<p>The notion that humans have specialized chemicals used for communication between conspecifics, so-called pheromones, has attracted much attention and discussion. This thesis demonstrates in four separate studies that a human endogenous steroidal compound that is abundant in male sweat, androstadienone, affects women in several ways that differ to that of common odors. Specifically, androstadienone was found in Study I to have unique psychophysical characteristics in that the sensitivity distribution of the odor is bimodal with a smaller subpopulation consisting of highly sensitive individuals. Trigeminal mediation of this bimodality was experimentally excluded. Moreover, Study II demonstrated that women’s cortical activation of androstadienone exposure was found to differ to that of common odorants in that androstadienone was processed faster than two perceptually similar control odors. It was further demonstrated that a non-detectable amount of androstadienone can reliably modulate both mood and physiology in women (Study III & IV); in particular mood referring to attention processes. Study IV showed that androstadienone-induced mood changes in heterosexual women were only evident when the experiment was administered by an experimenter of different sex. The combined results from these studies suggest that androstadienone serves as a human modulator pheromone that guides our behavior by inducing subtle changes in higher cognitive processes in relation to the ecological context at hand. A new definition of human pheromones is proposed and discussed in relation to the obtained results.</p>

The notion that humans have specialized chemicals used for communication between conspecifics, so-called pheromones, has attracted much attention and discussion. This thesis demonstrates in four separate studies that a human endogenous steroidal compound that is abundant in male sweat, androstadienone, affects women in several ways that differ to that of common odors. Specifically, androstadienone was found in Study I to have unique psychophysical characteristics in that the sensitivity distribution of the odor is bimodal with a smaller subpopulation consisting of highly sensitive individuals. Trigeminal mediation of this bimodality was experimentally excluded. Moreover, Study II demonstrated that women’s cortical activation of androstadienone exposure was found to differ to that of common odorants in that androstadienone was processed faster than two perceptually similar control odors. It was further demonstrated that a non-detectable amount of androstadienone can reliably modulate both mood and physiology in women (Study III &amp; IV); in particular mood referring to attention processes. Study IV showed that androstadienone-induced mood changes in heterosexual women were only evident when the experiment was administered by an experimenter of different sex. The combined results from these studies suggest that androstadienone serves as a human modulator pheromone that guides our behavior by inducing subtle changes in higher cognitive processes in relation to the ecological context at hand. A new definition of human pheromones is proposed and discussed in relation to the obtained results.

Olfaction plays an important role in human mate selection or in ratings of sexual attractiveness of potential mates. Many studies suggest that olfaction is associated with human sexuality and arousal as well, especially in women, for whom the perception of odors is an important aspect not only in mate selection, but also in sexual context. There are steroids called 16-androstenes, which have an unique importance in this issue. These steroids, produced by the apocrine glands, are compounds of human body odor. The aim of the empirical part of this thesis is to research the associations between olfactory abilities and sexual function in women, especially with particular focus on the association of olfactory sensitivity (particularly to androstadienone as well as in general), orgasmicity and arousal, which are two major domains of sexual function. Participants were 90 heterosexual and coupled female students aged 21-30. All participants were tested during the follicular phase of their menstrual cycle. The Sniffin Sticks olfactory test was employed to assess the general olfactory functions. Among others, olfactory sensitivity to androstadienone was measured, as well as the perceived intensity and hedonicity of androstenone, androstenol and andostadienone. Participants filled out set of questionnaires...