In lieu of an abstract, here is a brief excerpt of the content:Commentary on “Loopholes, Gaps, and What Is Held Fast”Lorraine Code (bio)Keywordsepistemology, incredulity, knowing other people, memory, testimonyNancy Potter’s compelling essay points to some of the limitations of the theoretical apparatus that the post-positivist empiricist epistemologies of the Anglo-American mainstream make available for evaluating experiential memory claims in general, and “false memory syndrome” in particular. The loopholes and gaps in these theories of knowledge push urgent questions about testimony, trust, (...) and the politics of knowledge into a prominent place on the agendas of successor epistemology projects. These politics are enacted in societies whose dominant rhetoric privileges eye-witness evidence and “knowledge by acquaintance” as sources of objective knowledge, yet whose practices of incredulity—of granting and withholding acknowledgement to testimonial knowledge claims—expose power-saturated structures of dominance and subordination and of arbitrarily uneven distributions of epistemic authority. 1For classical empiricists and their successors, perception, memory and testimony, hierarchically ordered with perception on top, count as the principal sources of empirical knowledge. This ordering maps the relative reliability of the processes, with perception ranking as most stable, reliable and secure, memory coming second on all of these scores, and testimony ranking a poor third, closer to opinion, hearsay and rumor than to the other more respectable sources. Perception, for these theories, is “immediate” in that it is direct, bare, uncontaminated either by the particularities of the perceiving subject or of the perceptual event: from its presumed (but contestable) immediacy, all the rest follows. Memory counts as perception at one remove, its reliability a function of the relative “vividness” of the perceptions it commemorates. The esteem commonly claimed for eye-witness testimony derives from this conception of memory, which is believed to ground the testimony because of its presumed proximity to “immediate” perception. Yet testimony, even in its restricted “knowledge by description” form, tends by contrast with perception and memory to be a shaky affair; and as the temporal distance between event and testimony increases, so knowledge of matters unavailable to direct observation fares less and less well in classical and post-positivist epistemologies. A distrust of testimony is at once understandable and odd, because so small a proportion both of communal and of “individual” knowledge indeed derives from first-hand observations and experiences: most of it comes from testimony in an extended sense that encompasses books, teachings, media reports, all of the sources and resources on which both secular and scholarly knowledge relies for much of its substance. This expanded construction of the term runs alongside [End Page 255] the first-personal “testimonial” sense that is more plainly operative in discussions of false memory syndrome which, despite its experiential source, is often likewise contested on grounds that discredit the “privileged access” status that these same epistemologies claim for experience at first hand.Epistemologists commonly assimilate testimony to monologic, observational knowledge, deriving its constitutive features from instances where a testimonial utterance can pose as another perception—this time an auditory one—in a personal set of knowledge-producing observations (e.g., Fricker 1987). Because the speaker may be lying or mistaken, the process may fail to transmit knowledge; but this failure can be read as a simple perceptual error or a misremembering. Such approaches ignore the constitutive function of an interpreter/listener in fostering or thwarting testimonial knowledge to subsume it, too, much under an observational model. Indeed, not only do they separate the knower from the known and the process of knowing, as Potter observes, they also separate the knower from other knowers to guard against their influencing (= contaminating) the knowledge-production process. Experiences where an interlocutor actually enables the production of knowledge do not figure in such analyses, 2 whose effect is to suggest that giving or hearing testimony invokes no more significant moral-political issues than do acts of perceiving tables and chairs: that hearing, like seeing, is believing. (Norman Malcolm’s analysis of memory, which Potter cites, would also underwrite such a view of testimony.) Yet standard empiricist and post-positivist epistemologies generate an inquisitorial model of eliciting testimony in which the more generalized “testimony” in the knowledge that people acquire from books, media reports, conversation, reference sources recedes from... (shrink)

I argue that sound-centric scholarship can be of use to feminist theorists if and only if it begins from a non-ideal theory of sound; this article develops such a theory. To do this, I first develop more fully my claim that perceptual coding was a good metaphor for the ways that neoliberal market logics (re)produce relations of domination and subordination, such as white supremacist patriarchy. Because it was developed to facilitate the enclosure of the audio bandwidth, perceptual (...) coding is especially helpful in centring the ways that patriarchal racial capitalism structures our concepts and experiences of both sound and technology. The first section identifies sonic cyberfeminist practices that function as a kind of perceptual coding because they subject ‘sound’ and/or ‘women’ to enclosure and accumulation by dispossession. The second section identifies a type of sonic cyberfeminism that tunes into the parts of the spectrum that this perceptual coding discards, building models of community and aesthetic value that do not rely on the exclusion of women, especially black women, from both humanist and posthuman concepts of personhood. Here I focus especially on Alexander Weheliye’s ‘phonographic’ approach to sound, technology and theoretical text. This approach, which he develops in his 2005 book of that title and in recent work in collaboration with Katherine McKittrick, avoids fetishising tech and self-transformation and focuses on practices that build registers of existence that hegemonic institutions perceptually code out of circulation. I conclude with examples of such phonographic compression, including Masters At Work’s ballroom classic ‘The Ha Dance’ and Nicki Minaj’s ‘Anaconda’. (shrink)

