RESUMO
A recent research revealed the capacity of the newborn to haptically detect, the weight of an object [12]. In this research, we tried to determine the means by which newborn infants, not having yet exploratory procedures, are able to treat this object property. We support the assumption that tactile perceptive capacities of the newborn infants derive from a fundamental property of the sensorimotor system: its primary variability. After a period of habituation with a heavy or light object, an object of new weight is presented (period test). Three parameters of the sensorimotor activity were analyzed during these two periods: holding times, amplitude of the pressure exerted on the object and frequency of the pressure. Analyses of these parameters demonstrate the neonate's capacity to discriminate objects weight.