Multisensory constraints on awareness

Given that multiple senses are often stimulated at the same time, perceptual awareness is most likely to take place in multisensory situations. However, theories of awareness are based on studies and models established for a single sense (mostly vision). Here, we consider the methodological and theoretical challenges raised by taking a multisensory perspective on perceptual awareness. First, we consider how well tasks designed to study unisensory awareness perform when used in multisensory settings, stressing that studies using binocular rivalry, bistable figure perception, continuous flash suppression, the attentional blink, repetition blindness and backward masking can demonstrate multisensory influences on unisensory awareness, but fall short of tackling multisensory awareness directly. Studies interested in the latter phenomenon rely on a method of subjective contrast and can, at best, delineate conditions under which individuals report experiencing a multisensory object or two unisensory objects. As there is not a perfect match between these conditions and those in which multisensory integration and binding occur, the link between awareness and binding advocated for visual information processing needs to be revised for multisensory cases. These challenges point at the need to question the very idea of multisensory awareness.     

Blinded by the load: attention,awareness and the role of perceptual load

What is the relationship between attention and conscious awareness? Awareness sometimes appears to be restricted to the contents of focused attention, yet at other times irrelevant distractors will dominate awareness. This contradictory relationship has also been reflected in an abundance of discrepant research findings leading to an enduring controversy in cognitive psychology. Lavie''s load theory of attention suggests that the puzzle can be solved by considering the role of perceptual load. Although distractors will intrude upon awareness in conditions of low load, awareness will be restricted to the content of focused attention when the attended information involves high perceptual load. Here, we review recent evidence for this proposal with an emphasis on the various subjective blindness phenomena, and their neural correlates, induced by conditions of high perceptual load. We also present novel findings that clarify the role of attention in the response to stimulus contrast. Overall, this article demonstrates a critical role for perceptual load across the spectrum of perceptual processes leading to awareness, from the very early sensory responses related to contrast detection to explicit recognition of semantic content.     

The interplay of attention and consciousness in visual search,attentional blink and working memory consolidation

Despite the acknowledged relationship between consciousness and attention, theories of the two have mostly been developed separately. Moreover, these theories have independently attempted to explain phenomena in which both are likely to interact, such as the attentional blink (AB) and working memory (WM) consolidation. Here, we make an effort to bridge the gap between, on the one hand, a theory of consciousness based on the notion of global workspace (GW) and, on the other, a synthesis of theories of visual attention. We offer a theory of attention and consciousness (TAC) that provides a unified neurocognitive account of several phenomena associated with visual search, AB and WM consolidation. TAC assumes multiple processing stages between early visual representation and conscious access, and extends the dynamics of the global neuronal workspace model to a visual attentional workspace (VAW). The VAW is controlled by executive routers, higher-order representations of executive operations in the GW, without the need for explicit saliency or priority maps. TAC leads to newly proposed mechanisms for illusory conjunctions, AB, inattentional blindness and WM capacity, and suggests neural correlates of phenomenal consciousness. Finally, the theory reconciles the all-or-none and graded perspectives on conscious representation.     

Neural correlates of the contents of visual awareness in humans

The immediacy and directness of our subjective visual experience belies the complexity of the neural mechanisms involved, which remain incompletely understood. This review focuses on how the subjective contents of human visual awareness are encoded in neural activity. Empirical evidence to date suggests that no single brain area is both necessary and sufficient for consciousness. Instead, necessary and sufficient conditions appear to involve both activation of a distributed representation of the visual scene in primary visual cortex and ventral visual areas, plus parietal and frontal activity. The key empirical focus is now on characterizing qualitative differences in the type of neural activity in these areas underlying conscious and unconscious processing. To this end, recent progress in developing novel approaches to accurately decoding the contents of consciousness from brief samples of neural activity show great promise.     

