Meta-analysis reveals support for the Social Intelligence Hypothesis

The Social Intelligence Hypothesis (SIH) is one of the leading explanations for the evolution of cognition. Since its inception a vast body of literature investigating the predictions of the SIH has accumulated, using a variety of methodologies and species. However, the generalisability of the hypothesis remains unclear. To gain an understanding of the robustness of the SIH as an explanation for the evolution of cognition, we systematically searched the literature for studies investigating the predictions of the SIH. Accordingly, we compiled 103 studies with 584 effect sizes from 17 taxonomic orders. We present four meta-analyses which reveal support for the SIH across interspecific, intraspecific and developmental studies. However, effect sizes did not significantly differ between the cognitive or sociality metrics used, taxonomy or testing conditions. Thus, support for the SIH is similar across studies using neuroanatomy and cognitive performance; those using broad categories of sociality, group size and social interactions; taxonomic groups; and tests conducted in captivity or the wild. Overall, our meta-analyses support the SIH as an evolutionary and developmental explanation for cognitive variation.

社会智能假说（Social Intelligence Hypothesis, SIH）是解释认知演化的主流理论之一。自该假说提出以来，学界已积累了大量采用不同研究方法、针对不同物种、围绕社会智能假说预测展开的研究文献。然而，该假说的普适性仍未明确。为明晰社会智能假说作为认知演化解释理论的稳健性，本研究对围绕该假说预测展开的相关文献进行了系统性检索，最终共纳入来自17个分类阶元的103项研究，总计584个效应量。本研究开展了四项元分析，结果显示，在种间、种内以及发育层面的研究中，均存在支持社会智能假说的证据。但研究结果显示，所采用的认知或社会性测量指标、分类阶元以及实验条件之间，效应量并未存在显著差异。由此可见，无论研究采用神经解剖学指标还是认知表现指标、采用社会性、群体规模或社会互动等宽泛分类维度、针对不同分类阶元，或是在圈养与野外环境下开展实验，相关研究对社会智能假说的支持程度均较为一致。综上，本研究的元分析结果支持社会智能假说，将其作为认知变异演化与发育层面的合理解释。