Sensorimotor contingency modulates breakthrough of virtual 3D objects during a breaking continuous flash suppression paradigm

Taking consciousness for real: Increasing the ecological validity of the study of conscious vs. unconscious processes

The study of consciousness has developed well-controlled, rigorous methods for manipulating and measuring consciousness. Yet, in the process, experimental paradigms grew farther away from everyday conscious and unconscious processes, which raises the concern of ecological validity. In this review, we suggest that the field can benefit from adopting a more ecological approach, akin to other fields of cognitive science. There, this approach challenged some existing hypotheses, yielded stronger effects, and enabled new research questions. We argue that such a move is critical for studying consciousness, where experimental paradigms tend to be artificial and small effect sizes are relatively prevalent. We identify three paths for doing so-changing the stimuli and experimental settings, changing the measures, and changing the research questions themselves-and review works that have already started implementing such approaches. While acknowledging the inherent challenges, we call for increasing ecological validity in consciousness studies.

Hybrid Life: Integrating biological, artificial, and cognitive systems

Artificial life is a research field studying what processes and properties define life, based on a multidisciplinary approach spanning the physical, natural, and computational sciences. Artificial life aims to foster a comprehensive study of life beyond "life as we know it" and toward "life as it could be," with theoretical, synthetic, and empirical models of the fundamental properties of living systems. While still a relatively young field, artificial life has flourished as an environment for researchers with different backgrounds, welcoming ideas, and contributions from a wide range of subjects. Hybrid Life brings our attention to some of the most recent developments within the artificial life community, rooted in more traditional artificial life studies but looking at new challenges emerging from interactions with other fields. Hybrid Life aims to cover studies that can lead to an understanding, from first principles, of what systems are and how biological and artificial systems can interact and integrate to form new kinds of hybrid (living) systems, individuals, and societies. To do so, it focuses on three complementary perspectives: theories of systems and agents, hybrid augmentation, and hybrid interaction. Theories of systems and agents are used to define systems, how they differ (e.g., biological or artificial, autonomous, or nonautonomous), and how multiple systems relate in order to form new hybrid systems. Hybrid augmentation focuses on implementations of systems so tightly connected that they act as a single, integrated one. Hybrid interaction is centered around interactions within a heterogeneous group of distinct living and nonliving systems. After discussing some of the major sources of inspiration for these themes, we will focus on an overview of the works that appeared in Hybrid Life special sessions, hosted by the annual Artificial Life Conference between 2018 and 2022. This article is categorized under: Neuroscience > Cognition Philosophy > Artificial Intelligence Computer Science and Robotics > Robotics.

A nasal visual field advantage in interocular competition

When our eyes are confronted with discrepant images (yielding incompatible retinal inputs) interocular competition (IOC) is instigated. During IOC, one image temporarily dominates perception, while the other is suppressed. Many factors affecting IOC have been extensively examined. One factor that received surprisingly little attention, however, is the stimulus’ visual hemifield (VHF) of origin. This is remarkable, as the VHF location of stimuli is known to affect visual performance in various contexts. Prompted by exploratory analyses, we examined five independent datasets of breaking continuous flash suppression experiments, to establish the VHF’s role in IOC. We found that targets presented in nasal VHF locations broke through suppression much faster than targets in temporal VHF locations. Furthermore, we found that the magnitude of this nasal advantage depended on how strongly the targets were suppressed: the nasal advantage was larger for the recessive eye than for the dominant eye, and was larger in observers with a greater dominance imbalance between the eyes. Our findings suggest that the nasal advantage reported here originates in processing stages where IOC is resolved. Finally, we propose that a nasal advantage in IOC serves an adaptive role in human vision, as it can aid perception of partially occluded objects.

Representational 'touch' and modulatory 'retouch'-two necessary neurobiological processes in thalamocortical interaction for conscious experience

Theories of consciousness using neurobiological data or being influenced by these data have been focused either on states of consciousness or contents of consciousness. These theories have occasionally used evidence from psychophysical phenomena where conscious experience is a dependent experimental variable. However, systematic catalog of many such relevant phenomena has not been offered in terms of these theories. In the perceptual retouch theory of thalamocortical interaction, recently developed to become a blend with the dendritic integration theory, consciousness states and contents of consciousness are explained by the same mechanism. This general-purpose mechanism has modulation of the cortical layer-5 pyramidal neurons that represent contents of consciousness as its core. As a surplus, many experimental psychophysical phenomena of conscious perception can be explained by the workings of this mechanism. Historical origins and current views inherent in this theory are presented and reviewed.

