Recent research on animal behavior has identified a set of common cognitive and behavioral principles that underlie animal collective decision-making. Although endeavor toward synthesizing knowledge about collective decision-making by different species has already begun, human collective phenomena, which have mainly been investigated by social scientists, are still largely left behind from this scope. However, delineating uniqueness and commonality of human collective decision-making in biological contexts is critically important to understand nature of human collectivity. Toward this end, this paper first defines the concept of collective decision-making from a biological perspective. We then review several recent key findings on collective behavior by several animal species (eusocial insects in particular), and argue that a set of fundamental processes such as positive feedback, nonlinear conformity bias and quorum-sensing, commonly underlie human and non-human collective decision-making. We sketch some future research directions to promote cross-fertilizations between the biological and social sciences for a better understanding of collective phenomena by humans and non-human animals.