Accuracy in discrimination of self-reported cooperators using static facial information

People readily ascribe personality traits to others and believe that faces hold important guides to character. Here we examined the relationship between static facial appearance and self-reported cooperation/defection using the prisoner’s dilemma (N = 193). Study 1 combined face images of those self-reporting they would be most and least likely to cooperate. The composites of cooperators were seen as more cooperative than non-cooperators. Study 2 demonstrated accuracy with ratings of individual faces. Masculinity of face shape was negatively related to self-reported cooperation for men, but not women. Further, ratings of smile intensity were positively, but not significantly, related to self-reported cooperation. Overall, individuals appear able judge the potential of others to cooperate from static facial appearance alone at rates greater than chance.     

Responses to Conflict and Cooperation in Adolescents with Anxiety and Mood Disorders

This study examined patterns of behavioral and emotional responses to conflict and cooperation in adolescents with anxiety/mood disorders and healthy peers. We compared performance on and emotional responses to the Prisoner’s Dilemma (PD) game, an economic exchange task involving conflict and cooperation, between adolescents with anxiety/depressive disorders (A/D) (N=21) and healthy comparisons (n = 29). Participants were deceived to believe their co-player (a pre-programmed computer algorithm) was another study participant. A/D adolescents differed significantly from comparisons in patterns of play and emotional response to the game. Specifically, A/D participants responded more cooperatively to cooperative overtures from their co-players; A/D girls also reported more anger toward co-players than did comparison girls. Our findings indicate that A/D adolescents, particularly females, respond distinctively to stressful social interchanges. These findings offer a first step toward elucidating the mechanisms underlying social impairment in youth with internalizing disorders. This research was supported by the Intramural Research Program of the NIH, NIMH.     

Training cooperation in the Prisoner's Dilemma

Female Ss' choices in two types of mixed-motive game situations were used to select Ss who had predominantly Own Gain and Ss who had predominantly Relative Gain goals. On the basis of simple reward notions, it was predicted that the former but not the latter would change from competitive to cooperative responding in decomposed Prisoner's Dilemma game situations when interacting with a conditionally cooperative other. Corresponding yoked controls were not expected to become cooperative. The availability of social comparison with an outcome which was smaller than the mutually cooperative outcome but larger than the mutually competitive out-come was expected to lead Own Gain Ss to more rapid learning of cooperation but not to affect the responses of corresponding yoked controls or of Relative Gain Ss. A 2 × 2 × 2 × 5 factorial design was used in which the factors were goal orientation (Own Gain vs Relative Gain), strategy of the other (conditionally cooperative vs yoked control), the availability vs unavailability of the social comparison, and trials. The results strongly supported each of the expectations. The results were discussed in terms of how the operation of the reward mechanism would be affected by the operation of some other social psychological processes.     

The spiral of distrust: (Non‐)cooperation in a repeated trust game is predicted by anger and individual differences in negative reciprocity orientation

This study investigated state anger and individual differences in negative reciprocity orientation as predictors of individuals' willingness to cooperate with strangers. In order to observe real behaviour, we used a trust game that was played over six periods. In the trust game, a first player (sender) determines how much of a certain endowment she/he wants to share with a second player (trustee), who then can give something back. We varied whether participants received feedback [feedback (yes, no)] about the trustee's behavioural decision (amount sent back). Supporting our hypotheses, the results suggest that feedback compared with no feedback about the trustee's behaviour increased anger. Specifically, information about low back transfers triggered anger and non‐cooperation in return. Importantly, participants with a strong negative reciprocity orientation reported higher levels of anger and were less willing to cooperate with the trustee compared with those with low negative reciprocity orientation. Moreover, even when anger was low, individuals with a strong negative reciprocity orientation were less willing to cooperate compared with those with a low negative reciprocity orientation. Thus, negative reciprocity orientation seems to arouse a spiral of distrust. Theoretical and practical implications of these findings are discussed.     

