We provide a new account of the oft-mentioned special character of touch, showing that its superior reliability is subjective rather than objective : Touch provides higher certainty than vision, for the same level of objective accuracy.

Representationalists hold that the phenomenal character of a perceptual experience is identical with, or supervenes on, an aspect of its representational content. As such, representationalism could be disproved by a counter-example consisting of two experiences that have the same representational content but differ in phenomenal character. In this paper, I discuss two recently proposed counter-examples to representationalism that involve ambiguous or reversible figures. I pursue two goals. My first, and most important, goal is to show that the representationalist can (...) offer plausible responses to both counter-examples. My second goal is to show the implications of these responses for the nature of the spatial representational contents of perceptual experiences. (shrink)

I argued in Nanay 2010 that we cannot characterize perceptual content without reference to attention. Here, I defend this account from three objections raised by Jagnow 2011. This mainly takes the form of clarifying some details not sufficiently elaborated in the original article and dispelling some potential misunderstandings.

While the recognition of ambiguous emotions is crucial for successful social interactions, previous work has shown that they are perceived differently depending on whether they are viewed on male or female faces. The present paper aims to shed light on this phenomenon by exploring two hypotheses: the confounded signal hypothesis, which posits the existence of perceptual overlaps between emotions and gendered morphotypes, and the social role hypothesis, according to which the observer's responses are biased by stereotypes. Participants were asked (...) to categorise blended faces (i.e. artificial faces made ambiguous by mixing two emotions) in a forced-choice task. Six emotions were used to create each blend (neutral, surprise, sadness, fear, happiness, anger), for a total of 15 expressions. We then applied signal detection theory – considering both the morphotype of the stimuli and the participants’ gender – to distinguish participants’ perceptual processes from their response biases. The results showed a perceptual advantage for anger on male faces and for sadness on female faces. However, different strategies were deployed when labelling emotions on gendered morphotypes. In particular, a response bias towards angry male faces establishes their special status, as they resulted in both excellent detection and a tendency to be over-reported, especially by women. (shrink)

Spontaneous eye blinks are modulated around perceptual events. Our previous study, using a visual ambiguous stimulus, indicated that blink probability decreases before a reported perceptual switch. In the current study, we tested our hypothesis that an absence of blinks marks a time in which perceptual switches are facilitated in‐ and outside the visual domain. In three experiments, presenting either a visual motion quartet in light or darkness or a bistable auditory streaming stimulus, we found a co‐occurrence of (...) blink rate reduction with increased perceptual switch probability. In the visual domain, perceptual switches induced by a short interruption of visual input (blank) allowed an estimate of the timing of the perceptual event with respect to the motor response. This provided the first evidence that the blink reduction was not a consequence of the perceptual switch. Importantly, by showing that the time between switches and the previous blink was significantly longer than the inter‐blink interval, our studies allowed to conclude that perceptual switches did not happen at random but followed a prolonged period of nonblinking. Correspondingly, blink rate and switch rate showed an inverse relationship. Our study supports the idea that the absence or presence of blinks maps perceptual processes independent of the sensory modality. (shrink)

Both common sense and dominant traditions in art criticism and philosophical aesthetics have it that aesthetic features or properties are perceived. However, there is a cast of reasons to be sceptical of the thesis. This paper defends the thesis—that aesthetic properties are sometimes represented in perceptual experience—against one of those sceptical opponents. That opponent maintains that perception represents only low-level properties, and since all theorists agree that aesthetic properties are not low-level properties, perception does not represent aesthetic properties. I (...) offer a novel argument—what I call the argument from seeing-as—against that sceptic which moves from consideration of ambiguous figures to consideration of visual art. It concludes that aesthetic properties are sometimes perceived and delivers a general lesson for philosophy of perception. Contrary to extant theories of rich perceptual content, aesthetic properties are far better candidates for high-level perceptual contents than standardly theorized rich contents like natural kinds. (shrink)

