Recent experimental findings reveal dissociations of conscious and nonconscious performance in many fields of psychological research, suggesting that conscious and nonconscious effects result from qualitatively different processes. A connectionist view of these processes is put forward in which consciousness is the consequence of construction processes taking place in three types of working memory in a specific type of recurrent neural network. The recurrences arise by feeding back output to the input of a central (representational) network. They are assumed to be (...) intemalizations of motor-sensory feedback through the environment. In this manner, a subvocal-phonological, a visuo-spatial, and a somatosensory working memory may have developed. Representations in the central network, which constitutes long-term memory, can be kept active by rehearsal in the feedback loops. The sequentially recurrent architecture allows for recursive symbolic operations and the formation of (auditory, visual, or somatic) models of the external world which can be maintained, transformed and temporarily combined with other information in working memory. Moreover, the quasi-input from the loop directs subsequent attentional processing. The view may contribute to a formal framework to accommodate findings from disparate fields such as working memory, sequential reasoning, and conscious and nonconscious processes in memory and emotion. In theory, but probably not very soon in practice, such connectionist models might simulate aspects of consciousness. (shrink)

The distinction made by Page between localist and distributed representations seems confounded by the distinction between competitive and associative learning. His manifesto can also be read as a plea for competitive learning. The power of competitive models can even be extended further, by simulating similarity effects in forced-choice perceptual identification (Ratcliff & McKoon 1997) that have defied explanation by most memory models.

Phillips & Silverstein emphasize the gain-control properties of NMDA synapses in cognitive coordination. We endorse their view and suggest that NMDA synapses play a crucial role in biased attentional competition and (visual) working memory. Our simulations show that NMDA synapses can control the storage rate of visual objects. We discuss specific predictions of our model about cognitive effects of NMDA-antagonists and schizophrenia.

The authors reject a computationally powerful unconscious. Instead, they suggest that simple unconscious processes give rise to complex conscious representations. We discuss evidence showing contrastive effects of conscious and unconscious processes, suggesting a distinction between these types of processes. In our view, conscious processes often serve to correct or control negative consequences of relatively simple unconscious processes.

O'Brien & Opie make unnecessary distinctions between vehicle and process theories and neglect empirically based distinctions between conscious and unconscious processing. We argue that phenomenal experience emerges, not just as a byproduct of input-driven parallel distributed processing, but as a result of constructive processing in recurrent neural networks. Stable network states may be necessary, but are not sufficient, for consciousness.

We note two important problems in the Theory of Event Coding. First, because the representational format of features and events is unspecified, the theory is difficult to test. Second, the theory lacks a mechanism for the integration of features into an event code when the features are shared by different events. Possible ways of solving these problems are suggested.