Summary: A new study reveals why we have a lateral preference when it comes to displaying social emotions. Researchers say that while handedness plays a part in why we prefer to hug or kiss on one side, emotional content also plays a role.
When touching others in a social context, for example kissing or hugging, people often have a lateral preference; they will, for example, tend to tilt their head to the right rather than to the left when kissing. There are many theories as to the causes. In a review article published in the journal Neuroscience und Biobehavioral Reviews, researchers from Ruhr-Universität Bochum, Heinrich-Heine-Universität Düsseldorf and Victoria University of Wellington have compiled existing data, which they utilise to verify the theories. The article was published online in October 2018.
The team headed by Associate Professor Sebastian Ocklenburg and Julian Packheiser from the Department of Biopsychology in Bochum has concluded that the observed results cannot be explained solely by right or left-handedness. The handedness does play a role, but so does the emotional context.
Left shift in emotional situations
“In general, the population at large has a preference of tilting the head to the right when kissing, to initiate a hug with the right hand, and to cradle a baby in the left arm,” elaborates Julian Packheiser. With regard to kissing and hugging, the assumption is that people have a dominant hand which they use to initiate the motion. According to the theory, the dominant hand is kept unoccupied when cradling a child so that it can be used to perform other tasks.
“As social touches are often associated with a hand motion, it is an obvious assumption to make that the handedness affects lateral preferences,” says Sebastian Ocklenburg. In their review article, the researchers have listed numerous studies that substantiate the influence of handedness. However, that alone cannot explain the lateral preferences; the emotional context, too, is relevant.
“In emotional situations, the lateral preference shifts to the right,” describes Packheiser. “It doesn’t matter if the emotions are positive or negative.” As far as the preference is concerned, it is irrelevant if two people hug because they are happy to see each other, or because one is comforting the other.
Emotions are processed asymmetrically in the brain
The researchers explain the left shift in emotional – as opposed to neutral – situations by speculating that emotions are primarily processed in the right brain hemisphere, which is responsible for movements of the left side of the body. “There is ample evidence of interaction and interconnection of motor networks and emotional networks in the brain,” points out Ocklenburg. The theory of right-hemispheric processing of emotions is backed by behavioural data from studies on social touch as well as by results gained in imaging and neurophysiological studies.
According to the authors, the asymmetry present in human social touch can be best explained by a combination of motor preferences and right-hemispheric emotional dominance.
Source: Raffaela Römer – RUB
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Original Research: Abstract for “Hugs and kisses – The role of motor preferences and emotional lateralization for hemispheric asymmetries in human social touch” by Sebastian Ocklenburg, Julian Packheiser, Judith Schmitz, Noemi Rook, Onur Güntürkün, Jutta Peterburs, and Gina M.,Grimshaw in Neuroscience & Biobehavioral Reviews. Published October 29 2018.
Hugs and kisses – The role of motor preferences and emotional lateralization for hemispheric asymmetries in human social touch
Social touch is an important aspect of human social interaction – across all cultures, humans engage in kissing, cradling and embracing. These behaviors are necessarily asymmetric, but the factors that determine their lateralization are not well-understood. Because the hands are often involved in social touch, motor preferences may give rise to asymmetric behavior. However, social touch often occurs in emotional contexts, suggesting that biases might be modulated by asymmetries in emotional processing. Social touch may therefore provide unique insights into lateralized brain networks that link emotion and action. Here, we review the literature on lateralization of cradling, kissing and embracing with respect to motor and emotive bias theories. Lateral biases in all three forms of social touch are influenced, but not fully determined by handedness. Thus, motor bias theory partly explains side biases in social touch. However, emotional context also affects side biases, most strongly for embracing. Taken together, literature analysis reveals that side biases in social touch are most likely determined by a combination of motor and emotive biases.