Although symmetry has been discussed in terms of a major law of perceptual organization since the early conceptual efforts of the Gestalt school (Wertheimer, Metzger, Koffka and others), the first quantitative measurements testing for effects of symmetry on processes of Gestalt formation have seen the day only recently. In this study, a psychophysical rating study and a “foreground”-“background” choice response time experiment were run with human observers to test for effects of bilateral symmetry on the perceived strength of figure-ground (...) in triangular Kanizsa configurations. Displays with and without bilateral symmetry, identical physically-specified-to-total contour ratio, and constant local contrast intensity within and across conditions, but variable local contrast polarity and variable orientation in the plane, were presented in a random order to human observers. Configurations with bilateral symmetry produced significantly stronger figure-ground percepts reflected by greater subjective magnitudes and consistently higher percentages of “foreground” judgments accompanied by significantly shorter response times. These effects of symmetry depend neither on the orientation of the axis of symmetry, nor on the contrast polarity of the physical inducers. It is concluded that bilateral symmetry, irrespective of orientation, significantly contributes to the, largely sign-invariant, visual mechanisms of figure-ground segregation that determine the salience of figure-ground in perceptually ambiguous configurations. (shrink)

We perceive the objective world through a subjective perceptual veil. Various perceived properties, particularly “secondary qualities” like colours and tastes, are mind-dependent. Although mind-dependent, our knowledge of many facts about the perceptual veil is immediate and secure. These are well-known facets of sense-datum theory. My aim is to carve out a conception of sense-datum theory that does not require the immediate and secure knowledge of a wealth of facts about experienced sense-data (§1). Such a theory is of value (...) on its own, given well-known challenges to epistemic foundationalism. Beyond this such a theory helps demonstrate how sense-datum theory can accommodate challenging perceptual phenomena like shape and size constancies (§3). These ideas are bridged by the roots of perceptual ambiguity (§2). In brief, tapering acquaintance knowledge creates space for perceptual representation to resolve the ambiguities in presented objects seemingly inherent in scenarios involving perceptual constancies. Thus, I offer a two-factor (acquaintance-representation) sense-datum theory to meet the challenge posed by constancies. Following Smith (2002), from whom this challenge is drawn, my focus is on shape and size constancies. Other constancies, notably colour constancy, are treated elsewhere (Brown 2014). (shrink)

Macpherson (Nous 40(1):82–117, 2006) argues that the square/regular diamond figure threatens representationalism, construed as the theory which holds that the phenomenal character is explained by the nonconceptual content of experience. Her argument is the claim that representationalism is committed to the thesis that differences in the experience of ambiguous figures, the gestalt switch, should be explained by differences in the NCC of perception of these figures. However, with respect to the square/regular diamond and some other ambiguous figure representationalism fails to (...) offer a unified account of how representational content makes them ambiguous. In this paper, I aim, first, to offer a representationalist account of ambiguous figures and, second, to examine and rebut Macpherson’s arguments. My main point is that in each ambiguous figure Macpherson discusses there are differences in representational content that can explain differences in phenomenal character or content. The representational differences are due to the ways the Cartesian frame of reference in which perceptual content is always cast cuts the figure, underlying different properties of the figure with respect to the axes of the Cartesian frame of reference. (shrink)

This paper aims to shed new light on certain philosophical theories of perceptual experience by examining the semantics of perceptual ascriptions such as “Jones sees an apple.” I start with the assumption, recently defended elsewhere, that perceptual ascriptions lend themselves to intensional readings. In the first part of the paper, I defend three theses regarding such readings: I) intensional readings of perceptual ascriptions ascribe phenomenal properties, II) perceptual verbs are not ambiguous between intensional and extensional (...) readings, and III) intensional perceptual ascriptions have a relational form. The second part of the paper describes the implications of I-III for theories of perceptual experience. I argue that I-III support and reconcile the three main views of perceptual experience, relationalism, disjunctivism, and representationalism. However, I-III leave open at least one important point of contention: particularism, the view that we experience external objects. I conclude by exploring the implications of accepting or denying particularism given I-III. (shrink)

