Unconscious vision spots the animal but not the dog: Masked priming of natural scenes

The functional role of consciousness has been traditionally assumed to be related to high-level executive functions, but recent theories of visual consciousness suggest qualitative differences between conscious and unconscious processes also in lower level visual processes. We tested how specific is the information that can be extracted by unconscious processes from natural scenes. Prime images which were suppressed from consciousness by continuous flash suppression facilitated categorization of visible targets at superordinate level (animal vs. non-animal) when the prime shared a category membership with the target. Suppressed prime images did not have any effect on categorization at the basic level (e.g., horse vs. other animal). Priming occurred at basic level categorization only when the prime images were available to consciousness. This pattern supports a “coarse-to-fine” model in which the visual system can unconsciously access coarse representations, but consciousness is needed for finer analysis of visual scenes.     

Vision and abstraction: an empirical refutation of Nico Orlandi’s non-cognitivism

This article argues against the non-cognitivist theory of vision that has been formulated in the work of Nico Orlandi. It shows that, if we understand ‘representation’ in the way Orlandi recommends, then the visual system’s response to abstract regularities must involve the formation of representations. Recent experiments show that those representations must be used by the visual system in the production of visual experiences. Their effects cannot be explained by taking them to be non-visual effects involving attention or memory. This contradicts Orlandi’s version of the non-cognitivist hypothesis, but does so while vindicating her methodological position.     

Embodiment, spatial categorisation and action

Despite the subjective experience of a continuous and coherent external world, we will argue that the perception and categorisation of visual space is constrained by the spatial resolution of the sensory systems but also and above all, by the pre-reflective representations of the body in action. Recent empirical data in cognitive neurosciences will be presented that suggest that multidimensional categorisation of perceptual space depends on body representations at both an experiential and a functional level. Results will also be resumed that show that representations of the body in action are pre-reflective in nature as only some aspects of the pre-reflective states can be consciously experienced. Finally, a neuro-cognitive model based on the integration of afferent and efferent information will be described, which suggests that action simulation and associated predicted sensory consequences may represent the underlying principle that enables pre-reflective representations of the body for space categorisation and selection for action.     

How could phenomenal consciousness be involved in mental function?

In a phylogenetic perspective, the phenomenal and the functional aspects of consciousness cannot be separated because consciousness, as a phenomenal experience, must be causally effective. The hypothesis I propose is that the fundamental property of consciousness consists of a self-organizing process: the differentiation of a content. The differentiation of a content occurs on the basis of the relations internal to a representational whole, which behaves like a field and tends towards a condition of equilibrium. This hypothesis can be somehow considered an extension of Gestalt visual perceptual theory. Unlike neurocomputational processes, which are non-conscious and extrinsic to the representation, conscious processes are intrinsic to the representational whole. Consciousness, as an intrinsically self-organizing process interwoven with its phenomenal aspects, can be more than epiphenomenal and it can be involved in mental function. The paper then discusses the implications of this hypothesis for subjectivity and the explanatory gap.     

Two theories of consciousness: Semantic pointer competition vs. information integration

Consciousness results from three mechanisms: representation by firing patterns in neural populations, binding of representations into more complex representations called semantic pointers, and competition among semantic pointers to capture the most important aspects of an organism’s current state. We contrast the semantic pointer competition (SPC) theory of consciousness with the hypothesis that consciousness is the capacity of a system to integrate information (IIT). We describe computer simulations to show that SPC surpasses IIT in providing better explanations of key aspects of consciousness: qualitative features, onset and cessation, shifts in experiences, differences in kinds across different organisms, unity and diversity, and storage and retrieval.     

A sensorimotor account of vision and visual consciousness

Many current neurophysiological, psychophysical, and psychological approaches to vision rest on the idea that when we see, the brain produces an internal representation of the world. The activation of this internal representation is assumed to give rise to the experience of seeing. The problem with this kind of approach is that it leaves unexplained how the existence of such a detailed internal representation might produce visual consciousness. An alternative proposal is made here. We propose that seeing is a way of acting. It is a particular way of exploring the environment. Activity in internal representations does not generate the experience of seeing. The outside world serves as its own, external, representation. The experience of seeing occurs when the organism masters what we call the governing laws of sensorimotor contingency. The advantage of this approach is that it provides a natural and principled way of accounting for visual consciousness, and for the differences in the perceived quality of sensory experience in the different sensory modalities. Several lines of empirical evidence are brought forward in support of the theory, in particular: evidence from experiments in sensorimotor adaptation, visual "filling in," visual stability despite eye movements, change blindness, sensory substitution, and color perception.     