Rationality and bounded information in repeated games, with application to the iterated Prisoner's Dilemma

Actions in a repeated game can in principle depend on all previous outcomes. Given this vast policy space, human players may often be forced to use heuristics that base actions on incomplete information, such as the outcomes of only the most recent trials. Here it is proven that such bounded rationality is often fully rational, in that the optimal policy based on some limited information about the game's history will be universally optimal (i.e., within the full policy space), provided that one's opponents are restricted to using this same information. It is then shown how this result allows explicit calculation of subgame-perfect equilibria (SPEs) for any repeated or stochastic game. The technique is applied to the iterated Prisoner's Dilemma for the case of 1-back memory. Two classes of SPEs are derived, which exhibit varying degrees of (individually rational) cooperation as a result of repeated interaction.     

Dynamic probability of reinforcement for cooperation: Random game termination in the centipede game

Experimental games have previously been used to study principles of human interaction. Many such games are characterized by iterated or repeated designs that model dynamic relationships, including reciprocal cooperation. To enable the study of infinite game repetitions and to avoid endgame effects of lower cooperation toward the final game round, investigators have introduced random termination rules. This study extends previous research that has focused narrowly on repeated Prisoner's Dilemma games by conducting a controlled experiment of two‐player, random termination Centipede games involving probabilistic reinforcement and characterized by the longest decision sequences reported in the empirical literature to date (24 decision nodes). Specifically, we assessed mean exit points and cooperation rates, and compared the effects of four different termination rules: no random game termination, random game termination with constant termination probability, random game termination with increasing termination probability, and random game termination with decreasing termination probability. We found that although mean exit points were lower for games with shorter expected game lengths, the subjects' cooperativeness was significantly reduced only in the most extreme condition with decreasing computer termination probability and an expected game length of two decision nodes.     

Self‐control in a Prisoner's Dilemma game: the role of trial spacing and an interfering task

Self‐control was studied in an iterated one‐player Prisoner's Dilemma game in which students' choices affected the payoff matrix on the next trial. The frequency of self‐control responses (choice of the smaller payoff now, but with the more generous payoff matrix more likely on the next trial) and defection responses (choice of the larger payoff now, but with the less generous payoff matrix more likely on the next trial) were measured. In Experiment 1, players achieved a criterion of five consecutive self‐control responses more quickly as a positive function of trial spacing, the presence between trials of a discriminative stimulus associated with the upcoming payoff matrix, and the probability that the self‐control or defection response would be reciprocated by the computer. Experiment 2 replicated the effect of trial spacing except when there was an interfering task during the interval, suggesting that trial spacing permits better appreciation of the contingencies. Copyright © 2006 John Wiley & Sons, Ltd.     

Behavioural Consistency Within the Prisoner's Dilemma Game: The Role of Personality and Situation

Mixed‐motive games represent situations that confront people with a conflict between cooperative and non‐cooperative alternatives. Despite this common basis, recent research has shown that the consistency of people's choices across different mixed‐motive games is rather low. The present research examined behavioural consistency within the same mixed‐motive game, by presenting participants with a series of one‐shot Prisoner's Dilemma Games. Across this set of games, payoffs were manipulated in order to intensify or weaken the conflict between self and the other party while maintaining the game's underlying structure. Our findings indicate that significant differences in choice behaviour are observed as a function of both situational (i.e. manipulations of the Prisoner's Dilemma Game's payoff structure) and personality differences (i.e. individual differences in personality and motivational traits). Moreover, our included situational variables and personality features did not interact with each other and were about equally impactful in shaping cooperation. Crucially, however, despite the significant behavioural differences across game variants, considerable consistency in choices was found as well, which suggests that the game's motivational basis reliably impacts choice behaviour in spite of situational and personality variations. We discuss implications for theorizing on mixed‐motive situations and elaborate on the question how cooperation can be promoted. © 2018 European Association of Personality Psychology     

Personality features and cognitive level in patients at an early stage of Alzheimer’s disease

