Nonconscious control of autonomic responses: a role for Pavlovian conditioning?

This paper reviews data demonstrating nonconscious control of autonomic responses and emotional processes. After briefly having considered theoretical attempts to encompass such processes within Pavlovian conditioning frameworks, it goes on the examine theories and evidence for nonconscious control of emotional processes. The phenomena covered include affective discrimination, neurophysiological mechanisms in the control of conditioned emotional responses, and attentional biases in anxiety disorders. The main section of the paper examines evidence for nonconscious, automatic control of autonomic responses. Such control is demonstrated by data on skin conductance responses to nonattended stimuli, by skin conductance responses in prosopagnosic patients, and by skin conductance responses to masked conditioned stimuli. There are also some data suggesting that responses can be learned to nonconsciously presented in stimuli. In the discussion, it is argued that controlled processing may be dissociated from awareness. That is to say, stimuli may be processed at a controlled level without being accessible for conscious awareness. The relevance of these findings for Pavlovian conditioning is discussed.