In haptic length perception biases occur that have previously been shown to depend on stimulus orientation and stimulus length. We propose that these biases arise from the muscular torque needed to counteract the gravitational forces acting on the arm. In a model study, we founded this hypothesis by showing that differences in muscular torque can indeed explain the pattern of biases obtained in several experimental studies.
Nienke B. Debats, Idsart Kingma, Peter J. Beek, Je