In this cross-sectional study, we explored the relationship between premorbid personality and its changes over 5 years, and cognitive deterioration in patients with mild Alzheimer’s disease. The cognitive level of 54 patients was compared with that of 64 control subjects using the Mini Mental State (MMSE). Family members completed the NEO-PI-R (form R) twice, once to evaluate the participants’ current personality and again to assess personality traits as they were remembered to be 5 years earlier. Furthermore, the family filled in the Informant Questionnaire on Cognitive Decline (IQCODE), the Activities of Daily Living (ADL), and the Instrumental Activities of Daily Living (IADL) scales to assess their proxies’ cognitive level and daily living functioning. Regarding the relationship between personality characteristics and cognitive status, we observed trends for premorbid personality and significant links for personality changes in the clinical group. Thus, changes in neuroticism and conscientiousness were associated with cognitive deterioration, whereas decreased openness to experience and conscientiousness over time predicted loss of independence in daily functioning in the clinical group. Our study suggests that premorbid features can be considered as latent traits linked to the neuropathology underlying the disease process, while personality changes are probably the consequences of the pathological process.     

Decision making in the prisoner's dilemma game: The effect of exit on cooperation and social welfare

The prisoner's dilemma game is a mixed‐motive game that offers two players the simultaneous choice between a cooperative and a defective alternative. An often neglected aspect of such a binary‐choice game, however, is that in many real‐life encounters, people can choose not only to cooperate or defect, but they also have a third option: to exit the social dilemma. Although in the literature a consensus has emerged that the addition of an exit opportunity benefits cooperation, there is only scant research into its effect on social welfare. In order to allow a direct comparison of cooperation rates and welfare levels across binary‐choice and trinary‐choice games, in this study, we used a design in which the same participants played similar games with and without an exit option (i.e., a within‐subjects design), and this in a range of structural variations. The findings of our study indicated that the aggregated outcome of both players is generally lower in games with an exit option than in games without an exit option. Moreover, our results showed that the efficiency of the exit option strongly depends on the specific outcome structure of the game (in terms of its endowment size, (a)symmetry, and level of noncorrespondence). In the discussion, it is argued that the implementation of an exit option as a strategy to increase social welfare should be critically assessed.     

The perceptual push: The interplay of implicit cues and explicit situational construals on behavioral intentions in the Prisoner’s Dilemma

Although it is clear that nonconscious primes can affect behavioral decisions, the extent to which the prime-to-behavior link is mediated by intervening interpretative processes is still unknown. The present research examined the mediational role of “situational construals” by assessing the effects of cooperative versus competitive primes on participants’ construals of, and responses to, the prisoner’s dilemma. As predicted, this priming manipulation influenced participants’ construals of the game (assessed by the participants’ ratings of the appropriateness of different “names for the game” and their estimates of how random others would play), and their own expressed willingness to cooperate versus defect. Most crucially, a mediational analysis and a manipulation of the order in which these dependent variables were measured established that the prime-to-behavior link can be strengthened by an intervening task calling for explicit construal of the situation. The interplay of situational construal and implicit primes in producing deliberative behavior is discussed.     

Exploring cooperation and competition in the Centipede game through verbal protocol analysis

The Centipede game is an abstract model of reciprocal relationships in which two individuals alternate in helping each other at relatively small personal cost. Whereas mutual cooperation can benefit both individuals in the long run, a paradoxical but logically compelling backward induction argument suggests that cooperation is irrational. Empirical studies have reported reliable deviations from the non‐cooperative backward induction solution, but their exclusively quantitative methods allow only a limited range of predefined motives to be explored. Our study uses verbal (‘think aloud’) protocols and qualitative data analysis to identify motives for cooperation in the Centipede game. The results provide little evidence for sophisticated backward induction reasoning. Instead, a wide range of motives emerged, their relative saliences varying according to the stage of the game. Activity bias affected decisions mainly at the beginning of the game, whereas cooperative and altruistic social value orientations most frequently accounted for cooperation towards its natural end.     

