Blake J
Demography. 1981 Nov;18(4):421-42.
If couples decide to have fewer children in order to achieve higher "quality" offspring, are they correct in assuming that the quality of children bears an important and inverse relation to family size? If they are correct, how does number of children operate to affect individual quality? This research (using U.S. whites primarily) takes educational attainment (among adults) and college plans (among youngsters) as the principal indicators of quality, but also directs some attention to measures of intelligence. The analysis supports the "dilution model" (on average, the more children the lower the quality of each child) and indicates that only children do not suffer from lack of siblings, and that other last-borns are not handicapped by a "teaching deficit." Number of siblings (relative to other background variables) is found to have an important detrimental impact on child quality--an impact compounded by the fact that, when couples are at a stage in life to make family-size decisions, most background factors (however important to the quality of their children) are no longer readily manipulable. A special path analysis of college plans among boys uses a modification of Sewell's Wisconsin Model as its base. The results show that number of siblings is a negative influence on intervening variables affecting college plans. In general, the research documents the unfavorable consequences for individual siblings of high fertility, even in a country that is (at least for whites) as socially, economically, and politically advantaged as the United States.
如果夫妻为了生育出“质量”更高的后代而决定少生孩子，那么他们认为孩子的质量与家庭规模呈重要的反比关系这一假设正确吗？如果他们是正确的，孩子的数量是如何影响个体质量的呢？这项研究（主要以美国白人作为研究对象）将教育程度（针对成年人）和大学计划（针对青少年）作为质量的主要指标，但也对智力测量给予了一定关注。分析支持了“稀释模型”（平均而言，孩子越多，每个孩子的质量越低），并表明独生子女不会因缺少兄弟姐妹而受影响，其他最小的孩子也不会因“教育不足”而处于劣势。研究发现，兄弟姐妹的数量（相对于其他背景变量）对孩子的质量有重要的不利影响——这种影响因以下事实而加剧：当夫妻处于做出家庭规模决策的人生阶段时，大多数背景因素（无论对孩子的质量多么重要）都不再容易控制。一项针对男孩大学计划的特殊路径分析以对休厄尔的威斯康星模型的修正版本为基础。结果表明，兄弟姐妹的数量对影响大学计划的中间变量有负面影响。总体而言，该研究证明了高生育率对个体兄弟姐妹产生的不利后果，即使是在一个（至少对白人而言）在社会、经济和政治方面像美国一样具有优势的国家。
