Unconscious Information Processing Research Articles

Multiple sources of unconscious-information processing affect a single response: independent unconscious priming effects

At present there is little knowledge on whether and how multiple pieces of unconscious information can simultaneously affect a single conscious response. In the present study, we manipulated the congruency relation between a masked prime arrow and the target arrow, as well as that between masked flankers and the target arrow. The results demonstrated that the masked prime and flankers produced independent unconscious priming effects on the response to the target. In the process of studying the above phenomenon, two secondary findings were made. First, although the prime congruency effect was obtained, the flanker congruency effect was smaller when the flankers were displayed simultaneously with the target than when they were displayed sequentially before the target. This suggested that priming stimulation required enough time to be processed to a sufficient extent to produce an unconscious priming effect. Second, when the prime stimulus was removed, leaving only the flankers, the flanker priming effect increased, suggesting that the attention attracted to the prime and its conscious mask could also reduce the flanker congruency effect. These results observed across several experiments were replicated in one within-subjects experiment. We proposed an “independent unconscious influence hypothesis” for the phenomenon. This hypothesis was further integrated into a more comprehensive unconscious information processing model. The possible causes of the observed phenomena were discussed.

Neural bases of freedom and responsibility.

This review presents a broad perspective of the Neuroscience of our days with special attention to how the brain generates our behaviors, emotions, and mental states. It describes in detail how unconscious and conscious processing of sensorimotor and mental information takes place in our brains. Likewise, classic and recent experiments illustrating the neuroscientific foundations regarding the behavioral and cognitive abilities of animals and, in particular, of human beings are described. Special attention is applied to the description of the different neural regulatory systems dealing with behavioral, cognitive, and emotional functions. Finally, the brain process for decision-making, and its relationship with individual free will and responsibility, are also described.

The Right Inferior Frontal Gyrus Plays an Important Role in Unconscious Information Processing: Activation Likelihood Estimation Analysis Based on Functional Magnetic Resonance Imaging.

Unconsciousness is a kind of brain activity that occurs below the level of consciousness, and the masked priming paradigm is a classic paradigm to study unconscious perceptual processing. With the deepening of unconscious perception research, different researchers mostly use different experimental materials and different masked priming paradigms in a single experiment but not for the comprehensive analysis of the unconscious information processing mechanism itself. Thus, the purpose of this study is to conduct a comprehensive analysis through a cross-experimental paradigm, cross-experimental materials, and cross-experimental purposes. We used activation likelihood estimation to test functional magnetic resonance imaging studies, involving 361 subjects, 124 foci in eight studies representing direct comparison of unconscious processing with baseline, and 115 foci in 10 studies representing direct comparison of unconscious priming effects. In the comparison of unconscious processing and baseline, clusters formed in the left superior parietal gyrus, the right insular gyrus, and the right inferior frontal gyrus (IFG) triangular part after correcting for familywise error (FWE). In the comparison of priming effects, clusters formed in only the right IFG triangular part after correcting for FWE. Here, we found that ventral and dorsal pathways jointly regulate unconscious perceptual processes, but only the ventral pathway is involved in the regulation of unconscious priming effects. The IFG triangular part is involved in the regulation of unconscious perceptual processing and unconscious priming effects and may be an important brain area in unconscious information processing. These preliminary data provide conditions for further study of the neural correlation of unconscious information processing.

The human visual system differentially represents subjectively and objectively invisible stimuli.

The study of unconscious processing requires a measure of conscious awareness. Awareness measures can be either subjective (based on participant's report) or objective (based on perceptual performance). The preferred awareness measure depends on the theoretical position about consciousness and may influence conclusions about the extent of unconscious processing and about the neural correlates of consciousness. We obtained functional magnetic resonance imaging (fMRI) measurements from 43 subjects while they viewed masked faces and houses that were either subjectively or objectively invisible. Even for objectively invisible (perceptually indiscriminable) stimuli, we found significant category information in both early, lower-level visual areas and in higher-level visual cortex, although representations in anterior, category-selective ventrotemporal areas were less robust. For subjectively invisible stimuli, similar to visible stimuli, there was a clear posterior-to-anterior gradient in visual cortex, with stronger category information in ventrotemporal cortex than in early visual cortex. For objectively invisible stimuli, however, category information remained virtually unchanged from early visual cortex to object- and category-selective visual areas. These results demonstrate that although both objectively and subjectively invisible stimuli are represented in visual cortex, the extent of unconscious information processing is influenced by the measurement approach. Furthermore, our data show that subjective and objective approaches are associated with different neural correlates of consciousness and thus have implications for neural theories of consciousness.

