Early last year, the GenEthics Consortium (GEC) of the Washington Metropolitan Area convened at George Washington University to consider a complex case about genetic testing for Alzheimer disease (AD). The GEC consists of scientists, bioethicists, lawyers, genetic counselors, and consumers from a variety of institutions and affiliations. Four of the 8 co-authors of this paper delivered presentations on the case. Supplemented by additional ethical and legal observations, these presentations form the basis for the following discussion.

G. A. Cohen was one of the most gifted, influential, and progressive voices in contemporary political philosophy. At the time of his death in 2009, he had plans to bring together a number of his most significant papers. This is the first of three volumes to realize those plans. Drawing on three decades of work, it contains previously uncollected articles that have shaped many of the central debates in political philosophy, as well as papers published here for the first (...) time. In these pieces, Cohen asks what egalitarians have most reason to equalize, he considers the relationship between freedom and property, and he reflects upon ideal theory and political practice. Included here are classic essays such as "Equality of What?" and "Capitalism, Freedom, and the Proletariat," along with more recent contributions such as "Fairness and Legitimacy in Justice," "Freedom and Money," and the previously unpublished "How to Do Political Philosophy." On ample display throughout are the clarity, rigor, conviction, and wit for which Cohen was renowned. Together, these essays demonstrate how his work provides a powerful account of liberty and equality to the left of Ronald Dworkin, John Rawls, Amartya Sen, and Isaiah Berlin. (shrink)

The genes involved in methionine biosynthesis are scattered throughout the Escherichia coli chromosome and are controlled in a similar but not coordinated manner. The product of the metJ gene and S‐adenosylmethionine are involved in the repression of this ‘regulon’.

© 2016 Elsevier LtdJumping spiders are famous for their visually driven behaviors [1]. Here, however, we present behavioral and neurophysiological evidence that these animals also perceive and respond to airborne acoustic stimuli, even when the distance between the animal and the sound source is relatively large and with stimulus amplitudes at the position of the spider of ∼65 dB sound pressure level. Behavioral experiments with the jumping spider Phidippus audax reveal that these animals respond to low-frequency sounds by freezing—a common (...) anti-predatory behavior characteristic of an acoustic startle response. Neurophysiological recordings from auditory-sensitive neural units in the brains of these jumping spiders showed responses to low-frequency tones —recordings that also represent the first record of acoustically responsive neural units in the jumping spider brain. Responses persisted even when the distances between spider and stimulus source exceeded 3 m and under anechoic conditions. Thus, these spiders appear able to detect airborne sound at distances in the acoustic far-field region, beyond the near-field range often thought to bound acoustic perception in arthropods that lack tympanic ears [2]. Furthermore, direct mechanical stimulation of hairs on the patella of the foreleg was sufficient to generate responses in neural units that also responded to airborne acoustic stimuli—evidence that these hairs likely play a role in the detection of acoustic cues. We suggest that these auditory responses enable the detection of predators and facilitate an acoustic startle response. Video. (shrink)

In reply to Narveson, I distinguish his no-proviso argument from his liberty argument, and I show that both fail. I also argue that interference lacks the strategic status he assigns to it, because it cannot be appropriately distinguished, conceptually and morally, from prevention; that natural resources do enjoy the importance he denies they have; that laissez-faire economies lack the superiority he attributes to them; that ownership can indeed be a reflexive relation; that anti-paternalism does not entail libertarianism; and that he (...) misrepresents the doctrines of a number of philosophers, including John Locke, Ronald Dworkin, and myself. In reply to Brenkert, I show that he seriously misconstrues my view of the nature of freedom, and of its relationship to self-ownership. I then refute his criticisms of my treatment of the contrasts between self-ownership, on the one hand, and autonomy and non-slavery, on the other. I also show that his attempt to exorcize the demon of self-ownership is multiply flawed. (shrink)

