The haptic illusion based force feedback, known as pseudo-haptics, is used to simulate haptic explorations, such as stiffness, without using a force feedback device. There are many computer mouse based pseudo-haptics work reported in the literature. However, none has explored the mechanics of the pseudohaptics. The objective of this paper is to derive an analytical relation between the displacement of the mouse to that of a virtual spring assuming equal work done in both cases (mouse and virtual spring displacement) and experimentally validate their relation. A psychophysical experiment was conducted on eight subjects to discriminate the stiffness of two virtual springs using 2 Alternative Force Choice (AFC) discrimination task, Constant Stimuli method to measure Just Noticeable Difference (JND) for pseudo-stiffness. The mean pseudo-stiffness JND and average Weber fraction were calculated to be 14% and 9.54% respectively. The resulting JND and the Weber fraction from the experiment were comparable to that of the psychophysical parameters in the literature. Currently, this study simulates the haptic illusion for 1 DOF, however, it can be extended to 6 DOF. © 2017 IEEE.