Lateralization of mother–infant interactions in a diverse range of mammal species (original) (raw)
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Visual Laterality of Calf–Mother Interactions in Wild Whales
PLoS ONE, 2010
Background: Behavioral laterality is known for a variety of vertebrate and invertebrate animals. Laterality in social interactions has been described for a wide range of species including humans. Although evidence and theoretical predictions indicate that in social species the degree of population level laterality is greater than in solitary ones, the origin of these unilateral biases is not fully understood. It is especially poorly studied in the wild animals. Little is known about the role, which laterality in social interactions plays in natural populations. A number of brain characteristics make cetaceans most suitable for investigation of lateralization in social contacts.
2016
The influence of the social environment on lateralized behaviors has now been investigated across a wide variety of animal species. New evidence suggests that the social environment can modulate behavior. Currently, there is a paucity of data relating to how primates navigate their environmental space and investigations that consider the naturalistic context of the individual are few and fragmented. Moreover, there are competing theories about whether only the right hemisphere or rather both cerebral hemispheres are involved in the processing of social stimuli, especially in emotion processing. Here we provide the first report of lateralized behaviors elicited by great apes. We employed a continuous focal animal sampling method to record the spontaneous interactions of a captive zoo-living colony of chimpanzees (Pan troglodytes) and a biological family group of peer-reared western lowland gorillas (Gorilla gorilla gorilla). We specifically focused on which side of the body (i.e., front, rear, left, right) the focal individual preferred to keep conspecifics. Utilizing a newly developed quantitative corpus-coding scheme, analysis revealed both chimpanzees and gorillas demonstrated a significant group-level preference for focal individuals to keep conspecifics positioned to the front of them compared to behind them. More interestingly, both groups also manifested a population-level bias to keep conspecifics on their left side compared with their right side. Our findings suggest a social processing dominance of the right hemisphere for context-specific social environments. Results are discussed in light of the evolutionary adaptive value of social stimulus as a triggering factor for the manifestation of group-level lateralized behaviors.
International Journal of Primatology, 2004
Left-sided maternal cradling has been widely reported in human populations. In this paper, I review the evidence of laterality in maternal cradling and infant positional biases in non-human primates. The review revealed some evidence of population-left sided cradling in great apes but little consistency in bias was found among Old and New World monkeys. Very little data have been reported in prosimians. I further describe how asymmetries in either maternal cradling or infant positional biases may explain individual and species differences in hand preference.
Asymmetries in mother-infant behaviour in Barbary macaques (Macaca sylvanus)
PeerJ, 2018
Asymmetries in the maternal behaviour and anatomy might play an important role in the development of primate manual lateralization. In particular, early life asymmetries in mother's and infant's behaviour have been suggested to be associated with the development of the hand preference of the offspring. The aim of this study was to investigate the presence of behavioural asymmetries in different behavioural categories of mother-infant dyads of zoo-living Barbary macaques (Macaca sylvanus). The study subjects were 14 Barbary macaques involved in seven mother-infant dyads housed in Parco Natura Viva, Italy. For the mothers, bouts of hand preference for maternal cradling and infant retrieval were collected. For the infants, we focused on nipple preference and hand preference for clinging on mother ventrum. Moreover, we collected bouts of hand preference for food reaching in both groups. No significant group-level bias was found for any of the behavioural categories in either mothers or infants. However, at the individual level, six out of seven mothers showed a significant cradling bias, three toward the right hand and three toward the left hand. Moreover, all infants showed a significant nipple preference, six toward the mother's right nipple, one toward the left nipple. Furthermore, a significant correlation was found between the infant nipple preference and their hand preference for food reaching, suggesting that maternal environment rather than behaviour might affect the development of hand preference in Old World monkeys. Our findings seem partially to add to previous literature on perceptual lateralization in different species of non-primate mammals, reporting a lateral bias in mother-infant interactions. Given the incongruences between our study and previous research in great apes and humans, our results seem to suggest possible phylogenetic differences in the lateralization of mothers and infants within the Primates order.
