early studies relied on the demonstration of 1) recovery by dishabituation (the brief recovery of the response to the eliciting stimulus when another stimulus is added) to distinguish habituation from sensory adaptation and fatigue. more recently, 2) "sensitivity of spontaneous recovery to rate-of-stimulation" and 3) "stimulus-specificity" have been used as experimental evidence for the habituation process. spontaneous recovery is sensitive to spontaneous recovery, showing recovery that is inversely correlated with the amount of response-decline. this is the opposite of what would be expected if sensory adaption or motor fatigue were the cause of the response-decline. sensory adaptation (or neural adaptation) occurs when an organism can no longer detect the stimulus as efficiently as when first presented and motor fatigue occurs when an organism is able to detect the stimulus but can no longer respond efficiently. stimulus-specificity stipulates that the response-decline is not general (due to motor fatigue) but occurs only to the original stimulus that was repeated. if a response-decline shows 1) dishabituation, 2) spontaneous recovery that is inversely correlated with the extent of decline, and/or 3) stimulus-specificity, then habituation learning is supported.