Experimental games

Although polygamy is common in many parts of the world, most economic analysis of the household focuses on monogamy. We use simple public good games to investigate experimentally theories of household behavior. A unique aspect of our research is that half our sample are polygynous households recruited systematically from villages in rural areas south of Kano, Northern Nigeria, one of the modern heartlands of polygyny. Spouses play two variants of a voluntary contributions game in which endowments are private knowledge, but contributions are public. In one variant, the common pool is split equally. In the other treatment the husband allocates the pool (and wives are forewarned of this). Most partners keep back at least half of their endowment from the common pool, but we find no evidence that polygynous households are less efficient than their monogamous counterparts. We reject a strong form of Bergstrom's model of polygyny in which all wives receive an equal allocation. Senior wives often receive more from their husbands, no matter what their contribution. Thus their return to contributions is higher compared to their junior counterparts. However, the clearest result is that when they control the allocation, polygynous men receive a higher payoff compared to both their wives and their monogamous counterparts.

Neuropsychological studies implicate disruption of frontal systems in personality disorders. Few studies have examined the performance of Cluster B and Cluster C personality disorder patients on tests of orbitofrontal (OFC) and prefrontal (PFC) cortex function. Patients carrying diagnoses of either Cluster B (n=56) or Cluster C (n=19) personality disorders were compared with healthy control subjects (n=61) on the Iowa Gambling Task and University of Pennsylvania Smell Identification Test. They also completed the Wechsler Abbreviated Scale of Intelligence as a control for general intellectual ability. On the gambling task, Cluster B and Cluster C patients made more disadvantageous decisions during certain portions of the task but overall did not differ from healthy controls. Whereas no appreciable differences in olfactory identification performances were detected between patient and healthy control groups, IQ was higher for controls and was related to Cluster B patients' lower educational levels. Overall, there was limited evidence for neurocognitive inefficiency for personality disorder groups on tests sensitive to OFC and PFC function. The present study is among the first to report neurocognitive findings for the full range of Cluster B personality disorders and any Cluster C personality disorder.

What is considered to be fair depends on context‐dependent expectations. Using a modified version of the Ultimatum Game, we demonstrate that both fair behavior and perceptions of fairness depend upon beliefs about what one ought to do in a situation—that is, upon normative expectations. We manipulate such expectations by creating informational asymmetries about the offer choices available to the Proposer, and find that behavior varies accordingly. Proposers and Responders show a remarkable degree of agreement in their beliefs about which choices are considered fair. We discuss how these results fit into a theory of social norms. Copyright © 2009 John Wiley & Sons, Ltd.

Social cooperation often relies on individuals' spontaneous norm obedience when there is no punishment for violation or reward for compliance. However, people do not consistently follow pro-social norms. Previous studies have suggested that an individual's tendency toward norm conformity is affected by empirical information (i.e. what others did or would do in a similar situation) as well as by normative information (i.e. what others think one ought to do). Yet little is known about whether people have an intrinsic desire to obtain norm-revealing information. In this paper, we use a dictator game to investigate whether dictators actively seek norm-revealing information and, if so, whether they prefer to get empirical or normative information. Our data show that although the majority of dictators choose to view free information before making decisions, they are equally likely to choose empirical or normative information. However, a large majority (more than 80%) of dictators are not willing to incur even a very small cost for getting information. Our findings help to understand why norm compliance is context-dependent, and highlight the importance of making norm-revealing information salient in order to promote conformity. .

A longstanding idea in the literature on human cooperation is that cooperation should be reinforced when conditional cooperators are more likely to interact. In the context of social networks, this idea implies that cooperation should fare better in highly clustered networks such as cliques than in networks with low clustering such as random networks. To test this hypothesis, we conducted a series of experiments on Amazon Mechanical Turk, in which 24 individuals played a local public goods game arranged on one of five network topologies that varied between disconnected cliques and a random regular graph. In contrast with previous work, we found that network topology had no significant effect on average contributions. This result implies either that individuals are not conditional cooperators, or else that cooperation does not benefit from positive reinforcement between connected neighbors. We then tested both of these possibilities in two subsequent series of experiments in which artificial "seed" players were introduced, making either full or zero contributions. First, we found that although players did generally behave like conditional cooperators, they were as likely to decrease their contributions in response to low contributing neighbors as they were to increase their contributions in response to high contributing neighbors. Second, we found that positive effects of cooperation did not spread beyond direct neighbors in the network. In total we report on 113 human subjects experiments, highlighting the speed, flexibility, and cost-effectiveness of web-based experiments over those conducted in physical labs.