Two universal functional principles of Grossberg’s Adaptive Resonance Theory decipher the brain code of all biological learning and adaptive intelligence. Low-level representations of multisensory stimuli in their immediate environmental context are formed on the basis of bottom-up activation and under the control of top-down matching rules that integrate high-level, long-term traces of contextual configuration. These universal coding principles lead to the establishment of lasting brain signatures of perceptual experience in all living species, from aplysiae to primates. They are (...) re-visited in this concept paper on the basis of examples drawn from the original code and from some of the most recent related empirical findings on contextual modulation in the brain, highlighting the potential of Grossberg’s pioneering insights and groundbreaking theoretical work for intelligent solutions in the domain of developmental and cognitive robotics. (shrink)

Two universal functional principles of Grossberg’s Adaptive Resonance Theory [19] decipher the brain code of all biological learning and adaptive intelligence. Low-level representations of multisensory stimuli in their immediate environmental context are formed on the basis of bottom-up activation and under the control of top-down matching rules that integrate high-level long-term traces of contextual configuration. These universal coding principles lead to the establishment of lasting brain signatures of perceptual experience in all living species, from aplysiae to primates. They (...) are re-visited in this concept paper here on the basis of examples drawn from the original code and from some of the most recent related empirical findings on contextual modulation in the brain, highlighting the potential of Grossberg’s pioneering insights and groundbreaking theoretical work for intelligent solutions in the domain of developmental and cognitive robotics. (shrink)

Pointing to similarities between challenges encountered in today's neural coding and twentieth-century behaviorism, we draw attention to lessons learned from resolving the latter. In particular, Perceptual Control Theory posits behavior as a closed-loop control process with immediate and teleological causes. With two examples, we illustrate how these ideas may also address challenges facing current neural coding paradigms.

The chapter argues from an ethology-inspired internalist perspective that ‘colour’ is not a homogeneous and autonomous attribute, but rather plays different roles in different conceptual forms underlying perception. It discusses empirical and theoretical evidence that indicates that core assumptions underlying orthodox conceptions are grossly inadequate. The assumptions pertain to the idea that colour is a kind of autonomous and unitary attribute. It is regarded as unitary or homogeneous by assuming that its core properties do not depend on the type of (...) ‘perceptual object’ to which it pertains and that‘colour per se’ constitutes a natural attribute in the functional architecture of the perceptual system. It is regarded as autonomous by assuming that it can be studied in isolation of other perceptual attributes. More generally, the chapter argues on the bases of corresponding empirical and theoretical evidence that perception cannot be understood as the ‘recovery’ of physical world structure from sensory structure by input-based computational processes. Rather, the sensory input serves as a kind of sign for biologically relevant aspects of the external world that activates biologically given conceptual forms with their internal parameters. Although the sensory input is a causally necessary requirement for the activation of conceptual forms, the perceptual computations triggered are under the control of an internal programme based on a set of conceptual forms. (shrink)

Recent evidence from cognitive neuroscience suggests that certain cognitive processes employ perceptual representations. Inspired by this evidence, a few researchers have proposed that cognition is inherently perceptual. They have developed an innovative theoretical approach that rests on the notion of perceptual simulation and marshaled several general arguments supporting the centrality of perceptual representations to concepts. In this article, I identify a number of weaknesses in these arguments and defend a multiple semantic code approach that posits both (...) perceptual and non-perceptual representations. (shrink)

Perceptual systems respond to proximal stimuli by forming mental representations of distal stimuli. A central goal for the philosophy of perception is to characterize the representations delivered by perceptual systems. It may be that all perceptual representations are in some way proprietarily perceptual and differ from the representational format of thought (Dretske 1981; Carey 2009; Burge 2010; Block ms.). Or it may instead be that perception and cognition always trade in the same code (Prinz 2002; Pylyshyn (...) 2003). This paper rejects both approaches in favor of perceptual pluralism, the thesis that perception delivers a multiplicity of representational formats, some proprietary and some shared with cognition. The argument for perceptual pluralism marshals a wide array of empirical evidence in favor of iconic (i.e., image-like, analog) representations in perception as well as discursive (i.e., language-like, digital) perceptual object representations. (shrink)

