Crossmodal Perception

Despite the recent surge in research on, and interest in, synesthesia, the mechanism underlying this condition is still unknown. Feedforward mechanisms involving overlapping receptive fields of sensory neurons as well as feedback mechanisms involving a lack of signal disinhibition have been proposed. Here I show that a broad range of studies of developmental synesthesia indicate that the mechanism underlying the phenomenon may involve reinstatement of brain activity in different sensory or cognitive streams in a way that is similar to what (...) happens during memory retrieval of semantically associated items. In the paper’s final sections I look at the relevance of synesthesia research, given the memory model, to our understanding of multisensory perception and common mapping patterns. (shrink)

Molyneux asked whether a newly sighted person could distinguish a sphere from a cube by sight alone, given that she was antecedently able to do so by touch. This, we contend, is a question about general ideas. To answer it, we must ask (a) whether spatial locations identified by touch can be identified also by sight, and (b) whether the integration of spatial locations into an idea of shape persists through changes of modality. Posed this way, Molyneux’s Question goes substantially (...) beyond question (a), about spatial locations, alone; for a positive answer to (a) leaves open whether a perceiver might cross-identify locations, but not be able to identify the shapes that collections of locations comprise. We further emphasize that MQ targets general ideas so as to distinguish it from corresponding questions about experiences of shape and about the property of tangible (vs. visual) shape. After proposing a generalized formulation of MQ, we extend earlier work (“Many Molyneux Questions,” Australasian Journal of Philosophy 2020) by showing that MQ does not admit a single answer across the board. Some integrative data-processes transfer across modalities; others do not. Seeing where and how such transfer succeeds and fails in individual cases has much to offer to our understanding of perception and its modalities. (shrink)

When we cook, by meticulously following a recipe, or adding a personal twist to it, we sometimes care not only to (re-)produce a taste that we can enjoy, but also to give our food a certain aftertaste. This is not surprising, given that we ordinarily take aftertaste to be an important part of the gustatory experience as a whole, one which we seek out, and through which we evaluate what we eat and drink—at least in many cases. What is surprising (...) is that aftertastes, from a psychological point of view, seem to be analogous to afterimages, and thus have little or no epistemic import. In this paper we tackle this puzzle, and argue that we are right in treating aftertastes seriously. The moral is that both from a metaphysical and an epistemic point of view aftertastes should be categorized differently from afterimages. (shrink)

Higher animals need to identify and track material objects because they depend on interactions with them for nutrition, reproduction, and social interaction. This paper investigates the perception of material objects. It argues, first, that material objects are tagged, in all five external senses, as bearers of the features detected by them. This happens through a perceptual process, here entitled Generalized Completion, which creates the appearance of objects that have properties that transcend the activation of sensory receptors. The paper shows, secondly, (...) that material objects are privileged subjects for perceived motion and interaction. That is, they are perceived as subjects for these properties while their parts seem to be subjects only derivatively. Material objects are the only perceptual subjects that are both multisensory and privileged. (shrink)

Within contemporary philosophy of perception, it is commonly claimed that flavour experiences are paradigmatic examples of multimodal perceptual experiences. In fact, virtually any sensory system, including vision and audition, is believed to influence how we experience flavours. However, there is a strong intuition, often expressed in these works, that not all of these sensory systems make an equal contribution to the phenomenology of flavour experiences. More specifically, it seems that the activities of some sensory systems are constitutive for flavour perception (...) while others merely influence how we experience flavours. This paper aims to answer the question regarding the constitutive factors of flavour perception in a twofold way. First, a theoretical framework is developed, relying on debates regarding constitutivity in analytic metaphysics and philosophy of science, which defines the stronger and weaker senses in which the activities of sensory systems may be constitutive for flavour perception. Second, relying on empirical results in flavour science, the constitutive status of activities related to distinct sensory systems in the context of flavour perception is investigated. (shrink)

Some philosophers have argued that we do not hear sounds as located in the environment. Others have objected that this straightforwardly contradicts the phenomenology of auditory experience. And from this they draw metaphysical conclusions about the nature of sounds—that they are events or properties of vibrating surfaces rather than waves or sensations. I argue that there is a minimal, but recognizable, notion of audition to which this phenomenal objection does not apply. While this notion doesn’t correspond to our ordinary notion (...) of auditory experience, it does—in conjunction with our lack of an uncontroversial individuation of the senses and recent interest in distinctively multisensory features of perceptual experiences—raise the possibility of more expansive notions of audition, including some that do plausibly count as corresponding to our everyday notion of audition, that lack the spatial phenomenology cited in the objection. Until this possibility is ruled out, the phenomenal objection and metaphysical conclusions drawn from it remain inconclusive. (shrink)