During childhood, schools are crucial environments for social interactions, making them ideal for evaluating the inclusion of students with special educational needs (SEN). In particular, autistic children often face challenges in peer relationships, yet the impact of autism on social dynamics in schools is not well understood. To address this issue, we examined social dynamics within elementary schools. We hypothesized that, compared to their non-autistic peers, autistic children occupy more peripheral positions in social networks and engage less in reciprocal relationships. To test these hypotheses, we introduced a novel ecological approach using experimental game theory to quantify social integration and reciprocity among autistic children. Social networks were constructed for each classroom based on the children's peer selections during a distributive game where they had to send tokens to their peers. Six elementary schools took part in this study. From these schools, 26 classrooms from first to fourth grade were included, comprising a total of 625 students aged 6 to 11. Among them, 464 were students without SEN, 143 were students with SEN excluding autism, and 18 were autistic students. Our analysis showed that autistic children and children with SEN were significantly less central and less involved in reciprocal peer relationships compared to children without SEN. Due to the small sample of autistic students, further research with greater statistical power is needed to clarify the specificity of the results. These findings highlight the need for support in promoting social inclusion while also emphasizing the importance of exploring the intersection of neurodevelopmental conditions and social dynamics.

This study examined the effects of mood and risk-taking on divergent and convergent thinking using a Q-learning computation model. The results revealed that while mood was not significantly related to divergent or convergent thinking (as creative thinking types), risk-taking exerted positive effects on divergent thinking in the face of negative rewards. The results were consistent with the representational change theory in insight problem solving. Although this theory accounts directly for insight, the underlying idea of going beyond current contexts and implicit constrains could be applied to creative thinking as well. The results indeed accounted for the relevance of this theory to divergent thinking. The current study is one of the first empirical studies simultaneously examining the role of mood and risk-taking in creativity. In particular, no related studies exist that took a computational approach to estimate the relevant parameters in the framework of dynamic optimization. Our Q learning model enables to distinguish and identify the different roles of mood and risk-taking in updating Q values and making decisions.

This study examined the effects of mood and risk-taking on divergent and convergent thinking using a Q-learning computation model. The results revealed that while mood was not significantly related to divergent or convergent thinking (as creative thinking types), risk-taking exerted positive effects on divergent thinking in the face of negative rewards. The results were consistent with the representational change theory in insight problem solving. Although this theory accounts directly for insight, the underlying idea of going beyond current contexts and implicit constrains could be applied to creative thinking as well. The results indeed accounted for the relevance of this theory to divergent thinking. The current study is one of the first empirical studies simultaneously examining the role of mood and risk-taking in creativity. In particular, no related studies exist that took a computational approach to estimate the relevant parameters in the framework of dynamic optimization. Our Q learning model enables to distinguish and identify the different roles of mood and risk-taking in updating Q values and making decisions.

While replay value is a common term in interactive entertainment, psychological research on its meaning in terms of user experiences is sparse. An exploratory experiment using the interactive drama ''Fac ¸ade'' was conducted (n = 50) to examine shifts and continuities in entertainment-related user experiences between first and second exposure to the same system. A questionnaire with brief scales measuring various user-experience dimensions (interaction-related facets such as usability, flow, and presence, as well as narrative-related facets such as suspense and curiosity) was administered after the first and the second round of exposure. Findings suggest that replay produces gains in action-related experience components such as presence and effectance, whereas narrative-related experiences such as curiosity and suspense remain stable across exposures. Implications for theorizing on interactive entertainment experiences are discussed.

Social exclusion inherently involves an element of expectancy violation, in that we expect other people to follow the unwritten rule to include us in social interactions. In this functional magnetic resonance imaging (fMRI) study, we employed a unique modification of an interactive virtual ball-tossing game called "Cyberball" and a novel paradigm called "Cybershape", in which rules are broken in the absence of social exclusion, to dissociate brain regions that process social exclusion from rule violations more generally. Our Cyberball game employed an alternating block design and removed evoked responses to events when the participant was throwing the ball in inclusion to make this condition comparable to exclusion, where participants did not throw. With these modifications, we replicated prior findings of ventral anterior cingulate cortex (vACC), insula, and posterior cingulate cortex activity evoked by social exclusion relative to inclusion. We also identified exclusion-evoked activity in the hippocampi, left ventrolateral prefrontal cortex, and left middle temporal gyrus. Comparing social exclusion and rule violation revealed a functional dissociation in the active neural systems as well as differential functional connectivity with vACC. Some overlap was observed in regions differentially modulated by social exclusion and rule violation, including the vACC and lateral parietal cortex. These overlapping brain regions showed different activation during social exclusion compared to rule violation, each relative to fair play. Comparing activation patterns to social exclusion and rule violation allowed for the dissociation of brain regions involved in the experience of exclusion versus expectancy violation.