Predictive coding – sometimes also known as ‘predictive processing’, ‘free energy minimisation’, or ‘prediction error minimisation’ – claims to offer a complete, unified theory of cognition that stretches all the way from cellular biology to phenomenology. However, the exact content of the view, and how it might achieve its ambitions, is not clear. This series of articles examines predictive coding and attempts to identify its key commitments and justification. The present article begins by focusing on possible confounds with (...) predictive coding: claims that are often identified with predictive coding, but which are not predictive coding. These include the idea that the brain employs an efficient scheme for encoding its incoming sensory signals; that perceptual experience is shaped by prior beliefs; that cognition involves minimisation of prediction error; that the brain is a probabilistic inference engine; and that the brain learns and employs a generative model of the world. These ideas have garnered widespread support in modern cognitive neuroscience, but it is important not to conflate them with predictive coding. (shrink)

A theory is proposed that views emotional feelings as pivotal for action control. Feelings of emotions are valued interoceptive signals from the body that become multimodally integrated with perceptual contents from registered and mentally simulated events. During the simulation of a perceptual change from one event to the next, a conative feeling signal is created that codes for the wanting of a specific perceptual change. A wanted perceptual change is weighted more strongly than alternatives, increasing its (...) activation level on the cognitive level and that of associated motor structures that produced this perceptual change in the past. As a consequence, a tendency for action is generated that is directed at the production of the wanted perception. (shrink)

“Neural coding” is a popular metaphor in neuroscience, where objective properties of the world are communicated to the brain in the form of spikes. Here I argue that this metaphor is often inappropriate and misleading. First, when neurons are said to encode experimental parameters, the neural code depends on experimental details that are not carried by the coding variable. Thus, the representational power of neural codes is much more limited than generally implied. Second, neural codes carry information only (...) by reference to things with known meaning. In contrast, perceptual systems must build information from relations between sensory signals and actions, forming an internal model. Neural codes are inadequate for this purpose because they are unstructured and therefore unable to represent relations. Third, coding variables are observables tied to the temporality of experiments, whereas spikes are timed actions that mediate coupling in a distributed dynamical system. The coding metaphor tries to fit the dynamic, circular, and distributed causal structure of the brain into a linear chain of transformations between observables, but the two causal structures are incongruent. I conclude that the neural coding metaphor cannot provide a valid basis for theories of brain function, because it is incompatible with both the causal structure of the brain and the representational requirements of cognition. (shrink)

Perceptual learning involves an improvement in perceptual judgment with practice, which is often specific to stimulus or task factors. Perceptual learning has been shown on a range of visual tasks but very little research has explored chromatic perceptual learning. Here, we use two low level perceptual threshold tasks and a supra-threshold target detection task to assess chromatic perceptual learning and category effects. Experiment 1 investigates whether chromatic thresholds reduce as a result of training and (...) at what level of analysis learning effects occur. Experiment 2 explores the effect of category training on chromatic thresholds, whether training of this nature is category specific and whether it can induce categorical responding. Experiment 3 investigates the effect of category training on a higher level, lateralized target detection task, previously found to be sensitive to category effects. The findings indicate that performance on a perceptual threshold task improves following training but improvements do not transfer across retinal location or hue. Therefore, chromatic perceptual learning is category specific and can occur at relatively early stages of visual analysis. Additionally, category training does not induce category effects on a low level perceptual threshold task, as indicated by comparable discrimination thresholds at the newly learned hue boundary and adjacent test points. However, category training does induce category effects on a supra-threshold target detection task. Whilst chromatic perceptual learning is possible, learnt category effects appear to be a product of left hemisphere processing, and may require the input of higher level linguistic coding processes in order to manifest. (shrink)

