Abstract

Startle reflex, an innate reaction of the body to sudden and strong stimuli, has assumed a primary role in cognitive and emotional investigations. The aim of this review is to offer an explanation of the success of this tool showing a picture of researches primarily concerned with startle, in the field of psychophysiology, that have used blink as index of the reflex. After an historical introduction are examined elicitation methods, its differentiation between orienting and defense reflexes, attentional modulation, experiments whit fear conditioning, emotional modulation and its use in psychopathology: fear and anxiety disorders, post-traumatic stress disorders, criminology and psychosis. Finally are reported advantages of its use in psychology researches of attention processes and emotions in their normal and pathological aspects. Key words: Startle reflex, eyeblink, attention, emotion.