According to cognitive psychology, virtually every sensory system influences the way in which flavours are experienced. However, it is less clear which systems are actually constitutive of flavour perception and which have merely causal influence. The paper focuses on the status of vision and audition, which are usually not treated as constitutive in the context of flavour perception. First, it is proposed that the mechanistic explanation debate provides conceptual resources which allow the constitutivity of sensory systems to be assessed. Second, (...) it is argued that the contemporary state of the art provides reasons for accepting the constitutive role of audition, but analogous evidence is not available in the case of vision. (shrink)

Analysis of grip force signals tailored to hand and finger movement evolution and changes in grip force control during task execution provide unprecedented functional insight into somatosensory cognition. Somatosensory cognition is a basis of our ability to manipulate, move, and transform objects of the physical world around us, to recognize them on the basis of touch alone, and to grasp them with the right amount of force for lifting and manipulating them. Recent technology has permitted the wireless monitoring of grip (...) force signals recorded from biosensors in the palm of the human hand to track and trace human grip forces deployed in cognitive tasks executed under conditions of variable sensory (visual, auditory) input. Non-invasive multi-finger grip force sensor technology can be exploited to explore functional interactions between somatosensory brain mechanisms and motor control, in particular during learning a cognitive task where the planning and strategic execution of hand movements is essential. Sensorial and cognitive processes underlying manual skills and/or hand-specific (dominant versus non-dominant hand) behaviors can be studied in a variety of contexts by probing selected measurement loci in the fingers and palm of the human hand. Thousands of sensor data recorded from multiple spatial locations can be approached statistically to breathe functional sense into the forces measured under specific task constraints. Grip force patterns in individual performance profiling may reveal the evolution of grip force control as a direct result of cognitive changes during task learning. Grip forces can be functionally mapped to from-global-to-local coding principles in brain networks governing somatosensory processes for motor control in cognitive tasks leading to a specific task expertise or skill. Under the light of a comprehensive overview of recent discoveries into the functional significance of human grip force variations, perspectives for future studies in cognition, in particular the cognitive control of strategic and task relevant hand movements in complex real-world precision task, are pointed out. (shrink)

We represent shape in both sight and touch, but how do these abilities relate to one another? This issue has been discussed in the context of Molyneux's question of whether someone born blind could, upon being granted sight, identify shapes visually. Some have suggested that we might look to real-world cases of sight restoration to illuminate the relation between visual and tactual shape representations. Here, I argue that newly sighted perceivers should not be relied on in this way because they (...) are unlikely to form the kinds of shape representations responsible for cross-modal recognition in normally sighted perceivers. I then argue that the available evidence makes a compelling case for the type identity view, on which the visual and tactual representations responsible for cross-modal recognition are type-identical. (shrink)

The puzzle of cross-modal shape experience is the puzzle of reconciling the apparent differences between our visual and haptic experiences of shape with their apparent similarities. This paper proposes that we can resolve the cross-modal puzzle by reflecting on another puzzle. The puzzle of perspectival character challenges us to reconcile the variability of shape experience through shifts in perspective with its constancy. An attractive approach to the latter puzzle holds that shape experience is complex, involving both perspectival aspects and constant (...) aspects. I argue here that parallel distinctions between perspectival and constant aspects of shape experience arise in sight and touch, and that perspectival aspects are modality-specific while at least some constant aspects are constitutively multisensory. I then address a powerful challenge to the idea that aspects of spatial phenomenology are shared cross-modally. (shrink)

The validity of the senses we use to experience the cosmos is something we take for granted. The majority of the people view the senses as the most effective and potentially the only tool they have to reach reality. But as Shestov rightfully questioned, when was the last time the majority decided correctly on an important philosophical problem? The role of science and philosophy is to question the obvious and this is what we should do if we are to uncover (...) the true role of the senses. This paper uses a series of philosophy articles to touch on the problem of the senses and the answer portrayed is exciting as well as terrifying: The senses are not a helpful tool but more of a hurdle when it comes to understanding the cosmos…. (shrink)