Blind tasting — tasting without knowing the wine’s producer, origin, or other details obtainable from the wine’s label— has become something of a fetish in the wine world. We are told, repeatedly and insistently, that blind tasting is the best, most neutral, least biased, and most honest evaluative procedure, and one that should be employed to the exclusion of non-blind/sighted tasting (which, in turn, is typically disparaged as confused, biased, or dishonest). Professional evaluators (e.g., the tasting panel of the Wine (...) Spectator, the Grand Jury Europ´een, virtually every judging panel in competitive wine events) routinely advertise that they use blind tasting exclusively. Wine books and tasting manuals at all levels consistently emphasize the importance of blind tasting. Thus, Michael Broadbent, perhaps the most prolific author of tasting notes in history, writes that “It is my firm opinion . . . that to assess the qualities of a wine by tasting it completely blind, without any hint of what it might be, is the most useful and salutary discipline that any self-respecting taster can be given” (quoted in ? , 156). Or, again, Ronald Jackson, in his industry-standard textbook on wine tasting, asserts categorically that “Tastings should always be conducted blind, usually with only the names of the wine noted in advance” ( ? , 334). (shrink)

The aim of this paper is to ponder the intricate issue of the right to die in dignity by focusing attention on the role of the patient's beloved people. I first provide critical examination of some of the arguments advanced by Ronald Dworkin. I proceed by contemplating relevant scenarios and examining three American court decisions: Saikewicz, Spring and Gray. The first case, Saikewicz, concerns a patient who had no family or other beloved people. I observe that this fact had (...) a significant bearing on the court's ruling not to provide him treatment. The second case, Spring, involves a patient whose family wanted to withhold treatment from him. I argue that we should be cautious of incidents in which the best interests of the patient's beloved people come at the expense of the best interests of the patient. Spring is an example of such a case. The third case, Gray, serves as an example whereby the best interests of the patient coincide with the best interests of her beloved people. I conclude by arguing that attention has to be given to the question of whether the patient's close-ones demonstrate a unified position in regard to the destiny of the patient. Gegenstand des Beitrags ist es, das schwierige Problem des Rechts, in Würde zu sterben, im Hinblick auf die Rolle der Personen zu überdenken, die dem Patienten nahestehen. Der Autor setzt sich zunächst kritisch mit einigen von Ronald Dworkin vorgetragenen Argumenten auseinander. Dann stellt er die relevanten Fallgestaltungen dar und untersucht drei Entscheidungen amerikanischer Gerichte: die Fälle Saikewicz, Spring und Gray. Der erste Fall, Saikewicz, betrifft einen Patienten ohne Familie oder andere ihm nahestehende Personen. Dieser Umstand hatte einen wesentlichen Einfluß auf die Entscheidung des Gerichts, von der Anordnung einer Behandlung des Patienten abzusehen. Im zweiten Fall, Spring, wünschte die Familie, daß der Patient nicht behandelt würde. Der Autor mahnt für alle die Fälle zur Vorsicht, bei denen die Umstände so beschaffen sind, daß das wohlverstandene Interesse der Angehörigen und das des Patienten kollidieren. Der Fall Spring ist ein Beispiel für eine solche Kollisionssituation. Der dritte Fall, Gray, dient als ein Beispiel, in dem sich das wohlverstandene Interesse des Patienten und das der ihm nahestehenden Personen decken. Zuletzt geht es um die Frage, ob die Angehörigen und andere dem Patienten nahestehende Personen in ihren Vorstellungen über das weitere Schicksal des Patienten übereinstimmen oder nicht. Die Frage verdient eine besondere Aufmerksamkeit. (shrink)

G. A. Cohen argues that egalitarians should compensate for expensive tastes or for the fact that they are expensive. Ronald Dworkin, by contrast, regards most expensive tastes as unworthy of compensation — only if a person disidentifies with his own such tastes (i.e. wishes he did not have them) is compensation appropriate. Dworkinians appeal, inter alia, to the so-called ‘first-person’ or ‘continuity’ test. According to the continuity test, an appropriate standard of interpersonal comparison reflects people's own assessment of (...) their relative standing: Person A can only legitimately demand compensation from person B if he regards himself as worse off, all things considered, than B. The typical bearer of expensive tastes does not regard herself as being worse off than others with less expensive tastes. Hence, in the typical case, pace Cohen, compensation for expensive tastes is inappropriate. The article scrutinizes this rationale for not compensating for expensive tastes. Especially, we try to bolster the continuity test by relating it to Dworkin's distinction between integrated and detached values, pointing out that an argument for the continuity test can be built on the assumption that equality has integrated value. In brief, the point is that a metric of equality should be assessed, partly, in virtue of its consequences for related ideals. One of these is the kind of justificatory community promoted by the continuity test. We defend this view against an objection to the effect that equality is a detached value. We conclude that the continuity test constitutes a strong foothold for the resourcist egalitarian reluctance to compensate people for their expensive tastes. (shrink)

