ISSN 0439-755X
CN 11-1911/B

Acta Psychologica Sinica ›› 2021, Vol. 53 ›› Issue (7): 758-772.doi: 10.3724/SP.J.1041.2021.00758

• Reports of Empirical Studies • Previous Articles     Next Articles

Spillover effects of third-party punishment on cooperation: A norm-based explanation

CHEN Sijing1, XING Yilin1, WENG Yijing1, LI Chang2()   

  1. 1School of Economics and Management, Zhejiang University of Science and Technology, Hangzhou 310023, China
    2School of Business Administration, Zhejiang Gongshang University, Hangzhou 310018, China
  • Received:2020-06-08 Published:2021-07-25 Online:2021-05-24
  • Contact: LI Chang
  • Supported by:
    National Natural Science Foundation of China(71701185);Zhejiang Provincial Soft Science Project(2020C35020);Zhejiang Provincial Natural Science Foundation(LQ18G010002)


A large body of experimental evidence demonstrates that in presence of third-party punishers, cooperators can gain higher payoffs than defectors. As a result, third-party punishment (TPP) that changes the payoff structure of defectors is believed to be a key in promoting cooperation. However, this rationale is contrary to an important finding in behavioral economics: individuals are not necessarily rational decision makers and do not have purely self-regarding preferences. This contradiction raises an interesting question: can this finding also be applied to defectors? We aim to explore this question through three experiments.
In Experiment 1, 240 undergraduates participated in a Public Goods Game and were divided randomly into three conditions: control condition (CC), low defection cost condition (LC), and high defection cost condition (HC). In each round of the game, participants in CC decided whether to contribute 10 tokens from the initial endowment to the public account. All the tokens contributed to the public account were doubled and evenly allocated to all group members. Participants who retained 10 tokens needed to pay a tax of 1 token. The procedures in LC and HC were identical to that in CC. An exception is that in LC and HC, independent punishers could discipline defectors by paying 5 tokens to reduce the payoff of defectors by 1 token in LC and 10 tokens in HC. In Experiment 2, 179 participants who defected in Stage 1 were selected as sample in Stage 2 and were divided randomly into two conditions: CC (89 participants) and punishment condition (PC, 90 participants). Participants in PC were told they had been punished in Stage 1, whereas those in CC received no feedback. All participants’ levels of norm activation and cooperation in different games were then measured. Experiment 2 was replicated in Experiment 3, where the participants were not game players but spectators, and their levels of norm activation and cooperation were measured before and after the game. The participants in defection condition observed a defection and the consequent punishment, whereas those in norm condition observed a fair offer and no punishment.
In Experiment 1, the defection cost in LC was lower than that in CC, so participants in LC had a stronger incentive to defect. However, the results revealed a significantly higher cooperation level in LC. A plausible explanation is that the defection cost in form of punishment served as a norm reminder, but cost in form of tax lacked this function, implying that even defectors are not necessarily benefit maximizers. The results of Experiment 2 confirmed this explanation: compared with unpunished defectors, the punished ones manifested a higher level of norm activation. The bootstrap analysis showed that the norm activation completely mediated TPP and cooperation. Experiment 2 also found a spillover effect of TPP: the punished defectors still demonstrated a high cooperation in a new different game where the sanction was absent. Finally, Experiment 3 found another spillover effect of TPP: bystanders who did not experience the punishment in person but witnessed it showed a significantly higher cooperation in subsequent interactions.
In conclusion, oftentimes, people defect simply because they are unaware of the existence of a certain norm and activating people’s norms through TPP can significantly reduce their selfish behaviors. In addition to being an economic means to reduce defectors’ payoff, TPP serves as a norm reminder. The two spillover effects found in this study suggest that TPP as a means of norm activation may be more efficient than as an economic means because of its cost-effectiveness. These findings shed new light on the understanding of extensive cooperation among genetically unrelated individuals.

Key words: third-party punishment, social norm, cooperation, focus theory, spillover effect