On the value(s) of time: Workers' value of their time depends on mode of valuation.

In this paper, we investigate how individuals make time-money tradeoffs in labor contexts in which they are either asked to work to earn money or to pay money to avoid work. Theory predicts that exchange rates between time and money are invariant to the elicitation method. Results from our experiments, however, show otherwise, highlighting inconsistencies in how individuals consider their time. In the first two experiments, participants work to earn money, and we compare two incentivized elicitation methods. In the first, "Fixed-Time mode," we fix the amount of time participants need to work and elicit the minimum dollar amount they require to do the job. In the second, "Fixed-Money mode," we fix the amount of money we pay participants and ask for the maximum amount of time they are willing to work for that pay. We similarly vary elicitation procedures in Experiment 3 for paying money to avoid work. Translating the results into pay per hour, we find that in Fixed-Time mode, valuation of time is stable across durations, based on an analytical approach. By contrast, in Fixed-Money mode, participants increase their pay-per-hour demand when the amount of money increases, indicating a less calculated and more emotional view of time. Our results demonstrate that individuals' value of their time of labor can be fluid and dependent on the compensation structure. Our findings have implications for theories of time valuation in the labor market.

Competitiveness, gender and handedness.

We conduct an intercultural experiment in three locations on three different continents to elicit competitiveness and study whether individual differences in competitiveness are related to handedness. Being a "lefty" (i.e., having either a dominant left hand or a dominant left foot) is associated with neurological differences which are determined prenatally, and can therefore be seen as a proxy for innate differences. In large-scale data with incentivized choices from 3664 participants from India, Norway and Tanzania, we find a significant gender gap in competitiveness in all cultures. However, we find inconsistent results when comparing the competitiveness of lefties and righties. In north-east India we find that lefties of both genders are significantly more competitive than righties. In Norway we find that lefty men are more competitive than any other group, but women's competitiveness is not related to handedness. In Tanzania, we find no relationship between handedness and the competitiveness of either gender. The merged data show weak evidence of a positive correlation between being a lefty and competitiveness for men, but no such evidence for women. Thus, our data provide suggestive but not robust evidence that individual and gender differences in competitiveness are partially determined by innate factors, where innate factors are proxied by the complex, prenatally shaped trait of handedness.

Nonreplicable publications are cited more than replicable ones.

We use publicly available data to show that published papers in top psychology, economics, and general interest journals that fail to replicate are cited more than those that replicate. This difference in citation does not change after the publication of the failure to replicate. Only 12% of postreplication citations of nonreplicable findings acknowledge the replication failure. Existing evidence also shows that experts predict well which papers will be replicated. Given this prediction, why are nonreplicable papers accepted for publication in the first place? A possible answer is that the review team faces a trade-off. When the results are more "interesting," they apply lower standards regarding their reproducibility.

The endowment effect: Loss aversion or a buy-sell discrepancy?

In a typical endowment effect experiment, individuals state a higher willingness-to-accept to sell an object than a willingness-to-pay to obtain the object. The leading explanation for the endowment effect is loss aversion for the object. An alternative explanation is based on a buy-sell discrepancy, according to which people price the object in a strategic way. Disentangling these two explanations is the goal of this research. To this end, we introduce a third condition, in which participants receive an object and are asked how much they are willing to pay to keep it (Pay-to-Keep). Comparing the three conditions we find no evidence for loss aversion in the endowment effect setting. We found support for the buy-sell strategy mechanism. Our results have important implications for the understanding of buyer and seller behaviors, subjective value, and elicitation methods. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Can Short Psychological Interventions Affect Educational Performance? Revisiting the Effect of Self-Affirmation Interventions.

Large amounts of resources are spent annually to improve educational achievement and to close the gender gap in sciences with typically very modest effects. In 2010, a 15-min self-affirmation intervention showed a dramatic reduction in this gender gap. We reanalyzed the original data and found several critical problems. First, the self-affirmation hypothesis stated that women's performance would improve. However, the data showed no improvement for women. There was an interaction effect between self-affirmation and gender caused by a negative effect on men's performance. Second, the findings were based on covariate-adjusted interaction effects, which imply that self-affirmation reduced the gender gap only for the small sample of men and women who did not differ in the covariates. Third, specification-curve analyses with more than 1,500 possible specifications showed that less than one quarter yielded significant interaction effects and less than 3% showed significant improvements among women.

Giving behavior of millionaires.

This paper studies conditions influencing the generosity of wealthy people. We conduct incentivized experiments with individuals who have at least €1 million in their bank account. The results show that millionaires are more generous toward low-income individuals in a giving situation when the other participant has no power, than in a strategic setting, where the other participant can punish unfair behavior. Moreover, the level of giving by millionaires is higher than in any other previous study. Our findings have important implications for charities and financial institutions that deal with wealthy individuals.

An experimental investigation of evolutionary dynamics in the Rock-Paper-Scissors game.

Game theory describes social behaviors in humans and other biological organisms. By far, the most powerful tool available to game theorists is the concept of a Nash Equilibrium (NE), which is motivated by perfect rationality. NE specifies a strategy for everyone, such that no one would benefit by deviating unilaterally from his/her strategy. Another powerful tool available to game theorists are evolutionary dynamics (ED). Motivated by evolutionary and learning processes, ED specify changes in strategies over time in a population, such that more successful strategies typically become more frequent. A simple game that illustrates interesting ED is the generalized Rock-Paper-Scissors (RPS) game. The RPS game extends the children's game to situations where winning or losing can matter more or less relative to tying. Here we investigate experimentally three RPS games, where the NE is always to randomize with equal probability, but the evolutionary stability of this strategy changes. Consistent with the prediction of ED we find that aggregate behavior is far away from NE when it is evolutionarily unstable. Our findings add to the growing literature that demonstrates the predictive validity of ED in large-scale incentivized laboratory experiments with human subjects.

