Two experiments are proposed which describe intermanual coordination and intermanual transfer of haptic experience during the period of infancy when the corpus callosum first begins to show electrophysiological evidence of function. Each of the proposed procedures have proven to be effective indicators of callosal functioning in animal studies and in studies of callosectomized patients but neither has been employed previously for investigating infant sensorimotor ability. Experiment 1 provides a description of the spatial and temporal pattern of organization involved in intermanual coordination of the movements of the two hands during the bimanual reaching of 7-15 month old infants. Examination of the effects of perturbing the actions of one hand (by unexpected and expected changes in load and trajectory) on the pattern of coordination, means that a procedure commonly used in study of the organization of motor control in adults will be applied to the study of infant motor control. Using equivalent procedures will help forge links between theory of motor control in infants and adults. Intermanual coordination is an important aspect of most theories of infant development. However, research has typically focused on describing the occurrence of this pattern rather than on the specific aspects of how it is organized. Experiment 2 uses a simple learning procedure (employing a novel but spontaneous behavioral response) to examine the ability of infants to discriminate the properties of objects by haptic perception. The experiment will identify the effects of stimulus properties (form, texture, temperature) and hand (right or left) used to perceive the stimuli on the infant's ability to learn a haptic discrimination and to transfer this learning to the use of the other (untrained) hand. This procedure opens the possibility of systematic examination of the information processing aspects of haptic perception and allows for direct psychological examination of the processes of interhemispheric communication. Both experiments approach the investigation of infant sensorimotor ability from a neuropsychological perspective. In each, the subject variables of sex, age, and handedness status are used as prediction variables because they have been known to contribute to important individual differences in neuropsychological investigations of hemispheric specialization of function and interhemispheric interaction.