Speech categories are defined by multiple acoustic dimensions and their boundaries are generally fuzzy and ambiguous in part because listeners often give differential weighting to these cue dimensions during phonetic categorization. This study explored how a listener's perception of a speaker's socio-indexical and personality characteristics influences the listener's perceptual cue weighting. In a matched-guise study, three groups of listeners classified a series of gender-neutral /b/-/p/ continua that vary in VOT and F0 at the onset of the following vowel. Listeners (...) were assigned to one of three prompt conditions and rated the talker in terms of vocal gender prototypicality, attractiveness, friendliness, confidence, trustworthiness, and gayness. Male listeners and listeners who saw a male face showed less reliance on VOT compared to listeners in the other conditions. Listeners' visual evaluation of the talker also affected their weighting of VOT and onset F0 cues, although the effects of facial impressions differ depending on the gender of the listener. The results demonstrate that individual differences in perceptual cue weighting are modulated by the listener's gender and his/her subjective evaluation of the talker. These findings lend support for exemplar-based models of speech perception and production where socio-indexical features are encoded as a part of the episodic traces in the listeners' mental lexicon. This study also shed light on the relationship between individual variation in cue weighting and community-level sound change by demonstrating that VOT and onset F0 co-variation in North American English has acquired a certain degree of socio-indexical significance. (shrink)

Ambiguous figures pose a problem for representationalists, particularly for representationalists who believe that the content of perceptual experience is non-conceptual (MacPherson in Nous 40(1):82–117, 2006). This is because, in viewing ambiguous figures, subjects have perceptual experiences that differ in phenomenal properties without differing in non-conceptual content. In this paper, I argue that ambiguous figures pose no problem for non-conceptual representationalists. I argue that aspect shifts do not presuppose or require the possession of sophisticated conceptual resources and that, although (...) viewing ambiguous figures often causes a change in phenomenal properties, this change is accompanied by a change in non-conceptual content. I illustrate the case by considering specific examples. (shrink)

In his book Action in Perception, Alva Noë poses what he refers to as the “problem of perceptual presence” and develops his enactive view as solution to the problem. Noë describes the problem of perceptual presence as the problem of how to conceive of the presence of that which, “strictly speaking,” we do not perceive. I argue that the “problem of perceptual presence” is ambiguous between two problems that need to be addressed by invoking very different resources. (...) On the one hand, there is the problem of how to conceive of the presence of objects as wholes, front side and back, and their constant properties. On the other hand, there is the problem of how to account for the presence of unattended detail. I focus on the first problem, which Noë approaches by invoking Husserlian ideas. I argue that Noë’s enactive view encounters difficulties, which can be dealt with by complementing it with Edmund Husserl’s idea of fulfillment and generally restoring the view to its original Husserlian context. Contrary to Noë’s purport, this involves regarding the view not as a theory of perception and perceptual content but as part of a descriptive–clarificatory project of conceptual analysis. The Husserlian phenomenologist analyzes, e.g., the concept of shape or color by investigating the fulfillment conditions pertinent to shape or color. In general, my critique of Noë’s enactive view serves to caution philosophers against unprincipled uses of Husserlian ideas. (shrink)

As for most measurement procedures in the course of their development, measures of consciousness face the problem of coordination, i.e., the problem of knowing whether a measurement procedure actually measures what it is intended to measure. I focus on the case of the Perceptual Awareness Scale to illustrate how ignoring this problem leads to ambiguous interpretations of subjective reports in consciousness science. In turn, I show that empirical results based on this measurement procedure might be systematically misinterpreted.

The question whether perceptual experiences justify perceptual beliefs is ambiguous. One problem is the well familiar skeptical one. How can perceptual experiences justify beliefs if those experiences may systematically deceive us? Our experiences might be just as they are and yet the world might be radically different. But there is also another problem about the justification of perceptual beliefs which arises independently of the above skeptical worry. This other problem has to do with our understanding of (...) the very notion of justification. It seems natural to think that justification can exist only in so far as what is justified is inferentially linked to the justifier. The question, then, is whether perceptual experiences can serve as an inferential basis for perceptual beliefs. The content of experiences does not seem to be the same sort of content that is possessed by beliefs. So the nature of the relation between experiences and beliefs is far from obvious. In this paper I survey various attempts of justifying the view that there is an inferential relation between experiences and beliefs so that the latter can be justified by the former and I argue that none of those attempts is satisfactory. I also suggest that the problem which those attempts address may be illusory. Even though it seems true that experiences and beliefs possess different kinds of contents, there may be no logical gap between those contents that needs to be bridged by some philosophical reflection. (shrink)