A Neuropsychological Study on Unconscious Information Processing when Receiving Affective and Non-Affective Visual Stimuli

A Neuropsychological Study on Unconscious Information Processing when Receiving Affective and Non-Affective Visual Stimuli

Модуляция вызванных ответов мозга на биологически и социально значимые стимулы у женщин с рекуррентной депрессией

Study Objective: To study characteristic features of brain activity in women with recurrent depression (RD) using the tasks with emotional stimuli possessing biological or social importance. Study Design: Controlled randomized experimental trial. Materials and Methods. There were two groups: 42 patients with RD and 72 healthy women. Patients did not take medications before electroencephalogram (EEG) recording. The task was to differentiate between people and animals at 160 pictures: 80 pictures were neutral, and 80 pictures depicted angry/aggressive people or animals. Simple figures (clues) were demonstrated 2s before pictures, and no association was explained. A 128-channel EEG was recorded, and evoked brain reactions were analysed (0–700 ms from the clue). Differences between neutral and emotional pairs of conditions were determined (emotional modulation, EM). Study Results. Previous results for women with RD obtained in a larger sampling size and with a higher level of significance were confirmed. In healthy patients, EM was noted from 50 ms to 500 ms, whereas in patients with RD – from 130 ms to 700 ms for conditions where the clue was associated with neutral or ominous pictures of people. In clues with animals, EM was normally noted for components N170 and P200, while in patients with RD – for P200. Conclusion. Unconscious EM to socially important stimuli is preserved in RD, but it differs from the norm. Unconscious processing of emotional information associated with a biological threat causes lower component modulation. We observed a displacement of an “inert” EM towards posterior sections of the right hemisphere in women with RD. It can be assumed that such pattern demonstrates typical rigidity, an inclination to “stick” to unpleasant impressions; there are similar to pessimistic rumination. Keywords: emotional modulation, electroencephalogram, recurrent depression, visually evoked potentials.

Motor expertise affects the unconscious processing of geometric forms.

BackgroundThe unconscious processing of information is an important skill used by competitive athletes to handle the rapidly changing movements of opponents and equipment. Previous studies have shown that unconscious information processing among athletes is better than that among non-athletes in the sports-specific domain. However, it is not yet clear whether athletes also show superior unconscious information processing in the general cognitive domain.MethodsTwenty-five competitive table tennis players (athletes) and 26 aged-matched non-athletic college students (non-athlete controls) were recruited for this study. Participants first performed a masked priming task that used geometric shapes as primes and targets to examine unconscious information processing in the general cognitive domain. As a control, participants then completed a prime identification task to determine whether they could consciously detect the priming geometric forms. Reaction times and error rates were analyzed to examine whether motor expertise influenced unconscious information processing in the general domain. Nineteen athletes and 17 non-athletes from our present study, which used general stimuli, also participated in our previous study, which used sport-specific stimuli. The strength of the unconscious response priming effect was analyzed to examine whether the effect of motor expertise on unconscious processing could be transferred from a sports-specific domain to a general domain.ResultsSignal detection analyses indicated that neither athletes nor non-athletes could consciously perceive the priming stimuli. Two-way repeated-measures analyses of variance followed by simple main effects analyses of the masked priming performance, indicating that athletes responded faster and committed fewer errors when the priming stimulus was congruent with the target stimulus. These results suggested that athletes exhibited a significant unconscious response priming effect of geometric forms. By contrast, non-athletes did not respond faster or commit fewer errors for congruent vs. incongruent conditions. No significant difference was detected between athletes and non-athletes in error rates for congruent trials, but athletes committed significantly more errors than non-athletes on incongruent trials. The strength of the unconscious response priming effect that athletes exhibited was greater than that for non-athletes, both in the present study with general stimuli and in our previous study with sport-specific stimuli.ConclusionThe results indicated that motor expertise facilitated the unconscious processing of geometric forms, suggesting that the influence of motor expertise on unconscious information processing occurs not only for the sports-specific domain but also transfers to the general cognitive domain.