Visual culture can be considered from semiotic point of view as a system of visual codes. Several of them have natural routs. So the perceptual code is formed already on biological level mediating translation of sensory data into perceptual images of the spatial world. The means of natural perceptual code are transformed in culture, where they are involved in communication by depictions. The depiction on the flat performs the function of a “perceptogram”, which, on one hand, is (...) an external record of an internal perceptual image or an idea, and, on the other hand, serves as a program for a spectator’s visual perception. The means of this “perceptography” form an artificial code, which is, on the contrary to the perceptual code, communicative, deliberately used and transformed in various ways at different periods of time in diverse kinds of practical and artistic activity. Not all perceptograms become pieces of art, but all history of pictorial arts can be considered as a process of development and mastering with the different versions of this perceptographic code. The changes of this code in visual culture are connected with the intrinsic development of “vision forms” as well with invention of external means of communication. (shrink)

Visual culture can be considered from semiotic point of view as a system of visual codes. Several of them have natural routs. So the perceptual code is formed already on biological level mediating translation of sensory data into perceptual images of the spatial world. The means of natural perceptual code are transformed in culture, where they are involved in communication by depictions. The depiction on the flat performs the function of a “perceptogram”, which, on one hand, is (...) an external record of an internal perceptual image or an idea, and, on the other hand, serves as a program for a spectator’s visual perception. The means of this “perceptography” form an artificial code, which is, on the contrary to the perceptual code, communicative, deliberately used and transformed in various ways at different periods of time in diverse kinds of practical and artistic activity. Not all perceptograms become pieces of art, but all history of pictorial arts can be considered as a process of development and mastering with the different versions of this perceptographic code. The changes of this code in visual culture are connected with the intrinsic development of “vision forms” as well with invention of external means of communication. (shrink)

In this paper, I discuss the strong thesis of cognitive penetrability (CPs), to wit, th at the perceptual states (P) of a subject (S) are pervasively influenced, affected, or caused by cognitive factors (C) as expectations, memories, thoughts, goals, and so on, at all levels of perceptual processing. I argue that following the predictive coding models of perception (PC), the strong thesis of cognitive penetrability is to be expected.

This article attempts to clarify the commitments of a predictive coding approach to perception. After summarizing predictive coding theory, the article addresses two questions. Is a predictive coding perceptual system also a Bayesian system? Is it a Kantian system? The article shows that the answer to these questions is negative.

In this commentary, I suggest that non-visual perceptual modalities provide counterexamples to Seth’s claim that perceptual presence depends on counterfactual richness. Then I suggest a modification to Seth’s view that is not vulnerable to these counterexamples.

Traditional approaches to human information processing tend to deal with perception and action planning in isolation, so that an adequate account of the perception-action interface is still missing. On the perceptual side, the dominant cognitive view largely underestimates, and thus fails to account for, the impact of action-related processes on both the processing of perceptual information and on perceptual learning. On the action side, most approaches conceive of action planning as a mere continuation of stimulus processing, thus (...) failing to account for the goal-directedness of even the simplest reaction in an experimental task. We propose a new framework for a more adequate theoretical treatment of perception and action planning, in which perceptual contents and action plans are coded in a common representational medium by feature codes with distal reference. Perceived events (perceptions) and to-be-produced events (actions) are equally represented by integrated, task-tuned networks of feature codes – cognitive structures we call event codes. We give an overview of evidence from a wide variety of empirical domains, such as spatial stimulus-response compatibility, sensorimotor synchronization, and ideomotor action, showing that our main assumptions are well supported by the data. Key Words: action planning; binding; common coding; event coding; feature integration; perception; perception-action interface. (shrink)

There is little doubt that predictive coding is an important mechanism in language processing–indeed, in information processing generally. However, it is less clear whether the action system is the source of such predictions during perception. Here I summarize the computational problem with motor prediction for perceptual processes and argue instead for a dual-stream model of predictive coding.

Consciousness is known to be limited in processing capacity and often described in terms of a unique processing stream across a single dimension: time. In this paper, we discuss a purely temporal pattern code, functionally decoupled from spatial signals, for conscious state generation in the brain. Arguments in favour of such a code include Dehaene et al.'s long-distance reverberation postulate, Ramachandran's remapping hypothesis, evidence for a temporal coherence index and coincidence detectors, and Grossberg's Adaptive Resonance Theory. A time-bin resonance model (...) is developed, where temporal signatures of conscious states are generated on the basis of signal reverberation across large distances in highly plastic neural circuits. The temporal signatures are delivered by neural activity patterns which, beyond a certain statistical threshold, activate, maintain, and terminate a conscious brain state like a bar code would activate, maintain, or inactivate the electronic locks of a safe. Such temporal resonance would reflect a higher level of neural processing, independent from sensorial or perceptual brain mechanisms. (shrink)

Frost presents an explanatory theory of reading that generalizes across several languages, based on a revised role of orthographic coding. Perceptual and psychophysical evidence indicates a decay of letter position encoding as a function of the eccentricity of letters ; this factor may account for some of the differences in the languages considered by Frost.