The Mona Lisa is probably the most celebrated example of ambiguous expression in art. Soranzo and Newberry demonstrated that a similar ambiguity can be perceived also in La Bella Principessa, another portrait credited to Leonardo da Vinci by many. The paper aims to show that an ambiguous expression can be perceived in a further painting attributed to Leonardo: The Lady with Dishevelled Hair, or La Scapigliata. An experiment was conducted whereby participants rated on a 7-point Likert scale the perceived (...) level of contentment of La Scapigliata and that of a comparable painting created by Andrea di Cione, alias Il Verrocchio. The two artworks were presented in random order to two groups of participants. One group could see the artworks from Close whilst the other group from Far from a Close or Far condition. Results show that the change of distance affected the perceived level of contentment of Leonardo’s figure but not that of Verrocchio’s. Specifically, whilst both artworks received similar ratings of contentment from the close-up condition, La Scapigliata was perceived to be more content from afar. It is concluded that La Scapigliata exhibits an ambiguous expression, and that this ambiguity is similar to the one observed in the Mona Lisa and La Bella Principessa. This result can be only partially interpreted within the spatial frequency hypothesis advanced by Livingstone and shows that a phenomenological account of Leonardo’s work might be more suited to capture the full extent of the phenomenon. Specifically, it is suggested that the principles of perceptual belongingness may need to be considered to fully capture the extent of the ambiguity depicted by Leonardo. (shrink)

Perceptual processes, in particular modular processes, have long been understood as being mandatory. But exactly what mandatoriness amounts to is left to intuition. This paper identifies a crucial ambiguity in the notion of mandatoriness. Discussions of mandatory processes have run together notions of automaticity and ballisticity. Teasing apart these notions creates an important tool for the modularist's toolbox. Different putatively modular processes appear to differ in their kinds of mandatoriness. Separating out the automatic from the ballistic can help (...) the modularist diagnose and explain away some putative counterexamples to multimodal and central modules, thereby helping us to better evaluate the evidentiary status of modularity theory. (shrink)

While distinguishing between the actions and physical boundaries of self and other (non-self) is usually straightforward there are contexts in which such differentiation is challenging. For example, self-other ambiguity may occur when actions of others are similar or complementary to those of the self. Even in the absence of such situational challenges, individuals experiencing hallucinations have difficulties with this distinction, often experiencing thoughts or actions of self as belonging to other agents. This paper explores the role of ambiguity (...) in self-other differentiation, drawing from developmental, psychodynamic and neurocognitive perspectives. A key proposal is that engagement in contexts that make distinctions between self and other challenging yet necessary allow reality-testing skills related to agency to develop. Attunement in typical caregiver-infant interactions is framed as a safe but inherently ambiguous environment that provides optimal condition for the infant to develop a coherent self-other sense. Vulnerability to psychosis may be related to limited access to such an environment in early development. However, the perceptual, cognitive and social skills that contribution to attribution are likely to be malleable following infancy and improve though opportunities for boundary play in similarly ambiguous settings. Using music-making to illustrate, we postulate that engagement in intricate joint-actions that blurs agentic boundaries can contribute to the continued development of an adaptive sense of self and other essential to healthy social functioning. Increased insight into the self-other ambiguity may enhance our understanding of mechanisms underlying ‘self-disorders’ such as schizophrenia and eventually extend the range of social and arts-based therapeutic possibilities. (shrink)

Victor Vasarely's (1906–1997) important legacy to the study of human perception is brought to the forefront and discussed. A large part of his impressive work conveys the appearance of striking three-dimensional shapes and structures in a large-scale pictorial plane. Current perception science explains such effects by invoking brain mechanisms for the processing of monocular (2D) depth cues. Here in this study, we illustrate and explain local effects of 2D color and contrast cues on the perceptual organization in terms of (...) figure-ground assignments, i.e. which local surfaces are likely to be seen as “nearer” or “bigger” in the image plane. Paired configurations are embedded in a larger, structurally ambivalent pictorial context inspired by some of Vasarely's creations. The figure-ground effects these configurations produce reveal a significant correlation between perceptual solutions for “nearer” and “bigger” when other geometric depth cues are missing. In consistency with previous findings on similar, albeit simpler visual displays, a specific color may compete with luminance contrast to resolve the planar ambiguity of a complex pattern context at a critical point in the hierarchical resolution of figure-ground uncertainty. The potential role of color temperature in this process is brought forward here. Vasarely intuitively understood and successfully exploited the subtle context effects accounted for in this paper, well before empirical investigation had set out to study and explain them in terms of information processing by the visual brain. (shrink)

