The physical contact, most commonly recognized in the form of a hand hold or embrace, is intended to comfort one or more of the participating individuals.
[3][4] It remains unclear whether the relationship between social touch and interpersonal emotional bonds reflect biologically driven or culturally normative behavior.
From 1950 through 1970, Harlow conducted controversial research on rhesus monkeys observing maladaptation resulting from maternal-separation and social isolation.
Those raised in complete isolation developed marked disturbed behavior such as pacing in cages, staring blankly, and self-mutilation.
From a developmental perspective touch plays a vital role in infants' physical and cortical growth, stress relief, and secure attachment formation.
[17][18][19] Though no laboratory studies exist due to ethical considerations, data emphasizing the necessity of consoling touch was taken from orphanages where the caretaker to child ratio was 1:25.
The electroencephalogram (EEG) results of children with depressed mothers had markedly reduced activity in the left frontal lobe.
[21] The likelihood of full neural recovery lessens as a child ages due to sensitive periods for brain development, the first year and a half being the most critical.
[23][24][25] In a 1993 study of young adults undergoing chemotherapy, hand holding was rated to be a significantly effective coping strategy in ameliorating treatment-related pain.
[30][31] In a 2019 study the neurobehavioral correlates of consoling touch were examined by showing participants photos of recently deceased relatives while undergoing functional magnetic resonance imaging (fMRI).
[32] The ACC has neural connections to both the limbic system, the emotional center, and the prefrontal cortex, known for higher cognitive function.
[33] The cerebellum, located in the brainstem, is classically responsible for coordinating voluntary movements; however, recent work suggests it may play a role in emotional valence determination.
[34] A similar fMRI experiment evaluated the neurological effects of viewing moderately disturbing images while holding the hand of a significant other.
[35][36] Decreased connectivity between these two regions in the hand holding condition suggest that consoling touch elicits a buffering effect.
This kind of processing involves type A nerve fibers, which relay information very quickly to the brains sensory regions.
The 'social touch hypothesis', coined by Håkan Olausson in 2010, proposes that C afferent nerve fibers are most sensitive to tactile stimuli occurring during close social interaction.
Patient G. L. had Guillain-Barré syndrome, a rare autoimmune disorder wherein an immune system attacks the body's own muscle and sensory neurons.
Further functional magnetic resonance imaging (fMRI) examination confirmed the patient lacked activation in the somatosensory cortex during touch.
[49] These variations in nerve processing manifest in different ways, be it wearing very specific fabrics, or avoiding rain because the sensation of drops on the skin is painful.
[50] Kevin Pelphrey, a clinical neuroscientist at Yale, recently evaluated response to social touch in non-autistic and autistic children.
The children on the Autism spectrum, however, elicited a similar neuronal response in both conditions with marked activation of the somatosensory cortex.