Social animals can improve their decisions by attending to those made by others. The benefit of this social information must be balanced against the costs of obtaining and processing it. Previous work has focused on rational agents that respond optimally to a sequence of prior decisions. However, full decision sequences are potentially costly to perceive and process. As such, animals may rely on simpler social information, which will affect the social behaviour they exhibit. Here, I derive the optimal policy for agents responding to simplified forms of social information. I show how the behaviour of agents attending to the aggregate number of previous choices differs from those attending to just the most recent prior decision, and I propose a hybrid strategy that provides a highly accurate approximation to the optimal policy with the full sequence. Finally, I analyse the evolutionary stability of each strategy, showing that the hybrid strategy dominates when cognitive costs are low but non-zero, while attending to the most recent decision is dominant when costs are high. These results show that agents can employ highly effective social decision-making rules without requiring unrealistic cognitive capacities, and indicate likely ecological variation in the social information different animals attend to.

社会性动物可以通过关注其他人的决定来改进他们的决定。这种社会信息的好处必须与获取和处理它的成本相平衡。以前的工作集中在对一系列先前决策做出最佳反应的理性代理上。然而，完整的决策序列的感知和处理成本可能很高。因此，动物可能依赖更简单的社会信息，这将影响它们表现出的社会行为。在这里，我推导出代理响应简化形式的社会信息的最佳策略。我展示了参与先前选择总数的代理的行为与仅关注最近的先前决策的代理的行为有何不同，并且我提出了一种混合策略，该策略为具有完整序列的最优策略提供了高度准确的近似。最后，我分析了每种策略的进化稳定性，表明当认知成本低但非零时，混合策略占主导地位，而当成本高时，关注最近的决策占主导地位。这些结果表明，代理可以采用高效的社会决策规则，而不需要不切实际的认知能力，并表明不同动物所关注的社会信息中可能存在的生态变化。