Note: The system response depends upon the noise level. Stochastic resonance occurs in biological systems, including sensory systems detecting weak signals of danger from predators and neural networks

Figure 6: The mechanism of stochastic resonance. The double well potential V(x) represents a physical system with two stable states. In absence of noise, a particle, which at one time is within one of the two wells, relaxes towards the intrawell minimum and then stops. When stochastic perturbation is added to this system the particle can hop between the two wells with a rate predicted by reaction-rate theory. If a weak periodic forcing is present the overall potential minimum changes periodically from one side to the other. Stochastic resonance happens when the typical escape time from the lower barrier and the periodic forcing are synchronized [136].