The sheep offers a unique model to study male sexual behavior and sexual partner preference. Rams are seasonal breeders and show the greatest libido during short days coincident with the resumption of ovarian cyclicity in the ewe. Threshold concentrations of testosterone are required for the acquisition and display of adult sexual behavior. In addition, estrogens produced from circulating testo...

Two experiments tested when and why women's typically negative, spontaneous reactions to sexual imagery would soften. Sexual economics theory predicts that women want sex to be seen as rare and special. We reasoned that this outlook would translate to women tolerating sexual images more when those images are linked to high worth as opposed to low worth. We manipulated whether an ad promoted an ...

To aid risk assessment, management, and treatment planning it is essential to assess child sexual abusers' deviant sexual interests (DSI) and preferences (DSP) for sex with children. However, measurement of DSI/DSP is fraught with psychometric problems. In consequence, research interest has shifted to latency-based indirect measures as a measurement approach to complement self-report and physio...

Darwin proposed an explicitly aesthetic theory of sexual selection in which he described mate preferences as a 'taste for the beautiful', an 'aesthetic capacity', etc. These statements were not merely colourful Victorian mannerisms, but explicit expressions of Darwin's hypothesis that mate preferences can evolve for arbitrarily attractive traits that do not provide any additional benefits to ma...

Conventional models of single district plurality elections show that with three parties anything can happen extreme policies can win regardless of voter preferences. I show that when there are multiple district elections for a legislature we get back to a world where the median voter matters: an extreme policy will generally only come about if it is preferred by the median voter in a majority o...

We consider a multilateral bargaining game in which the agents can be classified into two groups according to their instantaneous preferences. In one of these groups there is one agent with a different discount factor. We analyze how this time-preference heterogeneity may generate multiplicity of equilibria. When such an agent is sufficiently more patient than the rest, there is an equilibrium ...

BACKGROUND Research on gay and other men who have sex with men's (G/MSM) preferences for sexual healthcare services focuses largely on HIV testing and to some extent on sexually transmitted infections (STI). This research illustrates the frequency and location of where G/MSM interface with the healthcare system, but it does not speak to why men seek care in those locations. As HIV and STI preve...

Female mating preferences can influence both intraspecific sexual selection and interspecific reproductive isolation, and have therefore been proposed to play a central role in speciation. Here, we investigate experimentally in the African cichlid fish Pundamilia nyererei if differences in male coloration between three para-allopatric populations (i.e. island populations with gene flow) of P. n...

Sexual reproduction strategies vary both between and within species in the level of investment in offspring. Life-history theories suggest that the rate of sexual maturation is critically linked to reproductive strategy, with high investment being associated with few offspring and delayed maturation. For humans, age of puberty and age of first sex are two developmental milestones that have been...

Learned mate preferences may play an important role in speciation. Sexual imprinting is a process whereby mate preferences are a€ected by learning at a very young age, usually using a parent as the model. We suggest that while the origins of learning appear to lie in the advantages of individual recognition, sexual imprinting results from selection for recognition of conspeci®cs. This is becaus...