A recent study from The Clinical Hospital of Chengdu Brain Science Institute in Chengu, China, explored non-invasive and non-pharmacological ways to increase a person’s endogenous production of oxytocin, a hormone that is known for building trust and bond between one or more individuals. What better way to do so than “old-fashioned," affective touch. (1)
Lead researchers Dr. Keith Kendrick and Dr. Weihua recruited 40 healthy, heterosexual male university students in their early twenties, who had at least two experiences with Chinese style foot massage (pressure only, no strokes). Previous research on massage and oxytocin concentration in the bloodstream or saliva among children, the researchers reviewed, did not explore its effects on autistic children or adults.
They hypothesized that hand massage would be more effective at releasing oxytocin than a machine massage, and massage itself increases the response in brain regions that process cognitive and reward effects of social touch of the bilateral orbitofrontal cortex (OFC) and superior temporal sulcus (STS) of the brain, but not in the somatosensory cortex (S1), which responds to to physical touch and its intensity. They also hypothesized that “basal and/or evoked [oxytocin] release and neural responses to hand massage would be positively associated with pleasure/reward ratings and negatively associated with autistic traits and dislike of social touch but not with other personality traits." (1)
The time transitioned between the therapist and the machine was 15 minutes. After each session, the subjects filled out another questionnaire that asked:
- How much did the massage make you feel pleasure?
- How much did the massage arouse you?
- How strong was the massage? (i.e. how intense).
- How much would you be willing to pay for the massage (1-100 RMB).
- Is the massage therapist male or female?
There was also an inverse relationship between high oxytocin concentration and lower scores in the Autism Spectrum Questionnaire after the hand massage, but not so much after the machine massage. Seventeen subjects thought the massage therapist was a man while 23 thought a woman massaged them. There was no difference in brain activity between the gender-identification groups.
Overall, the subjects reported that hand massage felt better than machine massage, and they can tell the difference even though they were blindfolded, but there were some issues with the study.
Kendrick et al. mentioned that blood oxytocin was measured, and the concentration could be different in the cerebralspinal fluid in the brain. There is also a matter of culture where the gender of the therapist does not affect gender preference among subjects. Thus, it is possible that if this experiment were to be replicated in the US, Germany, or Iran, there might be a difference in brain activity and oxytocin concentration among male subjects.
Affective touch is essential for development of better social bonds, friendships, and romantic relationships. As humans, we need it everyday, perhaps as much as food and shelter for some of us. It is a cue to safety and a foundation to establish trust. (2) This is study is a stepping stone to unravel what goes on in the brain and our physiology, which may also help alleviate symptoms of ASD.
1. Li Q, Becker B, Wernicke J, Chen Y, Zhang Y, Li R, Le J, Kou J, Zhao W, Kendrick KM. Foot massage evokes oxytocin release and activation of orbitofrontal cortex and superior temporal sulcus. Psychoneuroendocrinology. 2019 Mar;101:193-203. doi: 10.1016/j.psyneuen.2018.11.016. Epub 2018 Nov 14.
2. Brosschot JF, Verkuil B, Thayer JF. The default response to uncertainty and the importance of perceived safety in anxiety and stress: An evolution-theoretical perspective. J Anxiety Disord. 2016 Jun;41:22-34. doi: 10.1016/j.janxdis.2016.04.012. Epub 2016 May 7.