Correspondence should be addressed to David A. Leopold [email protected] the viewing of certain patterns, widely known as ambiguous or puzzle figures, perception lapses into a sequence of spontaneous alternations, switching every few seconds between two or more visual interpretations of the stimulus. Although their nature and origin remain topics of debate, these stochastic switches are generally thought to be the automatic and inevitable consequence of viewing a pattern without a unique solution. We report here that in humans such perceptual (...) alternations can be slowed, and even brought to a standstill, if the visual stimulus is periodically removed from view. We also show, with a visual illusion, that this stabilizing effect hinges on perceptual disappearance rather than on actual removal of the stimulus. These findings indicate that uninterrupted subjective perception of an ambiguous pattern is required for the initiation of the brain-state changes underlying multistable vision.Visual perception involves coordination between sensory sampling of the world and active interpretation of the sensory data. Human perception of objects and scenes is normally stable and robust, but it falters when one is presented with patterns that are inherently ambiguous or contradictory. Under such conditions, vision lapses into a chain of continually alternating percepts, whereby a viable visual interpretation dominates for a few seconds and is then replaced by a rival interpretation. This multistable vision, or 'multistability', is thought to result from destabilization of fundamental visual mechanisms, and has offered valuable insights into how sensory patterns are actively organized and interpreted in the brain1, 2. Despite a great deal of recent research and interest in multistable perception, however, its neurophysiological underpinnings remain poorly understood. Physiological studies have suggested that disambiguation of ambiguous patterns. (shrink)

Background: Continuous viewing of ambiguous patterns is characterized by wavering perception that alternates between two or more equally valid visual solutions. However, when such patterns are viewed intermittently, either by repetitive presentation or by periodic closing of the eyes, perception can become locked or "frozen" in one configuration for several minutes at a time. One aspect of this stabilization is the possible existence of a perceptual memory that persists during periods in which the ambiguous stimulus is absent. Here, we (...) use a novel paradgim of temporally interleaved ambiguous stimuli to explore the nature of this memory, with particular regard to its potential impact on perceptual organization. Results: We found that the persistence of a perceptual configuration was robust to interposed visual patterns and, further, that at least three ambiguous patterns, when interleaved in time, could undergo parallel, stable time courses. Then, using an interleaved presentation paradigm, we established that the occasional reversal in one pattern could be coupled with that of its interleaved counterpart, and that this coupling was a function of the structural similarity between the patterns. Conclusions: We postulate that the stabilization observed with repetitive presentation of ambiguous patterns can be at least partially accounted for by processes that retain a recent perceptual interpretation, and we speculate that such memory may be important in natural vision. We further propose tha the interleaved paradigm introduced here may be of great value to gauge aspects of stimulus similarity that appeal to particular mechanisms of perceptual organization. (shrink)

Aging is accompanied by stereotyped changes in functional brain activations, for example a cortical shift in activity patterns from posterior to anterior regions is one hallmark revealed by functional magnetic resonance imaging (fMRI) of aging cognition. Whether these neuronal effects of aging could potentially contribute to an amelioration of or resistance to the cognitive symptoms associated with psychopathology remains to be explored. We used a visual illusion paradigm to address whether aging affects the cortical control of perceptual beliefs and (...) biases. Our aim was to understand the effective connectivity associated with volitional control of ambiguous visual stimuli and to test whether greater top-down control of early visual networks emerged with advancing age. Using a bias training paradigm for ambiguous images we found that older participants (n = 16) resisted experimenter-induced visual bias compared to a younger cohort (n = 14) and that this resistance was associated with greater activity in prefrontal and temporal cortices. By applying Dynamic Causal Models for fMRI we uncovered a selective recruitment of top-down connections from the middle temporal to Lingual gyrus (LIN) by the older cohort during the perceptual switch decision following bias training. In contrast, our younger cohort did not exhibit any consistent connectivity effects but instead showed a loss of driving inputs to orbitofrontal sources following training. These findings suggest that perceptual beliefs are more readily controlled by top-down strategies in older adults and introduce age-dependent neural mechanisms that may be important for understanding aberrant belief states associated with psychopathology. (shrink)

