Perception without awareness: perspectives from cognitive psychology

Four basic approaches that have been used to demonstrate perception without awareness are described. Each approach reflects one of two types of experi mental logic and one of two possible methods for controlling awareness. The experimental logic has been either to demonstrate a dissociation between a measure of perception with awareness and a measure that is sensitive to pe rception without awareness or to demonstrate a qualitative difference betwe en the consequences of perception with and without awareness. Awareness has been controlled either by manipulating the stimulus conditions or by instr ucting observers on how to distribute their attention. The experimental fin dings based on all four approaches lead to the same conclusion; namely, sti muli are perceived even when observers are unaware of the stimuli. This con clusion is supported by results of studies in which awareness has been asse ssed with either objective measures of forced-choice discriminations or mea sures based on verbalizations of subjective conscious experiences. Given th is solid empirical support for the concept of perception without awareness, a direction for future research studies is to assess the functions of info rmation perceived without awareness in determining what is perceived with a wareness. The available evidence suggests that information perceived withou t awareness both biases what stimuli are perceived with awareness and influ ences how stimuli perceived with awareness are consciously experienced, (C) 2001 Elsevier Science B.V. All rights reserved.