An example of spontaneous recovery from the Pavlov's dogs experiment is when extinction occurred after Pavlov presented the dog with food without sounding the bell, which stopped the salivation response. If Pavlov again sounded the bell after waiting for two hours, the dog salivated. The recovery of the previously conditioned response (drooling when a bell sounded) is spontaneous recovery.
Drug addiction is another example of spontaneous recovery. A cocaine addict presented with an object strongly connected to his addiction, such as white powder, can experience a relapse into addiction based on that exposure, even if physicians considered him cured of addiction, according to Reference.com.
A third example comes from a study demonstrating that honeybees are capable of being trained to extend their proboscises to certain scents. The study conditioned the bees over 10 trials on day one and then caused extinction by subjecting the bees to 23 non-reinforced trials on the second day. On the third day, the bees produced day one's conditioned response to the stimuli rather than day two's conditioned extinction response. They behaved as conditioned on day one and extended their proboscises to the scent, demonstrating spontaneous recovery of the original conditioned response, as noted in the US National Library of Medicine.