Observers matched patches (simulated Munsell papers) in two simultaneously presented computer-controlled displays, a standard array presented under 6500-K illumination and a test array under 4000 or 10,000 K. Adaptation to the test illuminants was limited. The adjusted patch was surrounded by a single color (annulus display) or by many colors (Mondrian display). Observers either matched hue and saturation or made surface-color (paper) matches in which the subject was asked to make the test patch look as if it were cut from (...) the same piece of paper as the standard patch. For two of the three subjects, the paper matches were approximately color constant. The hue- saturation matches showed little color constancy. Moreover, the illumination difference between the two displays was always visible. Our data show that simultaneous mechanisms alone (e.g., simultaneous color contrast) alter hues and saturations too little to produce hue constancy. (shrink)

This expanded edition of C L Hardin's ground-breaking work on colour features a new chapter, 'Further Thoughts: 1993', in which the author revisits the dispute ...

the Logische Untersuchungen,l phenomenology has been conceived as a substratum of empirical psychology, as a sphere comprising "imma nental" descriptions of psychical mental processes, a sphere compris ing descriptions that - so the immanence in question is understood - are strictly confined within the bounds of internal experience. It 2 would seem that my protest against this conception has been oflittle avail; and the added explanations, which sharply pinpointed at least some chief points of difference, either have not been understood (...) or have been heedlessly pushed aside. Thus the replies directed against my criticism of psychological method are also quite negative because they miss the straightforward sense of my presentation. My criticism of psychological method did not at all deny the value of modern psychology, did not at all disparage the experimental work done by eminent men. Rather it laid bare certain, in the literal sense, radical defects of method upon the removal of which, in my opinion, must depend an elevation of psychology to a higher scientific level and an extraordinary amplification ofits field of work. Later an occasion will be found to say a few words about the unnecessary defences of psychology against my supposed "attacks. (shrink)

This is a book about how we see: the environment around us (its surfaces, their layout, and their colors and textures); where we are in the environment; whether or not we are moving and, if we are, where we are going; what things are good for; how to do things (to thread a needle or drive an automobile); or why things look as they do.The basic assumption is that vision depends on the eye which is connected to the brain. The (...) author suggests that natural vision depends on the eyes in the head on a body supported by the ground, the brain being only the central organ of a complete visual system. When no constraints are put on the visual system, people look around, walk up to something interesting and move around it so as to see it from all sides, and go from one vista to another. That is natural vision—and what this book is about. (shrink)

This systematic investigation of computation and mental phenomena by a noted psychologist and computer scientist argues that cognition is a form of computation, that the semantic contents of mental states are encoded in the same general way as computer representations are encoded. It is a rich and sustained investigation of the assumptions underlying the directions cognitive science research is taking. 1 The Explanatory Vocabulary of Cognition 2 The Explanatory Role of Representations 3 The Relevance of Computation 4 The Psychological Reality (...) of Programs: Strong Equivalence 5 Constraining Functional Architecture 6 The Bridge from Physical to Symbolic: Transduction 7 Functional Architecture and Analogue Processes 8 Mental Imagery and Functional Architecture 9 Epilogue: What is Cognitive Science the Science of? (shrink)

The Embodied Mind provides a unique, sophisticated treatment of the spontaneous and reflective dimension of human experience.

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)

What ecological advantages do animals gain by being able to detect, extract and exploit wavelength information? What are the advantages of representing that information as hue qualities? The benefits of adding chromatic to achromatic vision, marginal in object detection, become apparent in object recognition and receiving biological signals. It is argued that this improved performance is a direct consequence of the fact that many animals' visual systems reduce wavelength information to combinations of four basic hues. This engenders a simple categorical (...) scheme that permits a rich amount of sensory information to be rapidly and efficiently employed by cognitive machinery of limited capacity. (shrink)

Colour has often been supposed to be a subjective property, a property to be analysed orretly in terms of the phenomenological aspects of human expereince. In contrast with subjectivism, an objectivist analysis of color takes color to be a property objects possess in themselves, independently of the character of human perceptual expereince. David Hilbert defends a form of objectivism that identifies color with a physical property of surfaces - their spectral reflectance. This analysis of color is shown to provide a (...) more adequate account of the features of human color vision than its subjectivist rivals. The author's account of colro also recognises that the human perceptual system provides a limited and idiosyncratic picture of the world. These limitations are shown to be consistent with a realist account of colour and to provide the necessary tools for giving an analysis of common sense knowledge of color phenomena. (shrink)

