Casey O'Callaghan

Perceptual malleability and diversity can stem from perceptual learning, expertise, genetics, disease, or accident. Perceptual malleability and diversity force us to reject the claim that perceptual capacities, perceptual experience, and perceptual content are universal across subjects and times. And it casts doubt on the presumption of a universal human perceptual nature. However, it does not directly challenge perceptual objectivity, understood as the claim that one can perceive a world of things and features that are independent from oneself and one's experiences and that could be perceived by other subjects.

In crossmodal identification, a subject token identifies an item perceived in one sensory modality with an item perceived in another sensory modality. Does crossmodal identification always occur in cognition, or does crossmodal identification sometimes take place in perception? This paper argues that crossmodal identification occurs in cognition, and not in perception. Nevertheless, multisensory perception is not unalive to crossmodal identity. Experimental evidence demonstrates that perception is differentially sensitive to the identity of individuals presented to distinct senses. Such sensitivity enhances recognition and improves action. This approach relies on distinguishing crossmodal identification from perceiving crossmodal identity. Perception registers crossmodal identity, but crossmodal identification as such belongs to thought.

Paradigms in philosophy and cognitive science until recently have treated perception in typical human beings as relatively fixed and unchanging. Recent research instead supports the claim that perception can be altered over time by training, deliberate practice or mere exposure. If so, we do not all bring to a scene the same stock of perceptual capacities, and our differences are not just deficits or superpowers. This paper describes six questions an account of perceptual learning ought to address, which pose difficult challenges to Kevin Connolly’s (2019) groundbreaking Offloading View of perceptual learning. In light of these questions, it sketches an alternative simple view according to which perceptual learning is acquiring a new or enhanced perceptual capacity in a particular way. The relevant capacity is a capacity perceptually to detect and differentiate a feature, where doing so constitutively if not wholly implicates perception. The relevant way is by means of an independently characterized learning process, rather than by adaptation, pure development, or mere accident. The perceptual change thus results from a smart process – one that is flexible, resilient, and responsive to feedback, rather than rigid, fragile and brute. Such a process can yield perceptual know-how. Thanks to perceptual learning, one comes to know how to perceive, in a sense that means being able to do so. Some specialists hone this to develop perceptual skills that are implicated in expert performance.

This paper presents an account of the senses and what differentiates them that is compatible with richly multisensory perception and consciousness. According to this proposal, senses are ways of perceiving. Each sense is a subfaculty that comprises a collection of perceptual capacities. What each sense shares and what differentiates one sense from another is the manner in which those capacities are exercised. Each way of perceiving involves a distinct type of information gathering, individuated by the information it functions to extract and the medium from which it does so. This approach distinguishes the project of characterizing and differentiating senses from that of attributing experiences to sensory modalities. Perceptual experiences are episodes in which perceptual capacities are exer- cised. Conscious perceptual episodes may be ascribed to distinct sensory modalities, according to the manners in which perceptual capacities are deployed on an occasion. According to this account, senses are not exclusive. First, their capacities may overlap. Second, perceptual episodes, including conscious experiences, may belong to multiple senses. Indeed, some episodes require the joint use of several senses. In this account, subjects have only limited first-person knowledge of the senses they employ.

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.

Sounds are audible, and sound sources are audible. What is the audible relation between audible sounds and audible sources? Common talk and philosophy suggest three candidates. The first is that sounds audibly are properties instantiated by their sources. I argue that sounds are audible individuals and thus are not audibly instantiated by audible sources. The second is that sounds audibly are effects of their sources. I argue that auditory experience presents no compelling evidence that sounds audibly are causally related to audible sources. The third is that sounds audibly are related mereologically to their sources. I present and offer a defence of this third candidate

I argue that sounds are best conceived not as pressure waves that travel through a medium, nor as physical properties of the objects ordinarily thought to be the sources of sounds, but rather as events of a certain kind. Sounds are particular events in which a surrounding medium is disturbed or set into wavelike motion by the activities of a body or interacting bodies. This Event View of sounds provides for a uni- ?ed perceptual account of several pervasive sound phenomena, including transmission through barriers, constructive and destructive interference, and echoes

