Block () highlights two experimental studies of neglect patients which, he contends, provide ‘dramatic evidence’ for unconscious seeing. In Block's hands this is the highly non-trivial thesis that seeing of the same fundamental kind as ordinary conscious seeing can occur outside of phenomenal consciousness. Block's case for it provides an excellent opportunity to consider a large body of research on clinical syndromes widely held to evidence unconscious perception. I begin by considering in detail the two studies of neglect to which (...) Block appeals. I show why their interpretation as evidence of unconscious seeing faces a series of local difficulties. I then explain how, even bracketing these issues, a long-standing but overlooked problem concerning our criterion for consciousness problematizes the appeal to both studies. I explain why this problem is especially pressing for Block given his view that phenomenal consciousness overflows access consciousness. I further show that it is epidemic—not only affecting all report-based studies of unconscious seeing in neglect, but also analogous studies of the condition most often alleged to show unconscious seeing, namely blindsight. (shrink)

Studying consciousness requires contrasting conscious and unconscious perception. While many studies have reported unconscious perceptual effects, recent work has questioned whether such effects are genuinely unconscious, or whether they are due to weak conscious perception. Some philosophers and psychologists have reacted by denying that there is such a thing as unconscious perception, or by holding that unconscious perception has been previously overestimated. This article has two parts. In the first part, I argue that the most significant attack on unconscious perception (...) commits the criterion content fallacy: the fallacy of interpreting evidence that observers were conscious of something as evidence that they were conscious of the task-relevant features of the stimuli. In the second part, I contend that the criterion content fallacy is prevalent in consciousness research. For this reason, I hold that if unconscious perception exists, scientists studying consciousness could routinely underestimate it. I conclude with methodological recommendations for moving the debate forward. (shrink)

This article reports four subliminal perception experiments using the relationship between confidence and accuracy to assess awareness. Subjects discriminated among stimuli and indicated their confidence in each discrimination response. Subjects were classified as being aware of the stimuli if their confidence judgments predicted accuracy and as being unaware if they did not. In the first experiment, confidence predicted accuracy even at stimulus durations so brief that subjects claimed to be performing at chance. This finding indicates that subjects's claims that they (...) are ''just guessing'' should not be accepted as sufficient evidence that they are completely unaware of the stimuli. Experiments 2-4 tested directly for subliminal perception by comparing the minimum exposure duration needed for better than chance discrimination performance against the minimum needed for confidence to predict accuracy. The latter durations were slightly but significantly longer, suggesting that under certain circumstances people can make perceptual discriminations even though the information that was used to make those discriminations is not consciously available. (shrink)

Most ?theories of consciousness? are based on vague speculations about the properties of conscious experience. We aim to provide a more solid basis for a science of consciousness. We argue that a theory of consciousness should provide an account of the very processes that allow us to acquire and use information about our own mental states ? the processes underlying introspection. This can be achieved through the construction of information processing models that can account for ?Type-C? processes. Type-C processes can (...) be specified experimentally by identifying paradigms in which awareness of the stimulus is necessary for an intentional action. The Shallice (1988b) framework is put forward as providing an initial account of Type-C processes, which can relate perceptual consciousness to consciously performed actions. Further, we suggest that this framework may be refined through the investigation of the functions of prefrontal cortex. The formulation of our approach requires us to consider fundamental conceptual and methodological issues associated with consciousness. The most significant of these issues concerns the scientific use of introspective evidence. We outline and justify a conservative methodological approach to the use of introspective evidence, with attention to the difficulties historically associated with its use in psychology. (shrink)

When the stored representation of the meaning of a stimulus is accessed through the processing of a sensory input it is maintained in an activated state for a certain amount of time that allows for further processing. This semantic activation is generally accompanied by conscious identification, which can be demonstrated by the ability of a person to perform discriminations on the basis of the meaning of the stimulus. The idea that a sensory input can give rise to semantic activation without (...) concomitant conscious identification was the central thesis of the controversial research in subliminal perception. Recently, new claims for the existence of such phenomena have arisen from studies in dichotic listening, parafoveal vision, and visual pattern masking. Because of the fundamental role played by these types of experiments in cognitive psychology, the new assertions have raised widespread interest. (shrink)

This is a bibliography of books and articles on consciousness in philosophy, cognitive science, and neuroscience over the last 30 years. There are three main sections, devoted to monographs, edited collections of papers, and articles. The first two of these sections are each divided into three subsections containing books in each of the main areas of research. The third section is divided into 12 subsections, with 10 subject headings for philosophical articles along with two additional subsections for articles in cognitive (...) science and neuroscience. Of course the division is somewhat arbitrary, but I hope that it makes the bibliography easier to use. This bibliography has first been compiled by Thomas Metzinger and David Chalmers to appear in print in two philosophical anthologies on conscious experience . From 1995 onwards it has been continuously updated by Thomas Metzinger, and now is freely available as a PDF-, RTF-, or HTML-file. This bibliography mainly attempts to cover the Anglo-Saxon and German debates, in a non-annotated, fully formatted way that makes it easy to "cut and paste" from the original file. To a certain degree this bibliography also contains items in other languages than English and German - all submissions in other languages are welcome. Last update of current version: July 13th, 2001. (shrink)