strength of laterality than did spontaneous activities. Although the size of our sample did not allow us to draw any conclusions concerning manual preference at the population level, this study stresses the importance of coordinated bimanual tasks to reveal manual laterality in non-human primates.
American Journal of Physical Anthropology, 1997
The last decade has seen a resurgence of interest in laterality of function in primates, especially in hand use as it links to handedness and language in Homo sapiens. Manual lateralization of behavior in humans reflects asymmetry in cerebral structure, which must have evolved from nonhuman progenitors. To what extent is hand function lateralized in our nearest living relations? First, we address current issues of theory and methodology: statistics, measurement, variables, setting, sensory modality, and sample size. Specific topics include preference vs. performance, posture, bimanuality, inheritance, and arm asymmetry. We categorize the published literature in a descriptive, classificatory framework of five levels that range from Level 1, ambilaterality, to Level 5, human-like handedness. In a meta-analysis we put 241 published data-sets to a methodological test of seven criteria and code the 48 survivors onto the levels framework, by taxonomic grouping (prosimian, New World monkey, Old World monkey, ape, chimpanzee). Primates at Level 1 are mostly wild or naturalistic populations performing spontaneous species-typical behavior patterns. Most primates are at Levels 2 and 3, that is, individually lateralized to either side, especially on complex, demanding or practiced tasks, usually as devised in captive settings. Only chimpanzees show signs of population-level bias (Levels 4 and 5) to the right, but only in captivity and only incompletely. We conclude that nonhuman primate hand function has not been shown to be lateralized at the species level-it is not the norm for any species, task, or setting, and so offers no easy model for the evolution of human handedness.
Journal of Comparative Psychology, 2003
Hand preferences for a coordinated bimanual task were assessed in a sample of 31 captive gorillas (Gorilla gorilla) and 19 captive orangutans (Pongo pygmaeus) and were compared with chimpanzee (Pan troglodytes) hand preferences in subjects that were matched on the basis of age, sex, and rearing history. The task required that the apes remove food from the inside edges of a symmetrical polyvinyl chloride pipe presented to them in their home cages. The results indicate significant species differences with chimpanzees showing population-level right-handedness and orangutans showing population-level left-handedness. The gorillas showed a nonsignificant trend toward righthandedness. The results are discussed in terms of possible ecological or biomechanical factors that may influence hand preferences in different ape species.
Behavioural Brain Research, 2006
Behavioural asymmetries, once thought to be exclusively human, appear to be widespread in vertebrates. A population-level bias should stem from natural selection and reflect a cerebral dominance, while individual preferences might be linked to individual characteristics. Manual laterality has been extensively investigated in non-human primates. However, despite a strong data base, no general patterns have emerged, resulting in a few explanatory theories and little consensus. This study was interested in manual laterality in 12 Campbell's monkeys (Cercopithecus c. campbelli). Several theories were examined, using both direct behavioural observations during feeding behaviour and six controlled experimental conditions, in which we varied task demands to investigate the effect of two factors. We systematically varied the individual posture (sat, tripedal, bipedal, clung) and the complexity of the task (box with or without a lid to open). Concerning the direction of preference, we found individual and action-specific preferences for experimental actions, which match previous reports. No population bias emerged and each subject appeared to react differently to the factors, hereby contradicting the theories. However, concerning the strength of preference, all individuals tended to be affected in similar ways. Spontaneous actions were less lateralized than experimental ones, and the simplest task and spontaneous category tended to show the weakest laterality. The relative complexity and novelty of these actions may account for these results.
Yearbook of Physical Anthropology, 1997
The last decade has seen a resurgence of interest in laterality of function in primates, especially in hand use as it links to handedness and language in Homo sapiens. Manual lateralization of behavior in humans reflects asymmetry in cerebral structure, which must have evolved from nonhuman progenitors. To what extent is hand function lateralized in our nearest living relations? First, we address current issues of theory and methodology: statistics, measurement, variables, setting, sensory modality, and sample size. Specific topics include preference vs. performance, posture, bimanuality, inheritance, and arm asymmetry. We categorize the published literature in a descriptive, classificatory framework of five levels that range from Level 1, ambilaterality, to Level 5, human-like handedness. In a meta-analysis we put 241 published data-sets to a methodological test of seven criteria and code the 48 survivors onto the levels framework, by taxonomic grouping (prosimian, New World monkey, Old World monkey, ape, chimpanzee). Primates at Level 1 are mostly wild or naturalistic populations performing spontaneous species-typical behavior patterns. Most primates are at Levels 2 and 3, that is, individually lateralized to either side, especially on complex, demanding or practiced tasks, usually as devised in captive settings. Only chimpanzees show signs of population-level bias (Levels 4 and 5) to the right, but only in captivity and only incompletely. We conclude that nonhuman primate hand function has not been shown to be lateralized at the species level-it is not the norm for any species, task, or setting, and so offers no easy model for the evolution of human handedness.