This dissertation proposes a new reading and appraisal of an important theory of distributive justice, Ronald Dworkin's "Equality of Resources" . ER is traditional in holding that choices made by rational, ignorant and purely self-interested beings are relevant to distributive justice. ER is novel both in its use of such choices and in incorporating the idea that one's success is largely one's own responsibility into liberal egalitarianism. ;I argue that the tax-and-redistribution scheme Dworkin proposes to make actual distributions just (...) is flawed because he misconceives the role of choice. He errs in thinking that the conditions for person X to receive compensation depend on the choices of such beings, although he is right, I argue, insofar as the relevant choices include X's hypothetical choices. Dworkin errs in that ER implies that whether X meets these conditions can depend on X's irrational choices, although he is right that whether X meets these conditions can depend on some of X's actual choices. ER becomes flawed, I argue, when Dworkin derives a tax-and-redistribution scheme designed to achieve distributive justice in reality from the auction he proposes for making hypothetical distributions just. ;I then consider whether ER withstands stock objections and how plausible it is relative to rival Theories. Dworkin argues that ER, but not Rawls' Theory, meets the following condition for a Theory to be plausible: the distributions a Theory deems just must be sensitive to choices. I argue that Dworkin's argument is no longer plausible once we realize to which choice sensitivity principle he is himself committed. However, I argue, Seana Shiffrin's objection to ER fails because she misunderstands the role of choice in ER, although she is right insofar as there is a related, though superficial, objection. I also argue that ER is inconsistent and show how to resolve this inconsistency without leaving ER vulnerable to attack by G. A. Cohen's rival Theory. I trace ER's inconsistency and the failure of Dworkin's argument against Rawls' Theory to Dworkin's method of justification. (shrink)

abstract G. A. Cohen argues that egalitarians should compensate for expensive tastes or for the fact that they are expensive. Ronald Dworkin, by contrast, regards most expensive tastes as unworthy of compensation — only if a person disidentifies with his own such tastes (i.e. wishes he did not have them) is compensation appropriate. Dworkinians appeal, inter alia, to the so‐called ‘first‐person’ or ‘continuity’ test. According to the continuity test, an appropriate standard of interpersonal comparison reflects people's own assessment (...) of their relative standing: Person A can only legitimately demand compensation from person B if he regards himself as worse off, all things considered, than B. The typical bearer of expensive tastes does not regard herself as being worse off than others with less expensive tastes. Hence, in the typical case, pace Cohen, compensation for expensive tastes is inappropriate. The article scrutinizes this rationale for not compensating for expensive tastes. Especially, we try to bolster the continuity test by relating it to Dworkin's distinction between integrated and detached values, pointing out that an argument for the continuity test can be built on the assumption that equality has integrated value. In brief, the point is that a metric of equality should be assessed, partly, in virtue of its consequences for related ideals. One of these is the kind of justificatory community promoted by the continuity test. We defend this view against an objection to the effect that equality is a detached value. We conclude that the continuity test constitutes a strong foothold for the resourcist egalitarian reluctance to compensate people for their expensive tastes. (shrink)

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)