In consideration of the spatial structures of sensory experiences, an ‘Externality Thesis’ is commonly proposed, according to which awareness of sensory boundaries is also an awareness of the presence of a space beyond these boundaries. The paper evaluates the Externality Thesis in the context of vision and touch. More specifically, relying on mereotopological theories, it is shown that the notion of spatial boundaries is ambiguous as it encompasses various distinct ways in which entities may be connected by a boundary. It (...) is argued that only some of these ways are able to support the Externality Thesis. In particular, it is claimed that while bodily boundaries of which one is aware in tactile sensations are such that the awareness of them provides support for the Externality Thesis, the analogous claim is not true about the boundaries of the visual field. (shrink)

I defend a solution to a long-standing problem with perceptual appearances, brought about by the phenomenon of perceptual constancy. The problem is that in conditions which are non-ideal, yet within the range that perceptual constancy works, we see things veridically despite an “appearance” which is traditionally taken to be non-veridical. For example, a tilted coin is often taken to have an “elliptical appearance”, shadowed surfaces a “darker appearance”. These appearances are puzzling for a number of reasons. I (...) defend and elaborate on an approach taken by Sean Kelly, and earlier by the art historian E.H. Gombrich, according to which we can be tricked by our ability to bring about a kind of Gesltalt shift between different possible perceptual interpretations of a scene. (shrink)

Cognitive systems face a tension between stability and plasticity. The maintenance of long‐term representations that reflect the global regularities of the environment is often at odds with pressure to flexibly adjust to short‐term input regularities that may deviate from the norm. This tension is abundantly clear in speech communication when talkers with accents or dialects produce input that deviates from a listener's language community norms. Prior research demonstrates that when bottom‐up acoustic information or top‐down word knowledge is available to disambiguate (...) speech input, there is short‐term adaptive plasticity such that subsequent speech perception is shifted even in the absence of the disambiguating information. Although such effects are well‐documented, it is not yet known whether bottom‐up and top‐down resolution of ambiguity may operate through common processes, or how these information sources may interact in guiding the adaptive plasticity of speech perception. The present study investigates the joint contributions of bottom‐up information from the acoustic signal and top‐down information from lexical knowledge in the adaptive plasticity of speech categorization according to short‐term input regularities. The results implicate speech category activation, whether from top‐down or bottom‐up sources, in driving rapid adjustment of listeners' reliance on acoustic dimensions in speech categorization. Broadly, this pattern of perception is consistent with dynamic mapping of input to category representations that is flexibly tuned according to interactive processing accommodating both lexical knowledge and idiosyncrasies of the acoustic input. (shrink)

Social exclusion is an emotionally painful experience that leads to various alterations in socio-emotional processing. The perceptual and emotional consequences that may arise from experiencing social exclusion can vary depending on the paradigm used to manipulate it. Exclusion paradigms can vary in terms of the severity and duration of the leading exclusion experience, thereby classifying it as either a short-term or long-term experience. The present study aimed to study the impact of exclusion on socio-emotional processing using different paradigms that (...) caused experiencing short-term and imagining long-term exclusion. Ambiguous facial emotions were used as socio-emotional cues. In study 1, the Ostracism Online paradigm was used to manipulate short-term exclusion. In study 2, a new sample of participants imagined long-term exclusion through the future life alone paradigm. Participants of both studies then completed a facial emotion recognition task consisting of morphed ambiguous facial emotions. By means of Point of Subjective Equivalence analyses, our results indicate that the experience of short-term exclusion hinders recognising happy facial expressions. In contrast, imagining long-term exclusion causes difficulties in recognising sad facial expressions. These findings extend the current literature, suggesting that not all social exclusion paradigms affect socio-emotional processing similarly. (shrink)

It has recently been claimed (1) that mental states such as beliefs are theoretical entities and (2) that they are therefore, in principle, subject to theoretical elimination if intentional psychology were to be supplanted by a psychology not employing mentalistic notions. Debate over these two issues is seriously hampered by the fact that the key terms 'theoretical' and 'belief' are ambiguous. This article argues that there is only one sense of 'theoretical' that is of use to the eliminativist, and in (...) this sense some kinds of "belief" (dispositional states, infra-conscious states and the Freudian unconscious) are indeed "theoretical" and hence possible candidates for elimination, while others (consciously occurring thoughts like judgements and perceptual Gestalten) are not theoretical and hence not candidates for elimination. (shrink)