There are serious reasons for accepting each of these propositions individually but there are apparently insurmountable difficulties with accepting all three of them simultaneously if we assume that color is a single property. 1) and 2) together seem to imply that there is some property which all organisms with color vision can see and 3) seems to imply that there can be no such property. If these implications really are valid then one or more of these propositions will have to (...) be rejected in spite of whatever reasons can be given for their apparent acceptability. Before going on to discuss possible resolutions of this apparent contradiction it is worth pointing out there our three propositions are not all of a kind. Proposition 1) is a metaphysical thesis about the ontological status of color and proposition 3) is an empirical thesis about what properties organisms with color vision are capable of detecting. If you accept 1) then 2) will appear to verge on the trivial, but if 1) is denied then the status of 2) will appear more problematic. In what follows I will have more to say about why we either should or should not accept all three of these propositions. (shrink)

Colour fascinates all of us, and scientists and philosophers have sought to understand the true nature of colour vision for many years. In recent times, investigations into colour vision have been one of the main success stories of cognitive science, for each discipline within the field - neuroscience, psychology, linguistics, computer science and artificial intelligence, and philosophy - has contributed significantly to our understanding of colour. Evan Thompson's book is a major contribution to this interdisciplinary project. Colour Vision provides an (...) accessible review of the current scientific and philosophical discussions of colour vision. Thompson steers a course between the subjective and objective positions on colour, arguing for a relational account. This account develops a novel `ecological' approach to colour vision in cognitive science and the philosophy of perception. It is vital reading for all cognitive scientists and philosophers whose interests touch upon this central area. (shrink)

Different explanations of color vision favor different philosophical positions: Computational vision is more compatible with objectivism (the color is in the object), psychophysics and neurophysiology with subjectivism (the color is in the head). Comparative research suggests that an explanation of color must be both experientialist (unlike objectivism) and ecological (unlike subjectivism). Computational vision's emphasis on optimally prespecified features of the environment (i.e., distal properties, independent of the sensory-motor capacities of the animal) is unsatisfactory. Conceiving of visual perception instead as the (...) visual guidance of activity in an environment that is determined largely by that very activity suggests new directions for research. (shrink)

Could there be genuinely novel colours — that is, visual qualities having a hue that bears a resemblance relation to red, green, yellow, and blue, yet is neither reddish, nor greenish, nor yellowish, nor blueish?1 And if there could be such colours, what would it be like to see them? How would the colours look? In his article,"Epiphenomenal Qualia,"2 Frank Jackson presents a philosophical thought experiment that raises these questions . Jackson asks us to imagine a perceiver named Fred who (...) is like us except that he has the ability to see a hue we cannot see. Jackson's question is: "What is the new colour or colours like?"3 Jackson argues that all the physical information about Fred, including the physiology of his brain and visual system, and his dispositions to behaviour, would not enable us to answer this question. The totality of physical information would still leave out something about Fred's experience, namely, what the extra hue is like from the subjective perspective of Fred. And if at some point we became able to see this extra hue , we would learn something that we did not know as a result of having all the physical information about Fred: We would learn how the extra hue looks and thereby learn just what it was that made Fred's experience different from ours. Jackson calls his argument "the knowledge argument." In his view, the argument is similar to Thomas Nagel's in his article "What is it Like to Be a Bat?,"4 but both its point and ultimate conclusion are different. Nagel argues that facts about what conscious experience is like for some creature are essentially connected to the subjective perspective of the creature. The problem that Nagel poses is, how could such facts be revealed in anything objective and physical about the creature? How could the objective characterization indicate what it is like to be the creature ? The point of Jackson's argument, however, is not that we would not know what it is like to be Fred even if we knew everything physical about him ; it is rather that there is still something we do not know about Fred's experience — a property that it has — even when we have all the physical information about him: We do not know how the extra hue that Fred sees looks to Fred, and so we do not know all that there is to know about how Fred's experience of seeing the extra hue differs from his experience of seeing red, green, yellow, and blue.5 Jackson's conclusion is also stronger than Nagel's. (shrink)

Perceptions "present" objects as red, as round, etc.-- in general as possessing some property. This is the "perceptual content" of the title, And the article attempts to answer the following question: what is a materialistically adequate basis for assigning content to what are, after all, neurophysiological states of biological organisms? The thesis is that a state is a perception that presents its object as "F" if the "biological function" of the state is to detect the presence of objects that are (...) "F". The theory contrasts with causal/informational theories, and with internalist theories, for example those which assign content on the basis of introspected feel. Its advantages are that it permits perceptual error while at the same time allowing content to be expressed in terms of external properties. The argument of the paper is illustrated throughout by examples from biology and computational psychology. (shrink)