Visual awareness and the levels of processing hypothesis: A critical review

Does a visual percept emerge to consciousness in a graded manner (i.e. evolving through increasing degrees of clarity), or according to a dichotomous, “all-or-none” pattern (i.e. abruptly transitioning from unawareness to awareness)? The level of processing hypothesis (LoP; B. Windey and A. Cleeremans, 2015) recently proposed a theoretical framework where the transition from unaware to aware visual experience is graded for low-level stimulus representations (i.e. stimulus “energy” or “feature” levels) whereas it is dichotomous for high-level (i.e. the perception of “letters”, “words” or “meaning”) stimulus perception. Here, we will critically review current behavioral and brain-based evidence on the LoP hypothesis and discuss potential challenges (such as differences in LoP conceptualizations, awareness scale related issues, attentional confounds and divergences on experimental factors or statistical analyses) which might be of use for future research within the field. Overall, the LoP hypothesis is a recent and promising proposal that attempts to integrate divergent evidence on the graded vs. dichotomous emergence of awareness debate. Whereas current evidence validates some of the assumptions proposed by the LoP account, there is still much work to do on both methodological and experimental levels. Future neuroimaging studies might help to disentangle the current complex pattern of results found in LoP studies and, importantly, shed some light on the ongoing debate about the search for the Neural Correlates of Consciousness (NCC).     

Avoiding minorities: Social invisibility

Three experiments examined how self‐consciousness has an impact on the visual exploration of a social field. The main hypothesis was that merely a photograph of people can trigger a dynamic process of social visual interaction such that minority images are avoided when people are in a state of self‐reflective consciousness. In all three experiments, pairs of pictures—one with characters of social minorities and one with characters of social majorities—were shown to the participants. By means of eye‐tracking technology, the results of Experiment 1 (n = 20) confirmed the hypothesis that in the reflective consciousness condition, people look more at the majority than minority characters. The results of Experiment 2 (n = 89) confirmed the hypothesis that reflective consciousness also induces avoiding reciprocal visual interaction with minorities. Finally, by manipulating the visual interaction (direct vs. non‐direct) with the photos of minority and majority characters, the results of Experiment 3 (n = 56) confirmed the hypothesis that direct visual interaction with minority characters is perceived as being longer and more aversive. The overall conclusion is that self‐reflective consciousness leads people to avoid visual interaction with social minorities, consigning them to social invisibility. Copyright © 2012 John Wiley & Sons, Ltd.     

Do the contents of visual working memory automatically influence attentional selection during visual search?

In many theories of cognition, researchers propose that working memory and perception operate interactively. For example, in previous studies researchers have suggested that sensory inputs matching the contents of working memory will have an automatic advantage in the competition for processing resources. The authors tested this hypothesis by requiring observers to perform a visual search task while concurrently maintaining object representations in visual working memory. The hypothesis that working memory activation produces a simple but uncontrollable bias signal leads to the prediction that items matching the contents of working memory will automatically capture attention. However, no evidence for automatic attentional capture was obtained; instead, the participants avoided attending to these items. Thus, the contents of working memory can be used in a flexible manner for facilitation or inhibition of processing.     

Visual indexes, preconceptual objects, and situated vision

This paper argues that a theory of situated vision, suited for the dual purposes of object recognition and the control of action, will have to provide something more than a system that constructs a conceptual representation from visual stimuli: it will also need to provide a special kind of direct (preconceptual, unmediated) connection between elements of a visual representation and certain elements in the world. Like natural language demonstratives (such as 'this' or 'that') this direct connection allows entities to be referred to without being categorized or conceptualized. Several reasons are given for why we need such a preconceptual mechanism which individuates and keeps track of several individual objects in the world. One is that early vision must pick out and compute the relation among several individual objects while ignoring their properties. Another is that incrementally computing and updating representations of a dynamic scene requires keeping track of token individuals despite changes in their properties or locations. It is then noted that a mechanism meeting these requirements has already been proposed in order to account for a number of disparate empirical phenomena, including subitizing, search-subset selection and multiple object tracking (Pylyshyn et al., Canadian Journal of Experimental Psychology 48(2) (1994) 260). This mechanism, called a visual index or FINST, is briefly discussed and it is argued that viewing it as performing a demonstrative or preconceptual reference function has far-reaching implications not only for a theory of situated vision, but also for suggesting a new way to look at why the primitive individuation of visual objects, or proto-objects, is so central in computing visual representations. Indexing visual objects is also, according to this view, the primary means for grounding visual concepts and is a potentially fruitful way to look at the problem of visual integration across time and across saccades, as well as to explain how infants' numerical capacity might arise.     