Humans routinely solve problems of immense computational complexity by intuitively forming simple, low-dimensional heuristic strategies. Citizen science (or crowd sourcing) is a way of exploiting this ability by presenting scientific research problems to non-experts. 'Gamification'--the application of game elements in a non-game context--is an effective tool with which to enable citizen scientists to provide solutions to research problems. The citizen science games Foldit, EteRNA and EyeWire have been used successfully to study protein and RNA folding and neuron mapping, but so far gamification has not been applied to problems in quantum physics. Here we report on Quantum Moves, an online platform gamifying optimization problems in quantum physics. We show that human players are able to find solutions to difficult problems associated with the task of quantum computing. Players succeed where purely numerical optimization fails, and analyses of their solutions provide insights...

Both genetic and environmental factors have been shown to influence decision making, but their relative contributions and interactions are not well understood. The present study aimed to reveal possible gene-environment interactions on decision making in a large healthy sample. Specifically, we examined how the frequently studied COMT Val 158 Met polymorphism interacted with an environmental risk factor (i.e., stressful life events) and a protective factor (i.e., parental warmth) to influence affective decision making as measured by the Iowa Gambling Task. We found that stressful life events acted as a risk factor for poor IGT performance (i.e., high reward sensitivity) among Met carriers, whereas parental warmth acted as a protective factor for good IGT performance (i.e., higher IGT score) among Val/Val homozygotes. These results shed some new light on gene-environment interactions in decision making, which could potentially help us understand the underlying etiology of several psychiatric disorders associated with decision making impairment.

Individuals with fetal alcohol spectrum disorders (FASD) have difficulties with cognitive-based executive function (EF) tasks. The goal of the present study was to determine if children with FASD have impairments on the Iowa Gambling Task (IGT), which measures affective EF (i.e., decision-making and risk-taking). Individuals with FASD (n = 31) and healthy controls (n = 31), aged 8–17 completed the IGT. Children with FASD were significantly impaired on the IGT compared to controls. Over the course of the task, control scores improved, whereas children with FASD exhibited an overall decrease in scores. Scores increased significantly with age in the control group but did not differ significantly with age for FASD participants. Children with FASD exhibited decision-making and risk-taking impairments on a hot EF task. Children with FASD did not appear to learn from negative experiences and shift to making more positive decisions over time and their performance did not improve with age. T...

In the mammalian brain, dopamine is a critical neuromodulator whose actions underlie learning, decision-making, and behavioral control. Degeneration of dopamine neurons causes Parkinson's disease, whereas dysregulation of dopamine signaling is believed to contribute to psychiatric conditions such as schizophrenia, addiction, and depression. Experiments in animal models suggest the hypothesis that dopamine release in human striatum encodes reward prediction errors (RPEs) (the difference between actual and expected outcomes) during ongoing decision-making. Blood oxygen level-dependent (BOLD) imaging experiments in humans support the idea that RPEs are tracked in the striatum; however, BOLD measurements cannot be used to infer the action of any one specific neurotransmitter. We monitored dopamine levels with subsecond temporal resolution in humans (n = 17) with Parkinson's disease while they executed a sequential decision-making task. Participants placed bets and experienced mo...

Game theory describes strategic interactions where success of players' actions depends on those of coplayers. In humans, substantial progress has been made at the neural level in characterizing the dopaminergic and frontostriatal mechanisms mediating such behavior. Here we combined computational modeling of strategic learning with a pathway approach to characterize association of strategic behavior with variations in the dopamine pathway. Specifically, using gene-set analysis, we systematically examined contribution of different dopamine genes to variation in a multistrategy competitive game captured by (i) the degree players anticipate and respond to actions of others (belief learning) and (ii) the speed with which such adaptations take place (learning rate). We found that variation in genes that primarily regulate prefrontal dopamine clearance--catechol-O-methyl transferase (COMT) and two isoforms of monoamine oxidase--modulated degree of belief learning across individuals. In...