The chapter argues from an ethology-inspired internalist perspective that ‘colour’ is not a homogeneous and autonomous attribute, but rather plays different roles in different conceptual forms underlying perception. It discusses empirical and theoretical evidence that indicates that core assumptions underlying orthodox conceptions are grossly inadequate. The assumptions pertain to the idea that colour is a kind of autonomous and unitary attribute. It is regarded as unitary or homogeneous by assuming that its core properties do not depend on the type of (...) ‘perceptual object’ to which it pertains and that‘colour per se’ constitutes a natural attribute in the functional architecture of the perceptual system. It is regarded as autonomous by assuming that it can be studied in isolation of other perceptual attributes. More generally, the chapter argues on the bases of corresponding empirical and theoretical evidence that perception cannot be understood as the ‘recovery’ of physical world structure from sensory structure by input-based computational processes. Rather, the sensory input serves as a kind of sign for biologically relevant aspects of the external world that activates biologically given conceptual forms with their internal parameters. Although the sensory input is a causally necessary requirement for the activation of conceptual forms, the perceptual computations triggered are under the control of an internal programme based on a set of conceptual forms. (shrink)

This paper concerns how extant theorists of predictive coding conceptualize and explain possible instances of cognitive penetration. §I offers brief clarification of the predictive coding framework and relevant mechanisms, and a brief characterization of cognitive penetration and some challenges that come with defining it. §II develops more precise ways that the predictive coding framework can explain, and of course thereby allow for, genuine top-down causal effects on perceptual experience, of the kind discussed in the context of (...) cognitive penetration. §III develops these insights further with an eye towards tracking one extant criterion for cognitive penetration, namely, that the relevant cognitive effects on perception must be sufficiently direct. Throughout these discussions, we extend the analyses of the predictive coding models, as we know them. So one open question that surfaces is how much of the extended analyses are genuinely just part of the predictive coding models, or something that must be added to them in order to generate these additional explanatory benefits. In §IV, we analyze and criticize a claim made by some theorists of predictive coding, namely, that (interesting) instances of cognitive penetration tend to occur in perceptual circumstances involving substantial noise or uncertainty. It is here that our analysis is most critical. We argue that, when applied, the claim fails to explain (or perhaps even be consistent with) a large range of important and uncontroversially interesting possible cases of cognitive penetration. We conclude with a general speculation about how the recent work on the predictive mind may influence the current dialectic concerning top-down effects on perception. (shrink)

Abstract Since their inception, distributional models of semantics have been criticized as inadequate cognitive theories of human semantic learning and representation. A principal challenge is that the representations derived by distributional models are purely symbolic and are not grounded in perception and action; this challenge has led many to favor feature-based models of semantic representation. We argue that the amount of perceptual and other semantic information that can be learned from purely distributional statistics has been underappreciated. We compare the (...) representations of three feature-based and nine distributional models using a semantic clustering task. Several distributional models demonstrated semantic clustering comparable with clustering-based on feature-based representations. Furthermore, when trained on child-directed speech, the same distributional models perform as well as sensorimotor-based feature representations of children’s lexical semantic knowledge. These results suggest that, to a large extent, information relevant for extracting semantic categories is redundantly coded in perceptual and linguistic experience. Detailed analyses of the semantic clusters of the feature-based and distributional models also reveal that the models make use of complementary cues to semantic organization from the two data streams. Rather than conceptualizing feature-based and distributional models as competing theories, we argue that future focus should be on understanding the cognitive mechanisms humans use to integrate the two sources. (shrink)

In this paper we address the issue of grounding for experiential concepts. Given that perceptual demonstratives are a basic form of such concepts, we examine ways of fixing the referents of such demonstratives. To avoid ‘encodingism’, that is, relating representations to representations, we postulate that the process of reference fixing must be bottom-up and nonconceptual, so that it can break the circle of conceptual content and touch the world. For that purpose, an appropriate causal relation between representations and the (...) world is needed. We claim that this relation is provided by spatial and object-centered attention that leads to the formation of object files through the function of deictic acts. This entire causal process takes place at a pre-conceptual level, meeting the requirement for a solution to the grounding problem. Finally we claim that our account captures fundamental insights in Putnam’s and Kripke’s work on “new” reference. (shrink)

