A Scent of Anxiety: Olfactory Context Conditioning and its Influence on Social Cues.

Perception and evaluation of objects are highly dependent on surrounding contexts. Threatening contexts enhance processing of faces. Because odors are assumed to deliver strong contextual information, the present study aimed at demonstrating 1) that odors can constitute threat and safety contexts, and 2) consequently modulate the processing of faces presented in these contexts. Therefore, previously neutral odors were used as contextual stimuli in a context conditioning paradigm, resulting in an olfactory anxiety and a safety context. Then, faces showing angry, neutral, or fearful expressions were presented within both contexts during a test phase to investigate the effects of threat versus safety contexts on face perception. The late positive potential (LPP) from the EEG, skin conductance level, and subjective ratings were recorded. Results reveal successful olfactory context conditioning as reflected in enhanced processing of the anxiety context, indicated by enhanced LPP after conditioning, increased skin conductance level, and marginally respectively increased ratings. Moreover, faces presented within the threat context were rated as more unpleasant and marginally more arousing than faces presented in the safety context. Thus, olfactory stimuli can serve as context in fear conditioning, and a threatening olfactory context seems to enhance processing of stimuli perceived within this context.