Dr Bogaert reasoned that if the effect were social, elder brothers would wield the same power even if they had not been born to the same mother.
博加尔特推论，如果影响来自社会生活，哥哥们即便不是出生自同一个母亲，也会对其弟弟造成同样的影响。
3
Because most of the men from these three study groups came from unbroken families, Bogaert looked at a fourth group, composed of men who had been adopted or raised with half - or step-siblings.