Infant allocare in traditional societies
Infant allocare in traditional societies
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DOI：
10.1016/j.physbeh.2018.02.054
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发表时间：
2018-09-01
影响因子：
2.9
通讯作者：
Veile, Amanda
中科院分区：
文献类型：
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作者：
Kramer, Karen L.;Veile, Amanda
在整个人类社会中，婴儿都得到母亲和其他人的照顾。生殖合作提出了两个重要的问题：分配护理如何使母亲和婴儿受益，以及为什么护理人员在可以将时间花在其他可能更有价值的方式上时要帮助母亲？我们使用来自三个小规模社会的行为和生物学数据来评估1）分配护理如何影响哺乳母亲的时间，2）母亲的生育间隔长度，存活生育率和婴儿体重是否随她接受的育儿帮助而变化，以及3）帮助者花时间照顾孩子的机会成本。在我们的狩猎采集者和农业样本中，我们发现母亲平均提供了婴儿所接受的直接护理的57%，并分配了43%（20%）。模型结果表明，分配保健每增加10%，母亲从事直接护理的可能性就会减少25%，估计每天可节省165千卡。虽然分配对母亲的时间有显着的直接影响，但对延迟健身措施（出生间隔和存活生育率）或婴儿体重状况没有明显的影响。跨文化研究发现，除了母亲，兄弟姐妹花在照顾婴儿上的时间最多，而且他们这样做不会影响他们可能花在玩耍、经济活动或教育上的时间。儿童提供帮助的机会成本很低，这提供了另一种解释，说明为什么在许多社会中，即使没有延迟的间接健身福利，青少年也是常见的照顾者。虽然我们预计具体的模式，以不同的文化，这些结果指出，婴儿allocare的重要性，其直接的时间效益为母亲保持灵活性，在平衡竞争的需求，以支持年长和年幼的孩子。
Across human societies infants receive care from both their mothers and others. Reproductive cooperation raises two important questions: how does allocare benefit mothers and infants, and why do caretakers help mothers when they could spend their time in other, perhaps more valuable ways? We use behavioral and biological data from three small-scale societies to evaluate 1) how allocare affects a nursing mother's time, 2) whether a mother's birth interval length, surviving fertility and infant weight vary as a function of the childcare help that she receives, and 3) the opportunity cost for helpers to spend time caring for children. Across our hunter-gatherer and agricultural samples we find that on average mothers provide 57% of the direct care that an infant receives and allocaretakers 43% (20%). Model results show that for every 10% increase in allocare the probability that a mother engages in direct care diminishes by 25%, a potential savings of an estimated 165 kcals per day. While allocate has a significant immediate impact on mother's time, no detectable effect on delayed fitness measures (birth interval and surviving fertility) or on infant weight status was evident. Cross culturally we find that other than mothers, siblings spend the most time caretaking infants, and they do so without compromising the time that they might otherwise spend in play, economic activities or education. The low opportunity cost for children to help offers an alternative explanation why juveniles are common caretakers in many societies, even in the absence of delayed indirect fitness benefits. While we expect specific patterns to vary cross culturally, these results point to the importance of infant allocare and its immediate time benefits for mothers to maintain flexibility in balancing the competing demands to support both older and younger children.