It primary adaptive advantage is that it allows the organism to focus the processing resources of the central nervous system upon the particular stimulus most relevant to it in the moment. Based upon the above criteria we would predict that global activation is transient, yet continuous. By this I mean that conscious percepts and images are the tip of a highly fluid iceberg of supporting and competing unconscious processes. 2.4 Conscious representations and processes are multimodal and unitive. By unitive I mean that consciousness naturally tends towards the integration into a single, unified percept of the outputs of those unconscious processors predominant in the global workspace at any one time.
Attended percepts are normally multimodal.
Brain research has shown that even stimuli presented in a single modality, like vision, are built up out of the activities of multiple processing areas specialized for edge detection, contrast, color, movement, etc. The CNS, then, requires some mechanism for binding the diverse representations generated by multiple unconscious processors into a coherent stream of consciousness. It is our contention that global activation, as described briefly above, provides the necessary basis for such binding. As these criteria and examples illustrate, any approach that hopes to define the nature of consciousness must develop contrasting perspectives for elucidating conscious and unconscious processes. These perspectives should be understood as complimentary rather than mutually exclusive, however.