- School of Psychology
University of Leicester
Leicester LE1 7RH
UK
Andrew M Colman
University of Leicester, Psychology, Faculty Member
Two experiments examined a form of singleton bias deducible from lexicographic choice and Tversky's theory of elimination by aspects. In Experiment 1, 100 decision makers who chose from a set of job applicants defined by equal numbers of... more
Two experiments examined a form of singleton bias deducible from lexicographic choice and Tversky's theory of elimination by aspects. In Experiment 1, 100 decision makers who chose from a set of job applicants defined by equal numbers of equally important qualifications tended to ignore the singleton defined by possession of a relevant attribute but tended to rank-order the attributes as predicted by lexicographic choice theory and showed various forms of singleton bias. In Experiment 2, 100 decision makers who chose from sets of unspecified alternatives, universities, and houses/apartments defined by attributes that they had individually rated as equally important ignored the attribute-defined singleton in every alternative set but manifested a different singleton bias in favor of the middle option of the on-screen display.
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A 10-hour workshop-based course designed to teach communication skills to undergraduates is described and evaluated. In five two-hour sessions, the course covered technical aspects of written communication, oral presentations to small and... more
A 10-hour workshop-based course designed to teach communication skills to undergraduates is described and evaluated. In five two-hour sessions, the course covered technical aspects of written communication, oral presentations to small and medium-sized groups, interview skills, non-verbal communication, and skills associated with assessing the presentations of others and providing constructive feedback. Evidence from a course evaluation questionnaire and from observations of the students’ performance suggests that the course was reasonably successful in achieving its aims.
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In this preregistered study, we attempted to replicate and substantially extend a frequently cited experiment by Schurr and Ritov, published in 2016, suggesting that winners of pairwise competitions are more likely than others to steal... more
In this preregistered study, we attempted to replicate and substantially extend a frequently cited experiment by Schurr and Ritov, published in 2016, suggesting that winners of pairwise competitions are more likely than others to steal money in subsequent games of chance against different opponents, possibly because of an enhanced sense of entitlement among competition winners. A replication seemed desirable because of the relevance of the effect to dishonesty in everyday life, the apparent counterintuitivity of the effect, possible problems and anomalies in the original study, and above all the fact that the researchers investigated only one potential explanation for the effect. Our results failed to replicate Schurr and Ritov's basic finding: we found no evidence to support the hypotheses that either winning or losing is associated with subsequent cheating. A second online study also failed to replicate Schurr and Ritov's basic finding. We used structural equation modelling to test four possible explanations for cheating—sense of entitlement, self-confidence, feeling lucky and inequality aversion. Only inequality aversion turned out to be significantly associated with cheating.
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Research Interests: Psychology, Cognitive Science, Game Theory, Decision Making, Ambiguity Aversion, and 15 moreCognition, Risk, Medicine, Strategy, Students, Humans, Female, Ambiguity, Male, Quarterly Journal of Experimental Psychology, Incomplete Information, Ellsberg paradox, Adult, Choice Behavior, and strategic complements
Data for: Far but finite horizons promote cooperation in the Centipede game. The file contains all exit points in the four Conditions of the Centipede game, which were tested in the reported experiment.
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Antibiotic prescribing can be conceptualised as a social dilemma in which the overuse of antibiotics, to minimise immediate risks to individual patients, results in a sub-optimal outcome for society (antimicrobial resistance) and... more
Antibiotic prescribing can be conceptualised as a social dilemma in which the overuse of antibiotics, to minimise immediate risks to individual patients, results in a sub-optimal outcome for society (antimicrobial resistance) and increased risks to all patients in the long run. Doctors face the challenge of balancing the interests of individual patients against the collective good when prescribing antibiotics. While evidence suggests that doctors tend to prioritise individual interests over those of the collective, the conventional interpretation of such decisions as selfish may be inappropriate because most doctors are motivated by prosocial concerns about their patients. This review of antibiotic decision research provides a more nuanced understanding of prosociality in the context of the social dilemma of antibiotic prescribing.
