This book concerns the foundations of epistemic modality and hyperintensionality and their applications to the philosophy of mathematics. I examine the nature of epistemic modality, when the modal operator is interpreted as concerning both apriority and conceivability, as well as states of knowledge and belief. The book demonstrates how epistemic modality and hyperintensionality relate to the computational theory of mind; metaphysical modality and hyperintensionality; the types of mathematical modality and hyperintensionality; to the epistemic status of large cardinal axioms, undecidable propositions, (...) and abstraction principles in the philosophy of mathematics; to the modal and hyperintensional profiles of the logic of rational intuition; and to the types of intention, when the latter is interpreted as a hyperintensional mental state. Chapter 2 argues for a novel type of expressivism based on the duality between the categories of coalgebras and algebras, and argues that the duality permits of the reconciliation between modal cognitivism and modal expressivism. I also develop a novel topic-sensitive truthmaker semantics for dynamic epistemic logic, and develop a novel dynamic epistemic two-dimensional hyperintensional semantics. Chapter 3 provides an abstraction principle for epistemic (hyper-)intensions. Chapter 4 advances a topic-sensitive two-dimensional truthmaker semantics, and provides three novel interpretations of the framework along with the epistemic and metasemantic. Chapter 5 applies the fixed points of the modal μ-calculus in order to account for the iteration of epistemic states in a single agent, by contrast to availing of modal axiom 4 (i.e. the KK principle). The fixed point operators in the modal μ-calculus are rendered hyperintensional, which yields the first hyperintensional construal of the modal μ-calculus in the literature and the first application of the calculus to the iteration of epistemic states in a single agent instead of the common knowledge of a group of agents. Chapter 6 advances a solution to the Julius Caesar problem based on Fine's `criterial' identity conditions which incorporate conditions on essentiality and grounding. Chapter 7 provides a ground-theoretic regimentation of the proposals in the metaphysics of consciousness and examines its bearing on the two-dimensional conceivability argument against physicalism. The topic-sensitive epistemic two-dimensional truthmaker semantics developed in chapters 2 and 4 are availed of in order for epistemic states to be a guide to metaphysical states in the hyperintensional setting. -/- Chapters 8-12 provide cases demonstrating how the two-dimensional hyperintensions of hyperintensional, i.e. topic-sensitive epistemic two-dimensional truthmaker, semantics, solve the access problem in the epistemology of mathematics. Chapter 8 examines the interaction between my hyperintensional semantics and the axioms of epistemic set theory, large cardinal axioms, the Epistemic Church-Turing Thesis, the modal axioms governing the modal profile of Ω-logic, Orey sentences such as the Generalized Continuum Hypothesis, and absolute decidability. These results yield inter alia the first hyperintensional Epistemic Church-Turing Thesis and hyperintensional epistemic set theories in the literature. Chapter 9 examines the modal and hyperintensional commitments of abstractionism, in particular necessitism, and epistemic hyperintensionality, epistemic utility theory, and the epistemology of abstraction. I countenance a hyperintensional semantics for novel epistemic abstractionist modalities. I suggest, too, that observational type theory can be applied to first-order abstraction principles in order to make first-order abstraction principles recursively enumerable, i.e. Turing machine computable, and that the truth of the first-order abstraction principle for hyperintensions is grounded in its being possibly recursively enumerable and the machine being physically implementable. Chapter 10 examines the philosophical significance of hyperintensional Ω-logic in set theory and discusses the hyperintensionality of metamathematics. Chapter 11 provides a modal logic for rational intuition and provides a hyperintensional semantics. Chapter 12 avails of modal coalgebras to interpret the defining properties of indefinite extensibility, and avails of hyperintensional epistemic two-dimensional semantics in order to account for the interaction between the interpretational and objective modalities and truthmakers thereof. This yields the first hyperintensional category theory in the literature. I invent a new mathematical trick in which first order structures are treated as categories, and Vopenka's principle can be satisfied because of the elementary embeddings between the categories and generate Vopenka cardinals while bypassing the category of Set in category theory. Chapter 13 examines modal responses to the alethic paradoxes. Chapter 14 examines, finally, the modal and hyperintensional semantics for the different types of intention and the relation of the latter to evidential decision theory. (shrink)

In this paper, I review the main criteria offered for distinguishing the modal and amodal approaches to conceptual format: the type of input to which the representations respond, the relation they bear to perceptual states, and the specific neural systems to which they belong. I evaluate different interpretations of them and argue that they all face difficulties. I further show that they lead to cross-classifications of certain types of representations, using approximate number representations as an example.

