There is currently no consensus regarding what measures are most valid to demonstrate perceptual processing without awareness. Likewise, whether conscious perception and unconscious processing rely on independent mechanisms or lie on a continuum remains a matter of debate. Here, we addressed these issues by comparing the time courses of subjective reports, objective discrimination performance and response priming during meta-contrast masking, under similar attentional demands. We found these to be strikingly similar, suggesting that conscious perception and unconscious processing cannot be dissociated (...) by their time course. Our results also demonstrate that unconscious processing, indexed by response priming, occurs, and that objective discrimination performance indexes the same conscious processes as subjective visibility reports. Finally, our results underscore the role of attention by showing that how much attention the stimulus receives relative to the mask, rather than whether processing is measured by conscious discrimination or by priming, determines the time course of meta-contrast masking. (shrink)

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. (shrink)

There are two distinct but related threads in this article. The first is methodological and is aimed at exploring the relative merits and faults of different operational definitions of consciousness. The second is conceptual and is aimed at understanding the prior commitments regarding the nature of conscious content that motivate these positions. I consider two distinct operationalizations: one defines consciousness in terms of dichotomous subjective reports, the other in terms of graded subjective reports. I ultimately argue that both approaches are (...) inadequate and that a third alternative that involves integration of subjective report and task performance should be adopted. (shrink)

Relative blindsight is said to occur when different levels of subjective awareness are obtained at equality of objective performance. Using metacontrast masking, Lau and Passingham reported relative blindsight in normal observers at the shorter of two stimulus-onset asynchronies between target and mask. Experiment 1 replicated the critical asymmetry in subjective awareness at equality of objective performance. We argue that this asymmetry cannot be regarded as evidence for relative blindsight because the observers’ responses were based on different attributes of the stimuli (...) at the two SOAs. With an invariant criterion content , there was no asymmetry in subjective awareness across the two SOAs even though objective performance was the same. Experiment 3 examined the effect of criterion level on estimates of relative blindsight. Collectively, the present results question whether metacontrast masking is a suitable paradigm for establishing relative blindsight. Implications for theories of consciousness are discussed. (shrink)

A series of five experiments investigated the extent of subliminal processing of negation. Participants were presented with a subliminal instruction to either pick or not pick an accompanying noun, followed by a choice of two nouns. By employing subjective measures to determine individual thresholds of subliminal priming, the results of these studies indicated that participants were able to identify the correct noun of the pair – even when the correct noun was specified by negation. Furthermore, using a grey-scale contrast method (...) of masking, Experiment 5 confirmed that these priming effects were evidenced in the absence of partial awareness, and without the effect being attributed to the retrieval of stimulus–response links established during conscious rehearsal. (shrink)

Consciousness is now a hot topic in both philosophy and the cognitive sciences, yet there is much controversy over how to measure it. First, it is not clear whether biased subjective reports should be taken as adequate for measuring consciousness, or if more objective measures are required. Ways to benefit from the advantages of both these measures in the form of ‘Type 2’ metacognitive measures are under development, but face criticism. Research into neurophysiological measures of consciousness is potentially very valuable, (...) but often hindered by its dependence on behavioural measures that are themselves controversial. Newer informational measures are theoretically interesting, but as yet not easily applicable, while other measures of consciousness are designed for application in clinical cases . Although much optimism accompanies research into measures of consciousness, the controversies and methodological problems reviewed here suggest that making progress in this area may be more difficult than is often acknowledged. (shrink)

Sandberg et al. show that the Perceptual Awareness Scale scale is sensitive compared to confidence ratings and wagering in detecting accurate perception. They go on to argue that the PAS scale is hence a sensitive measure of conscious perception compared to confidence ratings, a claim disputed here. The fact that some visual content is conscious does not entail that the visual content relevant to making a discrimination is conscious. For example, if one saw a square but was only aware of (...) seeing a flash of something, then one has not consciously seen a square. When PAS and confidence ratings come in conflict, we suggest that it is confidence ratings that more reliably indicate the conscious status of contents allowing discrimination. (shrink)

In their comment on Sandberg, Timmermans, Overgaard, and Cleeremans , Dienes and Seth argue that increased sensitivity of the Perceptual Awareness Scale is a consequence of the scale being less exclusive rather than more exhaustive. According to Dienes and Seth, this is because PAS may measure some conscious content, though not necessarily relevant conscious content, “If one saw a square but was only aware of seeing a flash of something, then one has not consciously seen a square.” In this reply, (...) we claim that there is a difference between conscious visual experience, which may be partial, and the resulting conscious content, which is conceptual. Whereas PAS measures the first, confidence judgments and post-decision wagering measure the second. (shrink)

The contrasts between so-called objective and subjective measures of consciousness have been a dominating topic of discussion for decades. The debate has classically been dominated by two positions – that subjective measures may be completely or partially reduced to objective measures, and, alternatively that they must exist in parallel. I argue that many problems relate to subjective reports as they can be imprecise and vulnerable to a number of potential confounding factors. However, I also argue that despite the fact that (...) subjective reports are fallible, all objective measures are derived from subjective measures, and, thus, will never under normal circumstances be more correct. I propose that the best and possibly only realistic way forward is a specific version of a “middle ground”: to attempt to improve subjective reports in a collaboration with objective research methods. (shrink)

