Cooperation driven by mutations in multi-person Prisoner's Dilemma

The n-person Prisoner's Dilemma is a widely used model for populations where individuals interact in groups. The evolutionary stability of populations has been analysed in the literature for the case where mutations in the population may be considered as isolated events. For this case, and assuming simple trigger strategies and many iterations per game, we analyse the rate of convergence to the evolutionarily stable populations. We find that for some values of the payoff parameters of the Prisoner's Dilemma this rate is so low that the assumption, that mutations in the population are infrequent on that timescale, is unreasonable. Furthermore, the problem is compounded as the group size is increased. In order to address this issue, we derive a deterministic approximation of the evolutionary dynamics with explicit, stochastic mutation processes, valid when the population size is large. We then analyse how the evolutionary dynamics depends on the following factors: mutation rate, group size, the value of the payoff parameters, and the structure of the initial population. In order to carry out the simulations for groups of more than just a few individuals, we derive an efficient way of calculating the fitness values. We find that when the mutation rate per individual and generation is very low, the dynamics is characterised by populations which are evolutionarily stable. As the mutation rate is increased, other fixed points with a higher degree of cooperation become stable. For some values of the payoff parameters, the system is characterised by (apparently) stable limit cycles dominated by cooperative behaviour. The parameter regions corresponding to high degree of cooperation grow in size with the mutation rate, and in number with the group size.Comment: 22 pages, 7 figures. Accepted for publication in Journal of Theoretical Biolog

Creating advantages with Franchising in healthcare

Background Franchising is a promising and increasingly used organizational form to improve strategic, organizational, professional and client-related results in healthcare. However, evidence is scarce regarding how franchises should be operated to actualize such results. This paper aimed to explore the association between the results achieved by healthcare franchises and the working relationships among actors in these franchises. Methods A sequential mixed methods approach was used to obtain both in-depth and broader quantifiable insights into a little-investigated phenomenon. We first employed a qualitative multiple embedded case study. Data were collected through observations, document analyses, and 96 in-depth semi-structured interviews in three Dutch healthcare franchises. Withincase and cross-case comparative analyses were conducted. Subsequently, a crosssectional survey was developed based on the qualitative study and disseminated among 19 healthcare franchises. 40 franchisors and 346 unit actors filled in the questionnaire. Findings It seems important to have open, committed, cooperative franchise relationships in which professional franchisees and unit managers feel and trust that they have the opportunity to introduce ideas and articulate their needs to the franchisor. Such relationships help ensure satisfaction, survival, and quality of care, because they serve to foster synergy realization and local fit and prevent reinventing the wheel and professional resistance

Taking Action Together: A YMCA-based protocol to prevent Type-2 Diabetes in high-BMI inner-city African American children

<p>Abstract</p> <p>Background</p> <p>Associated with a tripling in obesity since 1970, type 2 diabetes mellitus (T2DM) in children has risen 9-10 fold. There is a critical need of protocols for trials to prevent T2DM in children.</p> <p>Methods/Design</p> <p>This protocol includes the theory, development, evaluation components and lessons learned from a novel YMCA-based T2DM prevention intervention designed specifically for high-BMI African American children from disadvantaged, inner-city neighborhoods of Oakland, California. The intervention was developed on the basis of: review of epidemiological and intervention studies of pediatric T2DM; a conceptual theory (social cognitive); a comprehensive examination of health promotion curricula designed for children; consultation with research, clinical experts and practitioners and; input from community partners. The intervention, <it>Taking Action Together</it>, included culturally sensitive and age-appropriate programming on: healthy eating; increasing physical activity and, improving self esteem.</p> <p>Discussion</p> <p>Evaluations completed to date suggest that <it>Taking Action Together </it>may be an effective intervention, and results warrant an expanded evaluation effort. This protocol could be used in other community settings to reduce the risk of children developing T2DM and related health consequences.</p> <p>Trial registration</p> <p>ClinicalTrials.gov NCT01039116.</p

Technical Efficiency in the Malaysian Gill Net Artisanal Fishery

Artisanal fishing communities include some of the poorest fishers in Malaysia. The paper presents the first technical efficiency study, whichfinds that artisanal fishers are poor, but enjoy a higher level of technical efficiency than found in the other Malaysian gill net fisheries. It suggests that targeted development assistance to the harvesting sector may be better directed to other priorities in artisanal fishing communities.artisanal fisheries, fisheries development, technical efficiency

Examining punishment at different explanatory levels

Experimental studies on punishment have sometimes been over-interpreted not only for the reasons Guala lists, but also because of a frequent conflation of proximate and ultimate explanatory levels that Guala's review perpetuates. Moreover, for future analyses we may need a clearer classification of different kinds of punishmen

The social structure of cooperation and punishment

The standard theories of cooperation in humans, which depend on repeated interaction and reputation effects among self-regarding agents, are inadequate. Strong reciprocity, a predisposition to participate in costly cooperation and the punishment, fosters cooperation where self-regarding behaviors fail. The effectiveness of socially coordinated punishment depends on individual motivations to participate, which are based on strong reciprocity motives. The relative infrequency of high-cost punishment is a result of the ubiquity of strong reciprocity, not its absenc

Choice Flexibility and Long-Run Cooperation

Understanding how incentives and institutions help scaling up cooperation is important, especially when strategic uncertainty is considerable. Evidence suggests that this is challenging even when full cooperation is theoretically sustainable thanks to indefinite repetition. In a controlled social dilemma experiment, we show that adding partial cooperation choices to the usual binary choice environment can raise cooperation and efficiency. Under suitable incentives, partial cooperation choices enable individuals to cheaply signal their desire to cooperate, reducing strategic uncertainty. The insight is that richer choice sets can form the basis of a language meaningful for coordinating on cooperation

Response Bias in International Marketing Research.