The neural subjective frame: from bodily signals to perceptual consciousness

The report ‘I saw the stimulus’ operationally defines visual consciousness, but where does the ‘I’ come from? To account for the subjective dimension of perceptual experience, we introduce the concept of the neural subjective frame. The neural subjective frame would be based on the constantly updated neural maps of the internal state of the body and constitute a neural referential from which first person experience can be created. We propose to root the neural subjective frame in the neural representation of visceral information which is transmitted through multiple anatomical pathways to a number of target sites, including posterior insula, ventral anterior cingulate cortex, amygdala and somatosensory cortex. We review existing experimental evidence showing that the processing of external stimuli can interact with visceral function. The neural subjective frame is a low-level building block of subjective experience which is not explicitly experienced by itself which is necessary but not sufficient for perceptual experience. It could also underlie other types of subjective experiences such as self-consciousness and emotional feelings. Because the neural subjective frame is tightly linked to homeostatic regulations involved in vigilance, it could also make a link between state and content consciousness.     

The graded and dichotomous nature of visual awareness

Is our visual experience of the world graded or dichotomous? Opposite pre-theoretical intuitions apply in different cases. For instance, when looking at a scene, one has a distinct sense that our experience has a graded character: one cannot say that there is no experience of contents that fall outside the focus of attention, but one cannot say that there is full awareness of such contents either. By contrast, when performing a visual detection task, our sense of having perceived the stimulus or not exhibits a more dichotomous character. Such issues have recently been the object of intense debate because different theoretical frameworks make different predictions about the graded versus dichotomous character of consciousness. Here, we review both relevant empirical findings as well as the associated theories (i.e. local recurrent processing versus global neural workspace theory). Next, we attempt to reconcile such contradictory theories by suggesting that level of processing is an often-ignored but highly relevant dimension through which we can cast a novel look at existing empirical findings. Thus, using a range of different stimuli, tasks and subjective scales, we show that processing low-level, non-semantic content results in graded visual experience, whereas processing high-level semantic content is experienced in a more dichotomous manner. We close by comparing our perspective with existing proposals, focusing in particular on the partial awareness hypothesis.     

Selective prefrontal cortex responses to joint attention in early infancy

The process by which two people share attention towards the same object or event is called joint attention. Joint attention and the underlying triadic representations between self, other person and object are thought to be unique to humans, supporting teaching, cooperation and language learning. Despite the progress that has been made in understanding the behavioural importance of joint attention during early social development, almost nothing is known about the brain substrate that supports joint attention in the developing infant. We examined responses in five-month-old infants'' prefrontal cortex during triadic social interactions using near-infrared spectroscopy. The results demonstrate that, even by the age of five months, infants are sensitive to triadic interactions and, like adults, they recruit a specific brain region localized in left dorsal prefrontal cortex when engaged in joint attention with another person. This suggests that the human infant is neurobiologically prepared for sharing attention with other humans, which may provide the basis for a wide variety of uniquely human social and cultural learning processes.     

Selective visual processing across competition episodes: a theory of task-driven visual attention and working memory

The goal of this review is to introduce a theory of task-driven visual attention and working memory (TRAM). Based on a specific biased competition model, the ‘theory of visual attention’ (TVA) and its neural interpretation (NTVA), TRAM introduces the following assumption. First, selective visual processing over time is structured in competition episodes. Within an episode, that is, during its first two phases, a limited number of proto-objects are competitively encoded—modulated by the current task—in activation-based visual working memory (VWM). In processing phase 3, relevant VWM objects are transferred via a short-term consolidation into passive VWM. Second, each time attentional priorities change (e.g. after an eye movement), a new competition episode is initiated. Third, if a phase 3 VWM process (e.g. short-term consolidation) is not finished, whereas a new episode is called, a protective maintenance process allows its completion. After a VWM object change, its protective maintenance process is followed by an encapsulation of the VWM object causing attentional resource costs in trailing competition episodes. Viewed from this perspective, a new explanation of key findings of the attentional blink will be offered. Finally, a new suggestion will be made as to how VWM items might interact with visual search processes.     

