Fabric Softener Fragrances Modulate the Impression Toward Female Faces and Frontal Brain Activity

Abstract

This study aimed to investigate the modulatory effect of olfactory cues on impression toward faces. Twelve Japanese university students participated in the experiment. Before the participants had arrived, the experimental room had been filled with one of three fragrances of fabric softener as the ambient odor, or with no odor. All participants were exposed to each of the four odor conditions on separate days. In the experimental room, participants viewed 20 photographs of Japanese female faces and evaluated their impression toward the faces. The brain activity from the frontal brain region was recorded with functional near-infrared spectroscopy. The fragrances enhanced an effeminate impression for the faces, but the effect was face-dependent. A positive relationship between the impression change induced by the fragrances and the activity of the right frontal brain was observed. These findings indicated that olfactory cues modulate face perception in a manner that cannot be explained by a mood effect, and that the frontal brain region is involved in the reconstruction process of the integrated impression of face and olfactory cues.

fNIRS neuroimaging in olfactory research: A systematic literature review

“…Seven studies observed significant decreases in Δ[HbO2] in response to various odors, e.g., relaxing essential oil odors during a massage (Eto et al, 2015 , 2016 ), olive oil odor (Mitsukura et al, 2021 ), forest odor (Song et al, 2019 ), Hinoki oil (Ikei et al, 2015 ), rose and orange oil (Igarashi et al, 2014 ), and floral spray (Tanida et al, 2008 ). It is important to note that some studies observed no significant effect of odor on cerebral hemodynamics (Maharjan et al, 2018 ; Onuma and Sakai, 2018 ; Kaimal et al, 2021 ; Tomono et al, 2021 ). Two studies reported Δ[HbT] only (Fujii et al, 2007 ; Kokan et al, 2011 ).…”

“…fresh flower petals, collected on the day of testing as a stimulus, allowing the odor to diffuse into the air within a pressure container. Five studies implemented odor delivery mechanisms aiming to diffuse odor into the environment around the participant, including below the participants nose with the use of a wearable odor tray (Onuma and Sakai, 2018 ; Song et al, 2019 ; Tomono and Tomono, 2020 ; Kaimal et al, 2021 ; Tomono et al, 2021 ). One of these studies, Tomono and Tomono ( 2020 ) expelled odor vapor via a airflow generator toward the participant, whilst also measuring odor concentration produced to check odor concentration consistency ( Figure 11d ).…”

“…Takakura et al ( 2011 ) induced the presence of garlic odor on participants via the injection of intravenous thiamine propyl-disulphide, which is known to induce this effect unintentionally. Some studies utilized tasks, e.g., perception, face rating, within the odor paradigm (Onuma and Sakai, 2018 ; Onuma et al, 2018 ; Rajagoplan, 2018 ; Invitto et al, 2019 ; Moein et al, 2020 ). Another study investigated the effect of crossmodal haptic and olfactory stimulation combination with a paradigm involving 3D models (Invitto et al, 2019 ).…”

“…Odor stimuli presentation durations varied greatly between studies, however, most opted to add sufficient lengths of rest between odor stimuli to reduce carry-over effects. Rest periods were most often between 20 and 40 s long, with odor stimuli periods most commonly between 10 and 30 s. Odor stimuli repeats and block designs were not always included, particularly in cases where odors were diffused into the testing environment over time rather than delivered on various materials (Onuma and Sakai, 2018 ; Song et al, 2019 ; Kaimal et al, 2021 ) or in infant studies. One study of import used a longitudinal design, testing cognitive performance before and after a 4 week fragrance intervention using a floral spray (Tanida et al, 2008 ).…”

Editorial: fNIRS in Psychological Research: Functional Neuroimaging Beyond Conventional Fields

“…Another fNIRS application with social psychology for forming impressions through olfactory stimuli appears in the research article by Onuma and Sakai () entitled “Fabric Softener Fragrances Modulate the Impression Toward Female Faces and Frontal Brain Activity.” They investigated the modulatory effect of olfactory cues on impressions toward faces and sought possible neural correlates for the impressions. They revealed that the fragrances enhanced a feminine impression for the faces in a face‐dependent manner.…”