SIMPLE REGULARITIES ACQUISITION IN THE STUDIES OF IMPLICIT LEARNING

Background. According to modern empirical data, unconsciously processed information can have a significant impact on human behavior in all spheres of activity. Information about the unconscious information processing is fragmented and often contradictory. For the study of implicit learning different approaches are traditionally used, but none of them are effective for the clear results about the consciousness and abstractness degree of the knowledge obtained. We could more carefully inquire into the matter of unconscious knowledge and its influence on the cognitive problems solving with information about implicit learning of simple rules. This methodology makes it possible to apply more strong criteria for explicit knowledge and assumes purer experimental effects of implicit learning. Objective. To consider and analyze the experience of use experimental techniques with simple regularities acquisition in the studies of implicit learning. Methods. Review and analysis of studies using simple regularities in the field of implicit learning. Results. In the article researches within the experimental paradigms “invariant learning” and “hidden covariation detection” are considered. The most significant experiments, their results and the criticism has led to an improvement of experimental procedures are presented. The problems of using different types of tasks in the training and test stages are described. The main possibilities and limitations of using these paradigms for revealing the effect of implicit learning are outlined. Further perspectives for the application of these techniques are considered. But one needs for a more rigorous approach to measuring the level of awareness. Conclusion. Experimental paradigms with simple regularities acquisition may be promising for the study of implicit association learning mechanisms.

Neuronavigated TMS of early visual cortex eliminates unconscious processing of chromatic stimuli

Some neurological patients with primary visual cortex (V1) lesions can guide their behavior based on stimuli presented to their blind visual field. One example of this phenomenon is the ability to discriminate colors in the absence of awareness. These so-called patients with blindsight must have a neural pathway that bypasses V1, explaining their ability to unconsciously process stimuli. The pathways that have been most often hypothesized to be the cause of blindsight connect lateral geniculate nucleus (LGN) or superior colliculus (SC) to extrastriate cortex, most likely V5, and parietal areas. To test if similar pathways function in neurologically healthy individuals or if unconscious processing depends on early visual cortex, we disturbed the visibility of a chromatic stimulus with metacontrast masking (Experiment 1) or neuronavigated transcranial magnetic stimulation (TMS) of early visual cortex, exact target being retinotopically mapped V1 (Experiment 2). We measured unconscious processing using the redundant target effect (RTE), which is the speeding up of reaction times in response to dual stimuli compared with one stimulus, when the task is to respond to any number of stimuli. An unconscious chromatic RTE was found when the visibility of the redundant chromatic stimulus was suppressed with a visual mask. When TMS was targeted to the correct retinotopic location of V1, and conscious perception of the redundant chromatic stimulus suppressed, the RTE was eliminated. Whether the elimination of unconscious RTE during TMS was exclusively due to disruption of V1 activity, or whether it was due to the possible interference with processing in V2 or even V3, is discussed. Based on our results and converging evidence from previous studies, we conclude that unconscious processing of chromatic information depends on the early visual cortex, in neurologically healthy participants.

Pupillometry and Microsaccade Responses Reveal Unconscious Processing of Face Information Under Interoc-ular Suppression

Interocular suppression happens when a monocular stimulus is suppressed by strong competing masks from the other eye. Typically, researchers measure stimuli detection from interocular suppression or aftereffects of suppressed stimuli (e.g., priming and cueing) to reveal the visual processing outside of visual awareness. However, these psychophysical measurements only reveal the end-product of unconscious processing, not the temporal dynamics. In this work, we tested whether pupillary responses and microsaccades could be reliable indicators for revealing the dynamical unconscious processing of visual information. To demonstrate unconscious visual processing, we presented upright and inverted faces under interocular suppression, and participants were asked to press a response key as soon as they detected any part of the face. Meanwhile, their pupillary responses and eye movements were recorded by an infrared eye camera. The detection times showed the typical face inversion effect—upright faces were detected faster than inverted ones. Critically, upright faces evoked stronger pupil constriction than inverted ones roughly one second prior to the behavioral detection. On the other hand, while the microsaccade rate was similar for the upright and inverted faces, it generally decreased 500-ms before face detection. On top of these observations, we speculate that pupil constriction may be associated with a gradual unconscious accumulation of face information, presumably reflecting deeper memory processing and/or emotional arousal. In contrast, the microsaccade rate may reflect a general cognitive effort and/or decision-making process before awareness access, regardless of the content of the visual information. These pupillometry and microsaccade rate measurements represent a methodological improvement for revealing dynamical unconscious processing under interocular suppression.

A Novel Framework for Unconscious Processing

Understanding the distinction between conscious and unconscious cognition remains a priority in psychology and neuroscience. A comprehensive neurocognitive account of conscious awareness will not be possible without a sound framework to isolate and understand unconscious information processing. Here, we provide a brain-based framework that allows the identification of unconscious processes, even with null effects on behaviour.

Unconscious processing of coarse visual information during anticipatory threat.

