A Scientific Approach to Conscious Experience, Introspection, and Unconscious Processing: Vision and Blindsight.

To many observers, the study of unconscious psychological processes is personality psychology's greatest contribution to scientific knowledge. Advances in science usually involve increments in the understanding of well-known phenomena (Kuhn, 1962). Discovering entirely new phenomena is rare. Unearthing new phenomena of importance to society at large is rarer still. Evidence that psychological experience can be shaped by forces of which we are unaware (e.g., Janet, 1889; Freud, 1900) was that rarest of cases in which the field produced startling findings that altered society's view of human nature. Evidence of unconscious influences was surprising, of course, because of the obvious importance of conscious self-reflection in human affairs. The ability to reflect on the world, ourselves, and our very capacity for self-reflection is our species' most distinguishing characteristic. The obviousness of self reflective capabilities should not cause the personality psychologist to neglect a careful analysis of conscious experience. Subjective, private experience (Singer & Kolligian, 1987) is a critical phenomenon unto itself, and is a human capability that enables people to shape the nature of their life circumstances and to influence the course of their personal development (Bandura, 1997; Rychlak, 1997). This chapter reviews developments in the study of unconscious processes and conscious experience. After a brief historical overview, we outline important conceptual distinctions among conscious and unconscious phenomena. We then focus on unconscious processes in personality functioning. As we will see, some unconscious processes involve motivated states of psychological defense.

Our reasoning thus far has applied the basic thesis that any interpretation of ourselves and of other beings should not neglect, distort, or render unintelligible what is undergone in conscious and self-conscious experience. As C. I. Lewis has said: “That which explains experience is always something which the experience in question gives us some reason (some partial ground) for assuming.”1 The method of beginning with the data in conscious experience does not entail the conclusion that the person is no more than his conscious experience. For example, in chapter 2 we inferred, from what is given in conscious experience, that a person’s unconscious processes are more understandable as “extensions” of the dynamics of the self-identifying person. Our task now is to see what we can reasonably say about the person in the light of his conscious experience of his body.

Revealing robust neural correlates of conscious and unconscious visual processing: Activation likelihood estimation meta-analyses

Accounts of predictive processing propose that conscious experience is influenced not only by passive predictions about the world, but also by predictions encompassing how the world changes in relation to our actions—that is, on predictions about sensorimotor contingencies. We tested whether valid sensorimotor predictions, in particular learned associations between stimuli and actions, shape reports about conscious visual experience. Two experiments used instrumental conditioning to build sensorimotor predictions linking different stimuli with distinct actions. Conditioning was followed by a breaking continuous flash suppression task, measuring the speed of reported breakthrough for different pairings between the stimuli and prepared actions, comparing those congruent and incongruent with the trained sensorimotor predictions. In Experiment 1, counterbalancing of the response actions within the breaking continuous flash suppression task was achieved by repeating the same action within each block but having them differ across the two blocks. Experiment 2 sought to increase the predictive salience of the actions by avoiding the repetition within blocks. In Experiment 1, breakthrough times were numerically shorter for congruent than incongruent pairings, but Bayesian analysis supported the null hypothesis of no influence from the sensorimotor predictions. In Experiment 2, reported conscious perception was significantly faster for congruent than for incongruent pairings. A meta-analytic Bayes factor combining the two experiments confirmed this effect. Altogether, we provide evidence for a key implication of the action-oriented predictive processing approach to conscious perception, namely that sensorimotor predictions shape our conscious experience of the world.

OPINION article Front. Psychol., 06 May 2014Sec. Consciousness Research Volume 5 - 2014 | https://doi.org/10.3389/fpsyg.2014.00387

The fundamental question as to whether the neural correlates of any given conscious visual experience are expressed locally within a given cortical area or more globally within some widely distributed network remains unresolved. We inquire as to whether recursive processing-by which we mean the combined flow and integrated outcome of afferent and recurrent activity across a series of cortical areas-is essential for the emergence of conscious visual experience. If so, we further inquire as to whether such recursive processing is essential only for loops between extrastriate cortical areas explicitly representing experiences such as color or motion back to V1 or whether it is processing between still higher levels and the areas computing such explicit representations that is exclusively or additionally essential for visual experience. If recursive processing is not essential for the emergence of conscious visual experience, then it should also be possible to determine whether it is only the intracortical sensory processing within areas computing explicit sensory representations that is required for perceptual experience or whether it is the subsequent processing of the output of such areas within more anterior cortical regions that engenders perception. The present analysis suggests that the questions posed here may ultimately become experimentally resolvable. Whatever the outcome, the results will likely open new approaches to identify the neural correlates of conscious visual perception.