While we perceive events in our environment through multiple sensory systems, we nevertheless perceive all of these events as occupying a single unified timeline. Time, as we perceive it, is unified. I argue that existing accounts of the perceived unity of time fail. Instead, the perceived unity of time must be constructed by integrating our initially fragmented timekeeping capacities. However, existing accounts of multimodal integration do not tell us how this might occur. Something new is needed. I finish the paper (...) by articulating the hurdles that must be overcome to provide an account of the perceived unity of time. (shrink)

Visual experience is often characterised as being essentially spatial, and auditory experience essentially temporal. But this contrast, which is based upon the temporal structure of the objects of sensory experience rather than the experiences to which they give rise, is somewhat superficial. By carefully examining the various sources of temporal variation in the chemical senses we can more clearly identify the temporal profile of the resulting smell and taste (aka flavour) experiences. This in turn suggests that at least some of (...) the objects of olfactory experience have significant temporal structure, including interactions between odorants and the body’s own sensory systems. This can help to inform our understanding not only of the metaphysics of olfaction, but the temporal structure of sensory processing and experience in other sense-modalities, including vision and audition. (shrink)

Each of our sensory modalities—vision, touch, taste, etc.—works on a slightly different timescale, with differing temporal resolutions and processing lag. This raises the question of how, or indeed whether, these sensory streams are co-ordinated or ‘bound’ into a coherent multisensory experience of the perceptual ‘now’. In this paper I evaluate one account of how temporal binding is achieved: the temporal windows hypothesis, concluding that, in its simplest form, this hypothesis is inadequate to capture a variety of multisensory phenomena. Rather, the (...) evidence suggests the existence of a more complex temporal structure in which multiple overlapping windows support distinct functional mechanisms. To aid in the precise formulation of such views, I propose a taxonomy of temporal window types and their characteristics that in turn suggests promising avenues for future empirical and philosophical research. I conclude by examining some philosophical implications of multi-window models for the metaphysics of perception and perceptual experience more generally. (shrink)

What are the sensory individuals of audition? What are the entities our auditory system attributes properties to? We examine various proposals about the nature of the sensory individuals of audition, and show that while each can account for some aspects of auditory perception, each also faces certain difficulties. We then put forward a new conception of sensory individuals according to which auditory sensory individuals are composite individuals. A feature shared by all existing accounts of sounds and sources is that they (...) postulate sensory individuals that are non-composite. They identify the sensory individual of sound hearing or source hearing with one type of entity in the environment, be they sound waves, vibrations, or interactions. We question this assumption and argue that our perceptual systems represent two or more aspects of the environment as a single sensory individual. Finally, we show that taking auditory individuals to be composite sensory individuals allows for an account of audition that is less problematic than its existing alternatives. (shrink)

According to the decomposition thesis, perceptual experiences resolve without remainder into their different modality-specific components. Contrary to this view, I argue that certain cases of multisensory integration give rise to experiences representing features of a novel type. Through the coordinated use of bodily awareness—understood here as encompassing both proprioception and kinaesthesis—and the exteroceptive sensory modalities, one becomes perceptually responsive to spatial features whose instances couldn’t be represented by any of the contributing modalities functioning in isolation. I develop an argument for (...) this conclusion focusing on two cases: 3D shape perception in haptic touch and experiencing an object’s egocentric location in crossmodally accessible, environmental space. (shrink)

What is the correct procedure for determining the contents of perception? Philosophers tackling this question increasingly rely on empirically-oriented procedures in order to reach an answer. I argue that this constitutes an improvement over the armchair methodology constitutive of phenomenal contrast cases, but that there is a crucial respect in which current empirical procedures remain limited: they are unimodal in nature, wrongly treating the senses as isolatable faculties. I thus have two aims: first, to motivate a reorientation of the admissible (...) contents debate into a multimodal framework, charting its various significances. The second is to explore whether any experimental studies of multimodal perception support a so-called Liberal (or ‘high-level’ or ‘rich’) account of perception’s admissible contents. I conclude that the McGurk effect and the ventriloquist effect are both explicable without the postulation of high-level content, but that at least one multimodal experimental paradigm may necessitate such content: the rubber hand illusion. One upshot of this argument is that Conservatives who claim that the Liberal view intolerably broadens the scope of perceptual illusions, particularly from the perspective of perceptual psychology, should pursue other arguments against that view. (shrink)

