Are mature smokers misinformed?

While there are many reasons to continue to smoke in spite of its consequences for health, the concern that many smoke because they misperceive the risks of smoking remains a focus of public discussion and motivates tobacco control policies and litigation. In this paper we investigate the relative accuracy of mature smokers' risk perceptions about future survival, and a range of morbidities and disabilities. Using data from the survey on smoking (SOS) conducted for this research, we compare subjective beliefs elicited from the SOS with corresponding individual-specific objective probabilities estimated from the health and retirement study. Overall, consumers in the age group studied, 50-70, are not overly optimistic in their perceptions of health risk. If anything, smokers tend to be relatively pessimistic about these risks. The finding that smokers are either well informed or pessimistic regarding a broad range of health risks suggests that these beliefs are not pivotal in the decision to continue smoking. Although statements by the tobacco companies may have been misleading and thus encouraged some to start smoking, we find no evidence that systematic misinformation about the health consequences of smoking inhibits quitting.

Sexual selection and canine dimorphism in New World monkeys.

Social and ecological factors are important in shaping sexual dimorphism in Anthropoidea, but there is also a tendency for body-size dimorphism and canine dimorphism to increase with increased body size (Rensch's rule) (Rensch: Evolution Above the Species Level. London: Methuen, 1959.) Most ecologist interpret Rensch's rule to be a consequence of social and ecological selective factors that covary with body size, but recent claims have been advanced that dimorphism is principally a consequence of selection for increased body size alone. Here we assess the effects of body size, body-size dimorphism, and social structure on canine dimorphism among platyrrhine monkeys. Platyrrhine species examined are classified into four behavioral groups reflecting the intensity of intermale competition for access to females or to limiting resources. As canine dimorphism increases, so does the level of intermale competition. Those species with monogamous and polyandrous social structures have the lowest canine dimorphism, while those with dominance rank hierarchies of males have the most canine dimorphism. Species with fission-fusion social structures and transitory intermale breeding-season competition fall between these extremes. Among platyrrhines there is a significant positive correlation between body size and canine dimorphism However, within levels of competition, no significant correlation was found between the two. Also, with increased body size, body-size dimorphism tends to increase, and this correlation holds in some cases within competition levels. In an analysis of covariance, once the level of intermale competition is controlled for, neither molar size nor molar-size dimorphism accounts for a significant part of the variance in canine dimorphism. A similar analysis using body weight as a measure of size and dimorphism yields a less clear-cut picture: body weight contributes significantly to the model when the effects of the other factors are controlled. Finally, in a model using head and body length as a measure of size and dimorphism, all factors and the interactions between them are significant. We conclude that intermale competition among platyrrhine species is the most important factor explaining variations in canine dimorphism. The significant effects of size and size dimorphism in some models may be evidence that natural (as opposed to sexual) selection also plays a role in the evolution of increased canine dimorphism.