Three thoughts strongly influence recent work on sensory imagination, often without explicit articulation. The image thought says that all mental states involving a mental image are imaginative. The attitude thought says that, if there is a distinctive imaginative attitude, it is a single, monolithic attitude. The function thought says that the functions of sensory imagination are identical or akin to functions of other mental states such as judgment or belief. Taken together, these thoughts create a theoretical context within which eliminativism (...) appears attractive. Eliminativism is the idea that we needn’t refer to a distinctive attitude in order to characterize sensory imagination: the attitudes involved in other states provide all the resources we need. Peter Langland-Hassan’s account of sensory imagination provides an example of such eliminativism. Via close examination of this account, I make manifest the three thoughts and their collective tendency to support eliminativism. I argue that all three are dubious, and that we should reject eliminativism; we need a distinctive imaginative attitude if we are to adequately explicate sensory imagination. (shrink)

Several theorists argue that one does not experience something as being at or coming from a distance or direction in olfaction. In contrast to this, I suggest that there can be a variety of spatial aspects of both synchronic and diachronic olfactory experiences, including spatial distance and direction. I emphasise, however, that these are not aspects of every olfactory experience. Thus, I suggest renouncing the widespread assumption there is a uniform account of the nature, including the spatial nature, of what (...) is experienced in olfactory experience. (shrink)

The telepresence experience can be evoked in a number of ways. A well-known example is a player of videogames who reports about a telepresence experience, a subjective experience of being in one place or environment, even when physically situated in another place. In this paper we set the phenomenon of telepresence into a theoretical framework. As people react subjectively to stimuli from telepresence, empirical studies can give more evidence about the phenomenon. Thus, our contribution is to bridge the theoretical with (...) the empirical. We discuss theories of perception with an emphasis on Heidegger, Merleau-Ponty and Gibson, the role of the senses and the Spinozian belief procedure. The aim is to contribute to our understanding of this phenomenon. A telepresence-study that included the affordance concept is used to empirically study how players report sense-reactions to virtual sightseeing in two cities. We investigate and explore the interplay of the philosophical and the empirical. The findings indicate that it is not only the visual sense that plays a role in this experience, but all senses. (shrink)

This dissertation concerns the foundations of epistemic modality. I examine the nature of epistemic modality, when the modal operator is interpreted as concerning both apriority and conceivability, as well as states of knowledge and belief. The dissertation demonstrates how phenomenal consciousness and gradational possible-worlds models in Bayesian perceptual psychology relate to epistemic modal space. The dissertation demonstrates, then, how epistemic modality relates to the computational theory of mind; metaphysical modality; deontic modality; logical modality; the types of mathematical modality; to the (...) epistemic status of undecidable propositions and abstraction principles in the philosophy of mathematics; to the apriori-aposteriori distinction; to the modal profile of rational propositional intuition; and to the types of intention, when the latter is interpreted as a modal mental state. Examining the nature of epistemic logic itself, I develop a novel approach to conditions of self-knowledge in the setting of the modal μ-calculus, as well as novel epistemicist solutions to Curry's, the liar, and the knowability paradoxes. Solutions to previously intransigent issues concerning the first-person concept; the distinction between fundamental and derivative truths; and the unity of intention and its role in decision theory, are developed along the way. (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)

I argue that perceptual consciousness is constituted by a mental activity. The mental activity in question is the activity of employing perceptual capacities, such as discriminatory, selective capacities. This is a radical view, but I hope to make it plausible. In arguing for this mental activist view, I reject orthodox views on which perceptual consciousness is analyzed in terms of peculiar entities, such as, phenomenal properties, external mind-independent properties, propositions, sense-data, qualia, or intentional objects.

I consider the role of psychology and other sciences in telling us about our senses, via the issue of whether empirical findings show us that flavours are perceived partly with the sense of smell. I argue that scientific findings do not establish that we're wrong to think that flavours are just tasted. Non-naturalism, according to which our everyday conception of the senses does not involve empirical commitments of a kind that could be corrected by empirical findings is, I suggest, a (...) plausible view that is not easy to dismiss. (shrink)

Phenomenologists such as Husserl, Heidegger and Merleau-Ponty reject the kind of scientific naturalism or that takes empirical science to be epistemologically and metaphysically privileged over all other forms of enquiry. In this paper, I will consider one of their principal complaints against naturalism, that scientific accounts of things are oblivious to a that is presupposed by the intelligibility of science. Focusing mostly upon Husserl's work, I attempt to clarify the nature of this complaint and state it in the form of (...) an argument. I conclude that the argument is effective in exposing naturalism's reliance upon impoverished conceptions of human experience, and that it also weakens the more general case for naturalism. (shrink)