Rapid detection of threats has been proposed to rely on automatic processing of their coarse visual features. However, it remains unclear whether such a mechanism is restricted to detection of threat cues, or whether it reflects a broader sensitivity to even neutral coarse visual information features during states of threat. We used a backward masking task in which participants discriminated the orientation of subliminally presented low (3 cpd) and high (6 cpd) spatial frequency gratings, under threat (of shock) and safe conditions. Visual awareness of the gratings was assessed objectively using an additional localization task. When participants were unaware of the gratings, above chance and improved discrimination of low-spatial frequency gratings was observed under threat compared to safe trials. These findings demonstrate unconscious processing of neutral coarse visual information during threat state, supporting the view that automatic threat detection may rely on a general facilitation of coarse features irrespective of threat content.

Motor expertise modulates unconscious rather than conscious executive control.

BackgroundExecutive control, the ability to regulate the execution of a goal-directed task, is an important element in an athlete’s skill set. Although previous studies have shown that executive control in athletes is better than that in non-athletes, those studies were mainly confined to conscious executive control. Many recent studies have suggested that executive control can be triggered by the presentation of visual stimuli without participant’s conscious awareness. However, few studies have examined unconscious executive control in sports. Thus, the present study investigated whether, similar to conscious executive control, unconscious executive control in table tennis athletes is superior to that in non-athletes.MethodsIn total, 42 age-matched undergraduate students were recruited for this study; 22 nonathletic students lacking practical athletic experience comprised one group, and 20 table tennis athletes with many years of training in this sport comprised a second group. Each participant first completed an unconscious response priming task, the unconscious processing of visual-spatial information, and then completed a conscious version of this same response priming task.ResultsTable tennis athletes showed a significant response priming effect, whereas non-athletes did not, when participants were unable to consciously perceive the visual-spatial priming stimuli. In addition, the number of years the table tennis athletes had trained in this sport (a measure of their motor expertise) was positively correlated with the strength of the unconscious response priming effect. However, both table tennis athletes and non-athletes showed a response priming effect when the primes were unmasked and the participants were able to consciously perceive the visual-spatial priming stimuli.ConclusionOur results suggest that motor expertise modulates unconscious, rather than conscious, executive control and that motor expertise is positively correlated with unconscious executive control in table tennis athletes.

Conscious Perception: Time for an Update?

Understanding the neural mechanisms underlying conscious perception has become a central endeavor in cognitive neuroscience. In theories of conscious perception, a stimulus gaining conscious access is usually considered as a discrete neuronal event to be characterized in time or space, sometimes referred to as a conscious "episode." Surprisingly, the alternative hypothesis according to which conscious perception is a dynamic process has rarely been considered. Here, we discuss this hypothesis and its implications. We show how it can reconcile inconsistent empirical findings on the timing of the neural correlates of consciousness and make testable predictions. According to this hypothesis, a stimulus is consciously perceived for as long as it is recoded to fit an ongoing stream composed of all other perceived stimuli. We suggest that this "updating" process is governed by at least three factors (1) context, (2) stimulus saliency, and (3) observers' goals. Finally, this framework forces us to reconsider the typical distinction between conscious and unconscious information processing.

Digital visualization of the activity of neural networks of the human brain before, during, and after insight when images are being recognized

Technological resources have made it possible to begin experimental study of the activity of neural networks both in the conscious, systematic, analytic method of solving problems, and in sudden, abrupt enlightenment or insight. The purpose of this paper is to study the reconstruction of neural networks when they go from unconscious information processing to the conscious processes that accompany insight. Methods for digitally synthesizing tests (dynamic images) and methods for digitally analyzing images of brain responses can be used to establish the laws that govern the reconstruction of the activity of large-scale neural networks of the human brain at the instant of insight. The activity of large-scale neural networks reaches its maximum at the moment of insight, corresponding to the recognition threshold or the solution of a problem and is less under below-threshold and above-threshold conditions at which dynamic images are observed. The BOLD (blood-oxygen-level-dependent) value is initially maximized when the threshold is reached in some zones and the maximum falloff of the activity of the neural networks is reached in other zones of the brain.

Editorial: Sub- and Unconscious Information Processing in the Human Brain

This Special Issue about sub- and unconscious information processing in the human brain finally became a collection of 6 accepted contributions, 2 articles, 2 reviews, 1 opinion and 1 concept paper. Even though more papers were submitted this rather small number of accepted contributions mirrors the still existing lack of focus on non-conscious human brain processes that surely influence human behavior to a much larger extent than one would ever imagine. Our brains contain evolutionary old neural structures that much more primitive organisms have in their brains too and crucially those old structures have more or the less the same functional properties regardless of what brain they belong to. Consciousness as an individual experience is a rather young evolutionary product, which means that those older structures that are strongly involved in the generation of human behavior work largely without being associated with conscious experience. This explains why people not always do what they say. In other words, the brain knows more than it admits to consciousness and since we have more and more access to that knowledge we should be interested in gaining it. The evidence grows that demonstrates how non-conscious processing occurs and influences our decision making.

