Embodied communication through social odor, cortical spectral power and co-presence technology

Embodied communication (EC) happens through multisensory channels, involving not only linguistic and cognitive processes, but also complex cross-modal perceptive pathways. This type of bidirectional communication is applicable both to human interactions and to human-robot interaction (HRI). A cross-modal technological interface can increase the interaction and the feeling of co-presence (CP), highly related to an interactive relationship. Information Communication Technology (ICT) developed, in virtual interfaces, some embodied ‘communicative’ senses, placing little attention to the olfactory sense, which, instead, is developmentally and evolutionistically linked to social and affective relation. The purpose of this work is to investigate the EC through social odor (SO), EEG cortical spectral power and CP technology. 20 healthy subjects (mean age 23±2,4; 10 women) participated to the study. The subjects had to listen a story narrated via embodied communicative media (Hugvies), during an EEG high-density recording. The narrator’s voice was male (A) or female (B) and the Hugvie was presented in 3 balanced SO conditions. In particular, 2 putative pheromones (PP) and a control condition were volatilized on the Hugvies: Estratetraenol (X), 5a-Androst-16-en-3a-ol (Y) and Vaseline Oil as neutral odor (Z). To test our hypothesis of the effect of SO and voice gender on CP sense, a repeated-measures GLM was performed on behavioural and EEG variables, with Group as between-subject factor Group and social odor condition (X, Y and Z), voice (A and B) as within factors. Behavioral results, assessed through the CP test, highlighted a significant variability gender- and SO- related. The EEG spectral power showed significant differences in group, SO, voice gender and also significant interactions. Alpha and d rhythms showed a substantial rule in SO perception. The centroparietal is the most respondent area for both the SO, and for both a and d waves, differently by anterofrontal and occipital site, that highlighted a greater presence of d. As second explorative step, a canonical correlation analysis was performed to identify the main co-activated ROIs. An overall concordance was found in right orbitofrontal area with d rhythms; moreover, a rhythm was observed in the right inferior temporal gyrus (activated by the PP) and in right parietal cortex (linked to focused internal attention). In and in ß rhythms was observed a functional activation of the left dorsolateral prefrontal cortex. This pathway is strictly connected to the abstract categorical decision in ambiguous stimuli, transcending the task and the sensory modality. Our approach is the first of its kind and provides the framework to further integrated ICT model, where the SO, even with its component of relational meaning, becomes an element to investigate or elicit different behaviors and psychophysiological responses, especially in CP technology, and, in future, in HRI.