Many studies assume that selection molds social traits and have investigated the manner in which this occurs, yet very few studies have measured the strength of selection on social traits in natural populations. In this paper, I report results of phenotypic selection analyses on two social traits the size of social groups and the frequency of group foraging in Phyllostomus hastatus, the greater...

Two studies directed toward development and validation of a self-report measure of social competence in dating and assertion situations are described. An 18-item questionnaire consisting of items that assessed the likelihood of certain specific behaviors occurring and the degree of discomfort and expected incompetence in specific situations was derived. This questionnaire discriminated between ...

Adult sex ratio (ASR) is a central concept in population biology and a key factor in sexual selection, but why do most demographic models ignore sex biases? Vital rates often vary between the sexes and across life history, but their relative contributions to ASR variation remain poorly understood-an essential step to evaluate sex ratio theories in the wild and inform conservation. Here, we comb...

Using item response theory and confirmatory factor analysis, the current investigation examined the equivalence in responses derived from the widely used 21-item Beck Depression Inventory-II (BDI-II; Beck, Steer, & Brown, 1996) among 1229 college students (mean = 21.15, SD = 6.19) in the United States. Results from differential item functioning analyses indicated that the items endorsed by Blac...

Lawn S (2008) Tobacco control policies, social inequality and mental health populations: time for a comprehensive treatment response. alterations made during the publishing process may not appear in this version.

Deliberate deceptiveness intended to gain an advantage is commonplace in human and animal societies. In a social dilemma, an individual may only pretend to be a cooperator to elicit cooperation from others, while in reality he is a defector. With this as motivation, we study a simple variant of the evolutionary prisonerʼs dilemma game entailing deceitful defectors and conditional cooperators th...

We derive exact formulae for the allele frequency spectrum under the coalescent with mutation, conditioned on allele counts at some fixed time in the past. We consider unlinked biallelic markers mutating according to a finite sites, or infinite sites, model. This work extends the coalescent theory of unlinked biallelic markers, enabling fast computations of allele frequency spectra in multiple ...

Sex differences in central tendency, variability, and numbers of high scores on mental tests have been extensively studied. Research has not always seemed to yield consistent results, partly because most studies have not used representative samples of national populations. An analysis of mental test scores from six studies that used national probability samples provided evidence that although a...

When costs and benefits of raising sons and daughters differ between environments, parents may be selected to modify their investment into male and female offspring. In two recently colonized environments, breeding female house finches (Carpodacus mexicanus) modified the sex and growth of their offspring in relation to the order in which eggs were laid in a clutch. Here we show that, in both po...

Therapeutic trials in Alzheimer disease (AD) are notoriously difficult and have produced no new approved treatments in the past decade. Trial success often depends on decline in a placebo arm, and population characteristics that diminish placebo decline reduce the chance of detecting positive therapeutic effects of a drug. This study of data from multiple trials of AD dementia demonstrates that...