Some patients with lesions in visual cortex lack conscious visual experience but, when tested, exhibit a significant ability, termed 'blindsight', to discriminate visual stimuli. Here we report two different visual displays that induce blindsight in normal observers. Using an objective measure, we show that conscious experience remains defective at presentation times much longer (1 s) than the onset of visual sensitivity (approximately 60 ms). To obtain this effect, we generate a contrast between visual textures and then conceal the contrast by superimposing 'complementary' textures. Complementarity can involve either opposite motion or binocular rivalry and orthogonal orientation. In both cases, observers locate the texture contrast reliably but do not, by either subjective or objective measures, consciously experience it. Taken together with present knowledge of the visual cortical site(s) at which opposite motion and rivalrous orientation interact, this observation bears upon the functional anatomy of conscious visual experience.

Exploring the limits to our understanding of whether fish feel pain.

Thinking, both global and local

Towards solving the hard problem of consciousness: The varieties of brain resonances and the conscious experiences that they support

Primary sensory cortices, top-down projections and conscious experience

One major problem in the empirical investigation of consciousness is to identify a so-called objective measure of the presence or absence of a specific conscious experience. An objective measure, in this context, refers to a measure of how well a subject is able to solve a task or to a report, given by the subject, which does not explicity refer to his or her own conscious experience. Such task performance or report may be influenced by conscious as well as unconscious processes. Subjective measures, on the other hand, are defined as reports (verbal or other kinds) made by a subject directly about his or her conscious experience. The paper by Busch, Fründ, and Herrmann (2009) is an important and interesting suggestion of how to find neural correlates involved in change detection and change blindness, but it also claims to infer knowledge about conscious experiences from its data. This commentary will focus on this last claim.In their study, the authors present a change blindness experiment in which they investigated whether change detection (sensing) and change identification (seeing) rely on different or similar neural processes. The authors successfully identified some ERP components that were similar for both conditions (the VAN and the P3) and some other components that specifically occurred for changes that were identified (the change-related positivity and the N2pc). In a second experiment (visual search), the authors showed that the N2pc reflected selective attention, whereas the change-related positivity was specific for change identification. They conclude that sensing and seeing a change rely on different neural processes. These results are based on signal detection theory (SDT) according to which data are analyzed and interpreted.SDT is a model of how systems detect signals among noise, and it has repeatedly proven applicable to the human perceptual system (Green & Swets, 1966). SDT provides an objective measure of a subject's capacity to detect stimuli (d′) and a criterion for detection (C). Thus, the theory suggests a way to obtain data about a subject's perceptual capacity that is not based on subjective verbal reports but on “objective reports,” that is, their task performance.There is, however, an important conceptual and empirical distinction between signals and reports (Overgaard, 2009). In this terminology, different from the SDT terminology, signals refer to the “uncontrolled behaviors such as reflexes” of a subject (Overgaard, 2009, p. 16)—that is, the observation of behavior that is not as such intended to inform an observer yet may be of use as data to analyze some cognitive process. Reports, in contrast, are communications from the subject; this may be a verbal statement describing a complex scenery or something as simple as a button press when a target is present—the important part being that the subject is intending a communication using a report.SDT makes no such demands that reports are based on intended communications or on reports directly about consciousness. Accordingly, a signal in SDT is not necessarily an expression of what a subject has perceived consciously.In order to measure d′ and C, subjects are performing a task, for example, a visual detection task. One problem that has previously been identified is that task performance is not a good guide to conscious experiences because unconscious factors might also be involved (Lau, 2008). To illustrate this point, Lau (2007) describes an experiment where the same d′ is constant while reports of experience differed in subjects over time. Therefore, d′ as well as C seem blind to the conscious experience the subjects has while performing the task. They seem to be of use when describing those cognitive events that make an overt behavior possible (such as responding to the presence of a target), that is, the so-called objective aspects of perception. However, Busch et al. (2009) are more ambitious than that. They claim explicitly to be investigating the subjective aspects as well using SDT—an approach that we, as argued above, find problematic as a matter of principle.The experiments by Busch et al. (2009) do however contain two important deviations from what may be considered a “standard” SDT design. Those deviations, it could be argued, may better the case for the experiments' ability to give information about conscious experience. First, whenever the subjects scored a hit, they were asked to identify the changing object (reporting either the object in the first or the second display) out of eight possible objects. Second, subjects were asked not to guess about detecting a change or the identity of the changing object (but instead answer “not sure”) if they were uncertain.Busch et al. (2009) claim that a “full blown visual experience [is] required for [object] identification”—that is, in order to complete the additional task, subjects must as a matter of principle have a visual experience of the object. However, the task is simply selecting the right object out of small number of possible objects. Similar approaches have been used previously to show the exact opposite by adding a subjective scale of conscious experience: the presence of subliminal perception. Several experiments in cognitive science and, for example, the blindsight literature are classically interpreted to show that the performance of such identification tasks in the absence of reports about experience demonstrate that unconscious visual identification is possible (Overgaard & Timmermans, in press; Trevathan, Saharie, & Weiskrantz, 2007). Accordingly, we find it problematic that Busch et al. use no measure of conscious experience yet still use an exact opposite interpretation of this kind of observation without further argument.This further argument could then theoretically be that because the subjects are asked not to guess but only to respond when they are certain, they are in fact conscious of the changing object when they make a positive identification, as high confidence ratings such as “certain” are often associated with awareness (Dienes, Altmann, Kwan, & Goode, 1995). However, drawing an exact line when to “be guessing” and when to “respond to a vague experience” may not be a simple task to the subjects who, more likely than not, will use different criteria to solve this situation. Theory aside, the argument is in fact in conflict with the actual data. The problem is that subjects are only correct around 70% of the time when trying to detect a change (chance is 50%) and 54% of the time when identifying a changing object (chance is 25%). These numbers indicate that the subjects are guessing, at least to some extent. The simple instruction not to guess, in other words, seems not to be sufficient.In conclusion, we believe that our relatively simple arguments above support conclusions from several other recent publications (e.g., Seth, Dienes, Cleeremans, Overgaard, & Pessoa, 2008; Slagter, Lutz, Greischar, Nieuwenhuis, & Davidson, 2009) that the application of objective methods only to study conscious experience in all cases ends up in self-contradiction and methodological pitfalls.Reprint requests should be sent to Morten Overgaard, CNRU, Hammel Neurorehabilitation and Research Center, Aarhus University Hospital, Voldbyvej 15, 8450 Hammel, Denmark, or via e-mail: mortover@rm.dk.

