THE TRANSITION FROM AUTOMATIC TO CONTROLLED PROCESSING

The transition from automatic (unconscious) to controlled (conscious) processing is described in terms of a neural network model of classica l conditioning (Schmajuk et al., 1996). In the framework of the networ k, an environ mental stimulus is processed in controlled or conscious mode when Novelty and attention to the stimulus are large, and in auto matic or unconscious mode otherwise. In the model, indirect dopamine ( DA) agonists, such as amphetamine or nicotine, enhance the DA represen tation of Novelty, thereby increasing attention and engaging conscious processing of environmental stimuli. By contrast, DA receptor antagon ists, such as haloperidol, reduce the DA representation of Novelty, th ereby decreasing attention, and engaging unconscious processing of the stimuli. (C) 1997 Elsevier Science Ltd.