According to a long-standing belief, introspection provides privileged access to the mind, while objective methods, which we denote as “extrospection”, suffer from basic epistemic deficits. Here we will argue that neither an introspective privilege exists nor does extrospection suffer from such deficits.We will focus on two entailments of an introspective privilege: first, such a privilege would require that introspective evidence prevails in cases of conflict with extrospective information. However, we will show that this is not the case: extrospective claims can (...) prevail in cases of conflict. These conflicts are resolved by an inference to the explanation that best accounts for the available evidence. This explanation may speak in favor of extrospection.Second, given an introspective privilege, the development of extrospective measurement techniques should be restricted by the accuracy of introspective reports. We will argue that this problem is part of a more general issue that comes up with the establishment of measurement in the natural sciences. We will identify three strategies that have proven successful in dealing with the problem in the natural sciences. It will turn out that all these strategies are available for extrospective measurement as well. Consequently, the insufficiencies of introspective reports do not impose a limit on the accuracy of extrospective measurement methods.We conclude that neither an introspective privilege nor basic extrospective deficits exist. This does not mean that extrospection will ever replace introspection. Rather, both approaches provide independent and indispensable forms of epistemic access to the mind. (shrink)

The notion of subjective vividness plays a fundamental role in comparing different conscious experiences, yet it is poorly understood and lacks proper definition. Philosophical reflection on this topic is especially scarce. This article proposes a novel account of vividness arguing that its standard operationalisation in psychology conflates two major modality‐general dimensions along which experiences vary—subjective intensity and subjective specificity—which themselves are determined by further modality‐specific factors. The article identifies the neural underpinnings of these factors in the visual domain, demonstrates the (...) unificatory power of the account, and argues that vividness is part of the content of perception. (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 paper addresses what we consider to be the most pressing challenge for the emerging science of consciousness: the measurement problem of consciousness. That is, by what methods can we determine the presence of and properties of consciousness? Most methods are currently developed through evaluation of the presence of consciousness in humans and here we argue that there are particular problems in application of these methods to nonhuman cases—what we call the indicator validity problem and the extrapolation problem. The first (...) is a problem with the application of indicators developed using the differences between conscious and unconscious processing in humans to the identification of other conscious vs. nonconscious organisms or systems. The second is a problem in extrapolating any indicators developed in humans or other organisms to artificial systems. However, while pressing ethical concerns add urgency to the attribution of consciousness and its attendant moral status to nonhuman animals and intelligent machines, we cannot wait for certainty and we advocate the use of a precautionary principle to avoid causing unintentional harm. We also intend that the considerations and limitations discussed in this paper can be used to further analyze and refine the methods of consciousness science with the hope that one day we may be able to solve the measurement problem of consciousness. (shrink)

To study consciousness, scientists need to determine when participants are conscious and when they are not. They do so with consciousness detection procedures. A recurring skeptical argument against those procedures is that they cannot be calibrated: there is no way to make sure that detection outcomes are accurate. In this article, I address two main skeptical arguments purporting to show that consciousness scientists cannot calibrate detection procedures. I conclude that there is nothing wrong with calibration in consciousness science.

Within theoretical and empirical enquiries, many different meanings associated with consciousness have appeared, leaving the term itself quite vague. This makes formulating an abstract and unifying version of the concept of consciousness – the main aim of this article –into an urgent theoretical imperative. It is argued that consciousness, characterized as dually accessible (cognized from the inside and the outside), hierarchically referential (semantically ordered), bodily determined (embedded in the working structures of an organism or conscious system), and useful in action (...) (pragmatically functional), is a graded rather than an all-or-none phenomenon. A gradational approach, however, despite its explanatory advantages, can lead to some counterintuitive consequences and theoretical problems. In most such conceptions consciousness is extended globally (attached to primitive organisms or artificial systems), but also locally (connected to certain lower-level neuronal and bodily processes). For example, according to information integration theory (as introduced recently by Tononi and Koch, 2014), even such simple artificial systems as photodiodes possess miniscule amounts of consciousness. The major challenge for this article, then, is to establish reasonable, empirically justified constraints on how extended the range of a graded consciousness could be. It is argued that conscious systems are limited globally by the ability to individuate information (where individuated information is understood as evolutionarily embedded, socially altered, and private), whereas local limitations should be determined on the basis of a hypothesis about the action-oriented nature of the processes that select states of consciousness. Using these constraints, an abstract concept of consciousness is arrived at, hopefully contributing to a more unified state of play within consciousness studies itself. (shrink)

