Cross-modal processing of putative pheromones and gender-voice in a bodily contact medium can modulate behavioral and psychological state of the subject

The perception of putative pheromones or social odours (PPSO) in humans is a widely debated topic, as the results seem ambiguous. Our research aimed to evaluate how cross-modal processing of PPSO and gender-voice (GV) can affect both behavioural and psychophysiological state of the subject during a task with a bodily contact medium (i.e, Hugvie) and how these effects are gender-linked. 20 healthy subjects (mean age 23±2,4; 10 women), volunteers, participated to the study. Estratetraenol, 5α-Androst-16-en-3α-ol and Vaseline Oil (used as neutral condition), were volatilized to the Hugvies in three different conditions during a listening task, recorded through an EEG 64 active channels. Behavioural results, assessed though a co-presence test, showed how the established relationship with the Hugvie was gender dependent and was modulated by the PPSO and the GV. The psychophysiological data results followed the trend of the behavioural results. Also the electrophysiological results showed that men and women presented different variations in EEG spectra power, and that these variations were affected/modulated by PPSO and by GV. The most influenced rhythms were delta and alpha. The interaction of the ‘social odor’ with the voice-gender showed a balanced situation, conversely, there is a difference ascribed to the neutral condition that highlight an increased power activity related female gender-voice. The centroparietal localization presented a PPSO effect for both of 5α-Androst- 16-en-3α-ol and of Estradiol, that induced greater presence of alpha and delta waves, differently by anterofrontal and occipital site, that highlighted a greater presence of delta. Subsequently, a canonical correlation analysis was applied to investigate the main co-activations. Delta rhythms highlighted points of co- activity in right orbitofrontal area, involved in odor recognition memory and social behaviour and in left centroparietal site, involved in speech interpretation. Our results provide compelling evidence for PPSO and GV effect on co-presence perception and psychophysiological activations.