Conceptual analysis has fallen out of favor in political philosophy. The influence of figures like John Rawls and Ronald Dworkin has led political philosophy to focus on questions about what should be done, and to ignore questions about the usage of words. As a result, contemporary political philosophy lacks a shared understanding of the concept of justice, and a considerable amount of disagreement between political philosophers is, upon reflection, traceable to this. In my book, I call for renewed attention (...) to the manner in which the word ‘justice’ is and should be used. Focusing on the late work of G.A. Cohen, I argue that two major debates in contemporary political philosophy: the debate over luck-egalitarianism and the debate over whether justice imposes demands on citizens’ personal lives; are really just conceptual. Whereas some philosophers have been using the term ‘justice’ to refer to one among a plurality of values, others have been using it to refer to institutional rightness. Though the latter use of ‘justice’ is presently more dominant, I argue that much is to be gained from thinking of justice as one value among many. Doing so sheds light on the nature of both democracy and legitimacy, and, paradoxically, makes better sense of the idea that justice is ‘the first virtue of institutions’. (shrink)

Five aspects of visual change detection are reviewed. The first concerns the concept of change itself, in particular the ways it differs from the related notions of motion and difference. The second involves the various methodological approaches that have been developed to study change detection; it is shown that under a variety of conditions observers are often unable to see large changes directly in their field of view. Next, it is argued that this “change blindness” indicates that focused attention is (...) needed to detect change, and that this can help map out the nature of visual attention. The fourth aspect concerns how these results affect our understanding of visual perception—for example, the implication that a sparse, dynamic representation underlies much of our visual experience. Finally, a brief discussion is presented concerning the limits to our current understanding of change detection. (shrink)

A set of visual search experiments tested the proposal that focused attention is needed to detect change. Displays were arrays of rectangles, with the target being the item that continually changed its orientation or contrast polarity. Five aspects of performance were examined: linearity of response, processing time, capacity, selectivity, and memory trace. Detection of change was found to be a self-terminating process requiring a time that increased linearly with the number of items in the display. Capacity for orientation was found (...) to be about 5 items, a value comparable to estimates of attentional capacity. Observers were able to filter out both static and dynamic variations in irrelevant properties. Analysis also indicated a memory for previously-attended locations. These results support the hypothesis that the process needed to detect change is much the same as the attentional process needed to detect complex static patterns. Interestingly, the features of orientation and polarity were found to be handled in somewhat different ways. Taken together, these results not only provide evidence that focused attention is needed to see change, but also show that change detection itself can provide new insights into the nature of attentional processing. (shrink)

One of the more powerful impressions created by vision is that of a coherent, richly-detailed world where everything is present simultaneously. Indeed, this impression is so compelling that we tend to ascribe these properties not only to the external world, but to our internal representations as well. But results from several recent experiments argue against this latter ascription. For example, changes in images of real-world scenes often go unnoticed when made during a saccade, flicker, blink, or movie cut. This "change (...) blindness" provides strong evidence against the idea that our brains contain a picture-like representation of the scene that is everywhere detailed and coherent. (shrink)

'Principles Of Mental Imagery' offers a broad, balanced, and up-to-date introduction to the major findings of this research and identifies five general principles that can account for most of them. It considers the development of experimental techniques that have solved many of the challenging methodological problems inherent in imagery research and includes recent experimental findings not covered in other imagery books..

Over the centuries, magicians have developed extensive knowledge about the manipulation of the human mind—knowledge that has been largely ignored by psychology. It has recently been argued that this knowledge could help improve our understanding of human cognition and consciousness. But how might this be done? And how much could it ultimately contribute to the exploration of the human mind? We propose here a framework outlining how knowledge about magic can be used to help us understand the human mind. Various (...) approaches—both old and new—are surveyed, in terms of four different levels. The first focuses on the methods in magic, using these to suggest new approaches to existing issues in psychology. The second focuses on the effects that magic can produce, such as the sense of wonder induced by seeing an apparently impossible event. Third is the consideration of magic tricks—methods and effects together—as phenomena of scientific interest in their own right. Finally, there is the organization of knowledge about magic into an informative whole, including the possibility of a science centered around the experience of wonder. (shrink)

It is suggested that the relationship between visual attention and conscious visual experience can be simplified by distinguishing different aspects of both visual attention and visual experience. A set of principles is first proposed for any possible taxonomy of the processes involved in visual attention. A particular taxonomy is then put forward that describes five such processes, each with a distinct function and characteristic mode of operation. Based on these, three separate kinds—or possibly grades—of conscious visual experience can be distinguished, (...) each associated with a particular combination of attentional processes. (shrink)