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This chapter presents a historical outline, from 1930 to the present, of applications of game theory to evolution. It explains the concepts of game theory, which can be placed in one-to-one correspondence with those of natural selection:... more
This chapter presents a historical outline, from 1930 to the present, of applications of game theory to evolution. It explains the concepts of game theory, which can be placed in one-to-one correspondence with those of natural selection: players correspond to individual organisms, strategies to genotypes, and payoffs to changes in Darwinian fitness. The essential ideas are illustrated in the chapter with reference to the evolution of sex ratios. Conventional fighting can arise in some members of a population or in all members some of the time, by individual selection alone: Maynard Smith's two-person Hawk-Dove game can have a mixed evolutionarily stable strategy. The chapter provides an overview on an improved compound multi-person game model. This led to a typology of evolutionary games and to a new concept of an evolutionarily stable composition of a population. Retaliation, which ought to be a common feature of animal combat according to the theory, is often observed in practice.
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This paper reports the early stages of a funded project “Antimicrobial Resistance as a Social Dilemma: Approaches to Reducing Broad-Spectrum Antibiotic Use in Acute Medical Patients Internationally” to use ABM in understanding how the... more
This paper reports the early stages of a funded project “Antimicrobial Resistance as a Social Dilemma: Approaches to Reducing Broad-Spectrum Antibiotic Use in Acute Medical Patients Internationally” to use ABM in understanding how the prescribing behaviour of professionals in “medical institutions” may affect the prevalence of antimicrobial resistance (hereafter AMR), a situation in which standard treatments for infections fail. The first section explains the policy challenge of AMR and the research project strategy. The second section considers distinctive challenges raised by this kind of policy modelling. The third section presents preliminary results and the final section concludes.
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Theories of trust distinguish general trust in situations of social uncertainty from assurance-based trust in committed, long-term relationships. This study investigates European-Japanese differences using the Centipede game, in which two... more
Theories of trust distinguish general trust in situations of social uncertainty from assurance-based trust in committed, long-term relationships. This study investigates European-Japanese differences using the Centipede game, in which two players choose between cooperation and defection. The game models repeated reciprocal interactions, necessitating assurance-based trust to sustain cooperation. We included game conditions offering players the option of purchasing commitment-enhancing tools to increase social certainty. Japanese participants were more cooperative than Europeans, confirming higher assurance-based trust, and also purchased more commitment-enhancing tools, demonstrating their preferences for social certainty. Purchase of commitment-enhancing tools improved cooperativeness in both groups. However, if co-players refused tool purchase, the Japanese appeared to interpret this as non-cooperative intent and cooperativeness in the respective games decreased.
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journal homepage: www.elsevier.com/locate/joep Ambiguity aversion in the long run: Repeated decisions under risk
There is a long-standing debate in philosophy about whether it is morally permissible to harm one person in order to prevent a greater harm to others and, if not, what is the moral principle underlying the prohibition. Hypothetical... more
There is a long-standing debate in philosophy about whether it is
morally permissible to harm one person in order to prevent a greater
harm to others and, if not, what is the moral principle underlying the
prohibition. Hypothetical moral dilemmas are used in order to probe
moral intuitions. Philosophers use them to achieve a reflective equilibrium
between intuitions and principles, psychologists to investigate moral
decision-making processes. In the dilemmas, the harms that are traded off
are almost always deaths. However, the moral principles and psychological
processes are supposed to be broader than this, encompassing harms other
than death. Further, if the standard pattern of intuitions is preserved in
the domain of economic harm, then that would open up the possibility.
morally permissible to harm one person in order to prevent a greater
harm to others and, if not, what is the moral principle underlying the
prohibition. Hypothetical moral dilemmas are used in order to probe
moral intuitions. Philosophers use them to achieve a reflective equilibrium
between intuitions and principles, psychologists to investigate moral
decision-making processes. In the dilemmas, the harms that are traded off
are almost always deaths. However, the moral principles and psychological
processes are supposed to be broader than this, encompassing harms other
than death. Further, if the standard pattern of intuitions is preserved in
the domain of economic harm, then that would open up the possibility.
