Induction of Empathy by the Smell of Anxiety

Abstract

The communication of stress/anxiety between conspecifics through chemosensory signals has been documented in many vertebrates and invertebrates. Here, we investigate how chemosensory anxiety signals conveyed by the sweat of humans (N = 49) awaiting an academic examination are processed by the human brain, as compared to chemosensory control signals obtained from the same sweat donors in a sport condition. The chemosensory stimuli were pooled according to the donation condition and administered to 28 participants (14 males) synchronously to breathing via an olfactometer. The stimuli were perceived with a low intensity and accordingly only about half of the odor presentations were detected by the participants. The fMRI results (event-related design) show that chemosensory anxiety signals activate brain areas involved in the processing of social emotional stimuli (fusiform gyrus), and in the regulation of empathic feelings (insula, precuneus, cingulate cortex). In addition, neuronal activity within attentional (thalamus, dorsomedial prefrontal cortex) and emotional (cerebellum, vermis) control systems were observed. The chemosensory perception of human anxiety seems to automatically recruit empathy-related resources. Even though the participants could not attentively differentiate the chemosensory stimuli, emotional contagion seems to be effectively mediated by the olfactory system.

Involvement of glutamate in rest‐stimulus interaction between perigenual and supragenual anterior cingulate cortex: A combined fMRI‐MRS study

“…Both of the main findings of the study were specific to the empathy task employed, as distinct from the control empathy evaluation and reward tasks. This is in accordance with the reported central role of the sgACC in empathy [Prehn-Kristensen et al, 2009;Singer and Lamm, 2009]. The current findings extend these previous observations by showing that task-induced activity in the sgACC during empathy interacts with task-induced deactivation in the pgACC, providing evidence that such deactivation in the pgACC may play a similarly important role in empathy processing.…”

Adrenarche and Middle Childhood

“…Induction of anxiety in response to anxious sweat also involves the insula (Prehn-Kristensen et al 2009), as would be expected given the role of the insula in empathy (Lamm and Singer 2010). Furthermore, given the role of the insula in integrating somatic sensations (Craig 2002(Craig , 2009, its role in the detection of body odor suggests that body odor (own and others) provides information salient to bodily awareness.…”

The search for human pheromones: the lost decades and the necessity of returning to first principles

“…[62]) and other studies have used sweat from people exposed to exam stress (e.g. [63]). Both situations, sexual or fearful, would lead to emotional release from armpit apocrine glands [64] and we currently do not know if the secretions differ between the situations [5].…”