Reaching patterns in the mirror
The mirror mark task is commonly used to assess mirror self-recognition in humans and animals. This study utilized the test and an adapted procedure with a vibrotactile stimulus to characterize the reaching patterns of toddlers who demonstrate mirror self-recognition. In a longitudinal design, a vibrating disc was applied to the face of infants aged 14 to 20 months of age. After the participants were given the opportunity to remove the targets once while facing away and then once towards a mirror, face paint was applied to the same location and the infant was assessed for mirror self-recognition. The participants' successful mirror mark trials were then analyzed for handedness and grasp configurations. We found trials with a lateralized target were localized with the infant's ipsilateral hand while centralized targets yielded inconsistent hand preference based on the type of stimulus. We also found that infants adapted their grasp strategy for the different stimuli, by grasping the tactile stimulus and touching or wiping the mark. These results help to understand infants' body knowledge and sensorimotor development during the second year.