Graspability Modulates the Stronger Neural Signature of Motor Preparation for Real Objects vs. Pictures

The cognitive and neural bases of visual perception are typically studied using pictures rather than real-world stimuli. Unlike pictures, real objects are actionable solids that can be manipulated with the hands. Recent evidence from human brain imaging suggests that neural responses to real objects differ from responses to pictures; however, little is known about the neural mechanisms that drive these differences. Here, we tested whether brain responses to real objects versus pictures are differentially modulated by the "in-the-moment" graspability of the stimulus. In human dorsal cortex, electroencephalographic responses show a "real object advantage" in the strength and duration of mu (μ) and low beta (β) rhythm desynchronization-well-known neural signatures of visuomotor action planning. We compared desynchronization for real tools versus closely matched pictures of the same objects, when the stimuli were positioned unoccluded versus behind a large transparent barrier that prevented immediate access to the stimuli. We found that, without the barrier in place, real objects elicited stronger μ and β desynchronization compared to pictures, both during stimulus presentation and after stimulus offset, replicating previous findings. Critically, however, with the barrier in place, this real object advantage was attenuated during the period of stimulus presentation, whereas the amplification in later periods remained. These results suggest that the "real object advantage" is driven initially by immediate actionability, whereas later differences perhaps reflect other, more inherent properties of real objects. The findings showcase how the use of richer multidimensional stimuli can provide a more complete and ecologically valid understanding of object vision.

Dimensions of Perception: 3D Real-Life Objects Are More Readily Detected Than Their 2D Images

Most of our interactions with our environment involve manipulating real 3D objects. Accordingly, 3D objects seem to enjoy preferential processing compared with 2D images, for example, in capturing attention or being better remembered. But are they also more readily perceived? Thus far, the possibility of preferred detection for real 3D objects could not be empirically tested because suppression from awareness has been applied only to on-screen stimuli. Here, using a variant of continuous flash suppression (CFS) with augmented-reality goggles ("real-life" CFS), we managed to suppress both real 3D objects and their 2D representations. In 20 healthy young adults, real objects broke suppression faster than their photographs. Using 3D printing, we also showed in 50 healthy young adults that this finding held only for meaningful objects, whereas no difference was found for meaningless, novel ones (a similar trend was observed in another experiment with 20 subjects, yet it did not reach significance). This suggests that the effect might be mediated by affordances facilitating detection of 3D objects under interocular suppression.

Perceptual Awareness of Optic Flows Paced Optimally and Non-optimally to Walking Speed

Previous research suggests that visual processing depends strongly on locomotor activity and is tuned to optic flows consistent with self-motion speed. Here, we used a binocular rivalry paradigm to investigate whether perceptual access to optic flows depends on their optimality in relation to walking velocity. Participants walked at two different speeds on a treadmill while viewing discrepant visualizations of a virtual tunnel in each eye. We hypothesized that visualizations paced appropriately to the walking speeds will be perceived longer than non optimal (too fast/slow) ones. The presented optic flow speeds were predetermined individually in a task based on matching visual speed to both walking velocities. In addition, perceptual preference for optimal optic flows was expected to increase with proprioceptive ability to detect threshold-level changes in walking speed. Whereas faster (more familiar) optic flows showed enhanced access to awareness during faster compared with slower walking conditions, for slower visual flows, only a nonsignificant tendency for the analogous effect was observed. These effects were not dependent on individual proprioceptive sensitivity. Our findings concur with the emerging view that the velocity of one's locomotion is used to calibrate visual perception of self-motion and extend the scope of reported action effects on visual awareness.

What Is Consciousness? Integrated Information vs. Inference

Any successful naturalistic account of consciousness must state what consciousness is, in terms that are compatible with the rest of our naturalistic descriptions of the world. Integrated Information Theory represents a pioneering attempt to do just this. This theory accounts for the core features of consciousness by holding that there is an equivalence between the phenomenal experience associated with a system and its intrinsic causal power. The proposal, however, fails to provide insight into the qualitative character of consciousness and, as a result of its proposed equivalence between consciousness and purely internal dynamics, into the intentional character of conscious perception. In recent years, an alternate group of theories has been proposed that claims consciousness to be equivalent to certain forms of inference. One such theory is the Living Mirror theory, which holds consciousness to be a form of inference performed by all living systems. The proposal of consciousness as inference overcomes the shortcomings of Integrated Information Theory, particularly in the case of conscious perception. A synthesis of these two perspectives can be reached by appreciating that conscious living systems are self-organising in nature. This mode of organization requires them to have a high level of integration. From this perspective, we can understand consciousness as being dependent on a system possessing non-trivial amounts of integrated information while holding that the process of inference performed by the system is the fact of consciousness itself.

Forward optic flow is prioritised in visual awareness independently of walking direction

When two different images are presented separately to each eye, one experiences smooth transitions between them-a phenomenon called binocular rivalry. Previous studies have shown that exposure to signals from other senses can enhance the access of stimulation-congruent images to conscious perception. However, despite our ability to infer perceptual consequences from bodily movements, evidence that action can have an analogous influence on visual awareness is scarce and mainly limited to hand movements. Here, we investigated whether one's direction of locomotion affects perceptual access to optic flow patterns during binocular rivalry. Participants walked forwards and backwards on a treadmill while viewing highly-realistic visualisations of self-motion in a virtual environment. We hypothesised that visualisations congruent with walking direction would predominate in visual awareness over incongruent ones, and that this effect would increase with the precision of one's active proprioception. These predictions were not confirmed: optic flow consistent with forward locomotion was prioritised in visual awareness independently of walking direction and proprioceptive abilities. Our findings suggest the limited role of kinaesthetic-proprioceptive information in disambiguating visually perceived direction of self-motion and indicate that vision might be tuned to the (expanding) optic flow patterns prevalent in everyday life.

Sensorimotor predictions shape reported conscious visual experience in a breaking continuous flash suppression task

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.