在第二组实验中，研究人员研究了在高中就读的76对兄弟姐妹的人格差异。受试者在一系列评估人格的问卷上面做了测评。
Later born siblings were found to be more extroverted (sociable, outgoing), sentimental, forgiving and open to new experiences than their older siblings. First-borns were found to be more perfectionistic than their younger siblings.
结果显示，晚出生的孩子更加外向（社会化，开朗）、充满感情、宽容且对新事物抱有更加开放的态度。而先出生的孩子则比他们的弟弟妹妹们更加力求完美。