Smelling chemosensory signals of males in anxious versus nonanxious condition increases state anxiety of female subjects.

The hypothesis of this experiment was that humans in an anxious state compared with a nonanxious state are able to increase anxiety levels in other humans via their body odors. Specifically, we hypothesized that male chemosensory anxiety signals compared with neutral chemosignals increase state anxiety of female subjects. Thirteen male subjects participated in 2 different sweat donation sessions: chemosignals were collected during participation in a high rope course (anxiety condition) and in an ergometer workout (neutral condition). State and trait anxiety were evaluated in 20 female odor recipients using Spielberger's state-trait anxiety inventory in a double-blind design. Comparison of state anxiety of odor donors between control and anxiety condition differed significantly indicating that our model of anxiety induction successfully led to the expected change in emotion. Comparison of state anxiety of odor recipients showed a trend toward higher state anxiety in the anxiety condition compared with the neutral condition after 5 min of odor exposure. After 20 min of odor exposure, state anxiety of female subjects was significantly higher during the perception of sweat collected during the anxiety condition in comparison with the perception of sweat collected during the neutral condition. This experiment gives evidence that male anxiety chemosignals compared with neutral chemosignals are capable of inducing an increased state anxiety in female subjects.

No fear no risk! Human risk behavior is affected by chemosensory anxiety signals.

An important aspect of cognitive functioning is decision-making, which depends on the correct interpretation of emotional processes. High trait anxiety has been associated with increased risk taking behavior in decision-making tasks. An interesting fact is that anxiety and anxiety-related chemosignals as well as decision-making share similar regions of neuronal activation. In order to ascertain if chemosensory anxiety signals have similar effects on risk taking behavior of healthy participants as high trait anxiety we used a novel computerized decision-making task, called Haegler's Risk Game (HRG). This task measures risk taking behavior based on contingencies and can be played repeatedly without a learning effect. To obtain chemosensory signals the sweat of 21 male donors was collected in a high rope course (anxiety condition). For the chemosensory control condition sweat was collected during an ergometer workout (exercise condition). In a double-blind study, 30 healthy recipients (16 females) had to play HRG while being exposed to sweat samples or empty control samples (control condition) in three sessions of randomized order. Comparison of the risk taking behavior of the three conditions showed significantly higher risk taking behavior in participants for the most risky choices during the anxiety condition compared to the control conditions. Additionally, recipients showed significantly higher latency before making their decision in the most risky choices during the anxiety condition. This experiment gives evidence that chemosensory anxiety signals are communicated between humans thereby increasing participants' risk taking behavior.