Belmont L, Marolla F A
Science. 1973 Dec 14;182(4117):1096-101. doi: 10.1126/science.182.4117.1096.
The relation of birth order and family size to intellectual performance, as measured by the Raven Progressive Matrices, was examined among nearly all of 400,000 19-year-old males born in the Netherlands in 1944 through 1947. It was found that birth order and family size had independent effects on intellectual performance. Effects of family size were not present in all social classes, but effects of birth order were consistent across social class.
通过瑞文标准推理测验衡量出生顺序和家庭规模与智力表现之间的关系，对1944年至1947年在荷兰出生的近40万名19岁男性进行了研究。研究发现，出生顺序和家庭规模对智力表现有独立影响。家庭规模的影响并非在所有社会阶层中都存在，但出生顺序的影响在各社会阶层中是一致的。