Bayne and McClelland (2016) raise the matching content challenge for proponents of cognitive phenomenology: if the phenomenal character of thought is determined by its intentional content, why is it that my conscious thought that there is a blue wall before me and my visual perception of a blue wall before me don’t share any phenomenology, despite their matching content? In this paper, I first show that the matching content challenge is not limited to proponents of cognitive phenomenology but extends to (...) cases of cross-modal perception, threatening representationalism about consciousness in general. I then give two responses to the challenge, both of which appeal to intentional modes. The difference in intentional mode between a thought and a visual perception can either explain why we should not expect any phenomenal overlap between the two experiences, or it can make it clear why the phenomenal overlap is easy to overlook. I show that these responses are available to the representationalist about perceptual consciousness, as well as the proponent of cognitive phenomenology. The upshot is that, when it comes to the matching content challenge, both perceptual representationalism and cognitive representationalism stand on equal dialectical footing. (shrink)

This is the editors' Introduction to a special issue of the journal, Multisensory Research. European philosophers of the modern period found multisensory perception to be impossible because they thought that perceptual ideas are defined by how they are experienced. Under this conception, the individual modalities are determinables of ideas—just as colour is a determinable that embraces red and blue, so also the visual is a determinable that embraces colour and (visually experienced) shape. Since no idea is experienced as, for example, (...) both visual and auditory, there can be no such thing as audiovisual perception. This conception of modality is not directly contested, but a variety of perceptual phenomena are listed that could raise interesting questions if treated as multimodal in origin. (shrink)

The idea that there are five senses dates back to Aristotle, who was one of the first philosophers to examine them systematically. Though it has become conventional wisdom, many scientists and philosophers would argue that this idea is outdated and inaccurate. Indeed, they have given many different answers to this question, ranging from just three (the number of different kinds of physical energy we can detect) to 33 or more senses. Perhaps surprisingly, the issue remains controversial, partly because it is (...) not clear exactly what should count as a ‘sense’. Should proprioception, balance and kinaesthesis, amongst others, be considered additional senses? And if so, how do we figure out how many senses we really have? -/- (Published in Turkish under the title ‘Çok Duyumlu Algi’). (shrink)

From playing basketball to ordering at a food counter, we frequently and effortlessly coordinate our attention with others towards a common focus: we look at the ball, or point at a piece of cake. This non-verbal coordination of attention plays a fundamental role in our social lives: it ensures that we refer to the same object, develop a shared language, understand each other’s mental states, and coordinate our actions. Models of joint attention generally attribute this accomplishment to gaze coordination. But (...) are visual attentional mechanisms sufficient to achieve joint attention, in all cases? Besides cases where visual information is missing, we show how combining it with other senses can be helpful, and even necessary to certain uses of joint attention. We explain the two ways in which non-visual cues contribute to joint attention: either as enhancers, when they complement gaze and pointing gestures in order to coordinate joint attention on visible objects, or as modality pointers, when joint attention needs to be shifted away from the whole object to one of its properties, say weight or texture. This multisensory approach to joint attention has important implications for social robotics, clinical diagnostics, pedagogy and theoretical debates on the construction of a shared world. (shrink)

Many philosophers take experience to be an essential aspect of perceptual justification. I argue against a specific variety of such an experientialist view, namely, the Looks View of perceptual justification, according to which our visual beliefs are mediately justified by beliefs about the way things look. I describe three types of cases that put pressure on the idea that perceptual justification is always related to looks-related reasons: unsophisticated cognizers, multimodal identification, and amodal completion. I then provide a tentative diagnosis of (...) what goes wrong in the Looks View: it ascribes a specific epistemic role to beliefs about looks that is actually fulfilled by subpersonal perceptual processes. (shrink)

Molyneux's Question (MQ) concerns whether a newly sighted man would recognize/distinguish a sphere and a cube by vision, assuming he could previously do this by touch. We argue that (MQ) splits into questions about (a) shared representations of space in different perceptual systems, and about (b) shared ways of constructing higher dimensional spatiotemporal features from information about lower dimensional ones, most of the technical difficulty centring on (b). So understood, MQ resists any monolithic answer: everything depends on the constraints faced (...) by particular perceptual systems in extracting features of higher dimensionality from those of lower. Each individual question of this type is empirical and must be investigated separately. We present several variations on MQ based on different levels of dimensional integration—some of these are familiar, some novel adaptations of problems known elsewhere, and some completely novel. Organizing these cases in this way is useful because it unifies a set of disparate questions about intermodal transfer that have held philosophical and psychological interest, suggests a new range of questions of the same type, sheds light on similarities and differences between members of the family, and allows us to formulate a much-augmented set of principles and questions concerning the intermodal transfer of spatiotemporal organization. (shrink)