When more equals less: overtraining inhibits perceptual learning owing to lack of wakeful consolidation

Performance on perceptual tasks usually improves with training. However, too much consecutive training can be detrimental. Repeated within-day testing or overtraining demonstrates the detrimental effects this has on perceptual learning. Consolidation of learnt information during sleep has the power to prevent such deficits in learning. However, little is known regarding the role of wakeful consolidation in preventing the effects of overtraining. Here, we report that perceptual deterioration may result from the disruption of early wakeful consolidation processes. Three groups were tested on day 1 and again 24 h later, on a motion discrimination task. Participants who had a 1 h break between the two training sessions on the first day displayed improved accuracy on the second day (i.e. learning). Subjects who only completed the first training session on day 1 also exhibited learning. However, individuals who completed two blocks without a break ('overtraining') showed no improvement in accuracy on day 2. Interestingly, changes in reaction times were not susceptible to the effects of overtraining, but instead speeded up as a function of total performed trials. These data suggest that effects of overtraining might be due to disruption of wakeful consolidation processes.     

Learning to count begins in infancy: evidence from 18 month olds' visual preferences

We used a preferential looking paradigm to evaluate infants' preferences for correct versus incorrect counting. Infants viewed a video depicting six fish. In the correct counting sequence, a hand pointed to each fish in turn, accompanied by verbal counting up to six. In the incorrect counting sequence, the hand moved between two of the six fish while there was still verbal counting to six, thereby violating the one-to-one correspondence principle of correct counting. Experiment 1 showed that Australian 18 month olds, but not 15 month olds, significantly preferred to watch the correct counting sequence. In experiment 2, Australian infants' preference for correct counting disappeared when the count words were replaced by beeps or by Japanese count words. In experiment 3, Japanese 18 month olds significantly preferred the correct counting video only when counting was in Japanese. These results show that infants start to acquire the abstract principles governing correct counting prior to producing any counting behaviour.     

The relationship between visual working memory and attention: retention of precise colour information in the absence of effects on perceptual selection

We examined the conditions under which a feature value in visual working memory (VWM) recruits visual attention to matching stimuli. Previous work has suggested that VWM supports two qualitatively different states of representation: an active state that interacts with perceptual selection and a passive (or accessory) state that does not. An alternative hypothesis is that VWM supports a single form of representation, with the precision of feature memory controlling whether or not the representation interacts with perceptual selection. The results of three experiments supported the dual-state hypothesis. We established conditions under which participants retained a relatively precise representation of a parcticular colour. If the colour was immediately task relevant, it reliably recruited attention to matching stimuli. However, if the colour was not immediately task relevant, it failed to interact with perceptual selection. Feature maintenance in VWM is not necessarily equivalent with feature-based attentional selection.     

Real-time modulation of perceptual eye dominance in humans

Ocular dominance (OD) has long served as the model for neural plasticity. The shift of OD has been demonstrated by monocular deprivation in animals only during early visual development. Here, for the first time, we show that perceptual eye dominance can be modulated in real time in normal human adults by varying the spatial image content of movies seen dichoptically by the two eyes over a period as short as 2.5 h. Unlike OD shifts seen in early visual development, this modulation in human eye dominance is not simply a consequence of reduced interocular correlation (e.g. synchronicity) or overall contrast energy, but due to the amplitude reductions of specific image components in one eye''s view. The spatial properties driving this eye dominance change suggest that the underlying mechanism is binocular but not orientationally selective, therefore uniquely locating it to layer 4 B of area V1.     

Avian migrants adjust migration in response to environmental conditions en route

The onset of migration in birds is assumed to be primarily under endogenous control in long-distance migrants. Recently, climate changes appear to have been driving a rapid change in breeding area arrival. However, little is known about the climatic factors affecting migratory birds during the migration cycle, or whether recently reported phenological changes are caused by plastic behavioural responses or evolutionary change. Here, we investigate how environmental conditions in the wintering areas as well as en route towards breeding areas affect timing of migration. Using data from 1984 to 2004 covering the entire migration period every year from observatories located in the Middle East and northern Europe, we show that passage of the Sahara Desert is delayed and correlated with improved conditions in the wintering areas. By contrast, migrants travel more rapidly through Europe, and adjust their breeding area arrival time in response to improved environmental conditions en route. Previous studies have reported opposing results from a different migration route through the Mediterranean region (Italy). We argue that the simplest explanation for different phenological patterns at different latitudes and between migratory routes appears to be phenotypic responses to spatial variability in conditions en route.     

