Blackwell Reference Online

Extract

Habituation is a decrement in response to repeated stimuli. It is a learning mechanism through which organisms are able to filter sensory inputs from their environment and thereby allocate scarce attentional resources to only the most relevant stimuli ( Siddle 1991 ; →  Attention ). Habituation involves both peripheral and central nervous system processes. In the peripheral nervous system, the orienting response that alerts humans to novel stimuli originates in the reticular formation, a complex collection of nuclei in the upper brain stem with connections to the thalamus, hypothalamus and cortex. The orientation response explains reflexive physiological manifestations of attention – such as bodily reorientation toward the stimulus, elevated heart rate, accelerated eye blinking, and “sweaty palms” – in reaction to breaking news events, blaring commercial interruptions, or attention-grabbing sequences of violent or sexual activity (→  Emotions, Media Effects on ; Exposure to News ). The orientation response must be suppressed, otherwise novel stimuli would never cease to be novel and completely occupy human attention, rendering the world a “buzzing confusion.” Habituation of the orienting response is associated with a diminution of the P300 component (a cortical response that follows exposure to an external stimulus by 300 milliseconds) of the event-related potential in the brain's ... log in or subscribe to read full text