A puzzle arises in trying to separate the brain basis of phenomenal consciousness—the raw subjective experience—from the machinery needed to report that experience. The standard method of identifying neural correlates in clear cases (where people are certain and authoritative) is circular: it already assumes whether report-related machinery is part of the conscious state. The paper argues for an abstract solution and points to empirical evidence that phenomenal consciousness can overflow cognitive accessibility—that is, we can have conscious experiences we cannot report. It proposes that the neural basis of consciousness can be identified by excluding the neural basis of accessibility, an assumption justified by the explanations it enables.
The search for a single neural correlate of consciousness (NCC) may be misguided. Evidence increasingly supports a framework with at least two distinct NCCs: a phenomenal NCC and an access NCC. These can be distinguished using experimental methods such as signal-detection theory. Recent cognitive neuroscience findings provide empirical support for two separate NCCs rather than one.
A new technique suggests that people can consciously perceive more items at once than can be held in visual working memory. The method exploits unattended 'ensemble properties' that can be detected without reducing working memory capacity, offering a way to study phenomenal consciousness beyond memory limits.
A commentary argues that Dehaene et al.'s review on consciousness and machines asks and answers the wrong questions, implying that their conclusions about not being on the verge of creating conscious machines may be premature or misdirected.