Recent work on non-visual modalities aims to translate, extend, revise, or unify claims about perception beyond vision. This paper presents central lessons drawn from attention to hearing, sounds, and multimodality. It focuses on auditory awareness and its objects, and it advances more general lessons for perceptual theorizing that emerge from thinking about sounds and audition. The paper argues that sounds and audition no better support the privacy of perception’s objects than does vision; that perceptual objects are more diverse than an exclusively visual perspective suggests; and that multimodality is rampant. In doing so, it presents an account according to which audition affords awareness as of not just sounds, but also environmental happenings beyond sounds.

Listening to speech in a language you know differs phenomenologically from listening to speech in an unfamiliar language, a fact often exploited in debates about the phenomenology of thought and cognition. It is plausible that the difference is partly perceptual. Some contend that hearing familiar language involves auditory perceptual awareness of meanings or semantic properties of spoken utterances; but if this were so, there must be something distinctive it is like auditorily to perceptually experience specific meanings of spoken utterances. However, an argument from homophony shows that auditory experiences do not resolve differences in meaning not marked by differences in sound. I propose an alternative explanation of the perceptual phenomenal difference in terms of perceptual awareness of language-specific but non-semantic features

Object perception deploys a suite of perceptual capacities that constrains attention, guides reidentification, subserves recognition, and anchors demonstrative thought. Objects for perception—perceptual objects—are the targets of such capacities. Characterizing perceptual objects for multisensory perception faces two puzzles. First is the diversity of objects across sensory modalities. Second is the unity of multisensory perceptual objects. This paper resolves the puzzles. Objects for perception are structured mereologically complex individuals. Perceptual objects are items that bear perceptible features and have perceptible parts arranged to form a unified whole. This circumscribes the targets of object perception where neutral talk concerning intentional objects and objects of perception cannot. Nonetheless, it is more permissive than identifying perceptual objects with material bodies, which excludes too much and leans too heavily on vision. The account thus is tailored to capture the role of objects in perception beyond vision: tactual, auditory, and olfactory objects are individuals with differing structures. Its flexibility also enables the account to accommodate shared objects for multisensory perception: multisensory perceptual objects are mereologically complex individuals with hybrid structure. For instance, one can bimodally perceive a common whole with parts accessible to one but not both modalities. Each sense provides a partial perspective on a complex whole that is perceptible through the coordinated use of multiple senses. Understanding perceptual objects as structured mereologically complex individuals thus provides a theoretically useful notion of an object for multisensory perception that resolves the puzzles of diversity and of unity

Philosophers and cognitive scientists of perception by custom have investigated individual sense modalities in relative isolation from each other. However, perceiving is, in a number of respects, multimodal. The traditional sense modalities should not be treated as explanatorily independent. Attention to the multimodal aspects of perception challenges common assumptions about the content and phenomenology of perception, and about the individuation and psychological nature of sense modalities. Multimodal perception thus presents a valuable opportunity for a case study in mature interdisciplinary cognitive science. This chapter aims to raise these issues against the background of unimodal approaches in the study of perception. It presents some of the central empirical findings concerning multimodality, and it explains the philosophical implications of these findings. Foremost, it aims to encourage and open avenues for future research.

My thesis is that perceptual awareness is richly multisensory. I argue for this conclusion on the grounds that certain forms of multisensory perceptual experience are incompatible with the claim that each aspect of a perceptual experience is associated with some specific sensory modality or another. First, I explicate what it is for some feature of a conscious perceptual episode to be modality specific. Then, I argue based on philosophical and experimental evidence that some novel intermodal features are perceptible only through the coordinated use of multiple senses. I appeal to cases that involve consciously perceptible feature instances and feature types that could not be perceptually experienced through the use of individual sense modalities working on their own or simply in parallel and co-consciously. Finally, I offer an account of how to type perceptual experiences by modality that makes room for richly multisensory experiences

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.

