In this research we investigated the influence of muscle movement and vision in precision, sensitivity and level of confidence in the haptic perception of weight. The participants compared objects' weight placed on the palms of their hands and, according to the experimental condition, they could or could not make arm movements and make visual contact with the stimuli. The results showed that precision and sensitivity were mainly affected by movement and, to a less extent, by vision. In general, movements produced better precision and sensitivity, and vision contributed only in the conditions without movement. The confidence level was influenced by vision, especially in conditions without movement. Confidence was consistent with precision in conditions without vision, suggesting an implicit knowledge about precision.
cutaneous sense; tactual perception; somesthetic perception; pattern discrimination; psychophysics