Sensory substitution presents the philosopher of cognitive science with a particularly interesting case. Using prosthetics to map visual stimuli onto other modalities, such as touch or audition, otherwise blind individuals may develop perceptual capacities and behaviours commonly associated with sight. Experienced users can distinguish ‘visually’ presented objects and will even jerk back from a looming surface. Whether perception with sensory substitution devices should be classed as a type of vision, some other modality, or a new sense remains a matter of (...) debate, however. In the following, I review arguments commonly used to rebut the visual interpretation and, drawing on recent experimental studies and phenomenological self-reports, construct a novel case for treating sensory substitution as a visual process. (shrink)

In this paper, I argue that the conscious awareness one has of oneself as acting, i.e., agentive awareness, is not a type of sensory awareness. After providing some set up in Sect. 1, I move on in Sect. 2 to sketch a profile of sensory agentive experiences as representational states with sensory qualities by which we come to be aware of ourselves as performing actions. In Sect. 3, I critique two leading arguments in favor of positing such sensory experiences: the (...) argument from pathology and the argument from cognitive impenetrability. Since neither of these arguments succeeds, the case for positing SAEs is dealt a significant blow. I proceed in Sect. 4 to advance my positive argument against SAEs. The argument runs as follows: If SAEs exist, then they must exist in some sensory modality or set of sensory modalities. Either the relevant sensory modalities are ones that we already recognize, or they are novel sensory modalities. I will argue that neither of these options is workable, and so we have nowhere to locate SAEs. Agentive awareness is not sensory awareness. (shrink)

Some have claimed that there are laws of appearance, i.e. in principle constraints on which types of sensory experiences are possible. Within a representationalist framework, these laws amount to restrictions on what a given experience can represent. I offer an in-depth defence of one such law and explain why prevalent externalist varieties of representationalism have trouble accommodating it. In light of this, I propose a variety of representationalism on which the spatial content of experience is determined by intrinsic features of (...) conscious subjects. I conclude by considering an externalist-friendly reworking of my proposal, but suggest that the success of such a reworking is dubious. (shrink)

Objects are central to perception and our interactions with the world. We perceive the world as parsed into discrete entities that instantiate particular properties, and these items capture our attention and shape how we interact with the environment. Recently there has been some debate about whether the sense of smell allows us to perceive odours as discrete objects, with some suggesting that olfaction is aspatial and doesn’t allow for object-individuation. This paper offers two empirically tractable criteria for assessing whether particular (...) objects are exhibited in perceptual experience— susceptibility to figure-ground segregation and perceptual constancies—and argues that these criteria are fulfilled by olfactory perception, and thus there are olfactory objects. I argue that there are, in fact, two different ways that olfaction allows for figure-ground segregation. First, I look at various Gestalt grouping principles, which are thought to govern when features are perceived as grouped into structured wholes, segregated from everything around them. I argue that these principles apply to olfactory experience, providing evidence of non-spatial figure-ground segregation. Second, I defend the contentious idea that a spatial variety of figure-ground segregation can also occur in olfaction. To see this, however, we need to look to empirical evidence showing that tactile stimulation and bodily movements play a crucial role in olfactory phenomenology. Finally, I draw on empirical evidence and olfactory phenomenology to argue that there are perceptual constancies in olfactory experience, allowing us to perceive odours as coherent objects that survive shifts in our perspectives on the world. (shrink)

The purpose of this paper is to demonstrate that Francis Hutcheson’s moral sense theory offers a satisfactory account of moral perception. I introduce Hutcheson’s work in §1 and indicate why the existence of a sixth sense is not implausible. I provide a summary of Robert Cowan and Robert Audi’s respective theories of evaluative perception in §2, identifying three problematic objections: the Directness Objection to Cowan’s ethical perception and the aesthetic and perceptual model objections to Audi’s moral perception. §3 examines Hutcheson’s (...) moral sense theory, focusing on his discussion of benevolence, the desire for the happiness of others. I deal with the unresolved issues in Hutcheson’s account by recourse to Charles Darwin’s evolutionary perspective on the moral sense in §4, arguing for the moral sense as the second-order faculty for judging benevolence. I return, in §5, to the objections, showing that moral sense theory solves all three problems and therefore offers a satisfactory account of moral perception. (shrink)