Evidence concerning the relationship between attention and multisensory integration has long been thought to lead us into a paradox. The paradox has its roots in evidence that seems to show that attention exerts an influence on integration, and that integration also exerts an influence on attention. This creates an appearance of paradox only if it is understood to imply that particular instances of the integration process must occur both before and after particular instances of the attention process. But this appearance (...) of paradox can be removed if we can find a way to resist the idea that there must be fixed temporal relations between the instances of these processes. That idea can seem hard to resist if both are understood to be processes of the sort that are brought to a halt by their own completion. Reflection on a metaphysical distinction between different sorts of process shows this understanding can be rejected. The appearance of paradox is thereby removed. (shrink)

There has been a lot of discussion about how the cognitive penetrability of perception may or may not have important implications for understanding perceptual justification. The aim of this paper is to argue that a different set of findings in perceptual psychology poses an even more serious challenge to the very idea of perceptual justification. These findings are about the importance of perceptual processing that is not driven by corresponding sensory stimulation in the relevant sense modality (such as amodal completion (...) and multimodal completion). I argue that these findings show that everyday perception is in fact a mixture of sensory stimulation-driven perceptual processing and perceptual processing that is not driven by corresponding sensory stimulation in the relevant sense modality and we have strong reasons to doubt the epistemic pedigree of the latter process. The implication of this is not that we should become skeptics or deny the possibility of perceptual justification. It is, rather, that the only way in which we can understand when and whether a perceptual state justifies beliefs is by paying close attention to empirical facts about the reliability of perceptual processing that is not driven by corresponding sensory stimulation in the relevant sense modality. In this sense (a very narrow sense) epistemology needs to be naturalized. (shrink)

If the sight of cortically blind people were restored, could they visually recognize a cube or a sphere? This is Molyneux’s question. I argue that the answer to this question depends on the specificities of the mental setup of these cortically blind people. Some cortically blind people have (sometimes quite vivid) visual imagery. Others don’t. The answer to Molyneux’s question depends on whether the blind subjects have had visual imagery before their sight was restored. If they did, the answer to (...) Molyneux’s question is yes, if they didn’t, the answer is no. There is no generic answer to Molyneux’s question. (shrink)

It is tempting to think that one’s perceptual evidence comprises just what issues from perceiving with each of the respective sensory modalities. However, empirical, rational, and phenomenological considerations show that one’s perceptual evidence can outstrip what one possesses due to perceiving with each separate sense. Some novel perceptual evidence stems from the coordinated use of multiple senses. This paper argues that some perceptual evidence in this respect is distinctively multisensory.

Despite the large interest in the human ability to perceive space present in neuroscience, cognitive science and psychology, as well as philosophy of mind, the issues regarding egocentric space representation received relatively less attention. In this paper I take up a unique phenomenon related to this faculty: the “spatial purport” of perceptual experiences. The notion was proposed by Rick Grush to describe the subjective, qualitative aspects of egocentric representations of spatial properties and relations. Although Grush offered an explanation of the (...) mechanism giving rise to appearance of spatial purport, his model had considerable shortcomings. In the paper I thoroughly analyze both the notion of spatial purport and Grush’s explanation of the mechanism at its core in order to develop his theory using the insights provided by the predictive processing theory of mind, and more particularly by the active inference framework. The extended account I offer, named Predictive and Hierarchical Skill Theory, explains phenomena that escaped Grush’s model and furthers the research on egocentric space representation from the perspective of both neuroscience and philosophy of mind. (shrink)

Is the flavor of mint reducible to the minty smell, the taste, and the menthol-like coolness on the roof of one’s mouth, or does it include something over and above these—something not properly associated with any one of the contributing senses? More generally, are there features of perceptual experiences—so-called novel features—that are not associated with any of our senses taken singly? This question has received a lot of attention of late. Yet surprisingly little attention has been paid to the question (...) of what it means to say that a feature is associated with a sensory modality in the first place. Indeed, there is only one fully developed proposal in the literature, due to Casey O’Callaghan. I argue that this proposal is too permissive to inform the debate over novel features. I go on to argue that all attempts to formulate a better proposal along these lines fail. The corollary of my arguments is that the question of the existence of novel features is poorly formed. Furthermore, the problem generalizes, with the result that we should not rely on our pre-theoretical notions of the senses as the basis of theorizing about the features of perceptual experiences. (shrink)

