Kansei Science Research, Skincare Products Research, and Makeup Products Research laboratories of Kao Corporation have released information from their ongoing skin care research focusing on stimulation that generates positive emotions.
According to the research, tactile stimulation by touching the facial skin with the palm of the hands causes an increase in blood flow in the brain's prefrontal area of the cerebral cortex compared to the state of rest.
The findings indicate that the greater the change in blood flow in the prefrontal area caused by tactile stimulation by the palms to the face the greater degree of positive emotions evoked.
When cream is applied to the inside of the forearm, as one of the skin care activities, the change in blood flow in the brain's prefrontal area varies according to how application is sensed.
Part of the research was presented at the 20th Annual Meeting of Japan Society of Kansei Engineering earlier this fall.
In previous research on skin care linked to emotions, researcher found: 12 factors to evaluate emotions while applying cosmetics were extracted and an emotional assessment scale was created; tactile stimulation on the facial skin included in skin care behavior arouses positive emotions; continuous tactile stimulation on the facial skin, evokes positive
emotions and enhances the visual skin condition (skin appearance); and the relationship between the amount of oxytocin in saliva and skin appearance was confirmed.
Kao examined the effects of touching the facial skin with the palms on cerebral blood flow under the following testing conditions.
In Study 1 (20 women aged 20-49), a change in cerebral blood flow in the prefrontal area of the brain was measured using near-infrared spectroscopy (NIRS) under three conditions: one in which bare hands touched the facial skin and two other control conditions (touching facial skin with hands wearing rubber gloves and only placing the hands near the face). Then the association between the change in blood flow and the degree to which positive emotions were aroused was analyzed. Participants touched their facial skin with their palms for 15 seconds alternating with a rest time of 20 seconds in a cycle repeated six times. The standard score (Z-score) of the difference in cerebral blood flow during facial skin touch by the palms compared to the resting state was calculated.
The degree of positive emotion evoked was expressed as the evaluated value of positive emotions by measuring the degree of sensation ofpositive emotions with the use of a 10-cm visual analog scale.
Results showed that touch of the facial skin with the bare palms significantly increased the change in blood flow in the prefrontal area to a degree higher of that in a resting state. Moreover, a moderate positive correlation was observed between the difference in blood flow change in the prefrontal area under the condition of facial skin touch with the bare palms as well as the other control conditions, and in the difference in the evaluated values of positive emotions
The colored parts in the brain image show the varied probabilities of difference in blood flow from a resting state. The more reddish areas indicate a higher probability of the region being more active.
Study 2 involved 15 women aged 20-49 years). As an example of skin care activity, participants applied four types of cream with different application sensations (Creams A, B, C, and D) to the inside of the forearm. Changes in cerebral blood flow on application were measured by NIRS. Participants experienced stimulation by applying cream for 20 seconds
alternating with a rest time of 20 seconds in a cycle repeated four times. The areas showing a positive correlation with a level ofpositive emotion arousal in Study 1 were used as areas of interest. The standard score (Z-score) was calculated for the difference between cerebral blood flow changes in cream application and resting.
In the skin care activity of applying cream to the forearm, it wasconfirmed that the change in blood flow in the area of interest varied depending on the sensation during application. Cream C, with asignificant difference in cerebral blood flow change, had a rich, moisturizing feel and blended with the skin favorably.
Research results suggest that activity in the prefrontal area of the brain increased in response to the level of positive emotions aroused by facial skin touch with the palms and cream application.