A study released on October 8, 2013 confirms the importance of human touch to healthy brain
development. Researchers in the UK found that loving touch, characterized by a slow caress or gentle stroking increases the brain's ability to construct a sense of body ownership and plays a big part in creating and sustaining a healthy sense of self.
Much like the instinct to lovingly pet an animal, gently touching another person is a reflexive gesture that happens automatically in healthy, loving relationships between a parent and a child, romantic partners, and affectionate close friends. We all know from first hand experience that being touched makes us feel safe and comfortable in our environment.
The findings of this new study titled, "Bodily Pleasure Matters: Velocity of Touch Modulates Body Ownership During the Rubber Hand Illusion” were published online in Frontiers of Psychology. The research was led by Neuropsychoanalysis Centre Director Dr. Aikaterini (Katerina) Fotopoulou from University College London, and Dr. Paul Mark Jenkinson of the Department of Psychology, University of Hertfordshire in the UK.
Loving Touch Improves Proprioception
In a previous Psychology Today blog titled “The Neuroscience of Calming a Baby” I write about the role that the cerebellum plays in proprioception (a sense of your body's position in space) and how important it is for a baby to be held, especially when crying. The new study confirms the important role the cerebellum plays in constructing a mental picture and an understanding of the body, which ultimately helps to create a coherent sense of self.
For the study the researchers used a common experimental technique known as the rubber hand illusion, in which participants' brains are tricked into believing that a strategically placed rubber hand is their own. As they watch the rubber hand being stroked in synchrony with their own, they begin to think that the fake hand belongs to them. This technique demonstrates the changeable nature of the brain's perception of the body.
Dr. Fotopoulou's team wanted to test whether affective touch would affect the brain's understanding of the body and body ownership. “Affective touch” is characterized by slow speed tactile stimulation of the skin at a rate between 1 and 10cm per second. Caressing touch has been previously correlated with making people feel good and has been known to reduce symptoms of anxiety and other emotional symptoms in certain groups of adults and infants. This is common sense.
To test this in a laboratory setting the team adapted the 'rubber hand' technique to include four different types of touch: a synchronized touch, asynchronized touch, slow/affective touch, and a faster neutral touch. Participants were also asked to complete a standardized 'embodiment' questionnaire, to measure their subjective experience during the experiment.
The results confirm previous findings that a slow, light touch is perceived as being more pleasant than fast touch. Again, we all know intuitively the speed of caress that is naturally soothing. Interestingly, the study demonstrated that slow tactile stimulation made participants more likely to believe that the rubber hand was their own, compared with the faster neutral touch.
The perception of affective touch in the brain is one of a number of interoceptive signals that help us monitor homeostasis and proprioception. This study provides new evidence to support the existing idea that interoceptive signals, such as affective touch improve proprioception and literally make someone comfortable in their own skin. A decreased sensitivity to and awareness of interoceptive signals, such as affective touch, have been linked to body image problems, unexplained pain, as well as anorexia nervosa and bulimia.
"As affective touch is typically received from a loved one, these findings further highlight how close relationships involve behaviors that may play a crucial role in the construction of a sense of self," said Laura Crucianelli, the researcher who carried out the study.
"The next step for our team," concluded Dr. Katerina Fotopoulou, "is to examine whether being deprived of social signals, such as affective touch from a parent during early development, may also lead to abnormalities in the formation of a healthy body image and a healthy sense of self, for example in patients with eating disorders such as anorexia nervosa."
Boosting interoceptive awareness and an individual's sense of body ownership could be key to developing future treatments for some of these conditions, and the sensation of 'affective touch' could play an important role.
Conclusion: “Just a little of that human touch.”
Scientists have confirmed what Bruce Springsteen professed in his classic song—everybody needs “just a little of that human touch.” We all need human touch and loving affection at every stage of our lives for healthy emotional and neurobiological development.
Another study also released on October 8, 2013 found that babies learn how to anticipate touch while in the womb by touching their own faces. Lead author Dr Nadja Reissland, in the Department of Psychology, at Durham University, said: "Increased touching of the lower part of the face and mouth in fetuses could be an indicator of brain development necessary for healthy development, including preparedness for social interaction, self-soothing and feeding.”
Brian Francis, Professor of Social Statistics at Lancaster, added: "This effect is likely to be evolutionally determined, preparing the child for life outside the womb. Building on these findings, future research could lead to more understanding about how the child is prepared prenatally for life, including their ability to engage with their social environment, regulate stimulation and being ready to take a breast or bottle."
Earlier this year, in another of their studies, Reissland and Francis found that unborn babies instinctively practice facial expressions in the womb in what is thought to be preparation for communicating with other humans soon after birth.
If you’d like to read more on these topics please check out my Psychology Today blogs: "Parental Warmth Is Crucial for a Child's Well-Being", "Breastfeeding Boosts Brain Development of a Baby" and "Neuroscientists Confirm That Our Loved Ones Become Ourselves."