When looking at a scene, observers feel that they see its entire structure in great detail and can immediately notice any changes in it. However, when brief blank fields are placed between alternating displays of an original and a modified scene, a striking failure of perception is induced: identification of changes becomes extremely difficult, even when changes are large and made repeatedly. Identification is much faster when a verbal cue is provided, showing that poor visibility is not the cause of (...) this difficulty. Identification is also faster for objects mentioned in brief verbal descriptions of the scene. These results support the idea that observers never form a complete, detailed representation of their surroundings. In addition, results also indicate that attention is required to perceive change, and that in the absence of localized motion signals it is guided on the basis of high-level interest. (shrink)
Observers inspected normal, high quality color displays of everyday visual scenes while their eye movements were recorded. A large display change occurred each time an eye blink occurred. Display changes could either involve "Central Interest" or "Marginal Interest" locations, as determined from descriptions obtained from independent judges in a prior pilot experiment. Visual salience, as determined by luminance, color, and position of the Central and Marginal interest changes were equalized. -/- The results obtained were very similar to those obtained in (...) prior experiments showing failure to detect changes occurring simultaneously with saccades, flicker, or “mudsplashes” in the visual scene: Many changes were very hard to detect, and Marginal Interest changes were harder to detect than Central Interest changes. -/- Analysis of eye movements showed, as expected, that the probability of detecting a change depended on the eye’s distance from the change location. However a surprising finding was that both for Central and Marginal Interest changes, evenwhen observers were directly fixating the change locations (within 1 degree),more than 40% of the time they still failed to see the changes. It seems that looking at something does not guarantee you “ see” it. (shrink)
We address the thesis recently proposed by Andy Clark, that skill-mediated access to modality implies phenomenal feel. We agree that a skill theory of perception does indeed offer the possibility of a satisfactory account of the feel of perception, but we claim that this is not only through explanation of access to modality but also because skill actually provides access to perceptual property in general. We illustrate and substantiate our claims by reference to the recently proposed 'sensorimotor contingency' theory of (...) visual awareness. We discuss why this theory offers a distinctively attractive access-based approach to perceptual consciousness because it 'dereifies' experience and permits otherwise problematic aspects of phenomenal perceptual consciousness to be explained. We suggest our approach thus offers the prospect of 'naturalizing phenomenology'. (shrink)
The most important clarification we bring in our reply to commentators concerns the problem of the “explanatory gap”: that is, the gulf that separates physical processes in the brain from the experienced quality of sensations. By adding two concepts (bodiliness and grabbiness) that were not stressed in the target article, we strengthen our claim and clarify why we think we have solved the explanatory gap problem, – not by dismissing qualia, but, on the contrary, by explaining why sensations have a (...) “feel” and why “feels” feel the way they do. We additionally clarify our views on: internal representations (we claim internal representations cannot explain why sensation has a feel), on behaviorism (we are not behaviorists), on perception and action (we believe there can be perception without action), and on the brain (we believe the brain does do something important in perception). (shrink)
The target article appeals to recent empirical data to support the idea that there is more to phenomenality than is available to access consciousness. However, this claim is based on an unwarranted assumption, namely, that some kind of cortical processing must be phenomenal. The article also considerably weakens Block's original distinction between a truly nonfunctional phenomenal consciousness and a functional access consciousness. The new form of phenomenal consciousness seems to be a poor-man's cognitive access.
Call u the triplet of cone quantum catch for the light that is incident on a surface, and v the triplet of cone quantum catch for the light that is reflected off that surface. Philipona & O'Regan (2006) present results from numerical calculations showing that: 1. each surface can be associated with a 3 by 3 matrix A such that the relation v = A u to a very high degree of accuracy for any natural illuminant, 2. the vast majority (...) of such matrices associated with Munsell chips have three real eigenvalues, 3. Munsell chips that are most often given a name in the World Color Survey are chips whose associated matrices have a singular configuration of eigenvalues, as measured by a "singularity index". The conclusion of the paper is that this striking coincidence lends credence to the idea that data about color naming derive from facts about natural lights, surface reflexion properties, and human photopigments, rather than from facts about neural pathways or cortical representations. (shrink)
Overview. Consciousness is often considered to have a "hard" part and a not-so-hard part. With the help of work in artificial intelligence and more recently in embodied robotics, there is hope that we shall be able solve the not-so-hard part and make artificial agents that understand their environment, communicate with their friends, and most importantly, have a notion of "self" and "others". But will such agents feel anything? Building the feel into the agent will be the "hard" part.
Word recognition performance varies systematically as a function of where the eyes fixate in the word. Performance is maximal with the eye slightly left of the center of the word, and decreases drastically to both sides of this 'Optimal Viewing Position'. While manipulations of lexical factors have only marginal effects on this phenomenon, previous studies have pointed to a relation between the viewing position effect and letter legibility: When letter legibility drops, the viewing position effect becomes more exaggerated. To further (...) investigate this phenomenon, we improved letter legibility by magnifying letter size in a way that was proportional to the.. (shrink)