Consciousness is known to be limited in processing capacity and often described in terms of a unique processing stream across a single dimension: time. In this paper, we discuss a purely temporal pattern code, functionally decoupled from spatial signals, for conscious state generation in the brain. Arguments in favour of such a code include Dehaene et al.’s long-distance reverberation postulate, Ramachandran’s remapping hypothesis, evidence for a temporal coherence index and coincidence detectors, and Grossberg’s Adaptive Resonance Theory. A time-bin resonance model (...) is developed, where temporal signatures of conscious states are generated on the basis of signal reverberation across large distances in highly plastic neural circuits. The temporal signatures are delivered by neural activity patterns which, beyond a certain statistical threshold, activate, maintain, and terminate a conscious brain state like a bar code would activate, maintain, or inactivate the electronic locks of a safe. Such temporal resonance would reflect a higher level of neural processing, one that is independent from sensorial or perceptual brain mechanisms. (shrink)

We qualify Frost's proposals regarding letter-position coding in visual word recognition and the universal model of reading. First, we show that perceptual uncertainty regarding letter position is not tied to European languages – instead it is a general property of the cognitive system. Second, we argue that a universal model of reading should incorporate a developmental view of the reading process.

Spatial aspects of words are associated with their canonical locations in the real world. Yet little research has tested whether spatial associations denoted in language comprehension generalize to their corresponding images. We directly tested the spatial aspects of mental imagery in picture and word processing (Experiment 1). We also tested whether spatial representations of motion words produce similar perceptual-interference effects as demonstrated by object words (Experiment 2). Findings revealed that words denoting an upward spatial location produced slower responses to (...) targets appearing at the top of the display, whereas words denoting a downward spatial location produced slower responses to targets appearing at the bottom of the display. Perceptual-interference effects did not obtain for pictures or for words lacking a spatial relation. These findings provide greater empirical support for the perceptual-symbols system theory (Barsalou, 1999, 2008). (shrink)

Facial appearance changes with age and health affecting skin color as well as facial and head hair. Yet somehow the brain is able to see past shared structure and dynamic deformations to focus on subtle details that distinguish one face from another. This article argues that the brain takes an efficient approach to this problem using prior knowledge about the structure of faces in its analysis. It employs intrinsic norms to focus on subtle variations in the shared face configuration that (...) differentiate one face from another. The study reviews evidence that the brain uses multiple norms to extract face identity that these norms are shaped by visual experience, and that norm-based coding is well-suited to meeting the challenges of image-based face perception mentioned above. By encoding faces with reference to stored perceptual norms the visual system can focus on what is unique to each individual, allowing for the discrimination of thousands of faces despite their similarity. (shrink)

Chaotic itinerancy is useful for illustrating transitions in attractor dynamics seen in the olfactory system. Cantor coding is a good model for information processing, but so far it lacks perceptual proof. The theories presented provide a large step toward bridging the use of chaos as an interpretive tool and hard examination of chaotic neural activity during perception.

The debate about direct perception encompasses different topics, one of which concerns the richness of the contents of perceptual experiences. Can we directly perceive only low-level properties, like edges, colors etc., or can we perceive high-level properties and entities as well? The aim of the paper is to defend the claim that the content of our perceptual experience can include emotions and also person impressions. Using these examples, an argument is developed to defend a liberal-content view for core (...) examples of social cognition. This view is developed and contrasted with accounts which claim that in the case of registering another person’s emotion while seeing them, we have to describe the relevant content not as the content of a perceptual experience, but of a perceptual belief. The paper defends the view that perceptual experiences can have a rich content yet remain separable from beliefs formed on the basis of the experience. How liberal and enriched the content of a perceptual experience is will depend upon the expertise a person has developed in the field. This is supported by the argument that perceptual experiences can be systematically enriched by perceiving affordances of objects, by pattern recognition or by top-down processes, as analyzed by processes of cognitive penetration or predictive coding. (shrink)

Commentary on Andy Clark's target article on predictive coding.