Journal of Comparative Psychology, 1998
Hand preferences in 26 capuchin monkeys (Cebus apella) were examined in 2 reaching-forfood tasks under 2 postural conditions. In the 1st task (unimanual), monkeys were required to reach for food from both a quadrupedal and an upright posture. A right-hand bias was found for the upright but not for the quadrupedal condition. In the 2nd task (coordinated bimanual), monkeys were required to extract the food from a hanging Plexiglas tube from both a crouched and an upright posture. A right-hand bias was found for both conditions. A significant increase in fight-hand use was noted from the unimanual, quadrupedal, reaching task to the coordinated-bimanual task, with females exhibiting a greater right-hand preference than males. In addition, a significant effect of task complexity on strength in laterality was found. Results are discussed in the context of recent theories on primate laterality.
Journal of Human Evolution, 2010
The preferential use of one hand over the other is considered the primary behavioral expression of structural and functional asymmetry in cerebral structures, which is a decisive factor in human evolution. We present the first analysis of manual laterality in a form of object playdstone handling (SH) behaviordin a free-ranging group of Japanese macaques. Defined as a stone-directed manipulative activity, and comprised of multiple one-handed SH patterns (e.g., grabbing a stone in one hand and cradling it against its chest), as well as coordinated two-handed SH patterns with manual role differentiation (e.g., holding a stone with one hand and rubbing it with the other), SH behavior is a good candidate for the study of hand lateralization. We systematically followed the methodological framework developed by to measure and analyze the presence, strength, and direction of manual preference in the performance of SH behavior and in various SH patterns, both at the individual and group level. Some individuals showed a significant manual lateral bias on a single SH pattern (hand preference), whereas others showed consistency in laterality across all or most of the SH patterns they performed (hand specialization). At the group level, we found that, although their collective distribution of left versus right remained random, most subjects were either significantly but incompletely lateralized, or completely lateralized within particular SH patterns (pattern specialization), but not across all SH patterns (no handedness for SH behavior as a whole). As predicted by the task-complexity model, hand specialization and handedness were stronger in the coordinated bimanual SH patterns than in the unimanual patterns. We discuss the implications of our findings for the evolution of manual preferences in noninstrumental object manipulation versus stone tool use in nonhuman primates and hominins.
The relationship of handedness to a “lateralized” task
Neuropsychologia, 1978
There is a widespread belief that left-handers are less lateralized than right-handers, and consequently, are more likely to show deficits in performance on lateralized tasks. However, recent indications point to the possibility that it is the degree of handedness, regardless of direction, that accounts for differences in performance between handedness groups. We tested this notion through the use of a task developed by Nebes which involved matching of parts to wholes. Results indicated that performance on this lateralized task was indeed related to the degree of behaviorally-assessed preference and proficiency of handedness, and not to direction of hand preference.
Hand preference on unimanual and bimanual tasks in Barbary macaques (Macaca sylvanus)
American Journal of Primatology, 2018
Assessing manual lateralization in non-human primates could be an optimal way to understand the adaptive value of this asymmetry in humans. Though many studies have investigated hand preferences in Old and New World monkeys and apes, fewer studies have considered manual lateralization in strepsirrhines, especially in experimental tasks. This study investigated hand preferences for a unimanual and a bimanual task of 17 captive ring-tailed lemurs (Lemur catta), housed at Parco Natura Viva (VR), Italy. The effect of age on handedness has been also investigated. The lemurs were tested on a unimanual task, in which subjects were restricted to using one hand to retrieve the food inside an apparatus, and on a bimanual task, in which lemurs had to use one hand to keep the apparatus door open while reaching with the other hand to retrieve the food inside it. At the population-level, our results revealed an asymmetrical hand use distribution, in particular a bias toward a right hand preference for food reaching in both the unimanual and the bimanual tasks. Furthermore, at the individual-level, the bimanual task seems to elicit a greater hand preference than the unimanual task. Results of this study underline the importance of experimental tasks in determining hand preference in strepsirrhines. Furthermore, as bimanual tasks elicited a stronger degree of lateralization, they appear to be more suited to investigate manual laterality. Finally, findings from this study highlight the presence of a right hand preference in ring-tailed lemurs, shedding new light on the evolution of human right handedness. Am. J. Primatol.