Neuronal control of the fingertips is socially configured in touchscreen smartphone users

As a common neuroscientific observation, the more a body part is used, the less variable the corresponding computations become. We here report a more complicated scenario concerning the fingertips of smartphone users. We sorted 21-days histories of touchscreen use of 57 volunteers into social and non-social categories. Sensorimotor variability was measured in a laboratory setting by simple button depressions and scalp electrodes (electroencephalogram, EEG). The ms range trial-to-trial variability in button depression was directly proportional to the number of social touches and inversely proportional to non-social touches. Variability of the early tactile somatosensory potentials was also pr