The performance levels of human subjects in size identification and discrimination experiments in both real and virtual environments are presented. The virtual environments are displayed with a three degree-of-freedom haptic interface, developed at Vanderbilt University. Results indicate that performance of the size identification and discrimination tasks in the virtual environment is comparable to that in the real environment, implying that the haptic device does a good job of simulating reality for these tasks. Additionally, performance in the virtual environment was measured at below maximum machine performance levels for three machine parameters. The tabulated scores for the perception tasks in a sub-optimal virtual environment were found to be comparable to that in the real environment, supporting previous claims [1] that haptic interface hardware may be able to convey, for these perceptual tasks, sufficient perceptual information to the user with relatively low levels of machine quality in terms of the following parameters: maximum endpoint force, system bandwidth, and time delay.