Conscious Vision for Action Versus Unconscious Vision for Action?

David Milner and Melvyn Goodale’s dissociation hypothesis is commonly taken to state that there are two functionally specialized cortical streams of visual processing originating in striate (V1) cortex: a dorsal, action‐related “unconscious” stream and a ventral, perception‐related “conscious” stream. As Milner and Goodale acknowledge, findings from blindsight studies suggest a more sophisticated picture that replaces the distinction between unconscious vision for action and conscious vision for perception with a tripartite division between unconscious vision for action, conscious vision for perception, and unconscious vision for perception. The combination excluded by the tripartite division is the possibility of conscious vision for action. But are there good grounds for concluding that there is no conscious vision for action? There is now overwhelming evidence that illusions and perceived size can have a significant effect on action ( Bruno & Franz, 2009 ; Dassonville & Bala, 2004 ; Franz & Gegenfurtner, 2008 ; McIntosh & Lashley, 2008 ). There is also suggestive evidence that any sophisticated visual behavior requires collaboration between the two visual streams at every stage of the process ( Schenk & McIntosh, 2010 ). I nonetheless want to make a case for the tripartite division between unconscious vision for action, conscious vision for perception, and unconscious vision for perception. My aim here is not to refute the evidence showing that conscious vision can affect action but rather to argue (a) that we cannot gain cognitive access to action‐guiding dorsal stream representations, and (b) that these representations do not correlate with phenomenal consciousness. This vindicates the semi‐conservative view that the dissociation hypothesis is best understood as a tripartite division.     

Situating vision in the world

Recently, there has been a great deal of interest in what has been called 'situated cognition', which has included claims that certain forms of representation are inadequate for modeling active organisms or agents such as humans and robots. In this article, I suggest that a weakness in classical theories of visual representation is the way in which representations connect with the real world, which may account for many of the concerns expressed by the situated cognition community. Specifically, I claim that what current theories lack is any provision for a certain form of direct, preconceptual connection between objects in the visual world (visual objects or proto-objects) and their representations in the visual system. This type of connection is akin to what philosophers and semanticists have referred to as an 'indexical' or 'demonstrative' reference and what some cognitive scientists have referred to as 'deictic pointers'. I explain why such a mechanism is needed and suggest that many workers have, in fact, been studying precisely this under the term 'visual index'. The visual index hypothesis is illustrated with the results of some relevant experiments, including multiple object tracking, visual routines and subset-selected visual searches. Indexing theory provides a synthesis that has profound implications for explaining a wide range of psychophysical findings, certain results in infant cognitive development and also some ancient problems in the philosophy of mind.     

Discrete internal pattern representations and visual detection of small changes in pattern shape

A scheme is proposed that relates the internal representation of pattern stimuli to visual pattern discrimination performance. The main assumptions of the scheme are: (1) internal representations are assigned to patterns probabilistically; (2) internal representations are discrete; (3) visual discriminability of two patterns is determined by the differences in the assignment probabilities of their internal representations. It is suggested that the internal representations associated with a pattern may be analyzed by measuring the visual detectability of small changes in pattern shape at points along a continuum of shapes. This continuum is generated by a group of transformations smoothly parameterized by a single variable. In two experiments designed to test this approach, subjects discriminated pattern displays containing combinations of three-dot subpatterns. Under the hypothesis that there were just two relevant internal representations, specifying dot collinearity and dot noncollinearity, the qualitative characteristics of the discrimination performance were correctly predicted.     

Real Objects Can Impede Conditional Reasoning but Augmented Objects Do Not

In this study, Knauff and Johnson‐Laird's (2002) visual impedance hypothesis (i.e., mental representations with irrelevant visual detail can impede reasoning) is applied to the domain of external representations and diagrammatic reasoning. We show that the use of real objects and augmented real (AR) objects can control human interpretation and reasoning about conditionals. As participants made inferences (e.g., an invalid one from "if P then Q" to "P"), they also moved objects corresponding to premises. Participants who moved real objects made more invalid inferences than those who moved AR objects and those who did not manipulate objects (there was no significant difference between the last two groups). Our results showed that real objects impeded conditional reasoning, but AR objects did not. These findings are explained by the fact that real objects may over‐specify a single state that exists, while AR objects suggest multiple possibilities.     

