Currently there is a lack of psychological studies that evaluate the relationship between individual goals and unethical behaviours such as cheating, lying and stealing. However, Feldman and colleagues (2015) meta-analytically review studies on attitudes towards unethicality and find that self-enhancement values are consistently related to positive attitudes towards unethicality among 12 effect sizes that are based on a total sample of 125,908 individuals. As self-enhancement values are closely related to extrinsic materialistic goals (Grouzet et al., 2005; Maio et al., 2009), it is highly plausible that these goals would also positively predict unethical behaviours. Indeed, a meta-analysis (Moldes and Ku, 2020) that is based on 27 independent studies and 62 effect sizes (N = 3,649) reviews the experimental evidence of materialism’s effect on societal well-being, and shows that materialistic values are causally and positively related to antisocial tendency and behaviours such as unethical decision making, condonement of greed and stealing, and endorsement of business corruption.

One of the most common unethical behaviours is lying for monetary rewards, and hence our choice to focus on this particular behaviour in the project. In the experimental research paradigm on (dis)honesty and lying, a method commonly known as ‘die-under-the-cup’ (DUC; see Shalvi et al. 2011a; 2011b; Fischbacher and Follmi-Heusi, 2013; Gaetcher and Schulz, 2016) is the most well researched and used. In the original paradigm, each participant is to roll a 6-sided dice under a cup (to avoid the outcome being seen by others) and report the outcome, which determines the monetary payoff the participants receive. The researchers do not know whether individual participants are telling the truth or lying, and this is made clear to the participants. In addition, the decision to lie or not does not affect other participants, so there is no social cost or externality for lying behaviour. Many studies adopt an online variation of the DUC, such as Gaetcher and Schulz’s (2016) multi-country study, and have documented the lying tendency of participants. However, Charness et al. (2019) show that participants do not lie in the absence of financial incentives, whereas Alfonso-Costillo et al. (2022) demonstrate that participants’ lying behaviour is related to the monetary reward pattern.