This is a letter from an amateur philosopher to Alex Byrne expressing perplexity on reading Byrne's chapter in The Oxford Handbook of the Philosophy of Mind, "Sensory Qualities, Sensible Qualities, Sensational Qualities" (2009). A version of the theory of indirect perception is described using several analogies and one autobiographical episode. It is described as a realization that occurred historically and may occur to individuals, supplanting default naive realism. Byrne's readings of various philosophers' accounts of sensory qualities are then contrasted with (...) an interpretation consistent with the adduced theory of indirect perception. The difficulty of imagining the view from the opposite side of the direct/indirect perception divide is remarked upon. (shrink)

Farben sind für uns sowohl objektive, als auch phänomenale Eigenschaften. In seinem Buch argumentiert Fabian Dorsch, daß keine ontologische Theorie der Farben diesen beiden Seiten unseres Farbbegriffes gerecht werden k ann. Statt dessen sollten wir akzeptieren, daß letzterer sich auf zwei verschiedene Arten von Eigenschaften bezieht: die repräsentierten Reflektanzeigenschaften von Gegenständen und die qualitativen Eigenschaften unserer Farbwahrnehmungen, die als sinnliche Gegebenheitsweisen ersterer fungieren. Die Natur der Farben gibt einen detaillierten Überblick über die zeitgenössischen philosophischen und naturwissenschaftlichen Theorien der Farben und (...) bietet sich aufgrund seines systematischen und umfassenden Charakters auch als ein seminar- oder vorlesungsbegleitendes Textbuch an. (shrink)

In this paper I explore irrealist alternatives to orthodox realism about grounding, and claim that at least some of these alternatives represent fertile areas for future discussion.

I address the question of whether differences in color terminology cause differences in color experience in speakers of different languages. If linguistic representations directly affect color experience, then this is a case of what I call the linguistic penetrability of perception, which is a particular case of cognitive penetrability. I start with some general considerations about cognitive penetration and its alleged occurrence in the memory color effect. I then apply similar considerations to the interpretation of empirical (...) studies of color perception in speakers of different languages. I argue that findings such as differences in categorical perception in speakers of different languages do not show that language affects color experience. They therefore do not support the claim that color experience is linguistically penetrable. But even if we grant that color experience is different in speakers of different languages, I argue that this might still not be a case of linguistic penetration. Finally, I consider some epistemological consequences of the assumption that speakers of different languages have different color experiences. (shrink)

It has become a common-place to read the ‘no-self’ theory of the Buddhist philosophers as a reductionist account of persons. In Reasons and Persons, Derek Parfit himself seemed to endorse the association, having learned of the Buddhist theory from his colleague at All Souls College, Bimal Krishna Matilal. The Buddha’s denial that there are real selves metaphysically distinct from continuous streams of psycho-physical constituents lends itself, to be sure, to a reductionist interpretation. I believe, nevertheless, that there are good grounds (...) for scepticism, and I think it is time for scholars of Buddhism to be more cautious about the identification than they have been up until now. Different Buddhist schools, not to mention different thinkers within particular schools, have given widely varying philosophical construals of the Buddha’s claim about ‘no-self’, and, while some thinkers and some schools might favor a reductionist reading of the claim, others, I would argue, do not. In this paper, I will examine the theory of persons of one such, the Mādhyamika Buddhist Candrakīrti. Candrakīrti’s interpretation of the “no self” slogan is, I believe, anti-reductionist but irrealist: persons are not reducible to psycho-physical streams, nor are they real existents distinct from the stream. How is it possible for him to say both these things? Let us see. (shrink)

In this chapter, I critically examine two of the main approaches to colour categorization in cognitive science: the perceptual salience theory and linguistic relativism. I then turn to reviewing several decades of psychological research on colour categorical perception (CP). A careful assessment of relevant findings suggests that most of the experimental effects that have been understood in terms of CP actually fall on the cognition side of the perception-cognition divide: they are effects of colour language, for example, on memory or (...) decision-making. (shrink)

Should a principle of charity be applied to the interpretation of the colour concepts exercised in visual experience? We think not. We shall argue, for one thing, that the grounds for applying a principle of charity are lacking in the case of colour concepts. More importantly, we shall argue that attempts at giving the experience of colour a charitable interpretation either fail to respect obvious features of that experience or fail to interpret it charitably, after all. Charity to visual experience (...) is therefore no motive for resisting the natural, Galilean response to a scientific understanding of light and vision. The best interpretation of colour experience ends up convicting it of widespread and systematic error. (shrink)

