A new study had shown that even the slightest of support can help people to maintain their balance.
Led by the researchers of University of Birmingham, the study explains how neural and mechanical mechanisms synchronize our sway with another person.
The team looked at pairs of volunteers in a range of tests to understand how visual and mechanical interactions between them would affect their stability.
Participants stood on force platforms while undertaking a range of tests; with no physical contact, a shoulder grasp and a light touch. For each level of contact, the visual interactions also were varied to study both with closed eyes, both with open eyes, and with one participant closed/one participant open.
As expected, the volunteers experienced a 37 percent reduction in sway when grasping each others' shoulders. Even a non-forceful touch with the fingertip accounted for an 18 percent reduction in sway, and it is the underlying mechanisms behind this that the team has described for the first time.
Dr Raymond Reynolds said that grabbing the shoulder of someone to reduce sway can be explained entirely by the mechanical linkage between the two. But the light touch of the finger is down to a sensory weighting phenomenon by which people balance themselves.
The phenomenon in question describes how each person essentially estimates how 'upright' they are, based on a weighted combination of sensory feedback from themselves and feedback based upon the motion of their partner.
The study also pointed toward an unexpected finding; that we are able to obtain this benefit from someone with equal or even greater instability than ourselves.
The study is published in Interface.