Unlike those with type 1 blindsight, people who have type 2 blindsight have some sort of consciousness of the stimuli in their blind field. What is the nature of that consciousness? Is it visual experience? I address these questions by considering whether we can establish the existence of any structural—necessary—features of visual experience. I argue that it is very difficult to establish the existence of any such features. In particular, I investigate whether it is possible to visually, or more generally (...) perceptually, experience form or movement at a distance from our body, without experiencing colour. The traditional answer, advocated by Aristotle, and some other philosophers, up to and including the present day, is that it is not and hence colour is a structural feature of visual experience. I argue that there is no good reason to think that this is impossible, and provide evidence from four cases—sensory substitution, achomatopsia, phantom contours and amodal completion—in favour of the idea that it is possible. If it is possible then one important reason for rejecting the idea that people with type 2 blindsight do not have visual experiences is undermined. I suggest further experiments that could be done to help settle the matter. (shrink)

In this paper, I defend a new theory of the nature and individuation of perceptual capacities. I argue that we need a theory of perceptual capacities to explain modal facts about what sorts of perceptual phenomenal states one can be in. I defend my view by arguing for three adequacy constraints on a theory of perceptual capacities: perceptual capacities must be individuated at least partly in terms of their place in a hierarchy of capacities, where these capacities include the senses (...) themselves; an adequate account of perceptual capacities must be sensitive to empirical considerations; and an adequate account should accommodate the nature of the capacity to perceive. I arrive at these constraints by considering how Schellenberg’s view fails, before defending and developing my alternative in line with the constraints. I defend a view on which there are few, coarse-grained perceptual capacities which can fulfil complex explanatory roles because they are evaluatively gradable on many axes. Finally, on my view, perceptual capacities bear a particularly close relation to the sensory modalities themselves. (shrink)

How do we individuate the senses, what exactly do we do when we do so, and why does it matter? In the following article, I propose a general answer to these related questions based on Franz Brentano's views on the senses. After a short survey of various answers offered in the recent literature on the senses, I distinguish between two major ways of answering this question, causally and descriptively, arguing that only answers giving priority to description and to the classification (...) involved in it are on the right track for a general answer to the related questions. In the second part of the article, I argue that Brentano's descriptive psychology is an attractive candidate for such an answer. His descriptive psychology provides a plausible account of the classification involved in description, in particular regarding the classification of sensory qualities. I close the article by briefly explaining how Brentano spells out the priority of descriptive answers over causal ones. (shrink)

Though pain scientists now understand pain to be a complex experience typically composed of sensation, emotion, cognition, and motivational responses, many philosophers maintain that pain is adequately characterized by one privileged aspect of this complexity. Philosophically dominant unitary accounts of pain as a sensation or perception are here evaluated by their ability to explain actual cases—and found wanting. Further, it is argued that no forthcoming unitary characterization of pain is likely to succeed. Instead, I contend that both the motivating intuitions (...) behind unitary accounts and the wide range of pain phenomena are best accommodated by a componential view of pain that does not privilege any single component as necessary or sufficient. (shrink)

Some sensory modalities, such as sight, touch and audition, are arguably spatial, and one way to understand these spatial senses is to investigate spatial representations in them. Here I focus on a specific element in this area— the interplay between perspectival variation and spatial constancy—and discuss recent interdisciplinary works on this topic. With these relevant experimental works, we will see clearly how traditional controversies in philosophy, for example, whether we perceive perspectival shapes as well as objective shapes, and whether any (...) sensory field should be postulated in senses other than vision, can benefit from considerations in empirical sciences. (shrink)

Nowadays, philosophers and scientists tend to agree that, even though human and artificial intelligence work quite differently, they can still illuminate aspects of each other, and knowledge in one domain can inspire progress in the other. For instance, the notion of “artificial” or “synthetic” phenomenology has been gaining some traction in recent AI research. In this paper, we ask the question: what (if anything) is the use of thinking about phenomenology in the context of AI, and in particular machine learning? (...) We will isolate one sense of “phenomenology”, namely the sense in which it is commonly understood within analytic philosophy of perception. Then, we will give examples of projects within sensory substitution and restoration science that rely heavily on machine learning and to which, according to us, phenomenology in the sense specified makes a relevant contribution. Finally, we will shed some light on what this contribution looks like and why it is important. (shrink)

Multisensory processing encompasses all of the various ways in which the presence of information in one sensory modality can adaptively influence the processing of information in a different modality. In Part I of this survey article, I begin by presenting a cartography of some of the more extensively investigated forms of multisensory processing, with a special focus on two distinct types of multisensory integration. I briefly discuss the conditions under which these different forms of multisensory processing occur as well as (...) their important perceptual consequences and interrelations. In Part II, I then turn to examining of 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 attempts to individuate the senses. (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.

