Morten Overgaard

Blindsight is classically defined as residual visual capacity, e.g., to detect and identify visual stimuli, in the total absence of perceptual awareness following lesions to V1. However, whereas most experiments have investigated what blindsight patients can and cannot do, the literature contains several, often contradictory, remarks about remaining visual experience. This review examines closer these remarks as well as experiments that directly approach the nature of possibly spared visual experiences in blindsight.

What is the best way of assessing the extent to which people are aware of a stimulus? Here, using a masked visual identification task, we compared three measures of subjective awareness: The Perceptual Awareness Scale , through which participants are asked to rate the clarity of their visual experience; confidence ratings , through which participants express their confidence in their identification decisions, and Post-decision wagering , in which participants place a monetary wager on their decisions. We conducted detailed explorations of the relationships between awareness and identification performance, looking to determine which scale best correlates with performance, and whether we can detect performance in the absence of awareness and how the scales differ from each other in terms of revealing such unconscious processing. Based on these findings we discuss whether perceptual awareness should be considered graded or dichotomous. Results showed that PAS showed a much stronger performance-awareness correlation than either CR or PDW, particularly for low stimulus intensities. In general, all scales indicated above-chance performance when participants claimed not to have seen anything. However, such above-chance performance only showed when we also observed a correlation between awareness and performance. Thus PAS seems to be the most exhaustive measure of awareness, and we find support for above-chance performance in the absence of subjective awareness, but such unconscious knowledge only contributes to performance when we observe conscious knowledge as well. Similarities and differences between scales are discussed in the light of consciousness theories and response strategies

As is the case with other concepts about mental affairs, the concept of introspection has many different interpretations. Some seem to consider introspecting a perceptive act and others see it as a thinking activity . For the present purpose, we will claim it as a common understanding in all such theories that introspection presupposes consciousness . States of consciousness, broadly discussed in the philosophical and empirical literature as first order states of consciousness, are states in which a subject is aware of some or other object, thought, or feeling. Introspective states, however, are states in which a subject directs his or her attention towards their own conscious state. According to this understanding which we claim is a widespread one introspection can exist only in conscious subjects, and, furthermore, it is by way of introspection that a subject can learn about having this or that experience. To avoid misunderstandings, we wish to underline that the claim is not that experiencing as such is dependent upon such acts of introspection. On the contrary, we believe that a subject can have all kinds of intero- and exteroceptive experiences, directing attention towards the represented object . It is only when the subject directs attention not towards the object as such but towards the very state of being conscious of the object that he or she is introspective

Subliminal perception (SP) is today considered a well-supported theory stating that perception can occur without conscious awareness and have a significant impact on later behaviour and thought. In this article, we first present and discuss different approaches to the study of SP. In doing this, we claim that most approaches are based on a dichotomic measure of awareness. Drawing upon recent advances and discussions in the study of introspection and phenomenological psychology, we argue for both the possibility and necessity of using an elaborated measure of subjective states. In the second part of the article, we present findings where these considerations are implemented in an empirical study. The results and implications are discussed in detail, both with reference to SP, and in relation to the more general problem of using elaborate introspective reports as data in relation to studies of cognition

In the attempt to construct a scientific approach to consciousness, it has been proposed that transcendental phenomenology or phenomenological psychology be introduced into the framework of cognitive neuroscience. In this article, the consequences of such an approach in terms of basic assumptions, methods for the collection of data, and evaluation of the collected data are discussed. Especially, the proposed notions of mutual constraint and the second perso are discussed. It is concluded that even though naturalising of phenomenology might not prove impossible, the projec has not yet found a coherent basic ground

  Several authors within psychology, neuroscience and philosophy take for granted that standard empirical research techniques are applicable when studying consciousness. In this article, it is discussed whether one of the key methods in cognitive neuroscience – the contrastive analysis – suffers from any serious confounding when applied to the field of consciousness studies; that is to say, if there are any systematic difficulties when studying consciousness with this method that make the results untrustworthy. Through an analysis of theoretical arguments in favour of using contrastive analysis, combined with analyses of empirical findings, I conclude by arguing for three factors that currently are confounding of research using contrastive analysis. These are (1) unconscious processes, (2) introspective reports, and (3) attention

The relation between first and higher order mental states is currently unknown. In particular, the relation between conscious experience and introspection is difficult as the same methods are used to investigate them. In order to make progress in the scientific understanding of consciousness, introspection or both, it is fundamental to understand whether their relation is serial or reciprocal. Although the amount of empirical evidence directly addressing this question is sparse, the little that exists suggests a more complex situation that must be taken into account in order to characterise the relationship between first and higher order mental states. We propose a testable integrative model in an attempt to explain the existing data and to make new empirical predictions.

When consciousness is examined using subjective ratings, the extent to which processing is conscious or unconscious is often estimated by calculating task performance at the subjective threshold or by calculating the correlation between accuracy and awareness. However, both these methods have certain limitations. In the present article, we propose describing task accuracy and awareness as functions of stimulus intensity as suggested by Koch and Preuschoff . The estimated lag between the curves describes how much stimulus intensity must increase for awareness to change proportionally as much as accuracy and the slopes of the curves are used to assess how fast accuracy and awareness increases and whether awareness is dichotomous. The method is successfully employed to assess consciousness characteristics on data from four different awareness scales

In a recent paper, Brogaard presents counter-arguments to the conclusions of an experiment with blindsight subject GR. She argues that contrary to the apparent findings that GR’s preserved visual abilities relate to degraded visual experiences, she is in fact fully unconscious of the stimuli she correctly identifies. In this paper, we present arguments and evidence why Brogaard’s argument does not succeed in its purpose. We suggest that not only is relevant empirical evidence in opposition to Brogaard’s argument, her argument misconstrues necessary criteria to decide whether a conscious experience is visual or not visual

Experimental studies investigating the contribution of conscious intention to the generation of a sense of agency for one’s own actions tend to rely upon a narrow definition of intention. Often it is operationalized as the conscious sensation of wanting to move right before movement. Existing results and discussion are therefore missing crucial aspects of intentions, namely intention as the conscious sensation of wanting to move in advance of the movement. In the present experiment we used an intentional binding paradigm, in which we distinguished between immediate intention, as usually investigated, and longer standing intention. The results showed that the binding effect was significantly enhanced for distal intentions compared to proximal intentions, indicating that the former leads to stronger sense of agency. Our finding provides empirical support for a crucial distinction between at least two types of intention when addressing the efficacy of conscious intentions

This article presents the view that the “problem of consciousness” – per definition – can not be seen as a strictly scientific or strictly philosophical problem. The first idea, especially, leads to important difficulties: First of all, the idea has in most cases implied some rather superficial reductionistic or functionalistic a priori assumptions, and, secondly, it can be shown that some of the most commonly used empirical methods in these regards are inadequate. Especially so in the case of contrastive analysis, widely used in cognitive neuroscience. However, this criticism does not lead to the conclusion that scientific methods are inadequate as such, only that they always work on a pre-established background of theory, of which one must be explicit.