There is conscious vision, and there is unconscious visual processing. So far so good. But where lies the boundary between the two? What are the visual functions that shape the transition from “processing in the dark” to having a conscious visual percept? And what are the neural mechanisms that carry that transition? I review the findings on feature detection, object categorization, interference, inference, Gestalt grouping, and perceptual organization, and examine to what extent these functions correlate with the presence or absence of conscious vision. It turns out that a surprisingly large set of visual functions is executed unconsciously, indicating that unconscious vision is much “smarter” than we might intuitively think. Only when these unconscious mechanisms fail, and more elaborate and incremental processing steps are required, is consciousness necessary. The function of conscious vision may be to add a final layer to our interpretation of the world, to solve relatively “new” visual problems, and to enable visual learning.

The Scope and Limits of Top-Down Attention in Unconscious Visual Processing

For many years, since Baars (1988) explicitly formulated it, contrastive analysis has been the key methodological approach in experimental studies of consciousness. When certain properly chosen psychological experimental setups (allowing an invariant target stimulus either to be consciusly experienced or not) were combined with brain-imaging methods, contrastive analysis became a quite powerful tool of research (Crick, 1994; Koch, 2004). By subtracting markers of brain processes recorded in the conditions without conscious experience of the target from the markers recorded in the conditions where the same target is consciously experienced it was believed that the markers of neural correlates of consciousness (NCC) can be obtained. However, as it turned out in the subsequent theoretical and experimental analysis, the picture is not so clear and simple (Bachmann, 2000, 2009; Miller, 2007; Aru et al., 2012; de Graaf et al., 2012). For example, when in the invariant conditions of independent variables a masked visual stimulus was consciously perceived or not (consciousness of the target standed as a dependent variable), NCC which were measured as a spectral perturbation of EEG was present already before stimulus presentation (Aru and Bachmann, 2009). Thus, the neural correlate of consciousness of a stimulus was present earlier than the stimulus itself was presented. Now, a reader must not get excited here because instead of some paranormal explanations brain-science based explanations can be comfortably used. In order to overcome the conceptual crisis hitting the traditional contrastive analysis based NCC research it was suggested that unconscious prerequisite processes (NCCpr) emerging as a result of contrastive analysis of brain-process markers of consciousness and similarly unconscious consequent processes (NCCco) must be differentiated from the constitutive processes directly associated with conscious experience (Aru et al., 2012; de Graaf et al., 2012). Thus, new experimental approaches were in need to avoid the trap of distilling prerequisite, direct, and consequent processes as mutually confounded and empirically inseparable. Despite some first attempts in this direction (Aru and Bachmann, 2015), the specialist landscape in this domain has remained obscure and no breakthrough solutions have been in sight. Moreover, there seems to be a number of additional uncertainties when we try to disentangle the various sub-types of NCC. Even NCCpr and NCCco are not unitary in terms of their theoretical meaning and associated neural processes. First, as the contents on which the perceptual report is founded can be selective, the markers of unused conscious contents may be erroneously neglected as markers of unconscious processes. They actually belong to consciousness level processes, but related to contents of consciousness qualitatively different from the ones specified by NCC. Second, in measuring NCC we must be able to disentangle contributions of the general consciousness enabling mechanisms and the selective contents representing mechanisms because their markers can be different and thus confused. In what follows I will substantiate these two issues.