This collection of essays brings together research on sense modalities in general and spatial perception in particular in a systematic and interdisciplinary way. It updates a long-standing philosophical fascination with this topic by incorporating theoretical and empirical research from cognitive science, neuroscience, and psychology. The book is divided thematically to cover a wide range of established and emerging issues. Part I covers notions of objectivity and subjectivity in spatial perception and thinking. Part II focuses on the canonical distal senses, such (...) as vision and audition. Part III concerns the chemical senses, including olfaction and gustation. Part IV discusses bodily awareness, peripersonal space, and touch. Finally, the volume concludes with Part V, on multimodality. Spatial Senses is an important contribution to the scholarly literature on the philosophy of perception that takes into account important advances in the sciences. (shrink)

Philosophy and Phenomenological Research, EarlyView.

Cognitive scientists have long known that the modalities interact during perceptual processing. Cross-modal illusions like the ventriloquism effect show that the course of processing in one modality can alter the course of processing in another. But how do the modalities interact in the specific domain of object perception? This paper distinguishes and analyzes two kinds of multisensory interaction in object perception. First, the modalities may bind features to a single object or event. Second, the modalities may cooperate when differentiating an (...) object or event from its surroundings. I critically evaluate evidence for various forms of multisensory binding. I then consider the case for multisensory differentiation. I argue that existing evidence for multisensory differentiation is inconclusive. I highlight ways that the issue might be empirically resolved. (shrink)

Nearly every theory of perception just focuses on one sense at a time; but most of the time we perceive using multiple senses. Casey O'Callaghan offers a revisionist multisensory philosophy of perception: he explores how our senses work together and influence each other, leading to surprising perceptual illusions and novel forms of experience.

Restrictivists hold that visual experience only represents low-level properties such as shape, spatial location, motion, color, etc. Expansionists contend that visual experience also represents high-level properties such as being a pine tree. I outline a new approach to support expansionism called the conflict cross-modal argument. What I call the conflict cross-modal effects occur when at least two perceptual systems disagree about some property belonging to a common stimulus, and this disagreement causes a change in the representational and phenomenal content of (...) the perceptual experience associated with one, or both, modalities. The conflict cross-modal argument works by accepting that if a property figures in a conflict cross-modal effect, then prima facie that property is a strong common sensible between the two modalities, and vision and another modality disagree about a property that is high-level for vision. After outlining this argument, and showing how it overcomes two obstacles that face traditional methods employed to defend expansionism, I turn to the well known Mcgurk effect as a case where vision and audition disagree about phoneme properties in order to employ my argument for the conclusion that phoneme properties are represented in visual experience. The upshot is that since phoneme properties are high-level for vision, we have an argument supporting expansionism. (shrink)

When I am looking at my coffee machine that makes funny noises, this is an instance of multisensory perception – I perceive this event by means of both vision and audition. But very often we only receive sensory stimulation from a multisensory event by means of one sense modality, for example, when I hear the noisy coffee machine in the next room, that is, without seeing it. The aim of this paper is to bring together empirical findings about multimodal perception (...) and empirical findings about (visual, auditory, tactile) mental imagery and argue that on occasions like this, we have multimodal mental imagery: perceptual processing in one sense modality (here: vision) that is triggered by sensory stimulation in another sense modality (here: audition). Multimodal mental imagery is not a rare and obscure phenomenon. The vast majority of what we perceive are multisensory events: events that can be perceived in more than one sense modality – like the noisy coffee machine. And most of the time we are only acquainted with these multisensory events via a subset of the sense modalities involved – all the other aspects of these multisensory events are represented by means of multisensory mental imagery. This means that multisensory mental imagery is a crucial element of almost all instances of everyday perception. (shrink)

This paper is a defense of an internalist view of the perception of shapes. A basic assumption of the paper is that perceptual experiences have certain parts which account both for the phenomenal character associated with perceiving shapes—phenomenal shapes—and for the intentional content presenting shapes—intentional shapes. Internalism about perceptions of shapes is defined as the claim that phenomenal shapes determine the intentional shapes. Externalism is defined as the claim that perceptual experiences represent whatever shape the phenomenal shape reliably tracks. The (...) argument against externalism proceeds in three steps. First, it is argued that phenomenal shapes are modality specific, such that a phenomenal shape that features in a visual perceptual experience cannot feature in a haptic perceptual experience, and vice versa. Second, it is argued that intentional shapes are amodal. Third, it is argued that externalism is incompatible with the fact that phenomenal shapes are modality specific and intentional shapes amodal. (shrink)

