The uncanny valley is a hypothesis about robotics concerning the emotional response of humans to robots and other non-human entities. Although it stands today as one of the robots and synthetic characters, the uncanny valley was speculative and few studies have been performed to test the theory. In two experiments, a total of 183 participants were employed to explore this hypothesis. The results of experiment 1 indicate that the perceived human likeness of a robot is not a key factor causing uncanny valley. And the results of experiments 2 suggest that even if the appearance and motion of a robot become fully human, the emotional response of humans could not reach human-human empathy levels.