Michel J.J. Handgraaf

Wageningen University & Research | WUR · Economics of Consumers and Households Group

Any solution to rising levels of CO2 depends on human behavior. One common approach to changing human behavior is rewarding desired behavior. Because financial incentives often have side effects that diminish efficacy, we predict that social rewards are more effective, because they invoke adherence to descriptive and injunctive social norms. We inv...

Humans regulate intergroup conflict through parochial altruism; they self-sacrifice to contribute to in-group welfare and to aggress against competing out-groups. Parochial altruism has distinct survival functions, and the brain may have evolved to sustain and promote in-group cohesion and effectiveness and to ward off threatening out-groups. Here,...

The authors investigate the effect of power differences and associated expectations in social decision making. Using a modified ultimatum game, the authors show that allocators lower their offers to recipients when the power difference shifts in favor of the allocator. Remarkably, however, when recipients are completely powerless, offers increase....

Many campaigns targeting pro-environmental behavior combine multiple approaches without properly understanding how these different approaches interact. Here we study the effect of such combinations. We apply construal level theory to classify different intervention approaches, which can either be at a high construal level (abstract and distant) or...

Construal level manipulations. (PDF)

Initiative of experiment explained. (PDF)

Use of objective energy data for analyses. (PDF)

Results repeated measures analyses on self-report measures. (PDF)

Survey questions–Not previously published. (PDF)

Social distance manipulations. (PDF)

Correlations between self-reported values and measures warm water and electricity use during baseline. (PDF)

Main effects in repeated measures analyses on average energy and water use. (PDF)

Main effects in repeated measures analyses on the average self-report measures. (PDF)

Absolute change in water use throughout 6-week intervention period compared to baseline. (PDF)

The interaction between the covariates and time in the repeated measures analyses (p-values are reported). (PDF)

The effect of time and the interaction between time and the independent variables in the repeated measures analysis on objectively measured water use. (PDF)

Many everyday decisions have an intertemporal character and are consequently influenced by an individual’s time orientation. In Section 1, we discuss and compare various conceptualizations of time orientation, such as discounting, time perspective and consideration of future consequences, and ways to measure these concepts. In addition, we provide...

Eating and exercising behaviour are both characterized by immediate and future consequences. Consequently, consideration of these consequences (i.e., time orientation) predicts eating and exercising behaviour. We investigate whether construal level acts as an underlying mechanism of these relations. Students (N = 101) completed measures of consider...

Environmental and health issues are two of the most pressing issues society faces today. People often view both environmental and health issues as psychologically distant: they believe that the problems will occur in the future, to other people, in other places and that the exact outcomes are uncertain. This paper provides an overview of studies th...

In light of the current obesity epidemic, individual choices for food and exercise should be understood better. Consideration of the immediate and future consequences of these choices (i.e., time orientation) can be an important predictor of eating and exercising behavior. The objective was to show that behavior-specific time orientation differenti...

Intergroup conflict is often driven by an individual's motivation to protect oneself and fellow group members against the threat of out-group aggression, including the tendency to pre-empt out-group threat through a competitive approach. Here we link such defense-motivated competition to oxytocin, a hypothalamic neuropeptide involved in reproductio...

In intergroup competition and conflict, humans benefit from coalitions with strong partners who help them to protect their in-group and prevail over competing out-groups. Here, we link oxytocin, a neuropeptide produced in the hypothalamus, to ally selection in intergroup competition. In a double-blind placebo-controlled experiment, males self-admin...

Studying group decision-making is challenging for multiple reasons. An important logistic difficulty is studying a sufficiently large number of groups, each with multiple participants. Assembling groups online could make this process easier and also provide access to group members more representative of real-world work groups than the sample of col...

Previous research conducted in the United States has demonstrated that help-seekers fail to appreciate the embarrassment and awkwardness (i.e., social costs) targets would experience by saying "no" to a request for help. Underestimation of such social costs leads help-seekers to underestimate the likelihood that others will comply with their reques...

In bargaining, buyers aim to spend as little money as they can on the items they seek to purchase. Compared to promotion-oriented people, prevention-oriented people seek to avoid losses rather than to secure gains. Employing different negotiation scenarios, three lab experiments tested the prediction that prevention-oriented buyers would thus displ...