... ISBN0199215928 ... Abstract: Vision dominates philosophical thinking about perception, and theorizing about experience in cognitive science traditionally has focused on a visual model. This book presents a systematic treatment of sounds and auditory experience. It demonstrates how thinking about audition and appreciating the relationships among multiple sense modalities enriches our understanding of perception. It articulates the central questions that comprise the philosophy of sound, and proposes a novel theory of sounds and their perception. Against the widely accepted philosophical view that sounds are among the secondary or sensible qualities, and against the scientific view that sounds are waves that propagate through a medium such as air or water, the book argues that sounds are events in which objects or interacting bodies disturb a surrounding medium. This does not imply that sounds propagate through a medium, such as air or water. Rather, sounds are events that take place in one's environment at or near their sources. This account captures the way in which sounds essentially are creatures of time and situates sounds in the world. Sounds are not ethereal, mysterious entities. It also provides a powerful account of echoes, interference, reverberation, Doppler effects, and perceptual constancies that surpasses the explanatory richness of alternative theories. Investigating sounds and audition demonstrates that considering other sense modalities teaches what we could not otherwise learn from thinking exclusively about the visual. This book concludes by arguing that a surprising class of cross-modal perceptual illusions demonstrates that the perceptual modalities cannot be completely understood in isolation, and that a visuocentric model for theorizing about perception — according to which perceptual modalities are discrete modes of experience and autonomous domains of philosophical and scientific inquiry — ought to be abandoned.

Despite its admirable bottom-up methodology, Roy Sorensen's Seeing Dark Things (OUP, 2008) raises difficult theoretical questions concerning the metaphysics and perception of absences. Metaphysical difficulties include how to individuate, count, locate, and classify absences, and what determines their features. Perceptual difficulties include how to distinguish experiences of absences and presences, especially when nonveridical, and what subjects contribute to perceptual experience according to Sorensen's causal theory. In addition to articulating these difficulties, this paper also presents and explores, on Sorensen's terms, an alternative account of silence.

Vision has been the primary focus of naturalistic philosophical research concerning perception and perceptual experience. Guided by visual experience and vision science, many philosophers have focused upon theoretical issues dealing with the perception of objects. Recently, however, hearing researchers have discussed auditory objects. I present the case for object perception in vision, and argue that an analog of object perception occurs in auditory perception. I propose a notion of an auditory object that is stronger than just that of an intentional object of audition, but that does not identify auditory objects with the ordinary material objects we see.

Frequently, we learn of the locations of things and events in our environment by means of hearing. Hearing, I argue, is a locational mode of perceiving with a robustly spatial phenomenology. I defend three proposals. First, audition furnishes one with information about the locations of things and happenings in one’s environment because auditory experience itself has spatial content—auditory experience involves awareness of space. Second, we hear the locations of things and events by or in hearing the locations of their sounds. Third, we auditorily experience sounds themselves as having relatively stable distal locations. I reject skepticism about spatial audition and auditory experience tracing to Strawson’s Individuals , and suggest that spatial auditory experience grounds a form of perceptual access to objects and events that is critical to negotiating one’s environment.

Hearing and auditory perception are rapidly developing topics in the philosophy of perception. Recent work has focused on characterizing what we hear and on similarities and differences between audition and other modalities. Future work should address how theorizing about audition impacts theorizing about perception more generally. This entry concerns questions about the objects and contents of hearing. It includes discussion of the spatial content of audition, of the role of time and pitch in the individuation of auditory objects, and of audition's role in the perception of speech.

Sounds and Perception brings together original essays on auditory perception and the nature of sounds - an emerging area of interest in the philosophy of mind and perception, and in the metaphysics of sensible qualities. The essays discuss a wide range of issues, including the nature of sound, the spatial aspects of auditory experience, hearing silence, musical experience, and the perception of speech; a substantial introduction by the editors serves to contextualise the essays and make connections between them. The collection serves both as an introduction to the nature of auditory perception and as the definitive resource for coverage of the main questions that constitute the philosophy of sounds and audition.