This essay examines the recent Planet of the Apes films through the lens of recent research in primatology. The films lend imaginary support to primatologist Frans de Waal’s evolutionary moral sentimentalism; however, the movies also show that truly moral motions outstrip the cognitive capacities of the great apes. The abstract moral principles employed by the ape community in the movie require the ability to understand and apply a common underlying explanation to perceptually disparate situations; in contrast, recent research in comparative (...) psychology demonstrates that the great apes lack this capacity. Since the capacity for abstraction is required on even the most basic version of moral sentimentalism—Shaun Nichols’ sentimental rules account—the lack of the capacity for abstraction reveals a qualitative distinction between primate social behavior and human morality. (shrink)

A model of face representation, inspired by the biology of the visual system, is compared to experimental data on the perception of facial similarity. The face representation model uses aggregate primary visual cortex (V1) cell responses topographically linked to a grid covering the face, allowing comparison of shape and texture at corresponding points in two facial images. When a set of relatively similar faces was used as stimuli, this Linked Aggregate Code (LAC) predicted human performance in similarity judgment experiments. When (...) faces of perceivable categories were used, dimensions such as apparent sex and race emerged from the LAC model without training. The dimensional structure of the LAC similarity measure for the mixed category task displayed some psychologically plausible features but also highlighted differences between the model and the human similarity judgements. The human judgements exhibited a racial perceptual bias that was not shared by the LAC model. The results suggest that the LAC based similarity measure may offer a fertile starting point for further modelling studies of face representation in higher visual areas, including studies of the development of biases in face perception. (shrink)

Tactile exploration often involves sequential touches interspersed with stimulus-free durations. Whereas it is obvious that texture-related perceptual variables, irrespective of the encoding strategy, must be stored in memory for comparison, it is rather unclear which of those variables are held in memory. There are two established variables—“intensity” and “frequency”, which are “temporally global” variables because of the long stimulus integration interval required to average the signal or derive spectral components, respectively; on the other hand, a recently established third contender (...) is the “temporally local” variable that codes for kinematic profiles of very short, suprathreshold events in the vibrotactile signal. Here, we present the first psychophysical evidence that temporally local variables can be stored in memory. To that end, we asked participants to detect changes in pulsatile indentation stimuli at their fingertips with and without a gap of 1 s between stimulus presentations. The stimuli either contained global variables alone, or a mix of local and global variables. We found, first, that humans are much better at detecting a change in stimuli when local variables are available rather than global ones alone—as evident by the fact that 21 compared to only 6 participants out of 25 yielded a valid psychophysical curve, respectively. Second, this observation persists even when there is a gap between the stimuli, implying local variables must be stored in memory. Third, an extensive array of relevant intensity definitions failed to explain participants’ performance in any consistent manner, which implies that perceptual decisions were less likely to be driven by intensity coding. Taken together, our results suggest that humans perform pulsatile change detection utilizing local pulse shape, and to a lesser degree global pulse rate, and that both parameters can be stored in memory. (shrink)

The focus of this commentary is what Andy Clark takes to be the most groundbreaking of the philosophical import of the ‘bidirectional hierarchical model of brain functions’, namely, the claim that perceptual representations represent probabilities. This is what makes his account Bayesian and this is a philosophical or theoretical conclusion that neuroscientists and psychologists are also quick and happy to draw. My claim is that nothing in the ‘bidirectional hierarchical models of brain functions’ implies that perceptual representations are (...) probabilistic, or that they represent or ‘encode probability density distributions’. There is a much more parsimonious way of describing the representations in the bidirectional hierarchical model of brain functions: they attribute properties to objects (or to the perceived scene) that are not fully determinate. (shrink)

Juri Lotman distinguishes between two main types of communication. In addition to the classical I-YOU communication, he speaks about I-I communication, where both the addresser and the addressee are one and the same person. Contrary to how it sounds, autocommunication is not self-sufficient musing inside one’s self, it is remodelling oneself through a code from an entity outside oneself, be it animate or inanimate. According to Lotman, it is often the rhythmical phenomena like poetry, the rhythm of waves, etc. that (...) lend themselves for the act of autocommunication as external codes. After having received the message one is not identical to the original oneself anymore. Perceptual markers of landscape—specific rhythms, ephemera, the rhythm of human everyday activities, bodily movement—can be considered as a secondary code leading to autocommunication in the person who contemplates the landscape. Looking at the landscape—which also implies the rhythmical movement of the eyes—one uses it as a code to reconstitute oneself. A person who has confronted a landscape does not leave it as the same person. The present article poses a definition of autocommunication in landscapes and discusses the way in which other sensorial information apart from the visual—smell, movement, rhythms etc—are used culturally to reinforce autocommunication with oneself. It can be said that several institutionalised religious and cultural practices expect the subject to reconstitute him- or herself mainly through the bodily landscape experience. (shrink)

Western scholars have speculated for centuries about the perceptual capacities of non-western peoples, of children, and of animals; and, more recently, about the representation and communication of perceptual experience in language. Colour is a particularly intriguing domain within which to study the communication of experience because the physical stimulation necessary for the perception of colour, light radiation, can be specified with precision, and creates an aura of rigour and certainty.