Many favor representationalism about color experience. To a first approximation, this view holds that experiencing is like believing. In particular, like believing, experiencing is a matter of representing the world to be a certain way. Once you view color experience along these lines, you face a big question: do our color experiences represent the world as it really is? For instance, suppose you see a tomato. Representationalists claim that having an experience with this sensory character is necessarily (...) connected with representing a distinctive quality as pervading a round area out there in external space. Let us call it “sensible redness” to highlight the fact that the representation of this property is necessarily connected with the sensory character of the experience. Is this property, sensible redness, really co-instantiated with roundness out there in the space before you? (shrink)

A survey of color science and color vision.

Consider the distinctive qualitative property grass visually appears to have when it visually appears to be green. This property is an example of what I call sensuous color. Whereas early modern mechanists typically argue that bodies are not sensuously colored, Margaret Cavendish (1623–73) disagrees. In cases of veridical perception, she holds that grass is green in precisely the way it visually appears to be. In defense of her realist approach to sensuous colors, Cavendish argues that (i) it is impossible (...) to conceive of colorless bodies, (ii) the very possibility of color experience requires that bodies are sensuously colored, and (iii) the attribution of sensuous colors to bodies provides the best explanation of color constancy. Although some passages might suggest that Cavendish endorses a reductive account of sensuous color, according to which sensuous color reduces to a body's microscopic surface texture (or some other mechanistically respectable property), I argue that she accepts a nonreductive account, on which sensuous color is not thus reducible. (shrink)

According to unconscious perception hypothesis (UP), mental states of the same fundamental kind as ordinary conscious seeing can occur unconsciously. The proponents of UP often support it with empirical evidence for a more specific hypothesis, according to which colours can be seen unconsciously (UPC). However, UPC is a general claim that admits of many interpretations. The main aim of this paper is to determine which of them is the most plausible. To this end, I investigate how adopting various conceptions of (...) colour and perceptual phenomenal character affects UPC’s resilience to objections. This brings me to the conclusion that the most plausible reading of UPC is the one according to which the phenomenal character of colour perception (i) is constituted by colours qua primitive mind-independent qualities of the environment and (ii) is not essentially tied to consciousness. My conclusion not only identifies the most plausible interpretation of UPC, but also highlights and supports an unorthodox version of the relational theory of perception, which is a perfectly viable yet so far overlooked stance in the debate about unconscious perception. (shrink)

Is color experience cognitively penetrable? Some philosophers have recently argued that it is. In this paper, we take issue with the claim that color experience is cognitively penetrable. We argue that the notion of cognitive penetration that has recently dominated the literature is flawed since it fails to distinguish between the modulation of perceptual content by non-perceptual principles and genuine cognitive penetration. We use this distinction to show that studies suggesting that color experience can be modulated by (...) factors of the cognitive system do not establish that color experience is cognitively penetrable. Additionally, we argue that even if color experience turns out to be modulated by color-related beliefs and knowledge beyond non-perceptual principles, it does not follow that color experience is cognitively penetrable since the experiences of determinate hues involve post-perceptual processes. We conclude with a brief discussion of the implications that these ideas may have on debates in philosophy. (shrink)

The orthodox monadic determination thesis holds that we represent colour relations by virtue of representing colours. Against this orthodoxy, I argue that it is possible to represent colour relations without representing any colours. I present a model of iconic perceptual content that allows for such primitive relational colour representation, and provide four empirical arguments in its support. I close by surveying alternative views of the relationship between monadic and relational colour representation.