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<p>Payoffs from T (treat with antibiotics) and U (do not treat with antibiotics) for a representative probability of bacterial infection of <i>ϕ</i> = .5, showing T as a dominant strategy. For different values of... more
<p>Payoffs from T (treat with antibiotics) and U (do not treat with antibiotics) for a representative probability of bacterial infection of <i>ϕ</i> = .5, showing T as a dominant strategy. For different values of <i>ϕ</i> > 0, only the slope of the function changes. The values used to generate the graph are given in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0215480#pone.0215480.s001" target="_blank">S1 Table</a>.</p
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ABSTRACT This short document describes the WSLS Simulator, a C++ program designed by David Omtzigt to perform Monte Carlo Simulations of the minimal social situation based on repeated Mutual Fate Control games. A compiled copy of the... more
ABSTRACT This short document describes the WSLS Simulator, a C++ program designed by David Omtzigt to perform Monte Carlo Simulations of the minimal social situation based on repeated Mutual Fate Control games. A compiled copy of the software can be found here: https://lra.le.ac.uk/handle/2381/7813
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In a recent article in this journal, Duijf claims to have proved that team reasoning can be viewed as a payoff transformation. His formalization mimics team reasoning but ignores its essential agency switch. The possibility of such a... more
In a recent article in this journal, Duijf claims to have proved that team reasoning can be viewed as a payoff transformation. His formalization mimics team reasoning but ignores its essential agency switch. The possibility of such a payoff transformation was never in doubt, does not imply that team reasoning can be viewed as a payoff transformation, and makes no sense in a game in which payoffs represent players’ utilities. A theorem is proved here that a simpler and more intuitive payoff transformation can mimic any theory that predicts what strategies players will choose in a well-defined game.
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Player I chooses between rows C (cooperate) and row D (defect), Player II chooses between columns C and D, and the pair of numbers in each cell are the payoffs to Players I and II respectively in the corresponding outcome. Each player... more
Player I chooses between rows C (cooperate) and row D (defect), Player II chooses between columns C and D, and the pair of numbers in each cell are the payoffs to Players I and II respectively in the corresponding outcome. Each player does better by choosing D than C irrespective of what the co-player chooses; the D strategy is the unconditionally best or dominant strategy for both players. The puzzle arises from the fact that if both players choose D, as they are bound to if they are rational, then each is worse off than if both choose C, and many people ...
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A simple, evolutionary game-theoretic model yields the surprising prediction that cooperation can evolve without deliberate intention in a minimal social situation (MSS). This phenomenon was discovered in dyads by Sidowski (1957) and... more
A simple, evolutionary game-theoretic model yields the surprising prediction that cooperation can evolve without deliberate intention in a minimal social situation (MSS). This phenomenon was discovered in dyads by Sidowski (1957) and generalized to larger groups by Coleman, Colman, and Thomas (1990). Predictions about the multi-player minimal social situation (MMSS) remain untested. The primary objective of the proposed research is to test them.
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A significant increase in the probability of an action resulting from observing that action performed by another agent cannot, on its own, provide persuasive evidence of imitation. Simple models of social influence based on two-person... more
A significant increase in the probability of an action resulting from observing that action performed by another agent cannot, on its own, provide persuasive evidence of imitation. Simple models of social influence based on two-person sequential games suggest that both imitation and pseudo-imitation can be explained by a process more fundamental than priming, namely, subjective utility maximization.
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Most human relationships are characterized by reciprocal patterns of give-and-take that can be studied using a decision-making task called the Centipede game. The game involves 2 players alternating in choosing between cooperation and... more
Most human relationships are characterized by reciprocal patterns of give-and-take that can be studied using a decision-making task called the Centipede game. The game involves 2 players alternating in choosing between cooperation and defection, with their choices affecting payoffs to themselves and the co-player. We compared trust and cooperation of Japanese and U.K. samples in the Centipede game. To increase the game’s applicability to real-life decision situations, we added 3 treatment conditions to manipulate payoff information. Our between-subjects design comprised the following 4 conditions: (a) full payoff information, (b) full payoff information framed as percentages, (c) partial payoff information with absolute (own payoff) information only, and (d) partial payoff information with relative information only. Comparing Japanese and U.K. students’ decisions, the Japanese cooperated significantly more frequently than the British. The manipulation of payoff information also affe...