Recently, approach-avoidance tendencies and visual perception biases have been increasingly studied using bistable point-light walkers (PLWs). Prior studies have found a facing-the-viewer bias when one is primed with general threat stimuli (e.g. angry faces), explained by the “error management theory”, as failing to detect a threat as approaching is riskier than the opposite. Importantly, no study has explored how disease threat – linked to the behavioural immune system – might affect this bias. This study aimed to explore whether disease-signalling cues (...) can alter how we perceive the motion direction of ambiguous PLWs. Throughout 3 experiments, participants indicated the motion direction of a bistable PLW previously primed with a control or disease-signalling stimuli – that is, face with a surgical mask (Experiment 1), sickness sound (Experiment 2), or face with a disease cue (Experiment 3). Results showed that sickness cues do not significantly modulate the perception of approach-avoidance behaviours. However, a pattern emerged in Experiments 2 and 3, suggesting that sickness stimuli led to more facing away percepts. Unlike other types of threat, this implies that disease-related threat stimuli might trigger a distinct perceptual bias, indicating a preference to avoid a possible infection source. Nonetheless, this finding warrants future investigations. (shrink)

When a jazz, rock, or hip-hop drummer strikes certain notes in each measure slightly late, instead of hearing the degree to which those notes are late, we typically hear the effects of those variations; namely, a groove, the "feel" of a rhythm. Slight variations of pitch function similarly. In this essay, I argue that certain analytic theorists go astray due to their preoccupation with the variations themselves. By invoking Maurice Merleau- Ponty's insights into subtle visual perceptions, and his notion of (...) perceptual indeterminacy, I avoid an account of musical subtlety suggested by Daniel Dennett that is too coarse-grained, as well as the bleak conclusion that certain musical subtleties are ineffable, Diana Raffman's view. I conclude that elements of music that are perceived ambiguously can perform a positive function in such aesthetic experiences: they can mediate or foster emergent qualities; moreover, they must be perceived in this way to do so. (shrink)

The sensorimotor theory is an influential, non-mainstream account of perception and perceptual consciousness intended to improve in various ways on orthodox theories. It is often taken to be a variety of enactivism, and in common with enactivist cognitive science more generally, it de-emphasises the theoretical role played by internal representation and other purely neural processes, giving theoretical pride of place instead to interactive engagements between the brain, non-neural body and outside environment. In addition to offering a distinctive account of (...) the processing that underlies perceptual consciousness, the sensorimotor theory aims to offer a new and improved account the logical and phenomenological character of perceptual experience, and the relation between physical and phenomenal states. Since its inception in a 2001 paper by O’Regan and Noë, the theory has prompted a good deal of increasingly prominent theoretical and practical work in cognitive science, as well as a large body of secondary literature in philosophy of cognitive science and philosophy of perception. In spite of its influential character, many of the theory’s most basic tenets are incompletely or ambiguously defined, and it has attracted a number of prominent objections. This thesis aims to clarify the conceptual foundations of the sensorimotor theory, including the key theoretical concepts of sensorimotor contingency, sensorimotor mastery, and presence-as-access, and defends a particular understanding of the respective theoretical roles of internal representation and behavioural capacities. In so doing, the thesis aims to highlight the sensorimotor theory’s virtues and defend it from some leading criticisms, with particular attention to a response by Clark which claims that perception and perceptual experience plausibly depend on the activation of representations which are not intimately involved in bodily engagements between the agent and environment. A final part of the thesis offers a sensorimotor account of the experience of temporally extended events, and shows how with reference to this we can better understand object experience. (shrink)

The segregation of image parts into foreground and background is an important aspect of the neural computation of 3D scene perception. To achieve such segregation, the brain needs information about border ownership; that is, the belongingness of a contour to a specific surface represented in the image. This article presents psychophysical data derived from 3D percepts of figure and ground that were generated by presenting 2D images composed of spatially disjoint shapes that pointed inward or outward relative to the continuous (...) boundaries that they induced along their collinear edges. The shapes in some images had the same contrast (black or white) with respect to the background gray. Other images included opposite contrasts along each induced continuous boundary. Psychophysical results demonstrate conditions under which figure-ground judgment probabilities in response to these ambiguous displays are determined by the orientation of contrasts only, not by their relative contrasts, despite the fact that many border ownership cells in cortical area V2 respond to a preferred relative contrast. Studies are also reviewed in which both polarity-specific and polarity-invariant properties obtain perceptual figure-ground grouping results. The FACADE and 3D LAMINART models are used to explain these data. Keywords: figure-ground separation, border ownership, perceptual grouping, surface filling-in, V2, V4, FACADE Theory. (shrink)

