Kinematic parameters (Mean ± SE) during the reaching and the lifting phase of the 3 actions performed by the actor upon the light or the heavy object. Asterisks indicate significant comparisons (P < 0.05). (a) The pictures depict the 4 consecutive frames covering the reaching phase (i.e., the first contact point frame and the preceding 3 frames, for a total of 200 ms) and the 4 consecutive frames covering the lifting phase (i.e., the last frame preceding the lifting onset and the following 3 frames, for a total of 200 ms). (b) Whole movement duration. Bars represent the whole duration of the reaching (on the left) and lifting movement (on the right) performed during the deceptive (black bars), true (white bars), and deceived (gray bars) actions performed on the light and the heavy objects. The whole reaching duration was defined as the time (in ms) occurring between the beginning of the movement and the first hand-object contact. The whole lifting duration corresponds to the time interleaving between the frame at which the vertical position of the dorsal part of the wrist started to rise up and the frame at which it reached the 130% of its position at the contact point. (c–e) Spatial kinematic parameters. The pictures on the left represents: (c) the GA parameter, measuring the distance between the tips of the thumb and of the index finger (in pixels and then converted in mm); (d) the WA parameter; and (e) the index angle parameter. The graphs represent mean displacements, measured as the difference in the spatial parameter value at the last frame minus its value during the first frame considered in the reaching and in the lifting phases. For the GA (c), positive values indicate opening movement, while negative values indicate closing movement of the thumb and the index finger. For the wrist (d) and index (e) angle parameters, positive values indicate extension movement, while negative values indicate flexion movement.