Consciousness can be measured in various ways, but different measures often yield different conclusions about the extent to which awareness relates to performance. Here, we compare five different subjective measures of awareness in the context of an artificial grammar learning task. Participants expressed their subjective awareness of rules using one of five different scales: confidence ratings , post-decision wagering , feeling of warmth , rule awareness , and continuous scale . All scales were equally sensitive to conscious knowledge. PDW, however, (...) was affected by risk aversion, and both RAS and SDS applied different minimal criteria for rule awareness. CR seems to capture the largest range of consciousness, but failed to indicate unconscious knowledge with the guessing criterion. We close by discussing the theoretical implications of scale sensitivity and propose that CR’s unique features enable a finer assessment of subjective states of awareness. (shrink)

Here, we explore the sensitivity of different awareness scales in revealing conscious reports on visual emotion perception. Participants were exposed to a backward masking task involving fearful faces and asked to rate their conscious awareness in perceiving emotion in facial expression using three different subjective measures: confidence ratings , with the conventional taxonomy of certainty, the perceptual awareness scale , through which participants categorize “raw” visual experience, and post-decision wagering , which involves economic categorization. Our results show that the CR (...) measure was the most exhaustive and the most graded. In contrast, the PAS and PDW measures suggested instead that consciousness of emotional stimuli is dichotomous. Possible explanations of the inconsistency were discussed. Finally, our results also indicate that PDW biases awareness ratings by enhancing first-order accuracy of emotion perception. This effect was possibly a result of higher motivation induced by monetary incentives. (shrink)

Human behavior depends on the ability to effectively introspect about our performance. For simple perceptual decisions, this introspective or metacognitive ability varies substantially across individuals and is correlated with the structure of focal areas in prefrontal cortex. This raises the possibility that the ability to introspect about different perceptual decisions might be mediated by a common cognitive process. To test this hypothesis, we examined whether inter-individual differences in metacognitive ability were correlated across two different perceptual tasks where individuals made judgments (...) about different and unrelated visual stimulus properties. We found that inter-individual differences were strongly correlated between the two tasks for metacognitive ability but not objective performance. Such stability of an individual’s metacognitive ability across different perceptual tasks indicates a general mechanism supporting metacognition independent of the specific task. (shrink)

The interocular suppression technique termed continuous flash suppression (CFS) has become an immensely popular tool for investigating visual processing outside of awareness. The emerging picture from studies using CFS is that extensive processing of a visual stimulus, including its semantic and affective content, occurs despite suppression from awareness of that stimulus by CFS. However, the current implementation of CFS in many studies examining processing outside of awareness has several drawbacks that may be improved upon for future studies using CFS. In (...) this paper, we address some of those shortcomings, particularly ones that affect the assessment of unawareness during CFS, and ones to do with the use of ‘visible’ conditions that are often included as a comparison to a CFS condition. We also discuss potential biases in stimulus processing as a result of spatial attention and feature-selective suppression. We suggest practical guidelines that minimize the effects of those limitations in using CFS to study visual processing outside of awareness. (shrink)

The conceptual foundations, features, and scope of the notion of rationality are increasingly being affected by developments in embodied cognitive science. This article starts from the idea of embodied rationality, and aims to develop a frame in which a debate with the classical, possibly bounded, notion of rationality-as-consistency can take place. To this end, I develop a game theoretic description of a real time interaction setup in which participants' behaviors can be used to compare the enactive approach, which underlies embodied (...) rationality, with game theoretic approaches to human interaction. The Perceptual Crossing Paradigm is a minimal interaction interface where two participants each control an avatar on a shared virtual line, and are tasked with cooperatively finding each other among distractor objects. It is well known that the best performance on this task is obtained when both participants let their movements coordinate with the objects they encounter, which they do without any prior knowledge of efficient interaction strategies in the system. A game theoretic model of this paradigm shows that this task can be described as an Assurance game, which allows for comparing game theoretical approaches and the enactive approach on two main fronts. First, accounting for the ability of participants to interactively solve the Assurance game; second, accounting for the evolution of choice landscapes resulting from evolving normative realms in the task. Similarly to the series of paradoxes which have fueled debates in economics in the past century, this analysis aims to serve as an interpretation testbed which can fuel the current debate on rationality. (shrink)

This paper argues for a position of ‘dark pessimism’ towards introspective reports playing a strong justificatory role in consciousness science, based on the application of frameworks and concepts of measurement. I first show that treating introspective reports as measurements fits well within current discussions of the reliability of introspection, and argue that introspective reports must satisfy at least a minimal definition of measurement in order to play a justificatory role in consciousness science. I then show how treating introspective reports as (...) measurements makes it possible to identify the foundational methodological problems that underlie much of the current philosophical and scientific debate about the status of introspective evidence in studying consciousness. I argue that these problems prevent introspective reports from playing a strong justificatory role and resolving long-standing debates in consciousness science, both in contemporary work and in the future. (shrink)

As for most measurement procedures in the course of their development, measures of consciousness face the problem of coordination, i.e., the problem of knowing whether a measurement procedure actually measures what it is intended to measure. I focus on the case of the Perceptual Awareness Scale to illustrate how ignoring this problem leads to ambiguous interpretations of subjective reports in consciousness science. In turn, I show that empirical results based on this measurement procedure might be systematically misinterpreted.