Unlike other animals, human children will copy all of an adult's goal-directed actions, including ones that are clearly unnecessary for achieving the demonstrated goal. Here we highlight how social affiliation is key to this species-specific behavior. Preschoolers watched 2 adults retrieve a toy from a novel apparatus. One adult included irrelevant actions in her demonstration; the other only used actions causally related to opening the apparatus. After both adults took turns demonstrating, 1 left the test room, and the remaining adult gave the apparatus to the child. Children reproduced the irrelevant actions only when given the apparatus by the adult who had demonstrated them, even though the departed adult's actions emphasized how unnecessary these redundant actions were. Our results highlight the specialized skills for participating in cultural groups that have evolved in humans and provide insight into why finding such high fidelity copying in other animals has proven elusive.

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III.

Research in doping has focused on potential intervention strategies, increasingly targeting predicting factors. Yet, findings are inconsistent, mostly athlete-centred and explain only limited variances in behaviour. This critical review aims to (a) summarize studies that identified predictors of doping intentions, susceptibility, and behaviour in elite athletes and to (b) analyse in how far previous research included aspects beyond athlete-centred approaches, such as context and sporting culture. We reviewed 14 studies that focused on elite athletes. Situational temptation, attitudes, and subjective norms seem to be strong predicting variables of doping intentions (r ≥ 0.50), but intention was no predictor for behaviour. Attitudes were a significant predictor for both, doping susceptibility (r = 0.47) and behaviour (r = 0.30). Most of the predictors are athlete-centred and ignore macro-level factors that might help to explain how certain individual traits impact on the decision making process. The findings from this review call for a critical discussion of whether current doping-prevention research needs to take new directions. We propose future research to bridge findings of psychologists and sociologists, as it appears that doping behaviour cannot be explained by ignoring the one or the other. Impacts of sporting culture that have been identified in qualitative approaches need to be integrated in future quantitative approaches to test for its external validity. Inclusion of both, micro- and macro level factors may enable an integrative prevention program that creates a sporting culture without doping.

The Pliofilm cohort is the most intensely studied group of workers chronically exposed to benzene. Information on this cohort has been the basis for regulations and/or guidelines for occupational and environmental exposure to benzene. Rinsky et al. (1986, 1987) and Crump and Allen (1984) developed different approaches for reconstructing the exposure history of each member of the group. The predicted levels of exposure, combined with the data on the incidence of disease, have been used to estimate benzene's carcinogenic potency. In this paper, recent information from worker interviews and historical records from the National Archives and elsewhere were used to evaluate the accuracy of prior exposure estimates and to develop better ones for the cohort. The following factors were accounted for: (1) uptake of benzene due to short-term, high-level exposure to vapors, (2) uptake due to background concentrations in the manufacturing building, (3) uptake due to contact with the skin, (4) morbidity and mortality data on workers in the Pliofilm process, (5) the installation of industrial hygiene engineering controls, (6) extraordinarily long work weeks during the 1940s, (7) data indicating that airborne concentrations of benzene were underestimated due to inaccurate monitoring devices and the lack of adequate field calibration mated due to inaccurate monitoring devices and the lack of adequate field calibration of these devices, and (8) likely effectiveness of respirators and gloves. Our estimates suggest that Crump and Allen (1984) overestimated the exposure of workers in some job classifications and underestimated others, and that Rinsky et al. (1981, 1986) almost certainly underestimated the exposure of nearly all workers. Airborne concentrations of benzene at the St. Marys facility during the years of its operation were found (on average) to be about half those of the two Akron facilities. Our analysis indicates that short-term, high-level exposure to benzene vapors and dermal exposure significantly increased (by about 25-50%) the total absorbed dose of benzene for some workers. One of the key findings was that, unlike prior analyses, the three facilities probably had significantly different airborne concentrations of benzene, especially during the 1940s and 1950s.