Sensitisation and Desensitisation

• Sensitisation is an increase in response following repeated exposure to the stimulus. 
• Desensitisation is a decrease of a previously sensitized response following repeated exposure to the stimulus.
• Like habituation, but to a previously sensitized stimulus, desensitisation could lead to habituation if the stimulus becomes fully neutral. To be effective it must be gradual and not forceful.
• Systematic desensitization is widely used in behaviour modification.
• Spontaneous recovery is the recovery of a habituated response due to few presentations of stimuli or because of a strong extraneous stimulus.