Two simplified proofs for Roberts’ theorem

Roberts (Aggregation and Revelation of Preferences. Papers presented at the 1st European Summer Workshop of the Econometric Society, pp. 321–349. North-Holland, 1979) showed that every social choice function that is ex-post implementable in private value settings must be weighted VCG, i.e. it maximizes the weighted social welfare. This paper provides two simplified proofs for this. The first proof uses the same underlying key-point, but significantly simplifies the technical construction around it, thus helps to shed light on it. The second proof builds on monotonicity conditions identified by Rochet (J Math Econ 16:191–200, 1987) and Bikhchandani et al. (Econometrica 74(4):1109–1132, 2006). This proof is for a weaker statement that assumes an additional condition of “player decisiveness”. Supported by grants from the Israeli Ministry of Science and the Israeli Academy of Sciences.     

Similarity and Complementarity of Behavioral Profiles of Friendship Types and Types of Friends: Friendships and Psychosocial Adjustment

This study investigated different types of friendships and the behavioral profiles of different types of friends in relation to individual adjustment. In 102 classes with preadolescents (mean age 11), 737 independent friendship dyads, and in 149 classes with adolescents (mean age 14), 1,102 friendship dyads were identified. At each age group, cluster analyses on the behavioral profiles of the dyads yielded three friendship types, with two types of friends within each friendship type: Socially Withdrawn friendship (Victimized Withdrawn and Prosocial Withdrawn friends), Prosocial friendship (High Prosocial and Less Prosocial friends), and Antisocial friendship (Bullying Antisocial and Antisocial friends). The behavioral profiles of the two friends in Prosocial friendships were marked by similarity and in the other two types by complementarity. Both Victimized Withdrawn and Bullying Antisocial friends were less adjusted than participants without friends while Prosocial friends were more adjusted.     

A Mandate for Honesty: Jeff Young's No Bullshit Therapy

Jeff Young talks about having been trained to be formal with clients, and his gradual realisation that he could return to the more direct ways of speech he learned as a child, and combine that with warmth. He found that clients and fellow professionals welcomed a therapist who did not ‘beat around the bush’. Together, Jeff and Ron talk about when directness is appropriate, and how directness needs to be modified for particular clients.     

Health care as a social security benefit: Institutional approaches to extending coverage

Reaching universal health‐care coverage requires an appropriate mix of compulsory contributory social insurance schemes, with mechanisms to include the informal‐economy population, and tax‐based social assistance for those whose incomes preclude their own contributions. This article urges a reversal of the trend that favours the separate development of social health insurance by separate health authorities and makes the case for the extension of health‐care coverage using existing formal‐sector social security schemes, not least because they have the necessary political backing and institutional structures. The article reviews reasons for the slow pace of coverage extension to date, and stresses the added value of incorporating health care as a social security benefit while also acknowledging the importance of retaining linkages between statutory and well‐regulated community‐based or micro health‐insurance schemes.     

Gambling Behavior and Pathology in Relation to Impulsivity, Sensation Seeking, and Risky Behavior in Male College Students

Sensation seeking and impulsivity are two constructs of personality that are generally believed to be associated with risky behavior, including gambling. Despite the fact that pathological gambling is classified as an Impulsive Control Disorder in the DSM-IV, relatively little empirical research has investigated the relationship between gambling and impulsivity. The purpose of this study was to investigate the relationship between sensation seeking, impulsivity, risky behaviors and gambling. One hundred and forty-four male undergraduate university students completed several inventories measuring sensation seeking, impulsivity, gambling, and risky behaviors. Statistical analyses revealed a very high percentage of participants were classified in the pathological gambler range of scores. In addition, a significant difference was found between the relationships of sensation seeking, impulsivity, and risky behaviors with gambling scores in the pathological versus non-pathological groups. Pathological gambler's scores on measures of sensation seeking and impulsivity did not correlate with their degree of gambling pathology. In contrast, the sensation seeking and impulsivity scores of non-pathological gamblers did correlate with their scores of gambling pathology. These results have implications on Jacob's General Theory of Addiction. The findings of this study also suggest that the classification of gambling as an impulse control disorder rather than an addictive disorder needs to be reevaluated.     

Persistence and desistance in heavy cannabis use: the role of identity,agency, and life events

Many cannabis users ‘mature out’ of their drug use, and factors of cannabis use cessation have been identified. However, very little in-depth knowledge is available about the mechanisms underlying this phenomenon. Criminological studies have gained interesting insights in desistance from crime, yet these perspectives are rarely used in drug research. This qualitative, three-year longitudinal study explored the processes involved in desistance from frequent cannabis use for young adults. Using a narrative approach, desisters (frequent users who successfully quit their cannabis use) and persisters (frequent users with a persistent desire and unsuccessful attempts to quit) were compared. In the course of the study, desisters mainly exhibited increasing agency and goal setting, established strategies to achieve these goals, and could envision another self. Desistance was generally induced by life events that became turning points. Persisters experienced largely similar events, but lacked goals and strategies and held external factors responsible for their life course and failed quit attempts. Identity change is at the core of desistance from frequent cannabis use, and the meaning-giving to life events and experiences is essential. Agency is a necessary ingredient for desistance, develops over time and through action, and leads to a new drug-free identity with desistance in turn increasing agency.     

Large Contests

We consider contests with many, possibly heterogeneous, players and prizes, and show that the equilibrium outcomes of such contests are approximated by the outcomes of mechanisms that implement the assortative allocation in an environment with a single agent that has a continuum of possible types. This makes it possible to easily approximate the equilibria of contests whose exact equilibrium characterization is complicated, as well as the equilibria of contests for which there is no existing equilibrium characterization.