Endurviðbrögð

Endurviðbrögð is an Icelandic term used in psychology, neuroscience, and related fields to describe how an organism’s responses to a given stimulus change when that stimulus is repeated or sustained. The word combines endur, meaning “again” or “re-,” with viðbrögð, meaning “reactions” or “responses.” In this sense, endurviðbrögð covers several related phenomena that modify behavior or perception over time.

The core ideas are habituation, sensitization, and adaptation. Habituation is a decrease in response after repeated exposure to a neutral or non-harmful stimulus, allowing the organism to ignore irrelevant background signals. Sensitization is the opposite pattern, where the response increases due to particular circumstances, such as a salient or aversive stimulus. Adaptation refers to changes at the sensory level, where receptors become less sensitive with sustained stimulation. Fatigue or depletion of response resources can also contribute to reduced reactions during prolonged stimulation.

In practice, endurviðbrögð are relevant to both basic research and clinical contexts. In experimental psychology and neurophysiology, researchers study how reflexes and perceptual judgments change with repetition to understand learning, attention, and sensory processing. In medicine and rehabilitation, observing how patients’ reflexes or pain responses evolve during repeated testing or therapy can inform diagnosis and treatment planning. The term emphasizes dynamic change over time rather than a single, isolated reaction.

Endurviðbrögð is a broad umbrella term, and its precise interpretation can vary by field. It is closely related to, and often described through, concepts such as habituation, sensitization, adaptation, and fatigue.