Heart rate variability response to affective pictures processed in and outside of conscious awareness: Three consecutive studies on emotional regulation

Previous research has increased understanding of the neurobiological basis of emotional regulation. However, less is known concerning the unconscious processing of affective information. Three experiments were performed to investigate the extent to which complex affective stimuli can be processed outside of consciousness and demonstrate possible mechanisms for regulation of resulting emotional responses. In Experiment 1, participants were either instructed to passively observe blocked-picture cues (neutral and negative) or to downregulate their emotions by distancing. Resulting emotional regulation activity was assessed with 0.1-Hz heart rate variability (HRV) indices. In Experiment 2, participants were presented with affective pictures that were rendered consciously invisible by means of continuous flash suppression (CFS). In Experiment 3, two equivalent sets of negative affective pictures were covertly presented and the effect of a cognitive task on emotional regulation was evaluated. Our findings revealed that 0.1-Hz HRV indices exhibited greater change over baseline in response to negative compared to neutral stimuli for both presentation conditions (consciously perceived or not). The implementation of distancing and the cognitive task were both associated with higher 0.1-Hz HRV change scores. These results indicate that even complex affective stimuli can be processed without awareness, resulting in a congruent emotional response that is physiologically detectable. Cognitive strategies can help more effectively regulate this response, implying that conscious perception of a triggering stimulus may not be essential for cognitive regulation.

Unconscious decisional learning improves unconscious information processing

The idea that unconscious input can result in long-term learning or task improvement has been debated for decades, yet there is still little evidence to suggest that learning outside of awareness can produce meaningful changes to decision-making. Here we trained participants using noisy motion stimuli, which require the gradual accumulation of information until a decision can be reached. These stimuli were suppressed from conscious awareness by simultaneously presenting a dynamic dichoptic mask. We show that a short period of training on either a partially or fully suppressed motion stimulus resulted in improved accuracy when tested on a partially suppressed motion stimulus traveling in the orthogonal direction. We found this improvement occurred even when performance on the training task was at chance. Performance gains generalized across motion directions, suggesting that the improvement was the result of changes to the decisional mechanisms rather than perceptual. Interestingly, unconscious learning had a stronger effect on unconscious, compared to conscious decisional accumulation. We further show that a conscious coherent percept is necessary to reap the benefits of unconscious learning. Together, these data suggest that unconscious decisional processing can be improved via training.

Can Contrast-Response Functions Indicate Visual Processing Levels?

Many visual effects are believed to be processed at several functional and anatomical levels of cortical processing. Determining if and how the levels contribute differentially to these effects is a leading problem in visual perception and visual neuroscience. We review and analyze a combination of extant psychophysical findings in the context of neurophysiological and brain-imaging results. Specifically using findings relating to visual illusions, crowding, and masking as exemplary cases, we develop a theoretical rationale for showing how relative levels of cortical processing contributing to these effects can already be deduced from the psychophysically determined functions relating respectively the illusory, crowding and masking strengths to the contrast of the illusion inducers, of the flankers producing the crowding, and of the mask. The wider implications of this rationale show how it can help to settle or clarify theoretical and interpretive inconsistencies and how it can further psychophysical, brain-recording and brain-imaging research geared to explore the relative functional and cortical levels at which conscious and unconscious processing of visual information occur. Our approach also allows us to make some specific predictions for future studies, whose results will provide empirical tests of its validity.

The role of unconscious information processing in the acquisition and learning of instructional messages

This review investigates how the unconscious information processing can create satisfactory learning outcomes, and can be used to ameliorate the challenges of teaching students to regulate their learning processes. The search for the ideal model of human information processing as regards achievement of teaching and learning objectives is a recurring issue in educational studies. Although conscious processes are more conducive to the objectives than unconscious processes, they do not necessarily result in satisfactory learning of instructional messages. Studies reviewed here show that the unconscious can play a facilitatory role in the encoding, storage, retrieval processes of information and learning activities, even when the conscious fails to achieve this. To take advantages of both conscious and unconscious processes, relevant literature suggests educators utilizing visual teaching aids that optimize use of working memory capacity and allow students to form mental imageries, thereby facilitating the comprehension of instructional messages.