Koichi Negayama

Maternal aggression to its offspring in Japanese monkeys

Aggressive behaviors by mothers toward their offspring and the interactions related to them were observed for one year in six separately caged mother-offspring pairs of Japanese monkeys ( Macaca fuscata ). Maternal aggression showed changes both in quality and quantity in the course of the offsprings development, and it was caused mainly by behavior that the offspring directed toward the mother. It was interpreted that their actions increased irritability in the mother, and this interpretation, is supported by the fact that the offspring reacted to the mothers aggression by stopping these behaviors and/or, retreating from her. Maternal aggression functioned to promote the offsprings independence from its mother.

Behavior of Japanese monkey (Macaca fuscata) mothers and neonates at parturition

Parturitional behavior in 12 caged Macaca fuscatawas analyzed. Wild-caught mothers showed adequate maternal behaviors immediately following the neonate’s expulsion. Parity differences existed in the behaviors; primiparae were more idiosyncratic than were multiparae. Among multiparae, those with two or more offspring were uniformly adequate, but those with a single birth experience varied in the adequacy of the maternal care they provided at parturition. Mothers embraced and licked their neonates and had ventroventral contact with them frequently immediately after parturition but decreased these behaviors after expulsion of the placenta. In contrast, mothers showed allogrooming after consuming the placenta. Placentophagy was correlated with the level of orality represented by maternal licking behaviors. An isolation-reared primipara reacted to her newborn in a basically negative manner, although she showed little actual aggression. She showed a rapid shift in her negative behavior during the immediate postpartum period. This mother’s newborn sought contact with her, indicating the neonate’s active role in establishing a stable mother-neonate bond.

Japan–France–US comparison of infant weaning from mother's viewpoint

Background: Breastfeeding and weaning are strongly connected with infant–mother mutual autonomy, and hence are good touchstones to examine the characteristics of the mother–child relationship. Comparison of the weaning practice gives a framework to understand characteristics of the mother–infant relationship. Objective: The purpose of this study was to compare three industrialised countries concerning the relationship between feeding and weaning practices and its reasons, mother’s perception of child care, and of breast milk and formula. Methods: A questionnaire study on weaning practice was conducted for 310 Japanese, 756 French, and 222 American mothers with 4- to 20-month-old infants. Results: French mothers expected and had accomplished weaning at an earlier age of the infant, compared to Japanese and American mothers. Perceived insufficiency of breast milk was the leading reason for the termination of breastfeeding for Japanese mothers at the earlier stages, whereas back to work was the more important reason for French mothers. Japanese mothers were more negative in their image of themselves as mothers, whereas French mothers felt more burdened by child-care. Japanese mothers who terminated breastfeeding because of perceived breast milk insufficiency were also those who were less motivated to breastfeed. Conclusion: Weaning is a significant framework to interpret cultural differences in mother–infant relationship. The perceived insufficiency is interpreted as a solution of conflict between the social pressure to breastfeed and its burden.

Development of Reactions to Pain of Inoculation in Children and their Mothers

This is a naturalistic study focusing on developmental changes in the immediate reactions of 183 Japanese children under 7 years old and their mothers to pain caused by inoculation of the children. Under the age of 5 crying was a typical child behaviour, whereas 5- and 6-year-olds showed facial expressions instead. Their mothers were generally empathetic to the children’s distress on inoculation, but the empathetic reactions tended to decrease as the children grew older. However, children’s crying per se did not necessarily cause the reactions, and the mothers of the older children tended to react to the children’s pain with a smile. A greater proportion of 3-year-old females cried than males of the same age, but despite this their mothers had a stronger tendency to respond with a smile in comparison with the mothers of male children. The results were discussed with respect to development of emotional independence and competence of social manipulation by children.