Colour is, according to prevailing orthodoxy in perceptual psychology, a kind of autonomous and unitary attribute. It is regarded as unitary or homogeneous by assuming that its core properties do not depend on the type of ‘perceptual object’ to which it pertains and that‘colour per se’ constitutes a natural attribute in the functional architecture of the perceptual system. It is regarded as autonomous by assuming that it can be studied in isolation of other perceptual attributes. These (...) assumptions also provide the pillars for the technical field of colorimetry, and have proved very fruitful for neurophysiological investigations into peripheral colour coding. They also have become, in a technology-driven cultural process of abstraction, part of our common-sense conception of colour. With respect to perception theory, however, both assumptions are grossly inadequate, on both empirical and theoretical grounds. All the same, the idea of an internal homogeneous and autonomous attribute of ‘colour per se’, mostly taken not as an empirical hypothesis but as a kind of truism, became a guiding idea in perceptual psychology. Here, it has impeded the identification of relevant theoretical issues and consequently has become detrimental for the development of explanatory frameworks for the role of ‘colour’ within the structure of our perceptual system. The chapter argues that enquiries into colour perception cannot be divorced from general enquiries into the structure of the conceptual forms underlying perception. (shrink)

Can what we know change what we see? Does language affect cognition and perception? The last few years have seen increased attention to these seemingly disparate questions, but with little theoretical advance. We argue that substantial clarity can be gained by considering these questions through the lens of predictive processing, a framework in which mental representations—from the perceptual to the cognitive—reflect an interplay between downward-flowing predictions and upward-flowing sensory signals. This framework provides a parsimonious account of how what we (...) know ought to change what we see and helps us understand how a putatively high-level trait such as language can impact putatively low-level processes such as perception. Within this framework, language begins to take on a surprisingly central role in cognition by providing a uniquely focused and flexible means of constructing predictions against which sensory signals can be evaluated. Predictive processing thus provides a plausible mechanism for many of the reported effects of language on perception, thought, and action, and new insights on how and when speakers of different languages construct the same “reality” in alternate ways. (shrink)

Humans have the ability to learn surprisingly complicated statistical information in a variety of modalities and situations, often based on relatively little input. These statistical learning (SL) skills appear to underlie many kinds of learning, but despite their ubiquity, we still do not fully understand precisely what SL is and what individual differences on SL tasks reflect. Here, we present experimental work suggesting that at least some individual differences arise from stimulus-specific variation in perceptual fluency: the ability to rapidly (...) or efficiently code and remember the stimuli that SL occurs over. Experiment 1 demonstrates that participants show improved SL when the stimuli are simple and familiar; Experiment 2 shows that this improvement is not evident for simple but unfamiliar stimuli; and Experiment 3 shows that for the same stimuli (Chinese characters), SL is higher for people who are familiar with them (Chinese speakers) than those who are not (English speakers matched on age and education level). Overall, our findings indicate that performance on a standard SL task varies substantially within the same (visual) modality as a function of whether the stimuli involved are familiar or not, independent of stimulus complexity. Moreover, test–retest correlations of performance in an SL task using stimuli of the same level of familiarity (but distinct items) are stronger than correlations across the same task with stimuli of different levels of familiarity. Finally, we demonstrate that SL performance is predicted by an independent measure of stimulus-specific perceptual fluency that contains no SL component at all. Our results suggest that a key component of SL performance may be related to stimulus-specific processing and familiarity. (shrink)

Spatial facilitation has been observed with luminance-defined, achromatic stimuli on achromatic backgrounds as well as with targets and inducers defined by colour contrast. This paper reviews psychophysical results from detection experiments with human observers showing the conditions under which spatially separated contour inducers facilitate the detection of simultaneously presented target stimuli. The findings point towards two types of spatial mechanisms: (i) Short-range mechanisms that are sensitive to narrowly spaced stimuli of small size and, at distinct target locations, selective to the (...) contrast polarity of targets and inducers. (ii) Long-range mechanisms that are triggered by longer stimuli, generate facilitation across wider spatial gaps between targets and inducers, and are insensitive to their contrast polarity. Spatial facilitation with chromatic stimuli requires a longer inducer exposure than spatial facilitation with achromatic stimuli, which is already fully effective at inducer exposures of 30 ms. This difference in temporal dynamics indicates some functional segregation between mechanisms for colour and luminance contrast in the perception of space. (shrink)