The saturation of domestic markets in the industrialized parts of the world, combined with increased competition in home markets from foreign competitors forces many companies to look for opportunities beyond their national boundaries. Surveys are a crucial source of data in international marketing for theory building and answering managerial questions, as secondary data is seldom satisfactory. An important force that stymies the comparison of findings across countries is methodological in nature. Cross-national research presents researchers with a host of methodological challenges that hamper validity, such as differences in response styles and lack of measurement invariance. The dissertation contributes to the literature in three ways. First, hierarchical measurement models are presented that allow marketing researchers to compare countries substantively despite lack of measurement invariance and cross-national differences in response styles. Second, the relationship between culture and stylistic responding is investigated. Third, a procedure is presented that yields country-specific, yet internationally comparable short form marketing scales.

Play Together: How Watching the Cooperative Play of Violent Video Games Can Positively Influence Dyadic Relationships

Media effects research has shown that video games can have both antisocial and prosocial effects, depending on the content of the game. Individuals who play violent video games tend to display more aggressive attitudes and behaviors, while those who play games with prosocial content tend to display more prosocial, or helping, attitudes and behavior. The context in which a video game is played has also been shown to influence media effects, with competitive play leading to increased aggression while cooperative play leads to increased prosociality. However, the existing literature has not examined how these effects might influence the interpersonal relationships between those playing the video game. To test the effects of gaming context on interpersonal relationships, an experiment was conducted that compared two groups of participants exposed to two levels (competitive or cooperative) of a single factor (gaming context). In the competitive condition, participants watched gameplay footage of two individuals playing a video game competitively, while those in the cooperative condition watched gameplay footage of two individuals playing the same game cooperatively. After exposure, five dependent variables were examined to see how they differed between the two groups: state hostility, prosocial score, positive affect change, negative affect change, and change in perceived relationship quality. iii Upon initial analysis, only negative affect change was shown to significantly differ between the two conditions. However, this effect was actually due to an interaction between condition and sex. This study also identified that sex, personality, and media usage habits significantly covaried to some degree with all five dependent variables. These covariates provide evidence for how individual differences might influence the effects that result from watching a video game being played in different multiplayer contexts and, as an extension, how individual differences might influence the effects of gaming context in general

Understanding the Relationship Between Pharmacists’ Implicit and Explicit Bias and Perceptions of Pharmacist Services Among Arab and Black Individuals

Background. Recent studies suggest that Health Care Professionals’ (HCPs) unconscious bias about race contributes to health care disparities. The objective of this research was to estimate unconscious racial bias among pharmacists in order to understand its relationship with Black and Arab individuals’ perceptions and experience of pharmacist services and their interaction with pharmacists in Ontario. Methods. Multi-method research combining both quantitative and qualitative methods was employed. A secure, web-based survey was administered to Ontario community pharmacists. The survey included two Implicit Association Tests (IATs) to assess unconscious preferences and direct questions regarding community pharmacists’ explicit attitude to race. In a qualitative study using purposive sampling, face-to-face semi-structured interviews with 27 Black and Arab individuals were conducted to explore their interactions with pharmacists and their opinions, perceptions, attitudes, and experiences about community pharmacist services. Results. A total of 407 community pharmacists (40% male, mean age 47, 57% white) completed the survey. Evidence of race/ethnicity bias toward Black and Arab individuals was evident, as determined by both explicit and implicit measures. Moderate to high levels of implicit pro-white bias were found among Ontario community pharmacists on average. Explicit pro-white bias was less evident, but apparent for measures of racial/ethnic preference and, relative warmth (amount of warmth felt toward Black/Arab individuals subtracted from the amount of warmth felt toward whites). In addition, implicit bias appeared to be associated with pharmacist characteristics such as age, racial/ethnic background, years as a pharmacist, years as a licensed pharmacist in Canada practice location, and place of birth, and explicit preferences had a weak positive correlation. The qualitative data revealed that most Black and Arab individuals felt comfortable interacting v and seeking advice from their pharmacists. However, some Black and Arab participants experienced discrimination from community pharmacists. The data also provided information about some personal and systemic issues encountered by Black and Arab individuals when they interacted with community pharmacist. Conclusions. Race and ethnicity bias exists among most Ontario community pharmacists and may be associated with Black and Arab individuals’ perceptions of pharmacist services and their interaction with pharmacists. Future work needs to employ more rigorous approaches to explore whether, and under what conditions, community pharmacists’ implicit bias about race/ethnicity affect the quality of their services toward visible minority individuals, including Black and Arab people. Interventions to reduce bias may need to be comprehensive so that they can ultimately influence an individual’s implicit and explicit biases in all measured areas