Large changes that occur in clear view of an observer can become difficult to notice if made during an eye movement, blink, or other such disturbance. This change blindness is consistent with the proposal that focused visual attention is necessary to see change, with a change becoming difficult to notice whenever conditions prevent attention from being automatically drawn to it. -/- It is shown here how the phenomenon of change blindness can provide new results on the nature of visual attention, (...) including estimates of its capacity and the extent to which it can bind visual properties into coherent descriptions. It is also shown how the resultant characterization of attention can in turn provide new insights into the role that it plays in the perception of scenes and events. (shrink)

Large changes in a scene often become difficult to notice if made during an eye movement, image flicker, movie cut, or other such disturbance. It is argued here that this _change blindness_ can serve as a useful tool to explore various aspects of vision. This argument centers around the proposal that focused attention is needed for the explicit perception of change. Given this, the study of change perception can provide a useful way to determine the nature of visual attention, and (...) to cast new light on the way that it is?and is not?involved in visual perception. To illustrate the power of this approach, this paper surveys its use in exploring three different aspects of vision. The first concerns the general nature of _seeing_. To explain why change blindness can be easily induced in experiments but apparently not in everyday life, it is proposed that perception involves a _virtual representation_, where object representations do not accumulate, but are formed as needed. An architecture containing both attentional and nonattentional streams is proposed as a way to implement this scheme. The second aspect concerns the ability of observers to detect change even when they have no visual experience of it. This _sensing_ is found to take on at least two forms: detection without visual experience (but still with conscious awareness), and detection without any awareness at all. It is proposed that these are both due to the operation of a nonattentional visual stream. The final aspect considered is the nature of visual attention itself?the mechanisms involved when _scrutinizing_ items. Experiments using controlled stimuli show the existence of various limits on visual search for change. It is shown that these limits provide a powerful means to map out the attentional mechanisms involved. (shrink)

Papers presented at a symposium on philosophy and medicine at the Institute for the Medical Humanities at the University of Texas Medical Branch in 1974 were published in the inaugural volume of this series.

Prominent among the arguments against the legalization of assisted suicide is the contention that legalization will have a disproportionately adverse, or “disparate,” impact on various vulnerable groups. There are many versions of this argument, with different advocates of this argument focusing on different vulnerable groups, and some advocates confusedly blending slippery slope and social justice concerns. Also, the weight placed on this argument by its various advocates is not uniform, with some including the argument in a list of multiple, apparently (...) similarly persuasive, reasons for not legalizing assisted suicide, while others place significant reliance on it and yet others advance the argument without any clear indication of its importance. Nonetheless, the various versions share a common core: One reason assisted suicide should not be legalized is that members of certain vulnerable groups are more likely to be pressured into requesting it, whether directly by those hostile or indifferent to their interests, or indirectly by social circumstances, such as an inability to pursue other healthcare choices. (shrink)

Experiments are presented showing that visual search for Mueller-Lyer (ML) stimuli is based on complete configurations, rather than component segments. Segments easily detected in isolation were difficult to detect when embedded in a configuration, indicating preemption by low-level groups. This preemption—which caused stimulus components to become inaccessible to rapid search—was an all-or-nothing effect, and so could serve as a powerful test of grouping. It is shown that these effects are unlikely to be due to blurring by simple spatial filters at (...) early visual levels. It is proposed instead that they are due to more sophisticated processes that rapidly bind contour fragments into spatially-extended assemblies. These results support the view that rapid visual search cannot access the primitives formed at the earliest stages of visual processing; rather, it can access only higher-level, more ecologically-relevant structures. (shrink)

Human vision briefly retains a trace of a stimulus after it disappears. This trace—iconic memory—is often believed to be a surrogate for the original stimulus, a representational structure that can be used as if the original stimulus were still present. To investigate its nature, a flicker-search paradigm was developed that relied upon a full scan (rather than partial report) of its contents. Results show that for visual search it can indeed act as a surrogate, with little cost for alternating between (...) visible and iconic representations. However, the duration over which it can be used depends on the type of task: some tasks can use iconic memory for at least 240 ms, others for only about 190 ms, while others for no more than about 120 ms. The existence of these different limits suggests that iconic memory may have multiple layers, each corresponding to a particular level of the visual hierarchy. In this view, the inability to use a layer of iconic memory may reflect an inability to maintain feedback connections to the corresponding representation. (shrink)