Intermodal representationalists hold that the phenomenal characters of experiences are fully determined by their contents. In contrast, intramodal representationalists hold that the phenomenal characters of experiences are determined by their contents together with their intentional modes or manners of representation, which are nonrepresentational features corresponding roughly to the sensory modalities. This paper discusses a kind of experience that provides evidence for an intermodal representationalist view: intermodal experiences, experiences that unify experiences in different modalities. I argue that such experiences are much (...) easier to explain on the intermodal view. (shrink)

The first part of this survey article presented a cartography of some of the more extensively studied forms of multisensory processing. In this second part, I turn to examining some of the different possible ways in which the structure of conscious perceptual experience might also be characterized as multisensory. In addition, I discuss the significance of research on multisensory processing and multisensory consciousness for philosophical debates concerning the modularity of perception, cognitive penetration, and the individuation of the senses.

Many philosophers use findings about sensory substitution devices in the grand debate about how we should individuate the senses. The big question is this: Is “vision” assisted by (tactile) sensory substitution really vision? Or is it tactile perception? Or some sui generis novel form of perception? My claim is that sensory substitution assisted “vision” is neither vision nor tactile perception, because it is not perception at all. It is mental imagery: visual mental imagery triggered by tactile sensory stimulation. But it (...) is a special form of mental imagery that is triggered by corresponding sensory stimulation in a different sense modality, which I call “multimodal mental imagery.”. (shrink)

Psychophysics and neuroscience demonstrate that different sensory systems interact and influence each other. Perceiving involves extensive cooperation and coordination among systems associated with sight, hearing, touch, smell, and taste. Nonetheless, it remains unclear in what respects conscious perceptual awareness is multisensory. This paper distinguishes six differing varieties of multisensory awareness, explicates their consequences, and thereby elucidates the multisensory nature of perception. It argues on these grounds that perceptual awareness need not be exhausted by that which is associated with each of (...) the respective sensory modalities along with whatever accrues thanks to simple co-consciousness. (shrink)

We can discern two opposing viewpoints regarding synesthesia. According to the first, it is an oddity, an outlier, or a disordered condition. According to the second, synesthesia is pervasive, driving creativity, metaphor, or language itself. Which is it? Ultimately, I favor the first perspective, according to which cross-sensory synesthesia is an outlying condition. But the second perspective is not wholly misguided. My discussion has three lessons. First, synesthesia is just one of a variety of effects in which one sense modality (...) causally impacts and reshapes experience associated with another. These effects are utterly common. However, due to their unfamiliarity, and to their conflict with a widespread conception of the role of the senses in perception and perceptual experience, until recently they have been surprising. Second, synesthesia nevertheless must be distinguished from other inter-modal effects that lead to misperception, such as crossmodal illusions. Third, synesthesia also may be distinguished from the potentially much broader class of synesthetic effects, which could be common across the population and within individuals. (shrink)

Beyond Vision brings together eight essays by Casey O'Callaghan which draw theoretical and philosophical lessons about perception, the nature of its objects, and sensory awareness. O'Callaghan focuses on auditory perception, perception of spoken language, and multisensory perception.

Inducing the rubber hand illusion (RHI) requires that participants look at an imitation hand while it is stroked in synchrony with their occluded biological hand. Previous explanations of the RHI have emphasized multisensory integration, and excluded higher cognitive functions. We investigated the relationship between the RHI and higher cognitive functions by experimentally testing task switch (as measured by switch cost) and mind wandering (as measured by SART score); we also included a questionnaire for attentional control that comprises two subscales, attention-shift (...) and attention-focus. To assess experience of RHI, the Botvinick and Cohen (1998) questionnaire was used and illusion onset time was recorded. Our results indicate that rapidity of onset reliably indicates illusion strength. Regression analysis revealed that participants evincing less switch cost and higher attention-shift scores had faster RHI onset times, and that those with higher attention-shift scores experienced the RHI more vividly. These results suggest that the multi-sensory hypothesis is not sufficient to explain the illusion: higher cognitive functions should be taken into account when explaining variation in the experience of ownership for the rubber hand. (shrink)