Since the 1970s, researchers have focused on visual joint attention as a way to observe and operationalize joint attention. I will argue that this methodological choice has neglected other modalities and as a consequence might be missing important elements in the account of the development of JA and the evolutionary history of JA. I argue that by including other modes of interaction, such as touch, we open the possibility of finding that non-human primates and younger human infants engage in basic (...) forms of JA. Moreover, I argue that touch, as a proximal mode of perception, is the ontogenetic precursor of social communication. (shrink)

According to a traditional view, perceptual experiences are composites of distinct sensory and cognitive components. This dual-component theory has many benefits; in particular, it purports to offer a way forward in the debate over what kinds of properties perceptual experiences represent. On this kind of view, the issue reduces to the questions of what the sensory and cognitive components respectively represent. Here, I focus on the former topic. I propose a theory of the contents of the sensory aspects of perceptual (...) experience that provides clear criteria for identifying what kinds of properties they represent. (shrink)

Normal 0 21 false false false MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Tabela normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Times New Roman"; mso-ansi-language:#0400; mso-fareast-language:#0400; mso-bidi-language:#0400;} Podemos ver na ausência de luz, e ouvir na ausência de som? Em seu livro Seeing Dark Things: The Philosophy of Shadows (2008), Roy Sorensen defende que sim, que podemos ver a escuridão na ausência de luz, e ouvir o silêncio na ausência de som. Neste artigo, defendo que (...) na escuridão nada vemos, no silêncio nada ouvimos, e que experienciar a ausência de luz e som é uma questão afetiva, e não perceptual. (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)

Quality-space theory (QST) explains the nature of the mental qualities distinctive of perceptual states by appeal to their role in perceiving. QST is typically described in terms of the mental qualities that pertain to color. Here we apply QST to the olfactory modalities. Olfaction is in various respects more complex than vision, and so provides a useful test case for QST. To determine whether QST can deal with the challenges olfaction presents, we show how a quality space (QS) could be (...) constructed relying on olfactory perceptible properties and the olfactory mental qualities then defined by appeal to that QS of olfactory perceptible properties. We also consider how to delimit the olfactory QS from other modalities. We further apply QST to the role that experience plays in refining our olfactory discriminative abilities and the occurrence of olfactory mental qualities in non-conscious olfactory states. QST is shown to be fully applicable to and useful for understanding the complex domain of olfaction. (shrink)

Ordinary Language Philosophy has largely fallen out of favour, and with it the belief in the primary importance of analyses of ordinary language for philosophical purposes. Still, in their various endeavours, philosophers not only from analytic but also from other backgrounds refer to the use and meaning of terms of interest in ordinary parlance. In doing so, they most commonly appeal to their own linguistic intuitions. Often, the appeal to individual intuitions is supplemented by reference to dictionaries. In recent times, (...) Internet search engine queries for expressions of interest have become quite popular. Apparently, philosophers attempt to surpass the limits of their own linguistic intuitions by appealing to experts or to factual uses of language. I argue that this attempt is commendable but that its execution is wanting. Instead of appealing to dictionaries or Internet queries, philosophers should employ computer-based linguistic corpora in order to confirm or falsify hypotheses about the factual use of language. This approach also has some advantages over methods employed by experimental philosophers. If the importance of ordinary language is stressed, the use of linguistic corpora is hardly avoidable. (shrink)

Distributive egalitarians believe that distributive justice is to be explained by the idea of distributive equality (DE) and that DE is of intrinsic value. The socio-relational critique argues that distributive egalitarianism does not account for the “true” value of equality, which rather lies in the idea of “equality as a substantive social value” (ESV). This paper examines the socio-relational critique and argues that it fails because – contrary to what the critique presupposes –, first, ESV is not conceptually distinct from (...) DE, and second, the idea of ESV cannot serve as a “foundation” or “root” of distributive egalitarianism. (shrink)

It is hoped that modern sensory substitution and augmentation devices will be able to replace or expand our senses. But to what extent has this been achieved to date? To what extent are the experiences created by sensory substitution devices like the sensory experiences that we are trying to replace? To what extent can we augment people’s senses providing them with new information and new experiences? The first aim of this introduction is to delve deeply into this question to discover (...) the usefulness of these devices, to outline the different sorts of experience that might be created, and what the evidence tells us about these experiences. While there are some reasons to be hopeful about the powers of sensory substitution devices, there are also reasons to wonder whether they will ever really have the practical applications that we hope they might have. The second aim is to look to see whether the study of modern sensory substitution and augmentation devices can shed light on the nature of our senses and perception in general. Much of the philosophical, psychological, and neuroscientific work that takes place concerning sensory substitution and augmentation is keenly aware of the possibility that it might help our understanding and it seeks to comprehend many different aspects of perception. (shrink)