Human-like maternal left-cradling bias in monkeys is altered by social pressure
Scientific Reports, 2020
About 66–72% of human mothers cradle their infants on their left side. Given that left-cradling exposes the baby’s face to the mother’s left visual field (i.e., mainly projected to her right hemisphere) and is altered by emotional states such as stress, maternal left-cradling was interpreted as reflecting right-hemispheric dominance for emotional processing. Whether this phenomenon is unique to human evolution is still in debate. In the present study we followed 44 olive baboon (Papio anubis) mothers and their infants in different social groups. We found that a maternal cradling bias exists and is predominantly towards the left in a similar proportion as in humans, but shifts toward a right bias in mothers living in high density groups. The sensitivity of left-cradling to social pressure highlights its potential links with the mother’s stress as reported in humans. Our finding clearly illustrates the phylogenetic continuity between humans and Old-World monkeys concerning this latera...
Developmental Psychobiology, 1993
The current study extends previous documentation of behavioral asymmetries in hand-to-mouth, self-consoling behaviors of infant chimpanzees. The underlying source of lateralized hand-to-mouth, self-calming behavior was investigated by comparing individual differences in neonatal arousal levels, regulatory ability, and motor performance with individual differences in the degree of laterality at 3 months. Asymmetrical hand-to-mouth, self-calming behaviors at 3 months of age were significantly related to general arousal at 2 days of age (i.e., the Range of State cluster scores measured by the Brazelton Neonatal Behavioral Assessment Scale). Simply stated, chimpanzees with a right-hand bias in hand-to-mouth behavior exhibited lower arousal at 2 days of age compared with nonright-handed individuals. The only item of the Range of State cluster to distinguish subjects was irritability: Righthanded subjects were less irritable. Previously, a trend was reported with respect to sex differences in the laterality of hand-to-mouth behavior. With the greater number of subjects in the present study, we found that females exhibited a significantly greater right-hand bias for hand-to-mouth behaviors (12 of 13) than did males (9 of 15). We conclude that neonatal arousability, and not regulatory capacity or motor performance, predicts the degree of laterality found in hand-to-mouth, self-calming behaviors in 3-month-old chimpanzees. These data are discussed from the standpoint of early pari-parturitional or intrauterine factors affecting lateralized development.
Social environment elicits lateralized behaviours in gorillas and chimpanzees
Journal of Comparative Psychology, 2014
The influence of the social environment on lateralized behaviors has now been investigated 26 across a wide variety of animal species. New evidence suggests that the social environment 27 can modulate behavior. Currently, there is a paucity of data relating to how primates navigate 28 their environmental space and investigations that consider the naturalistic context of the 29 individual are few and fragmented. Moreover, there are competing theories about whether 30 only the right or rather both cerebral hemispheres are involved in the processing of social 31 stimuli, especially in emotion processing. Here we provide the first report of lateralized social 32 behaviors elicited by great apes. We employed a continuous focal animal sampling method to 33 record the spontaneous interactions of a captive zoo-living colony of chimpanzees (Pan 34 troglodytes) and a biological family group of peer-reared western lowland gorillas (Gorilla 35 gorilla gorilla). We specifically focused on which side of the body (i.e., front, rear, left, right) 36 the focal individual preferred to keep conspecifics. Utilizing a newly developed quantitative 37 corpus-coding scheme, analysis revealed both chimpanzees and gorillas demonstrated a 38 significant group-level preference for focal individuals to keep conspecifics positioned to the 39 front of them compared to behind them. More interestingly, both groups also manifested a 40 population-level bias to keep conspecifics on their left side compared with their right side. 41
Comparative vertebrate lateralization, 2002
This chapter is concerned with the question of the relations and possible influences of environmental factors on the establishment of patterns of manual lateralization in human and non-human primates. More specifically, we are interested in the relation between maternal postures and laterality in nonhuman primates (e.g. bias in cradling behaviour and hand preference of the mother) and the development of patterns of manual preferences in infants. In order to understand fully the many ways in which these variables could interact, we first review the evidence of postural biases in human adults when cradling and carrying their offspring. Next, we examine the divergent hypotheses advanced to explain the observed biases. The same is then done for non-human primates. A second part of our chapter (see Section 9.3) describes the different asymmetric patterns observed during the development of the infant concerning head turning, nipple preference, etc. i n both human and non-human primates.