We perform a meta analysis of gender differences in the standard windfall gains dictator game (DG) by collecting raw data from 53 studies with 117 conditions, giving us 15,016 unique individual observations. We find that women on average give 4 percentage points more than men (Cohen’s $d=0.16$), and that this difference decreases to $3.1\%$ points (Cohen’s $d=0.13$) if we exclude studies where dictators can only give all or nothing. The gender difference is larger if the recipient in the DG is a charity, compared to the standard DG with an anonymous individual as the recipient (a 10.9 versus a $2.3\%$ points gender difference). These effect sizes imply that many individual studies on gender differences are underpowered; the median power in our sample of standard DG studies is only $9\%$ to detect the meta-analytic gender difference at the $5\%$ significance level. Moving forward on this topic, sample sizes should thus be substantially larger than what has been the norm in the past.

Do people discriminate between men and women when they have the option to punish defectors or reward cooperators? Here, we report on four pre-registered experiments that shed some light on this question. Study 1 (N = 544) shows that people do not discriminate between genders when they have the option to punish (reward) defectors (cooperators) in a one-shot prisoner’s dilemma with third-party punishment/reward. Study 2 (N = 253) extends Study 1 to a different method of punishing/rewarding: participants are asked to rate the behaviour of a defector/cooperator on a scale of 1–5 stars. In this case too, we find that people do not discriminate between genders. Study 3a (N = 331) and Study 3b (N = 310) conceptually replicate Study 2 with a slightly different gender manipulation. These latter studies show that, in situations where they do not have specific beliefs about the gender of the defector/cooperator’s partner, neither men nor women discriminate between genders.

We study the effects on performance of incentives framed as gains or losses, as well as the effort channels through which individuals increase performance. We also explore potential spill-over effects on a non-incentivised activity. Subjects participated in a medically framed real-effort task under one of the three contracts, varying the type of performance incentive received: (1) no incentive; (2) incentive framed as a gain; or (3) incentive framed as a loss. We find that performance improved similarly with incentives framed as losses or gains. However, individuals increase performance differently under the two frames: potential losses increase participants’ performance through a greater attention (fewer mistakes), while bonuses increase the time spent on the rewarded activity. There is no spill-over effect, either negative or positive, on the non-incentivised activity. We discuss the meaning and implications of our results for the design of performance contracts.

Cooperation motives are traditionally elicited in experimental games where players have misaligned interests that yield noncooperation in equilibrium. Research finds a typology of behavioral types such as free riders and conditional cooperators. However, intrinsic motives in conflict settings such as appeasement, punishment, and greed are elusive in such games where noncooperation is the equilibrium prediction. To identify types in the dark side of human interaction, we apply hierarchical cluster analysis to data from the Vendetta Game, which has a payoff structure similar to public goods games but a dynamic move structure that yields cooperation in equilibrium. It allows us to observe diverse non-equilibrium conflict strategies, and to understand how feuds perpetuate. We relate our method and typology to other social dilemmas.

Internet services are often free of charge but ask for customers’ personal data in exchange for usage. We experimentally study whether the provision of information-based public goods is susceptible to restraint when contributions not only make contributors better off but also enable a non-contributing “big player” to acquire substantial profits. We show that the presence of the big player crowds out the willingness to provide neutral tokens, but no such effect is observed for the provision of private information. Hence, collecting anonymized personal data instead of monetary fees can be more profitable to service providers and create greater benefits for customers.

We establish whether the efficacy of mutual monitoring in fostering cooperation is dependent on the degree of approval motivation within teams. Approval motivation is defined as the desire to produce positive perceptions in others and the incentive to acquire the approval of others as well as the desire to avoid disapproval, (Martin in J Personality Assess 48(5):508–519, 1984). Contrary to the theoretical predictions, the results from the experiment suggest that mutual monitoring was not effective in fostering cooperation in teams. Furthermore, the efficacy of mutual monitoring in fostering cooperation was not correlated with the degree of approval motivation within teams.

The famous linguistic-savings hypothesis states that languages that grammatically separate the future from the present (like English) causally induce less future-oriented behavior than languages in which speakers can refer to the future using present tense (like German or Chinese). Chen et al., European Economic Review 120 (2019) experimentally investigate the effect of using future-oriented language on incentivized intertemporal choices and find no support for the hypothesis. We replicate Chen et al., European Economic Review 120 (2019)’s study in the German-speaking context. In our experiment with 332 subjects, we randomly refer to future payments using present or future tense and find no causal effect of language on intertemporal choice. Given the importance of replications for confidence in scientific findings, our results provide corroborating evidence that the linguistic-savings hypothesis is not empirically tenable. Eventually, the results provide a methodological contribution to the conduct of experiments.