Jamison Cheryl Sorenson, Cornell Laurel L, Jamison Paul L, Nakazato Hideki
Department of Anthropology, Indiana University, Bloomington, Indiana 47405, USA.
Am J Phys Anthropol. 2002 Sep;119(1):67-76. doi: 10.1002/ajpa.10070.
An unresolved question arising from human evolutionary research relates to the function of the postreproductive period in human females. If menopause is not merely an artifact resulting from the benefits of civilization, there must be an adaptive mechanism favoring the offspring of women who continue to thrive well past the time of their last ovulation. The "grandmother hypothesis" was developed on the basis of the original suggestion by Williams (1957 Evolution 11:32-39) that "stopping early" would benefit already-born children. This idea, combined with the concepts of kin selection (Hamilton 1964 J Theor Biol 7:1-52) and parental investment (Trivers 1972 Sexual Selection and the Descent of Man, Chicago: Aldine, p. 136-179), was expanded to suggest that postreproductive women (in contrast to males) contribute to their inclusive fitness by extending support to their grandchildren. We used discrete time event history analysis (Allison [1984] Event History Analysis, Newbury Park: Sage; Allison [1995] Survival Analysis, Cary, NC: SAS Institute) and logistic regression on data provided in population registers (Shūmon Aratame Chō, or SAC) from a village in central Japan, covering the period from 1671-1871, in a preliminary investigation of the effects of household grandparental presence on the probability of a child's death. We found that after accounting for the presence of other household members, the only grandparent whose presence exerted a consistent negative effect on the likelihood of a child's death was the mother's mother. Due to the small sample size of households that contained maternal grandmothers, these results failed to achieve statistical significance. Their importance, however, is in what they suggest about future research, i.e., census data from preindustrial societies can provide a basis for testing evolutionary proposals, including the "grandmother hypothesis."
人类进化研究中一个尚未解决的问题与人类女性绝经后期的功能有关。如果绝经不仅仅是文明带来的益处所导致的一种假象，那么必然存在一种适应性机制，有利于那些在最后一次排卵后仍能健康生活的女性的后代。“祖母假说”是在威廉姆斯（1957年，《进化》第11卷：32 - 39页）最初提出的“早停止生育”对已出生子女有益这一观点的基础上发展而来的。这个观点，结合亲缘选择（汉密尔顿，1964年，《理论生物学杂志》第7卷：1 - 52页）和亲代投资（特里弗斯，1972年，《性选择与人类的起源》，芝加哥：阿尔丁出版社，第136 - 179页）的概念，进一步拓展为认为绝经后期的女性（与男性不同）通过向孙辈提供支持来提高其广义适合度。我们运用离散时间事件史分析（艾利森[1984年]，《事件史分析》，纽伯里公园：塞奇出版社；艾利森[1995年]，《生存分析》，北卡罗来纳州卡里：SAS研究所）以及逻辑回归，对日本中部一个村庄在1671年至1871年期间人口登记册（《住民案内帐》，简称SAC）中提供的数据进行分析，初步研究家庭中祖父母的存在对孩子死亡概率的影响。我们发现，在考虑了其他家庭成员的存在之后，唯一一位其存在对孩子死亡可能性产生持续负面影响的祖父母是孩子母亲的母亲。由于包含外祖母的家庭样本量较小，这些结果未能达到统计学显著性。然而，它们的重要性在于对未来研究的启示，即来自前工业化社会的人口普查数据可为检验包括“祖母假说”在内的进化假设提供依据。