Behavioral economics. Avoiding overhead aversion in charity.

Donors tend to avoid charities that dedicate a high percentage of expenses to administrative and fundraising costs, limiting the ability of nonprofits to be effective. We propose a solution to this problem: Use donations from major philanthropists to cover overhead expenses and offer potential donors an overhead-free donation opportunity. A laboratory experiment testing this solution confirms that donations decrease when overhead increases, but only when donors pay for overhead themselves. In a field experiment with 40,000 potential donors, we compared the overhead-free solution with other common uses of initial donations. Consistent with prior research, informing donors that seed money has already been raised increases donations, as does a $1:$1 matching campaign. Our main result, however, clearly shows that informing potential donors that overhead costs are covered by an initial donation significantly increases the donation rate by 80% (or 94%) and total donations by 75% (or 89%) compared with the seed (or matching) approach.

Paying more when paying for others.

Social behavior is heavily influenced by the perception of the behaviors of others. We considered how perceptions (and misperceptions) of kindness can increase generosity in economic transactions. We investigated how these perceptions can alter behavior in a novel real-life situation that pitted kindness against selfishness. That situation, consumer elective pricing, is defined by an economic transaction allowing people to purchase goods or services for any price (including zero). Field and lab experiments compared how people behave in 2 financially identical circumstances: pay-what-you-want (in which people are ostensibly paying for themselves) and pay-it-forward (in which people are ostensibly paying on behalf of someone else). In 4 field experiments, people paid more under pay-it-forward than pay-what-you-want (Studies 1-4). Four subsequent lab studies assessed whether the salience of others explains the increased payments (Study 5), whether ability to justify lowered payments (Study 6), and whether the manipulation was operating through changing the perceptions of others (Studies 7 and 8). When people rely on ambiguous perceptions, pay-it-forward leads to overestimating the kindness of others and a corresponding increase in personal payment. When those perceptions are replaced with explicit descriptive norms (i.e., others' payment amounts), that effect is eliminated. Finally, subsequent studies confirmed that the effects were not driven by participant confusion (Studies 9A and 9B) and not limited by the specificity of the referent other in the pay-it-forward framing (Study 9C).

Materazzi effect and the strategic use of anger in competitive interactions.

We propose that individuals use anger strategically in interactions. We first show that in some environments angering people makes them more effective in competitions, whereas in others, anger makes them less effective. We then show that individuals anticipate these effects and strategically use the option to anger their opponents. In particular, they are more likely to anger their opponents when anger negatively affects the opponents' performances. This finding suggests people understand the effects of emotions on behavior and exploit them to their advantage.

Rise and fall of competitiveness in individualistic and collectivistic societies.

Competitiveness pervades life: plants compete for sunlight and water, animals for territory and food, and humans for mates and income. Herein we investigate human competitiveness with a natural experiment and a set of behavioral experiments. We compare competitiveness in traditional fishing societies where local natural forces determine whether fishermen work in isolation or in collectives. We find sharp evidence that fishermen from individualistic societies are far more competitive than fishermen from collectivistic societies, and that this difference emerges with work experience. These findings suggest that humans can evolve traits to specific needs, support the idea that socio-ecological factors play a decisive role for individual competitiveness, and provide evidence how individualistic and collectivistic societies shape economic behavior.

Pay-what-you-want, identity, and self-signaling in markets.

We investigate the role of identity and self-image consideration under "pay-what-you-want" pricing. Results from three field experiments show that often, when granted the opportunity to name the price of a product, fewer consumers choose to buy it than when the price is fixed and low. We show that this opt-out behavior is driven largely by individuals' identity and self-image concerns; individuals feel bad when they pay less than the "appropriate" price, causing them to pass on the opportunity to purchase the product altogether.

Nurture affects gender differences in spatial abilities.

Women remain significantly underrepresented in the science, engineering, and technology workforce. Some have argued that spatial ability differences, which represent the most persistent gender differences in the cognitive literature, are partly responsible for this gap(.) The underlying forces at work shaping the observed spatial ability differences revolve naturally around the relative roles of nature and nurture. Although these forces remain among the most hotly debated in all of the sciences, the evidence for nurture is tenuous, because it is difficult to compare gender differences among biologically similar groups with distinct nurture. In this study, we use a large-scale incentivized experiment with nearly 1,300 participants to show that the gender gap in spatial abilities, measured by time to solve a puzzle, disappears when we move from a patrilineal society to an adjoining matrilineal society. We also show that about one-third of the effect can be explained by differences in education. Given that none of our participants have experience with puzzle solving and that villagers from both societies have the same means of subsistence and shared genetic background, we argue that these results show the role of nurture in the gender gap in cognitive abilities.

Shared social responsibility: a field experiment in pay-what-you-want pricing and charitable giving.

A field experiment (N = 113,047 participants) manipulated two factors in the sale of souvenir photos. First, some customers saw a traditional fixed price, whereas others could pay what they wanted (including $0). Second, approximately half of the customers saw a variation in which half of the revenue went to charity. At a standard fixed price, the charitable component only slightly increased demand, as similar studies have also found. However, when participants could pay what they wanted, the same charitable component created a treatment that was substantially more profitable. Switching from corporate social responsibility to what we term shared social responsibility works in part because customized contributions allow customers to directly express social welfare concerns through the purchasing of material goods.