Perceived social norm and behavior quickly adjusted to legal changes during the COVID-19 pandemic.

Exploring the joint dynamics of laws and social norms helps understand when social norms are sticky or adaptive. Using the example of the social and physical distancing measures introduced to contain the COVID-19 pandemic in 2020, we studied whether introducing, and then lifting, distancing regulations led individuals to quickly change their habits, not only by modifying the monetary incentives of rule violators but also by shifting the individuals' perception of the appropriateness of social encounters. We conducted an online incentivized experiment in France, where we elicited the same participants' perceived norm and social distancing behavior every week for three months. We find that both norm perception and behavior shifted as soon as the government introduced or removed social distancing measures. This effect was fast acting and long lasting, a result that highlights the importance of the expressive power of the law for norm formation and behavior.

Unethical amnesia responds more to instrumental than to hedonic motives.

Humans care about morality. Yet, they often engage in actions that contradict their moral self. Unethical amnesia is observed when people do not remember or remember less vividly these actions. This paper explores two reasons why individuals may experience unethical amnesia. Forgetting past unethical behavior may be motivated by purely hedonic or affective reasons, such as the willingness to maintain one's moral self-image, but also by instrumental or strategic motives, in anticipation of future misbehavior. In a large-scale incentivized online experiment (n = 1,322) using a variant of a mind game, we find that hedonic considerations are not sufficient to motivate the forgetting of past cheating behavior. This is confirmed in a follow-up experiment (n = 1,005) in which recalls are elicited the same day instead of 3 wk apart. However, when unethical amnesia can serve as a justification for a future action, such as deciding on whether to keep undeserved money, motivated forgetting is more likely. Thereby, we show that motivated forgetting occurs as a self-excuse to justify future immoral decisions.

Endogenous testosterone is associated with increased striatal response to audience effects during prosocial choices.

The role of testosterone on cognitive functions in humans remains controversial. One recent hypothesis suggests that this steroid hormone advances social status. As being observed by others is known to modulate a range of behaviors because of image concerns, we hypothesized that such an audience effect might be an important component of status seeking that is under the control of testosterone. Thus, we investigated to which extent testosterone levels are associated with the effect of being observed during prosocial choices and the neural mechanisms underlying this effect. We enrolled twenty-four male participants, aged 22.47 ± 2.62 years, in an fMRI experiment to examine the relationship between testosterone levels and brain activity engaged in deciding whether to accept or reject monetary transfers to two types of organizations (a positively evaluated organization and a negatively evaluated organization) in presence or absence of an audience. When comparing the public to the private condition, the rate of acceptance increased for the positively evaluated organization, while the rate of rejection increased for the negatively evaluated one. Higher testosterone levels were linked to greater activation in the striatum in the public compared to the private condition, regardless of the organization type. These results indicate a relationship between testosterone levels and striatal activity induced by the audience effect. These findings provide new insights on the role of testosterone in human social behavior.

Dishonesty is more affected by BMI status than by short-term changes in glucose.

There is evidence that human decision-making is affected by current body energy levels and physiological states. There is less clear evidence linking decision-making to long-term changes in energy, as those associated with obesity. We explore the link between energy, obesity and dishonesty by comparing the behaviour of obese and lean subjects when hungry or sated while playing an anonymous die-under-cup task. Participants performed the task either before or after breakfast. We find that short-term switches in energy have only a mild effect on dishonesty, as only lean females lie less when sated. By contrast, obese subjects lie more than lean subjects in both conditions, and they lie more to avoid the lowest payoff than to get the highest payoff. Our findings suggest that the observed patterns are more likely mediated by factors associated with obesity than by short term energy dynamics, and call for a better integration of the psychological, economic and biological drivers of moral behaviour.

Neurocomputational mechanisms at play when weighing concerns for extrinsic rewards, moral values, and social image.

Humans not only value extrinsic monetary rewards but also their own morality and their image in the eyes of others. Yet violating moral norms is frequent, especially when people know that they are not under scrutiny. When moral values and monetary payoffs are at odds, how does the brain weigh the benefits and costs of moral and monetary payoffs? Here, using a neurocomputational model of decision value (DV) and functional (f)MRI, we investigated whether different brain systems are engaged when deciding whether to earn money by contributing to a "bad cause" and when deciding whether to sacrifice money to contribute to a "good cause," both when such choices were made privately or in public. Although similar principles of DV computations were used to solve these dilemmas, they engaged 2 distinct valuation systems. When weighing monetary benefits and moral costs, people were willing to trade their moral values in exchange for money, an effect accompanied by DV computation engaging the anterior insula and the lateral prefrontal cortex (PFC). In contrast, weighing monetary costs against compliance with one's moral values engaged the ventral putamen. Moreover, regardless of the type of dilemma, a brain network including the anterior cingulate cortex (ACC), anterior insula, and the right temporoparietal junction (TJP) was more engaged in public than in private settings. Together, these findings identify how the brain processes three sources of motivation: extrinsic rewards, moral values, and concerns for image.