Stochastic Resonance

Noise enhances weak signal detection

0.60
0.80
1.5 Hz
1.00
—Output SNR (dB)
—Detection rate
—False positives
Stochastic resonance: a subthreshold signal (amplitude < threshold) cannot be detected alone. Adding the right amount of noise causes the combined signal to occasionally cross the threshold in sync with the signal, enhancing detection. Too little or too much noise reduces performance — there's an optimal noise level. First observed in climate models (Benzi 1981), now seen in neurons, sensory systems, and electronic devices.