Habituaatio

Habituaatio, commonly translated as habituation, is a basic form of non-associative learning in which an organism reduces its behavioral response to a repeated, non-harmful stimulus. The effect is typically gradual and reversible, reflecting adaptive filtering of irrelevant information rather than a change in the stimulus itself. Habitual responses may occur in reflexive systems (such as startle or orienting responses) or in more complex behaviors.

Mechanisms involve changes in neural processing rather than memory of a specific event. In many animals, repeated stimulation decreases neurotransmitter release at synapses in the reflex pathway, producing a weaker response. Short-term habituation lasts from seconds to minutes, while long-term habituation can persist for hours or days and may require new protein synthesis and synaptic restructuring. Habituation is generally stimulus-specific, but generalization can occur to similar stimuli under some conditions.

Habituaatio is observed across taxa, from invertebrates like Aplysia and Drosophila to vertebrates including humans. In developmental psychology, habituation paradigms assess learning and recognition in infants by measuring decreases in attention to a repeatedly shown stimulus, followed by dishabituation when a novel stimulus appears.

Distinctions are drawn between habituation and fatigue or sensory adaptation. Unlike fatigue, habituation is not simply the result of diminished motor capacity, nor is it inevitable with continued exposure; spontaneous recovery and dishabituation demonstrate that the original responsiveness can return after a break or a new stimulus.

Etymology derives from Latin habitus, “acquired condition.”