Orienting is the gateway to attention, the first step in processing stimulus information. This volume examines these initial stages of information intake, focusing on the sensory and motivational mechanisms that determine such phenomena as stimulus selection and inhibition, habituation, pre-attentive processing and expectancy. Psychophysiological methods are emphasized throughout. The contributors consider analyses based on cardiovascular and electrodermal changes, reflex reactions and neural events in the cortex and subcortex.