The relation of phoneme discrimination, lexical access, and short-term memory: A case study and interactive activation account

A brain-damaged patient (AP) is reported who had a strong tendency to identify nonwords as words on auditory lexical decision and to lexicalize nonwords in repetition, yet who showed a normal ability to perceive individual phonemes. It was initially hypothesized that these findings could be accounted for in terms of disrupted lexical phonological representations. This hypothesis was rejected on the basis of an interactive activation model of word recognition which revealed that modifications at the lexical level did not mimic the patient's pattern of results. Instead, it was found that increasing the rate of decay of activation at the phoneme level produced output that was consistent with the phoneme discrimination, lexical decision, and repetition results. This hypothesis of increased phoneme level decay led to the prediction that speech discrimination would decline with increased interstimulus interval and that short-term memory performance would be impaired. Both predictions were confirmed. The results of this study provide support for an interactive activation model of word recognition with feedback from the lexical to the phonemic level and for a close connection between the processes involved in word recognition and short-term memory.     

Representational change and children's numerical estimation

We applied overlapping waves theory and microgenetic methods to examine how children improve their estimation proficiency, and in particular how they shift from reliance on immature to mature representations of numerical magnitude. We also tested the theoretical prediction that feedback on problems on which the discrepancy between two representations is greatest will cause the greatest representational change. Second graders who initially were assessed as relying on an immature representation were presented feedback that varied in degree of discrepancy between the predictions of the mature and immature representations. The most discrepant feedback produced the greatest representational change. The change was strikingly abrupt, often occurring after a single feedback trial, and impressively broad, affecting estimates over the entire range of numbers from 0 to 1000. The findings indicated that cognitive change can occur at the level of an entire representation, rather than always involving a sequence of local repairs.     

Word form access dyslexia: understanding the basis of visual reading errors

We report the case of a patient V.E.M. who exhibits the infrequently described syndrome of visual dyslexia. V.E.M. read many single words accurately and rapidly; however, when words were read inaccurately, the majority of responses were alternate real words bearing a strong visual relationship to the target items. A series of observational and experimental investigations of her reading skills revealed that response accuracy was strongly affected by word frequency and mildly affected by concreteness but not influenced by word length, orthographic neighbourhood size, or semantic priming. It is argued that V.E.M.'s visual dyslexia results from a deficit of the visual word form system. More specifically, we propose that this deficit has an “access” quality, with visual word form representations remaining relatively intact despite an impairment in the processes by which these representations are activated. Taking the results of this study together with previous reports of dyslexic patients who make a high proportion of visual paralexic errors, we also suggest that visual dyslexia represents a multicomponent dyslexic syndrome for which phonological impairment and not semantic impairment may be a necessary condition.     

Is Iconic Memory Iconic?

Short-term memory in vision is typically thought to divide into at least two memory stores: a short, fragile, high-capacity store known as iconic memory, and a longer, durable, capacity-limited store known as visual working memory (VWM). This paper argues that iconic memory stores icons, i.e., image-like perceptual representations. The iconicity of iconic memory has significant consequences for understanding consciousness, nonconceptual content, and the perception–cognition border. Steven Gross and Jonathan Flombaum have recently challenged the division between iconic memory and VWM by arguing against the idea of capacity limits in favor of a flexible resource-based model of short-term memory. I argue that, while VWM capacity is probably governed by flexible resources rather than a sharp limit, the two memory stores should still be distinguished by their representational formats. Iconic memory stores icons, while VWM stores discursive (i.e., language-like) representations. I conclude by arguing that this format-based distinction between memory stores entails that prominent views about consciousness and the perception–cognition border will likely have to be revised.     

Word form access dyslexia: Understanding the basis of visual reading errors

We report the case of a patient V.E.M. who exhibits the infrequently described syndrome of visual dyslexia. V.E.M. read many single words accurately and rapidly; however, when words were read inaccurately, the majority of responses were alternate real words bearing a strong visual relationship to the target items. A series of observational and experimental investigations of her reading skills revealed that response accuracy was strongly affected by word frequency and mildly affected by concreteness but not influenced by word length, orthographic neighbourhood size, or semantic priming. It is argued that V.E.M.'s visual dyslexia results from a deficit of the visual word form system. More specifically, we propose that this deficit has an “access” quality, with visual word form representations remaining relatively intact despite an impairment in the processes by which these representations are activated. Taking the results of this study together with previous reports of dyslexic patients who make a high proportion of visual paralexic errors, we also suggest that visual dyslexia represents a multicomponent dyslexic syndrome for which phonological impairment and not semantic impairment may be a necessary condition.