When to (or not to) trust intelligent machines: Insights from an evolutionary game theory analysis of trust in repeated games

The actions of intelligent agents, such as chatbots, recommender systems, and virtual assistants are typically not fully transparent to the user. Consequently, users take the risk that such agents act in ways opposed to the users’ preferences or goals. It is often argued that people use trust as a cognitive shortcut to reduce the complexity of such interactions. Here we formalise this by using the methods of evolutionary game theory to study the viability of trust-based strategies in repeated games. These are reciprocal strategies that cooperate as long as the other player is observed to be cooperating. Unlike classic reciprocal strategies, once mutual cooperation has been observed for a threshold number of rounds they stop checking their co-player’s behaviour every round, and instead only check it with some probability. By doing so, they reduce the opportunity cost of verifying whether the action of their co-player was actually cooperative. We demonstrate that these trust-based strategies can outcompete strategies that are always conditional, such as Tit-for-Tat, when the opportunity cost is non-negligible. We argue that this cost is likely to be greater when the interaction is between people and intelligent agents, because of the reduced transparency of the agent. Consequently, we expect people to use trust-based strategies more frequently in interactions with intelligent agents. Our results provide new, important insights into the design of mechanisms for facilitating interactions between humans and intelligent agents, where trust is an essential factor.     

Affine representations in psychophysics and the near-miss to Weber’s law

A theoretical account for the near-miss to Weber’s law in the form of a power function, with a special emphasis on the interpretation of the exponent, was proposed by Falmagne [Falmagne, J.-C. (1985). Elements of psychophysical theory. New York: Oxford University Press] within the framework of a subtractive representation, P(x,y)=F(u(x)−g(y)). In this paper, we examine a more general affine representation, P(x,y)=F(u(x)h(y)+g(y)). We first obtain a uniqueness theorem for the affine representation. We then study the conditions that force an affine representation to degenerate to a subtractive one. Part of that study involves the case for which two different affine representations co-exist for the same data. We also show that the balance condition P(x,y)+P(y,x)=1 constrains an affine representation to be a special kind of subtractive representation, a Fechnerian one. We further show that Falmagne’s power law takes on a special form for a so-called weakly balanced system of probabilities, in which case the affine representation is Fechnerian. Finally, following Iverson [Iverson, G.J. (2006a). Analytical methods in the theory of psychophysical discrimination I: Inequalities, convexity and integration of just noticeable differences. Journal of Mathematical Psychology, 50, 271-282], we generalize the Fechner method to construct the sensory scales in a weakly balanced affine representation by integrating (derivatives of) just noticeable differences.     

Personality and altruism in the dictator game: Relationship to giving to kin, collaborators, competitors, and neutrals

We investigate altruism in the context of the economic dictator game experiment where subjects are presented with different persons who can be classified as kin, collaborator, competitor and neutral based on their similarity/relationship to the subject. The classification is based on the role others play in facilitating or impeding an individual’s access to resources needed for reproductive success. The role of the Big Five personality traits in giving to the different target persons is examined. We find that kin are treated most generously, followed by collaborators, neutrals, and competitors. Personality has no effect on giving to kin, but a significant effect on giving to collaborator, neutral and competitor. We also find non-linear relationships between personality and giving.     

Mutual support in games: Some properties of Berge equilibria

The Berge equilibrium concept formalizes mutual support among players motivated by the altruistic social value orientation in games. We prove some basic results for Berge equilibria and their relations to Nash equilibria, and we provide a straightforward method for finding Berge equilibria in n-player games. We explore some specific examples, and we explain how the Berge equilibrium provides a compelling model of cooperation in social dilemmas. We show that the Berge equilibrium also explains coordination in some common interest games and is partially successful in explaining the payoff dominance phenomenon, and we comment that the theory of team reasoning provides alternative solutions to these problems.     

Time processing in children with Tourette’s syndrome

Background

Tourette syndrome (TS) is characterized by dysfunctional connectivity between prefrontal cortex and sub-cortical structures, and altered meso-cortical and/or meso-striatal dopamine release. Since time processing is also regulated by fronto-striatal circuits and modulated by dopaminergic transmission, we hypothesized that time processing is abnormal in TS.

