Chimp study highlights importance of emotional care in childhood
Orphaned chimpanzees given special 'mothering' care by humans are happier and smarter than chimps raised in a more institutional setting that takes care of their physical needs but largely neglects their emotional development. The EU-funded research, which is published in the journal Developmental Psychobiology, has implications for the way human orphans are raised.
EU support for the study came from the FEELIX GROWING ('Feel, interact, express: a global approach to development with interdisciplinary grounding') project, which is financed through the Sixth Framework Programme's thematic area for information society technologies (IST) to the tune of EUR 2.5 million.
The study is the first to investigate how different styles of care impact on the emotional and cognitive development of chimpanzees. The researchers followed 46 chimpanzees raised in the Great Ape Nursery at the Yerkes National Primate Research Center in Atlanta, US. The young chimps were in the centre because their mothers lacked basic maternal skills.
One group of chimps received standard care, which focused essentially on the young animals' physical needs. The second group received 'responsive care'; these animals spent more time with their human carers, and the carers devoted considerable amounts of time to grooming, playing and interacting with the youngsters, mimicking the parenting behaviour of the best chimp mothers.
Assessments of the animals' behaviour and development revealed that chimps that had been mothered were happier, more advanced and better adjusted than those raised less attentively. In fact at nine months, these chimps were more cognitively advanced compared to human infants of the same age.
'Those given responsive care were less easily stressed, less often attached to 'comfort blankets', had healthier relationships with their caregivers and were less likely to develop stereotypic rocking,' summarised Professor Kim Bard of the University of Portsmouth in the UK, one of the authors of the study. 'They were also more advanced intellectually than chimpanzees reared with standard institutionalised care.'
The same could not be said for the chimps raised in a more 'institutional' style; these animals were more likely to display 'disorganised attachment' behaviours, such as rocking or clutching a security blanket when distressed instead of turning to their carer. The paper's authors note that similar behaviour has been observed in human orphanages and in children who have been abused or neglected.
'We propose that by increasing sensitive care-giving to nursery chimpanzees, their cognitive development and their attachment relationships improved, and that a similar approach to stimulate responsive care in residential settings such as orphanages may be successful as well,' the researchers write.
'The attachment system of infant chimpanzees appears surprisingly similar to that found in human infants. Early experiences, either of warm, responsive care-giving or of extreme deprivation, have a dramatic impact on emotional and cognitive outcomes in both chimpanzees and humans,' commented Professor Bard. 'Parental sensitivity is an important factor in human infant development, and it would seem the same is true for great apes, as well.'
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Data Source Provider: University of Portsmouth; Developmental Psychology
Document Reference: Van IJzendoorn, ME et al. (2009) Enhancement of attachment and cognitive development of young nursery-reared chimpanzees in responsive versus standard care. Developmental Psychology. DOI: 10.1002/dev.20356.
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