Investigating the dimensions of conversational agents' social competence using objective neurophysiological measurements

Assessing the social competence of anthropomorphic artificial agents developed to produce engaging social interactions with humans has become of primary importance to effectively compare various appearances and/or behaviours. Here we attempt to objectify the social competence of artificial agents, across different dimensions, using human brain neurophysiology. Whole brain activity is recorded with functional Magnetic Resonance Imaging (fMRI) while participants, naïve to the real purpose of the experiment, discuss either with a human confederate or with an artificial agent, presently the robotic conversational head Furhat controlled with a Wizard of Oz procedure. This allows a direct comparison of local brain responses, not only at the cortical level but also in subcortical structures associated with motivational drive and impossible to investigate with non-invasive neurophysiology techniques such as surface recordings. The present data (n = 21 participants) demonstrates the feasibility of this approach, and results confirm an increased activity in subcortical structures, in particular the amygdala involved in emotional processing and the hypothalamus, known to secrete, among others, the neurohormone oxytocin involved in social bonding, as well as the temporoparietal junction bilaterally involved in the attribution of mental states, when interacting with a human compared to an artificial agent. The reverse contrast revealed more dorsal cortical areas. Altogether, these results support the use of fMRI to objectify the social competence of artificial agents along distinct dimensions.