Methods

We compared time processing abilities between nine children with TS-only (i.e. without major psychiatric comorbidities) and 10 age-matched healthy children, employing a time reproduction task in which subjects actively reproduce different temporal intervals, and a time comparison task in which subjects judge whether a test interval is longer or shorter than a reference interval. IQ, sustained and divided attention, and working memory were assessed in both groups using the Leiter International Performance Scale-Revised, and the Digit Span sub-test of the WISC-R.

Results

Children with TS-only reproduced in an overestimated fashion over-second, but not sub-second, time intervals. The precision of over-second intervals reproduction correlated with tic severity, in that the lower the tic severity, the closer the reproduction of over-second time intervals to their real duration. Time reproduction performance did not significantly correlate with IQ, attention and working memory measures in both groups. No differences between groups were documented in the time comparison task.

Conclusions

The improvement of time processing in children with TS-only seems specific for the over-second range of intervals, consistent with an enhancement in the ‘cognitively controlled’ timing system, which mainly processes longer duration intervals, and depends upon dysfunctional connectivity between the basal ganglia and the dorso-lateral prefrontal cortex. The absence of between-group differences on time comparison, moreover, suggests that TS patients manifest a selective improvement of ‘motor’ timing abilities, rather than of perceptual time abilities. Our data also support an enhancement of cognitive control processes in TS children, probably facilitated by effortful tic suppression.     

Testing the effects of end-goal during reach-to-grasp movements in Parkinson’s disease

Previous evidence suggests that hand shaping during reaching is modulated by the presence and the nature of the end-goal following object’s grasp. Here we test whether such modulation is maintained in Parkinson’s disease (PD). Six participants with PD and six healthy participants took part in the study. Participants were requested to reach towards a bottle filled with water, and then: (1) grasp it without performing any subsequent action; (2) grasp it and place it accurately on a target area; (3) grasp it and pour its contents within a container. The results showed that participants shaped their hand differently depending on the presence or absence of an action following object’s grasp. However, the request to perform an action after grasp determined a modulation of hand kinematics which was delayed for PD than for control participants. Further, whereas for control participants the nature of the end-goal determined a modulation of hand shaping, for PD patients such modulation was not evident. Data are discussed in terms of the role played by basal ganglia in implementing anticipatory mechanisms for the control of manipulative activities. We contend that in PD patients these mechanisms are not totally compromised, but their implementation depends on the action information that has to be anticipated.     

The role of mathematical skill in sex differences on Raven’s Matrices

This study replicated a previously reported male advantage on certain items of Raven’s Matrices and found no sex differences in performance on other items. We refer to the latter as analytic (1) items and the former as analytic (2) items. Reasons for the male advantage were investigated by correlating scores obtained by male and female high school students on analytic (1) and analytic (2) items with their scores on tests of spatial, verbal and mathematical ability. There were no sex differences in the magnitude of the correlations between scores on analytic (2) items and the two spatial and verbal tests. In contrast, males but not females showed a significantly higher correlation of maths with analytic (2) than with analytic (1). The results suggest the Raven’s Matrices may engage different, more specific cognitive processes in males and more general cognitive processes in females.     

囚徒困境博弈中对手面部表情对合作行为的影响及其作用机制

3个实验逐步深入地考察了囚徒困境博弈中, 对手的高兴、中性和愤怒面部表情对个体合作行为的影响及相关变量的中介和调节作用。实验1的结果表明, 对手的高兴表情比愤怒表情诱发了更高的合作水平, 且高兴和中性表情均比愤怒表情产生了更高的合作预期, 合作预期中介了面部表情与合作行为的关系; 实验2引入指导语操纵被试的直觉或理性决策模式, 发现实验1的结果仅出现在直觉条件下, 却未出现在理性条件下, 且整体而言直觉决策模式下比理性决策模式下更合作; 实验3采用更加严格的时间压力范式操纵被试的直觉或理性决策模式, 发现除了高兴表情比中性表情也诱发了更多的合作行为外, 其他几乎复制了实验2的结果。基于这些结果, 建立了有调节的中介模型, 以期揭示他人面部表情、合作预期、合作行为及个体决策模式之间的复杂关系。