Objectives: Research of sexuality often times includes individuals who choose to be researched and are willing to undergo the procedures. Samples of the population (students and self-selected enthusiasts) may not resemble the nation’s population structure nor the general idea of random human even though the psychological mechanisms researched are thought to be universal. The aim of this study was to investigate the relationship between proximal measures of domain specific and non-specific excitation and inhibition in two (probabilistic and non-probabilistic) samples. Sample and settings: The authors collected approximately 400 individuals from the Central European country – Czech Republic – via the specialized agency to match the probabilistic sample (stratified sample) and a second similarly sized sample (chance sample) via snowball sampling and online advertisements at the same time. The participants were asked to fill in two questionnaires widely used by sex researchers (Sexual Inhibition and Excitation Scale, and Sociosexual Orientation Inventory Revised), and one scale designed to map broader motivations to avoid aversive outcomes and motivation to approach goal-oriented outcomes (Behavioral Inhibition and Activation Scale). Hypotheses: The authors expected partial or complete confirmation of previously found results (general and sexuality specific activation and inhibition and sociosexuality), and also that the replication will be affected by the sample choice Statistical analyses: To follow methodologies of previous studies used to create hypotheses the authors decided to use partial correlation controlling for age of the participants. Results: Generally, the chance sample findings resembled the published results whereas the stratified sample showed bigger differences. The results, relying on correlational analyses as majority of studies does, provided a valuable insight to impact of sampling on results. Using the SEM methodology the study provided further support for the incomparability of the results obtained employing different sampling. Limitations: The sample size, thus larger than usual studies, could be higher.
Latent toxoplasmosis has been previously found to cause behavioural and personality changes in humans, which are specific for each gender. Here we tested the stress hypothesis of these gender differences based on the assumption that latent toxoplasmosis causes long-term subliminal stress. In line with this hypothesis, the gender difference will appear specifically in situations with interpersonal context because in contrast to the typical individualistic coping style of men, women have a tendency to express elevated prosocial behaviour under stress. Altogether 295 biology students (29/191 females and 27/104 males infected by T. gondii) played a modified version of the Dictator Game and the Trust Game. As predicted, a gender difference in the effect of latent toxoplasmosis was found for the measure of reciprocal altruism in the Trust Game (p = 0.016), but both genders appeared less generous when infected in the Dictator Game modified to minimize social connotation (p = 0.048).