Are color adjectives ("red", "green", etc.) relative adjectives or absolute adjectives? Existing theories of the meaning of color adjectives attempt to answer that question using informal ("armchair") judgments. The informal judgments of theorists conflict: it has been proposed that color adjectives are absolute with standards anchored at the minimum degree on the scale, that they are absolute but have near-midpoint standards, and that they are relative. In this paper we report two experiments, one based on entailment patterns (...) and one based on presupposition accommodation, that investigate the meaning of scalar adjectives. We find evidence confirming the existence of subgroups of the population who operate with different standards for color adjectives. The evidence of interpersonal variation in where standards are located on the relevant scale and how those standards can be adjusted indicates that the existing theories of the meaning of color adjectives are at best only partially correct. We also find evidence that paradigmatic relative adjectives ("tall", "wide") behave in ways that are not predicted by the standard theory of scalar adjectives. We discuss several different possible explanations for this unexpected behavior. We conclude by discussing the relevance of our findings for philosophical debates about the nature and extent of semantically encoded context sensitivity in which color adjectives have played a key role. (shrink)

The problem of colour exclusion is not fatal to Ludwig Wittgenstein’s early philosophy, nor was it the catalyst for his later philosophy. The remarks in the Tractatus about the impossibility of the simultaneous occurrence of two colours at a point in the visual field sit comfortably with the remarks in the rest of the book, the discussion of mathematical physics above all. Furthermore Wittgenstein’s second thoughts about the impossibility were a consequence, not the cause, of the subsequent turn in his (...) philosophy. (shrink)

Dispositional theories of colour have been attacked by McGinn and others on the ground that ‘Colours do not look like dispositions’. Langsam has argued that on the contrary they do, in ‘Why Colours Do Look Like Dispositions’, The Philosophical Quarterly, 50 , pp. 68–75. I make three claims. First, neither side has made its case. Secondly, it is true, at least on one interpretation, that colours do not look like dispositions. Thirdly, this does not show that dispositionalism about colours is (...) false. (shrink)

One prominent ambition of theories of colour is to pay full justice to how colours are subjectively given to us; and another to reconcile this first-personal perspective on colours with the third-personal one of the natural sciences. The goal of this article is to question whether we can satisfy the second ambition on the assumption that the first should and can be met. I aim to defend a negative answer to this question by arguing that the various kinds of experienced (...) colour resemblances – notably similarities in hue distance, sameness in superdeterminables, and colour resemblances between surfaces, volumes and illuminants – cannot be accounted for in terms of the mental representation of the scientifically studied properties, which colours are best identified with in response to the second ambition. (shrink)

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)

This and the following lessons cover the topic of Vedānta and ethics. Vedānta has two meanings. The first is the literal sense – “End of Vedas” – and refers to the Āraṇyakas and Upaniṣads—the latter part of the Vedas. The second sense of “Vedanta” is a scholastic one, and refers to a philosophical orientation that attempts to explain the cryptic Vedānta Sūtra (Brahma Sūtra) of Bādarāyaṇa, which aims at being a summary of the End of the Vedas. We shall pursue (...) the question of ethics in both senses of Vedānta. In this module we shall examine the ethical theory of Deontology found in the Upaniṣads. Having explored the implications of this model for moral philosophy, we can reflect upon the three commentarial approaches. In this lesson, we will examine Śaṅkara’s Advaita approach. Advaita Vedānta, especially in Śaṅkara's form, presents a version of moral scepticism, or more strongly, moral irrealism. In this account, there is nothing objective about ethics: it mediates our desires-oriented psychology, and should be dispensed with along with the desire-oriented psychology. Śaṅkara seems to come close to doing the impossible: saying insightful things about what he takes to be a fiction, which is the individual self, for which ethics is essential. (shrink)

This paper critically examines color relationalism and color relativism, two theories of color that are allegedly supported by variation in normal human color vision. We mostly discuss color relationalism, defended at length in Jonathan Cohen's The Red and the Real, and argue that the theory has insuperable problems.

This paper investigates some classical oppositional categories, like synthetic vs. analytic, posterior vs. prior, imagination vs. grammar, metaphor vs. hermeneutics, metaphysics vs. observation, innovation vs. routine, and image vs. sound, and the role they play in epistemology and philosophy of science. The epistemological framework of objective cognitive constructivism is of special interest in these investigations. Oppositional relations are formally represented using algebraic lattice structures like the cube and the hexagon of opposition, with applications in the contexts of modern color (...) theory, Kantian philosophy, Jungian psychology, and linguistics. (shrink)

I will develop a new problem for almost all realist theories of colour. The problem involves fluctuations in our colour experiences that are due to visual noise rather than changes in the objects we are looking at.

