Habituation
Habituation is a form of learning in which an organism decreases or ceases to respond to a stimulus after repeated presentations. Essentially, the organism learns to stop responding to a stimulus which is no longer biologically relevant. For example, organisms may habituate to repeated sudden loud noises when they learn these have no consequences.
Habituation usually refers to a reduction in innate behaviours, rather than behaviours developed during conditioning in which the process is termed "extinction".