Better together: 14-month-old infants expect agents to cooperate even when it’s costly

Humans engage in cooperative activities from early on and the breadth of human cooperation is unparalleled. Human preference for cooperation might reflect cognitive and motivational mechanisms that reinforce engagement in cooperative activities. We applied the naive utility calculus model to cooperation and investigated if 14-month-old infants expect agents to prefer cooperative over individual goal achievement. Two groups of infants saw videos of agents facing a choice between two actions that led to identical rewards but differed in the individual costs. First, we established that infants expect agents to make instrumentally rational choices (prefer less costly individual actions). We then demonstrated that when one of the action alternatives is cooperative, infants expected agents to choose cooperation over individual action, despite the cooperative action demanding more effort from each agent to achieve the same outcome. This supports the proposal that infants may ascribe additional rewards to cooperative actions that go beyond the observable utility of instrumental actions.

人类自幼年时期起便参与合作活动，且人类合作的广度无可匹敌。人类对合作的偏好，或许反映了能够强化合作参与行为的认知与动机机制。我们将朴素效用计算模型（naive utility calculus model）应用于合作行为研究，并探究14月龄婴儿是否会期望智能体（agent）更倾向于选择合作而非单独达成目标。两组婴儿观看了智能体进行选择的视频：智能体需在两种行动方案中择一，两种方案的奖励结果完全一致，但个体所需付出的成本各不相同。首先，我们证实了婴儿会期望智能体做出工具理性的选择，即偏好个体成本更低的行动。随后我们发现，当其中一种行动方案具备合作属性时，即便该合作行动需要每位智能体付出更多努力才能达成相同结果，婴儿仍会期望智能体选择合作而非单独行动。这一结果佐证了相关假说：婴儿或许会为合作行动赋予超出工具性行为可观测效用之外的额外奖励。