Adaptation is an adjustment in sensory capacity after prolonged exposure to unchanging stimuli. Adaptation occurs as people become accustomed to a stimulus and change their frame of reference. In a sense, our brain mentally turns down the volume of the stimulation it’s experiencing.
Adaptation is the originally a biological term used to describe physical or behavioural changes that increased an organism's chances ofsurvival. Used in psychology to describe responses to changes in the environment, e.g. where the eye adjusts to changes in the light or where the changed expectations of their society demand some kind of social adaptation in people's behaviour.