Narrow self-interest is often used as a simplifying assumption when studying people making decisions in social contexts. Nonetheless, people exhibit a wide range of different motivations when choosing unilaterally among interdependent outcomes. Measuring the magnitude of the concern people have for others, sometimes called Social Value Orientation...

This study examined how caregivers‟ biased perceptions of ability to help traumatized patients relates to these caregivers‟ secondary traumatic stress (STS). There is reason to believe that caregivers overestimate their ability to help, and underestimate their vulnerability to develop STS, but it is unclear how such unrealistic optimism relates to...

Information advantage enables people to benefit themselves by deceiving their counterparts. Using a modified ultimatum bargaining game with an exit option, we find that people are more likely to avoid settings enabling them to privately deceive their counterparts than settings which do not enable deception. This tendency is explained by people's re...

Employing a die-under-cup paradigm, we study the extent to which people lie when it is transparently clear they cannot be caught. We asked participants to report the outcome of a private die roll and gain money according to their reports. Results suggest that the degree of lying depends on the extent to which self-justifications are available. Spec...

Individual differences in decision making are a topic of longstanding interest, but often yield inconsistent and contradictory results. After providing an overview of individual difference measures that have commonly been used in judgment and decision-making (JDM) research, we suggest that our understanding of individual difference effects in JDM m...

Chen et al. (1) raise several issues with the data and interpretations published in De Dreu et al. (2). We appreciate their constructive remarks. Here, we address their concerns and explain why our data do, in fact, show that oxytocin promotes human ethnocentrism.

This research examines whether and why people manoeuvre their unethical behaviour so as to maximize material gains at a minimal psychological cost. Employing an anonymous die-under-cup paradigm, we asked people to report the outcome of a private die roll and gain money as a function of their reports. Supporting self-concept maintenance theory, resu...

Human ethnocentrism--the tendency to view one's group as centrally important and superior to other groups--creates intergroup bias that fuels prejudice, xenophobia, and intergroup violence. Grounded in the idea that ethnocentrism also facilitates within-group trust, cooperation, and coordination, we conjecture that ethnocentrism may be modulated by...

Any solution to rising levels of CO2 depends on human behavior. One common approach to changing human behavior is rewarding desired behavior. Because financial incentives often have side effects that diminish efficacy, we predict that more psychologically oriented social rewards are more effective, because they invoke adherence to descriptive and i...

At a top psychology journal, Psychological Science (PS), submissions peak during the summer months. We tested whether this seasonal submission bias decreases the likelihood of a paper being accepted in that period. Month of submission data was obtained for all 575 publications in PS for the period 2003-2006. Whereas submissions to PS were higher in...

Two choice tasks known to produce framing effects in individual decisions were used to test group sensitivity to framing, relative to that of individuals, and to examine the effect of prior, individual consideration of a decision on group choice. Written post-decision reasons and pre-decision group discussions were analyzed to investigate process e...

Psychologists and economists used to see the world from their own perspectives, but currently we observe a growing common perspective, called behavioral economics or economic psychology. Traditional differences between economists and psychologists concerned self-interest and rationality of people. Psychologists now are interested in the economists’...

One of the main issues in research on ultimatum bargaining is whether bargainers are motivated by self-interest or by a concern for fairness. It is difficult to distinguish between both motivations, because it may be in the own interest to make fair offers. In the current paper on ultimatum bargaining, it is investigated whether bargainers are trul...

In bargaining, two components are important for assessing the utility of a decision outcome: self-interest and fairness. Each of these components corresponds to a comparison of possible outcomes—an interpersonal comparison for fairness, and an intrapersonal comparison for self-interest. We propose that the relative weights these components receive...

In this article we will provide an overview of factors that influence the weight that self-interest and equity related motives receive in ultimatum bargaining. These factors are grouped into three main categories: factors relating to the context of the game, factors relating to the parties involved, and factors related to characteristics of the gam...

The social utility model suggests that in social decision-making, both inter- and intrapersonal comparisons are important in assessing the utility of a decision outcome. In the ultimatum game both these comparisons play a role. This is especially true for recipients reacting to an unfair offer. We propose that the relative weights inter- and intrap...