title: Dynamics of autonomic nervous system responses and facial expressions to odors.
abstract: Why we like or dislike certain products may be better captured by physiological and behavioral measures of the autonomic nervous system (ANS) than by conscious or classical sensory tests. Responses to pleasant and unpleasant food odors presented in varying concentrations were assessed continuously using facial expressions and responses of the ANS. Results of 26 young and healthy female participants showed that the unpleasant fish odor triggered higher heart rates and skin conductance responses, lower skin temperature, fewer neutral facial expressions and more disgusted and angry expressions (p < 0.05). Neutral facial expressions differentiated between odors within 100 ms, after the start of the odor presentation followed by expressions of disgust (180 ms), anger (500 ms), surprised (580 ms), sadness (820 ms), scared (1020 ms), and happy (1780 ms) (all p-values < 0.05). Heart rate differentiated between odors after 400 ms, whereas skin conductance responses differentiated between odors after 3920 ms. At shorter intervals (between 520 and 1000 ms and between 2690 and 3880 ms) skin temperature for fish was higher than that for orange, but became considerable lower after 5440 ms. This temporal unfolding of emotions in reactions to odors, as seen in facial expressions and physiological measurements supports sequential appraisal theories.
authors.affiliation: Consumer Science and Intelligent Systems, Food and Biobased Research, Wageningen University and Research Centre Wageningen, Netherlands ; Division of Human Nutrition, Sensory Science and Eating Behaviour, Wageningen University Wageningen, Netherlands.
authors.forename: Wei
authors.initials: W
authors.lastname: He
authors.affiliation: Division of Human Nutrition, Sensory Science and Eating Behaviour, Wageningen University Wageningen, Netherlands.
authors.forename: Sanne
authors.initials: S
authors.lastname: Boesveldt
authors.affiliation: Division of Human Nutrition, Sensory Science and Eating Behaviour, Wageningen University Wageningen, Netherlands.
authors.forename: Cees
authors.initials: C
authors.lastname: de Graaf
authors.affiliation: Consumer Science and Intelligent Systems, Food and Biobased Research, Wageningen University and Research Centre Wageningen, Netherlands.
authors.forename: René A
authors.initials: RA
authors.lastname: de Wijk
keywords: ANS responses; concentration; facial expressions; heart rate; odor; skin conductance; skin temperature; valence