This paper (from 2006) is now defunct. I argue against "realist primitivism". One of my arguments is a kind of "evolutionary debunking argument". Some of the material of this was incorporated into “Can Disjunctivists Explain Our Access to the Sensible World?” and "How Does Color Experience Represent the World?".

I show that the mathematical description of opponent-colors theory is identical to the mathematical description of two-state quantum systems in a mixed state. Based on the dual-aspect theory of phenomenal consciousness, which suggests that one or more physical entities in our universe have phenomenal aspects that are dual to their physical aspects and therefore predicts an exact correspondence between a system’s phenomenal states and the objective states of its underlying physical substrate, I hypothesize that color sensations are phenomenal dual (...) aspects of two-state quantum systems in a mixed state. Since nothing in this hypothesis suggests that what brings about the phenomenal experience that is dual to two-state quantum systems is the two-dimensionality of these systems, it is natural to generalize this hypothesis and suggest that other types of phenomenal experience (e.g., taste, odor, sound) are phenomenal dual aspects of quantum systems of higher dimensionalities. Finally, I propose that the two-state quantum systems that give rise to color in the brain are two-state ion-channels. (shrink)

What is the relationship between color experience and color? Here, I defend the view that it is semantic: color experience denotes color in a code innately known by the perceiver. This semantic theory contrasts with a variety of theories according to which color is defined as the cause of color experience (in a special set of circumstances). It also contrasts with primary quality theories of color, which treat color as a physical quantity. (...) I argue that the semantic theory better accounts for the kinds of knowledge we have regarding both the color of objects that we see and of the colors themselves. (shrink)

Most philosophical or scientific theories suppose that colour composition judgments refer to the way colours appear to us. The dominant view is therefore phenomenalist in the sense that colour composition is phenomenally given to perceivers. This paper argues that there is no evidence for a phenomenalist view of colour composition and that a conventionalist approach should be favoured.

It seems intuitively obvious that metameric matching of color samples entails a loss of information, for spectrophotometrically diverse materials appear the same. This intuition implicitly relies on a conception of the function of color vision and on a related conception of how color samples should be individuated. It assumes that the function of color vision is to distinguish among spectral energy distributions, and that color samples should be individuated by their physical properties. I challenge these (...) assumptions by articulating a different conception of the function of color vision, according to which color vision serves to partition object surfaces into discrimination classes. (shrink)

In this paper I argue that all transparent objects are colorless. This thesis is important for at least three reasons. First, if transparent objects are colorless, there is no need to distinguish between colors which characterize three-dimensional bodies, like transparent colors, and colors which lie on the surface of objects. Second, traditional objections against color physicalism relying on transparent colors are rendered moot. Finally, an improved understanding of the relations between colors, light and transparency is provided.

This article considers distinct ways of understanding the world, referred to in psychology as Functions of Consciousness or as Cognitive Modes, having as the scope of interest epistemology and natural sciences. Inspired by C.G. Jung's Simile of the Spectrum, we consider three basic cognitive modes associated to: (R) embodied instinct, experience, and action; (G) reality perception and learning; and (B) concept abstraction, rational thinking, and language. RGB stand for the primary colors: red, green, and blue. Accordingly, a conceptual map between (...) cognitive modes and primary and secondary colors is built based on the physics and physiology of color perception and epistemological characteristics of the aforementioned cognitive modes, leading to logical relations structured as an Hexagon of Opposition. Finally, this model of cognitive modes is applied to the analysis and interpretation of some important episodes in the historical development of physics and technology. (shrink)

Defenders of moral perception have famously argued that seeing value is relevantly similar to seeing color. Some critics think, however, that the analogy between color-seeing and value-seeing breaks down in several crucial respects. Defenders of moral perception, these critics say, have not succeeded in providing examples of non-moral perception that are relevantly analogous to cases of moral perception. Therefore, it can be doubted whether there is such a thing as moral perception at all. I argue that, although the (...) analogy between color perception and moral perception does indeed break down in several crucial respects, that conclusion does not weaken the case of defenders of moral perception, because better analogies are available. If defenders of moral perception seek to draw support from an analogy, then seeing emotion will protect them better against criticisms than will seeing color. (shrink)