Prior to passage of the Oregon Death with Dignity Act, opponents of assistance in dying argued that legalization would have serious harmful consequences. Specifically, they argued that the quality and availability of palliative care would decline, that the harms of legalization would affect certain vulnerable groups disproportionately, that legal assisted dying could not be confined to the competent terminally ill who voluntarily request assistance, and that the practice would result in frequent abuses. Data from Oregon's decade-long experience decisively refute the (...) first three predictions. As to abuses, the record is not quite as clear, but if an appropriate framework for analysis is utilized, the most reasonable conclusion is that the risks of abuse do not outweigh the benefits of legalization. To the extent projected harmful consequences are relevant to the debate over legalization, Oregon's experience argues in favor of legalization of assistance in dying. (shrink)

Traditionally, vision science and information/data visualization have interacted by using knowledge of human vision to help design effective displays. It is argued here, however, that this interaction can also go in the opposite direction: the investigation of successful visualizations can lead to the discovery of interesting new issues and phenomena in visual perception. Various studies are reviewed showing how this has been done for two areas of visualization, namely, graphical representations and interaction, which lend themselves to work on visual processing (...) and the control of visual operations, respectively. The results of these studies have provided new insights into aspects of vision such as grouping, attentional selection and the sequencing of visual operations. More generally yet, such results support the view that the perception of visualizations can be a useful domain for exploring the nature of visual cognition, inspiring new kinds of questions as well as casting new light on the limits to which information can be conveyed visually. (shrink)

This paper critically appraises the applied action-guide approach to bioethics and finds it wanting in two ways: it is tethered to a social contract view of the doctor-patient relationship that is largely incompatible with experiences of illness and care; and, as a formalist doctrine, it lacks critical edge and tends toward accommodationism. An alternative approach is recommended that involves interpreting moral experience by means once associated with the rhetorical arts — practical reasoning, hermeneutics, casuistry, and thick description.

It has often been assumed that when we use vision to become aware of an object or event in our surroundings, this must be accompanied by a corresponding visual experience (i.e., seeing). The studies reported here show that this assumption is incorrect. When observers view a sequence of displays alternating between an image of a scene and the same image changed in some way, they often feel (or sense) the change even though they have no visual experience of it. The (...) subjective difference between sensing and seeing is mirrored in several behavioral differences, suggesting that these are two distinct modes of conscious visual perception. (shrink)

Prominent among the arguments against the legalization of assisted suicide is the contention that legalization will have a disproportionately adverse, or “disparate,” impact on various vulnerable groups. There are many versions of this argument, with different advocates of this argument focusing on different vulnerable groups, and some advocates confusedly blending slippery slope and social justice concerns. Also, the weight placed on this argument by its various advocates is not uniform, with some including the argument in a list of multiple, apparently (...) similarly persuasive, reasons for not legalizing assisted suicide, while others place significant reliance on it and yet others advance the argument without any clear indication of its importance. Nonetheless, the various versions share a common core: One reason assisted suicide should not be legalized is that members of certain vulnerable groups are more likely to be pressured into requesting it, whether directly by those hostile or indifferent to their interests, or indirectly by social circumstances, such as an inability to pursue other healthcare choices. (shrink)

This festschrift collects a number of insightful essays by a group of accomplished Christian scholars, all of who have either worked with or studied under Hendrik Hart during his 35-year tenure as Senior Member in Systematic Philosophy at the Institute for Christian Studies, Toronto, Canada.