Asked on the Dick Cavett show about her former Stalinist comrade Lillian Hellman, Mary McCarthy replied, "Every word she says is a lie, including 'and' and 'the'." The language used to describe sensory and perceptual consciousness is worthy of about the same level of trust. One must adapt oneself to the fact that every ordinary word used to describe this domain is ambiguous; that different theoreticians use the same words in very different ways; and that every speaker naturally thinks (...) that his or her usage is, of course, the correct one. Notice that we have already partially vindicated Mary McCarthy: even the word "the" cannot always be trusted. (shrink)

There is a debate in philosophy and cognitive science over whether concepts – the building blocks of thought—are couched in a perceptual modality or are amodally represented. The empirical evidence so far collected seems not to have adjudicated this question yet, as reinterpretation of the same set of evidence by both supporters of modalism and amodalism have been provided. I offer a critique of such reinterpretations, arguing that they ultimately derive from theoretical problems in the definition of a modal (...) representation. In particular, I will review three criteria which have been offered to distinguish amodal concepts from modal ones: the isomorphism criterion, the neural location criterion, and the input specificity criterion. I will explain how these criteria often lack theoretical clarity, making it possible in most cases to propose a parsimonious explanation of the same set of data from both an amodalist and a modalist perspective. As a result, it becomes impossible to empirically discriminate between the two interpretations. My conclusion is that the main problem with the discussed criteria is that they frame the question on the format of concept as an either/or debate, by overlooking more interesting empirical questions. (shrink)

We investigated the possible causes of perceptual switching in ambiguous figures. Ambiguous figures are a special class of visual stimuli that can give rise to at least two alternative interpretations. Because the figures themselves stay the same, these stimuli are particularly suitable to study the dynamic changes in our visual apparatus that enable us to see the world in different ways. Recent studies stress the importance of both low-level and high-level processes in switching. We show that these processes lead (...) to switching independently, and that, when they co-occur, they do not occur at exactly the same time.We take these results to indicate that perceptual switching is a radically multiply realizable process, in that various neurological states can instantiate it in a single individual from time to time. We reflect on the consequences of this conclusion for experiential realism, in particular the notion that embodiment misleads us in identifying psychological types. (shrink)

In this chapter, data concerning the development of principal aspects of vision is reviewed. First, the development of colour vision and luminance perception is discussed. Relevant data accumulated so far indicates that perception of colour and luminance is present by 6-9 months of age. The presence of typical color illusions at this age suggests that the phenomenal character of color experience is comparable to that of adults well before the first birthday. Thus it seems plausible that color perception develops on (...) the grounds of genetically preprogrammed maturation, in which perceptual learning and plasticity play a limited role. This claim also seems to be supported by case studies of newly sighted patients. On the other hand, perceptual integration of edges and forms in the visual environment as well as the development of binocular vision, and the perception of ambiguous figures seem to depend crucially on early perceptual learning. Both developmental and clinical data indicate a more significant involvement of perceptual learning in such mid-level and higher level perceptual phenomena. (shrink)

Modality specificity in priming is taken as evidence for independent perceptual systems. However, Easton, Greene, and Srinivas (1997) showed that visual and haptic cross-modal priming is comparable in magnitude to within-modal priming. Where appropriate, perceptual systems might share like information. To test this, we assessed priming and recognition for visual and auditory events, within- and across- modalities. On the visual test, auditory study resulted in no priming. On the auditory priming test, visual study resulted in priming that was (...) only marginally less than within-modal priming. The priming results show that visual study facilitates identification on both visual and auditory tests, but auditory study only facilitates performance on the auditory test. For both recognition tests, within-modal recognition exceeded cross-modal recognition. The results have two novel implications for the understanding of perceptual priming: First, we introduce visual and auditory priming for spatio-temporal events as a new priming paradigm chosen for its ecological validity and potential for information exchange. Second, we propose that the asymmetry of the cross-modal priming observed here may reflect the capacity of these perceptual modalities to provide cross-modal constraints on ambiguity. We argue that visual perception might inform and constrain auditory processing, while auditory perception corresponds to too many potential visual events to usefully inform and constrain visual perception. (shrink)