Gaze-contingent reinforcement learning reveals incentive value of social signals in young children and adults

While numerous studies have demonstrated that infants and adults preferentially orient to social stimuli, it remains unclear as to what drives such preferential orienting. It has been suggested that the learned association between social cues and subsequent reward delivery might shape such social orienting. Using a novel, spontaneous indication of reinforcement learning (with the use of a gaze contingent reward-learning task), we investigated whether children and adults' orienting towards social and non-social visual cues can be elicited by the association between participants' visual attention and a rewarding outcome. Critically, we assessed whether the engaging nature of the social cues influences the process of reinforcement learning. Both children and adults learned to orient more often to the visual cues associated with reward delivery, demonstrating that cue–reward association reinforced visual orienting. More importantly, when the reward-predictive cue was social and engaging, both children and adults learned the cue–reward association faster and more efficiently than when the reward-predictive cue was social but non-engaging. These new findings indicate that social engaging cues have a positive incentive value. This could possibly be because they usually coincide with positive outcomes in real life, which could partly drive the development of social orienting.

尽管已有大量研究证实婴儿与成人会优先定向于社会性刺激，但目前仍未明确驱动此类优先定向行为的核心机制。有研究提出，社会性线索与后续奖励递送之间的习得性联结，或许会塑造这类社会性定向行为。本研究采用注视依存型奖励学习任务（gaze contingent reward-learning task）作为强化学习（reinforcement learning）的新颖自发性指标，探究参与者的视觉注意力与奖励结果之间的联结，是否能够引发儿童与成人对社会性及非社会性视觉线索的定向行为。关键在于，我们评估了社会性线索的互动性特质是否会对强化学习过程产生影响。结果显示，儿童与成人均会更频繁地定向于与奖励递送相关联的视觉线索，证实了线索-奖励联结可强化视觉定向行为。更为重要的是，当奖励预测性线索为具有互动性的社会性线索时，儿童与成人学习线索-奖励联结的速度与效率，均显著高于奖励预测性线索为非互动性社会性线索的情况。上述新发现表明，具有互动性的社会性线索具备正向激励价值。这可能是因为在现实生活中，此类线索通常与正向结果相伴，进而在一定程度上推动了社会性定向能力的发展。