The past few years have seen a resurgence of interest in the scientific study of magic. Despite being only a few years old, this “new wave” has already resulted in a host of interesting studies, often using methods that are both powerful and original. These developments have largely borne out our earlier hopes (Kuhn et al., 2008) that new opportunities were available for scientific studies based on the use of magic. And it would seem that much more can still be (...) done along these lines. -/- But in addition to this, we also suggested that it might be time to consider developing an outright science of magic—a distinct area of study concerned with the experience of wonder that results from encountering an apparently impossible event1. To this end, we proposed a framework as to how this might be achieved (Rensink and Kuhn, 2015). A science can be viewed as a systematic method of investigation involving three sets of issues: (i) the entities considered relevant, (ii) the kinds of questions that can be asked about them, and (iii) the kinds of answers that are legitimate (Kuhn, 1970). In the case of magic, we suggested that this could be done at three different levels, each focusing on a distinct set of issues concerned with the nature of magic itself: (i) the nature of magical experience, (ii) how individual magic tricks create this experience, and (iii) organizing knowledge of the set of known tricks in a more comprehensive way (Rensink and Kuhn, 2015). Our framework also included a base level focused on how the methods of magic could be used as tools to investigate issues in existing fields of study. -/- Lamont (2010) and Lamont et al. (2010) raised a number of concerns about the possibility of such a science, which we have addressed (Rensink and Kuhn, 2015). More recently, Lamont (2015) raised a new objection, arguing that although base-level work (i.e., applications of magic methods) might be useful, there is too little structure in magic tricks for them to be studied in a systematic way at the other levels, ruling out a science of magic. We argue here, however, that although this concern raises some interesting challenges for this science, it does not negate the possibility that it could exist, and could contribute to the study of the mind. (shrink)

We show that early vision can use monocular cues to rapidly complete partially-occluded objects. Visual search for easily detected fragments becomes difficult when the completed shape is similar to others in the display; conversely, search for fragments that are difficult to detect becomes easy when the completed shape is distinctive. Results indicate that completion occurs via the occlusion-triggered removal of occlusion edges and linking of associated regions. We fail to find evidence for a visible filling-in of contours or surfaces, but (...) do find evidence for a "functional" filling-in that prevents the constituent fragments from being rapidly accessed. As such, it is only the completed structures—and not the fragments themselves—that serve as the basis for rapid recognition. (shrink)

When brief blank fields are placed between alternating displays of an original and a modified scene, a striking failure of perception is induced: the changes become extremely difficult to notice, even when they are large, presented repeatedly, and the observer expects them to occur (Rensink, O'Regan, & Clark, 1997). To determine the mechanisms behind this induced "change blindness", four experiments examine its dependence on initial preview and on the nature of the interruptions used. Results support the proposal that representations at (...) the early stages of visual processing are highly volatile, and that focused attention is needed to stabilize them sufficiently to support the perception of change. (shrink)

Our visual experience of the world is one of diverse objects and events, each with particular colors, shapes, and motions. This experience is so coherent, so immediate, and so effortless that it seems to result from a single system that lets us experience everything in our field of view. But however appealing, this belief is mistaken: there are severe limits on what can be visually experienced. -/- For example, in a display for air-traffic control it is important to track all (...) moving items. For a single item, this can be done without problem. Three or four can also be tracked, although some degree of effort may be needed. As the number is increased further, accurate tracking becomes more and more difficult—and eventually, impossible. Performance is evidently affected by a factor within the observer which enables certain kinds of perception to occur, but is limited in some way. This factor is generally referred to as attention. -/- At various times, attention has been associated with clarity of perception, intensity of perception, consciousness, selection, or the allocation of a limited “resource” enabling various operations (see Hatfield, 1998). During the past several decades, considerable progress has been achieved by focusing on the idea of selection (Broadbent, 1982). In particular, attention can be productively viewed as contingently selective processing. This can be embodied in various ways by various processes—there need not be a single quantity identified with all forms of attention, or a single site where it operates (Allport, 1993; Tsotsos, 2011). Although “paying attention” is often considered to be a unitary operation, it may simply refer to the control of one or more selective processes, ideally in a co-ordinated way. While this view has some cost in terms of conceptual simplicity, it can help make sense of a large set of phenomena. -/- This article surveys several of the major issues in our understanding of attention and how it relates to perception. It focuses on vision, since many—if not all—considerations are similar for all sensory modalities, and the level of understanding achieved in this domain is currently the most advanced. (shrink)