- In this paper, we investigate the grasping of rigid objects in a unilateral robot-assisted minimally invasive surgery (RAMIS). We define a human-centered transparency that quantifies the natural action and perception in RAMIS. We demonstrate this human-centered transparency analysis for different values of gripper scaling—the scaling between the grasp aperture of the surgeon-side manipulator and the aperture of the surgical instrument grasper. A total of 31 participants performed teleoperated grasping and perceptual assessment of rigid objects in one of three gripper scaling conditions ( fine , normal , and quick , trading off precision and responsiveness). A psychophysical analysis of the variability of the maximal grasping aperture during prehension and of the reported size of the object revealed that under normal and quick (but not under the fine ) gripper scaling conditions, the teleoperated grasping with our system was similar to natural grasping and, therefore, human-centered transparent. We anticipate that using motor control and psychophysics for human-centered optimization of teleoperation control will eventually improve the usability of RAMIS.