Colour relationalism holds that the colours are constituted by relations to subjects. Anti-relationalists have claimed that this view stands in stark contrast to our phenomenally-informed, pre-theoretic intuitions. Is this claim right? Cohen and Nichols’ recent empirical study suggests not, as about half of their participants seemed to be relationalists about colour. Despite Cohen and Nichols’ study, we think that the anti-relationalist’s claim is correct. We explain why there are good reasons to suspect that Cohen and Nichols’ experimental design skewed their (...) results in favour of relationalism. We then run an improved study and find that most of our participants seem to be anti-relationalists. We find some other interesting things too. Our results suggest that the majority of ordinary people find it no less intuitive that colours are objective than that shapes are objective. We also find some evidence that when those with little philosophical training are asked about the colours of objects, their intuitions about colour and shape cases are similar, but when asked about people’s colour ascriptions, their intuitions about colour and shape cases differ. (shrink)

This paper articulates a case for supposing that all shades of colour are visually complex.

Relationalism is a view popularized by Cohen according to which the colors are relational properties. Cohen’s view has the unintuitive consequence that the following propositions are false: (i) no object can be more than one determinate or determinable color all over at the same time; (ii) ordinary illusion cases occur whenever the color perceptually represented conflicts, according to (i) above, with the object’s real color; and (iii) the colors we perceive obey (i). I investigate Cohen’s attempt to (...) address these intuitive propositions with which his view struggles and find it to be incompatible with how he motivates his view. (shrink)

In this Handbook entry, I review how colour similarity spaces are constructed, first for physical sources of colour and secondly for colour as it is perceptually experienced. The unique hues are features of one of the latter constructions, due initially to Hering and formalized in the Swedish Natural Colour System. I review the evidence for a physiological basis for the unique hues. Finally, I argue that Tye's realist approach to the unique hues is a mistake.

The dominant view among philosophers of perception is that color experiences, like color judgments, are essentially representational: as part of their very nature color experiences possess representational contents which are either accurate or inaccurate. My starting point in assessing this view is Sydney Shoemaker’s familiar account of color perception. After providing a sympathetic reconstruction of his account, I show how plausible assumptions at the heart of Shoemaker’s theory make trouble for his claim that color experiences (...) represent the colors of things. I consider various ways of trying to avoid the objection, and find all of the responses wanting. My conclusion is that we have reason to be skeptical of the orthodox view that color experiences are constitutively representational. (shrink)

Martine Nida-Rümelin (1996) argues that color science indicates behaviorally undetectable spectrum inversion is possible and raises this possibility as an objection to functionalist accounts of visual states of color. I show that her argument does not rest solely on color science, but also on a philosophically controversial assumption, namely, that visual states of color supervene on physiological states. However, this assumption, on the part of philosophers or vision scientists, has the effect of simply ruling out certain (...) versions of functionalism. While Nida-Rümelin is quite right to search for empirical tests for claims about the nature of visual states, philosophical issues remain pivotal in determining the correctness of these claims. (shrink)

In this paper, I present the enactive theory of color that implies a form of color relationism. I argue that this view constitutes a better alternative to color subjectivism and color objectivism. I liken the enactive view to Husserl’s phenomenology of perception, arguing that both deconstruct the clear duality of subject and object, which is at the basis of the other theories of color, in order to claim the co-constitution of subject and object in the (...) process of experience. I also extend the enactive and phenomenological account of color to the more general topic of the epistemological and ontological status of sensory qualities (qualia), outlining the fields of enactive phenomenology and enactive ontology. (shrink)

Tracking theories of mental representation posit a privileged relation between color representations and the color properties of objects. Tracking theories of mental representation have been used to motivate color realism as they posit that the function of color vision is to represent the colors of objects. It has been argued that tracking theories have a major flaw, namely they cannot account for reliable misrepresentation. It has further been suggested that reliable color misrepresentation is a live (...) possibility. In this chapter, I argue that the current evidence indicates that our color representations reliably misrepresent. This conclusion undermines tracking theories and the color realist theories they purport to motivate. (shrink)

For a stable visual world, the colours of objects should appear the same under different lights. This property of colour constancy has been assumed to be fundamental to vision, and many experimental attempts have been made to quantify it. I contend here, however, that the usual methods of measurement are either too coarse or concentrate not on colour constancy itself, but on other, complementary aspects of scene perception. Whether colour constancy exists other than in nominal terms remains unclear.

