Abstract
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.
Highlights
The lateralization in mother-infant interactions has recently been hypothesised to have a perceptual origin in different mammal species, from non-primate mammals (Karenina et al, 2017) to humans (Todd & Banerjee, 2016)
Research on humans revealed that mothers prefer to cradle their infant on the left side (Salk, 1960; Damerose & Vauclair, 2002) and similar findings have been reported in chimpanzees (Pan troglodytes) (Manning & Chamberlain, 1990; Hopkins et al, 1993; Manning, Heaton & Chamberlain, 1994; E Toback, 1999, unpublished data) and gorillas (Gorilla gorilla) (Manning, Heaton & Chamberlain, 1994) (Table 1)
The results of this study showed that at the individual level, infant Barbary macaques showed a distinct nipple preference and similar findings have been found for maternal cradling in mother macaques
Summary
The lateralization in mother-infant interactions has recently been hypothesised to have a perceptual origin in different mammal species, from non-primate mammals (Karenina et al, 2017) to humans (Todd & Banerjee, 2016). The right hemisphere is competent in processing the visuo-spatial information, resulting in an attentional bias toward the left visual hemifield (Karenina et al, 2017) This view has been supported in other studies of social affiliative behaviour. The right hemisphere involvement in social stimuli control has been hypothesized to be a reason for the left-cradling bias reported in the maternal behaviour of humans and some great apes (Hopkins, 2004; Rosa Salva et al, 2012; Giljov, Karenina & Malashichev, 2018). Research on rhesus macaques and olive baboons did not report any group-level side preferences in the hand used to retrieve the infant by the mother (Tomaszycki et al, 1998; Damerose & Hopkins, 2002) (Table 1)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