The importance of subjectivity in perceptual errors on the emergence of indirect reciprocity

Indirect reciprocity is one mechanism that allows for unilateral resource giving among n-persons. Using analytical methods and computer simulations, previous studies have examined a number of strategies that make indirect reciprocity possible. In particular, previous investigations have concentrated on whether differentiating between justified and unjustified not-giving is important. However, whether or not a given strategy is ESS depends on the type of perceptual errors that are assumed. When errors are objective, regarding those who do not give to "bad" as "good" is critical. When perceptual errors are subjective, however, regarding those who give to "bad" as "bad" is critical. Since we believe that there is no guarantee that perceptual errors are shared among all individuals in a society, we argue that the latter moral principle may play a more important role in human interactions.     

Public and healthcare providers awareness of Coronavirus (COVID-19) in Qassim Region,Saudi Arabia

BackgroundThe rapid and extensive spread of the COVID-19 pandemic has become a major cause of concern for both general public and healthcare profession.ObjectiveThe aim of this study is to analyze and evaluate the awareness of both the general public and healthcare providers in Qassim region in Saudi Arabia.MethodA cross-sectional study was conducted randomly in different shopping malls in Qassim region from 10th of February to 10th of March 2020. All participants have answered the designed questionnaire. The structured questionnaire recorded demographics and awareness of both public participants as well as health care providers.ResultA total of 130 participants have answered the designed questionnaire, out of which 67participants were males (58.5%) and 54 were females (41.5%). Overall, 129 (99%) out of the 130 participants are aware of COVID-19, and 116 (90%) have recognize it as a respiratory disease and 100% of the participants have recognized it as a contagious disease. Around 94% of the participants were able to recognize the correct incubation period of the virus. Participants of the age group 20–40 showed higher awareness level than other age groups (P value = 0.005). In addition, government employees showed higher awareness level than other profession groups (P = 0.039). Results showed significant positive correlation between the recognition of high-risk groups, reliable source of information, infection symptoms, disease prevention and available treatments.ConclusionGeneral public and health care professionals from Qassim Region showed adequate awareness of COVID-19. However, there is a strong need to implement periodic educational interventions and training programs on infection control practices for COVID-19 across all healthcare professions.     

Evolution of structure and information processing in the nervous system: Part IV of a general theory

Starting from fundamental principles, evolution of the nervous system is modelled as a random walk process in a multidimensional representation space (the F-space). This space is not flat, it is highly structured in terms of step probability. Fundamental considerations of evolutionary speed, efficiency of information processing, and priorities lead to specific theoretical predictions of the most probable pathways of evolution of the nervous system and its mechanisms of information processing. These processes are represented as vector paths (F-paths) in the F-space. Cognition becomes a process of correlations of the input signal to information stored in memories. Higher level brain processes involve extrapolation and interpolation along F-paths, input data reduction by clearly specifiable abstraction methods, and a unique process using abstracted analogs. These processes define and limit what the brain does and how it can do it. These considerations lead to certain inevitable conclusions (consequences of the fundamental principles) for the basis of our logical reasoning, decision-making, the process of dreaming (conscious and sleep), and explicit definitions of consciousness, unconsciousness, and personality. Detailed applications of this theory for analyzing empirical findings are suggested in the final paragraphs.     

辽宁省重化工业地区公众的环境意识调查与评价

公众环境意识对国家环境保护政策的制定与实施具有重要影响.辽宁省中部重化工业区公众环境意识水平的调查对象为5个城市的居民、决策者、教师、学生、企业职工与农民,主要调查内容包括公众对环境质量变化的评价、对所居住社区环境的满意程度、公众关注的环境问题、环境污染类型、环境污染和生态破坏的原因、造成地区环境质量差异的原因、对环境保护的认知程度及国家未来的发展目标等.调查表明,78.7%的公众认为环境质量同5年前相比明显好转;但65.3%的公众认为居住社区环境一般,公众对于环保经费的使用排序为垃圾处理＞植树造林＞建污水处理厂＞改善空气质量.总体来看,多数公众缺乏必要的环境保护知识,对水体、食品污染的严重性普遍认识不足;居民环保意识差对环境质量改善具有明显制约作用;公众对环境意识宣传具有很强要求.本调查结果可为研究辽宁地区的环境保护、生态建设、经济可持续发展和政府部门制定各种环保政策法规提供依据.