In this essay I consider Kaplan’s challenge to Frege’s so-called dictum: “Logic (and perhaps even truth) is immune to epithetical color”. I show that if it is to challenge anything, it rather challenges the view (attributable to Frege) that logic is immune to pejorative colour. This granted, I show that Kaplan’s inference-based challenge can be set even assuming that the pejorative doesn’t make any non-trivial truth-conditional (descriptive) contribution. This goes against the general tendency to consider the truth-conditionally inert logically (...) irrelevant. But I take it that Kaplan is right and take his examples to show that truth-conditional inertness need not entail inferential inertness. I end up assessing the Kaplan-Frege “debate” as giving edge to the former to the extent that clarity is achieved through Kaplanian inferences on what should be considered part of the explanandum. (shrink)

This article considers distinct ways of understanding the world, referred to in psychology as functions of consciousness or as cognitive modes, having as the scope of interest epistemology and natural sciences. Inspired by C.G. Jung’s simile of the spectrum, we consider three basic cognitive modes associated to: (R) embodied instinct, experience, and action; (G) reality perception and learning; and (B) concept abstraction, rational thinking, and language. RGB stand for the primary colors: red, green, and blue. Accordingly, a conceptual map between (...) cognitive modes and primary and secondary colors is built based on the physics and physiology of color perception and epistemological characteristics of the aforementioned cognitive modes, leading to logical relations structured as an hexagon of opposition. Finally, this model of cognitive modes is applied to the analysis and interpretation of some important episodes in the historical development of physics and technology. (shrink)

In a recent paper, Gow raised a new and interesting problem for externalist representationalism, the conclusion of which is that its proponents are unable to provide an acceptable account of the phenomenal character of colour hallucination. In contrast to Gow, we do not believe that the problem is particularly severe – indeed, that there is any problem at all. Thus our aim is to defend externalist representationalism against the problem raised by Gow. To this end, we will first reconstruct her (...) reasoning, and then show that it poses no real challenge to externalist representationalism. (shrink)

"The Location Problem for Color Subjectivism" response to commentators.

The goal of the present paper is to defend against a certain line of attack the view that conscious experience of color is no more fine-grained that the repertoire of non- demonstrative concepts that a perceiver is able to bring to bear in perception. The line of attack in question is an alleged empirical argument - the Diachronic Indistinguishability Argument - based on pairs of colors so similar that they can be discriminated when simultaneously presented but not when presented (...) across a memory delay. My aim here is to show that this argument fails. (shrink)

I argue that Leibniz's rejection of the hypothesis of thinking matter on grounds of unintelligibility conflicts with his position on sensible qualities such as color. In the former case, he argues that thought must be a modification of something immaterial because we cannot explain thought in mechanical terms. In the latter case, however, he (rightly) grants that we cannot explain sensible qualities in mechanical terms, that is, cannot explain why a certain complex mechanical quality gives rise to the appearance (...) of a certain sensible quality, even while insisting that sensible qualities are modifications of bodies. I argue that the two cases are analogous in the relevant respects, and that Leibniz's (plausible) position on sensible qualities should have thrown his Principle of Intelligibility into doubt. (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)

Colour information not only helps sustain the survival of animal species by guiding sexual selection and foraging behaviour but also is an important factor in the cultural and technological development of our own species. This is illustrated by examples from the visual arts and from state-of-the-art imaging technology, where the strategic use of colour has become a powerful tool for guiding the planning and execution of interventional procedures. The functional role of colour information in terms of its potential benefits to (...) behavioural success across the species is addressed in the introduction here to clarify why colour perception may have evolved to generate behavioural success. It is argued that evolutionary and environmental pressures influence not only colour trait production in the different species but also their ability to process and exploit colour information for goal-specific purposes. We then leap straight to the human primate with insight from current research on the facilitating role of colour cues on performance training with precision technology for image-guided surgical planning and intervention. It is shown that local colour cues in two-dimensional images generated by a surgical fisheye camera help individuals become more precise rapidly across a limited number of trial sets in simulator training for specific manual gestures with a tool. This facilitating effect of a local colour cue on performance evolution in a video-controlled simulator (pick-and-place) task can be explained in terms of colour-based figure-ground segregation facilitating attention to local image parts when more than two layers of subjective surface depth are present, as in all natural and surgical images. (shrink)