Experimental study on sexual behavior between mother and son in Japanese monkeys (Macaca fuscata)

A mother, her adult son, four adult males and six adult females from a free-ranging group at Katsuyama were paired in a cage in the sexual seasons from 1976 to 1980. The paired subjects were classified into the following three types: mother and son, familiar pairs and unfamiliar pairs. The familiar pairs consisted of monkeys who had been in the Katsuyama group until about six months before the experiment. The unfamiliar pairs consisted of monkeys who had not met each other at all or who had not met each other for more than eight years before the experiment. Serial mounts which terminated with ejaculation occurred in nine of ten unfamiliar pairs, four of five familiar pairs, but there were none between the son and mother. The son and mother did not appear to be sexually aroused between themselves, although they were sexually active to other partners. However, on rare occasions, the son mounted singly on the mother, and on one occasion he ejaculated. Their interaction did not change essentially during the three years. The son rarely mounted serially on a female who had a close relationship with his mother.

Embodied intersubjective engagement in mother-infant tactile communication: a cross-cultural study of Japanese and Scottish mother-infant behaviors during infant pick-up.

This study examines the early development of cultural differences in a simple, embodied, and intersubjective engagement between mothers putting down, picking up, and carrying their infants between Japan and Scotland. Eleven Japanese and ten Scottish mothers with their 6- and then 9-month-old infants participated. Video and motion analyses were employed to measure motor patterns of the mothers’ approach to their infants, as well as their infants’ collaborative responses during put-down, pick-up, and carry phases. Japanese and Scottish mothers approached their infants with different styles and their infants responded differently to the short duration of separation during the trial. A greeting-like behavior of the arms and hands was prevalent in the Scottish mothers’ approach, but not in the Japanese mothers’ approach. Japanese mothers typically kneeled before making the final reach to pick-up their children, giving a closer, apparently gentler final approach of the torso than Scottish mothers, who bent at the waist with larger movements of the torso. Measures of the gap closure between the mothers’ hands to their infants’ heads revealed variably longer duration and distance gap closures with greater velocity by the Scottish mothers than by the Japanese mothers. Further, the sequence of Japanese mothers’ body actions on approach, contact, pick-up, and hold was more coordinated at 6 months than at 9 months. Scottish mothers were generally more variable on approach. Measures of infant participation and expressivity indicate more active participation in the negotiation during the separation and pick-up phases by Scottish infants. Thus, this paper demonstrates a culturally different onset of development of joint attention in pick-up. These differences reflect cultures of everyday interaction.

Kowakare: A New Perspective on the Development of Early Mother–Offspring Relationship

The mother–offspring relationship has components of both positivity and negativity. Kowakare is a new concept introduced to explain an adaptive function of the negativity in the early mother-offspring relationship. Kowakare is the psycho-somatic development of the relationship as the process of accumulation in the otherness of offspring. Early human Kowakare has two frameworks, biological inter-body antagonism and socio-cultural allomothering compensating the antagonism. Some features of feeding/weaning, parental aversion to offspring’s bodily products, and transition from dyad to triad relationship (proto–triad relationship) in tactile play are discussed. Early human Kowakare is promoted by allomothering with the nested systems of objects/persons/institutions as interfaces between mother and offspring. Kowakare makes mother–offspring relationship a mutually autonomous and cooperative companionship.

Developmental trends in mother-infant interaction from 4-months to 42-months: using an observation technique.

Background It is clear that early social interaction follows from mother-infant interaction after pregnancy. Many researchers have illuminated this interaction in the first years of life. Most common mother-infant interaction is the attachment behavior of an infant. The Japan Children’s Study (JCS) development psychology group hypothesis is that the early mother-infant interaction will predict later social behaviors. But the method applied to evaluate this interaction mainly comes from the evaluation of the whole observation situation and is dependent upon the coder. We applied a new observational method that checked the on/off status of behavior and recorded sequentially. Methods Using a semi-structured observation setting as our method, we analyzed the developmental change of mother-infant interaction within a toy situation. Results The result indicated that mother-infant interaction with a toy altered at around 9-months and is salient to the usual developmental change of joint attention. Additionally cluster analysis suggested that the developmental pattern is divided into two clusters. This is the first report on a developmental pattern of joint attention. Conclusions These results indicated that the developmental trend of gaze direction and vocalization is one candidate of measure for evaluating the mother infant social interaction from the point of joint attention.