The task of visual search is to determine as rapidly as possible whether a target item is present or absent in a display. Rapidly detected items are thought to contain features that correspond to primitive elements in the human visual system. In previous theories, it has been assumed that visual search is based on simple two-dimensional features in the image. However, visual search also has access to another level of representation, one that describes properties in the corresponding three-dimensional scene. Among (...) these properties are three dimensionality and the direction of lighting, but not viewing direction. These findings imply that the parallel processes of early vision are much more sophisticated than previously assumed. (shrink)

Previous theories of early vision have assumed that visual search is based on simple two-dimensional aspects of an image, such as the orientation of edges and lines. It is shown here that search can also be based on three-dimensional orientation of objects in the corresponding scene, provided that these objects are simple convex blocks. Direct comparison shows that image-based and scene-based orientation are similar in their ability to facilitate search. These findings support the hypothesis that scene-based properties are represented at (...) preattentive levels in early vision. (shrink)

Advances in neuroscience implicate reentrant signaling as the predominant form of communication between brain areas. This principle was used in a series of masking experiments that defy explanation by feed-forward theories. The masking occurs when a brief display of target plus mask is continued with the mask alone. Two masking processes were found: an early process affected by physical factors such as adapting luminance and a later process affected by attentional factors such as set size. This later process is called (...) masking by object substitution, because it occurs whenever there is a mismatch between the reentrant visual representation and the ongoing lower level activity. Iterative reentrant processing was formalized in a computational model that provides an excellent fit to the data. The model provides a more comprehensive account of all forms of visual masking than do the long-held feed-forward views based on inhibitory contour interactions. (shrink)

It has generally been assumed that rapid visual search is based on simple features and that spatial relations between features are irrelevant for this task. Seven experiments involving search for line drawings contradict this assumption; a major determinant of search is the presence of line junctions. Arrow- and Y-junctions were detected rapidly in isolation and when they were embedded in drawings of rectangular polyhedra. Search for T-junctions was considerably slower. Drawings containing T-junctions often gave rise to very slow search even (...) when distinguishing arrow- or Y-junctions were present. This sensitivity to line relations suggests that preattentive processes can extract 3-dimensional orientation from line drawings. A computational model is outlined for how this may be accomplished in early human vision. (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)

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)

Boyer's formulation neglects that humans are embodied agents. It is a biological imperative to distinguish self from other. Ownership of ideas, bodies, objects, and locations is an inevitable extension of this. We argue that (1) the body's capability influences the inputs that guide future actions, and (2) bodies in action influence all of cognition, from perception to decision making.

Researchers have long suspected that grapheme-color synaesthesia is useful, but research on its utility has so far focused primarily on episodic memory and perceptual discrimination. Here we ask whether it can be harnessed during rule-based Category learning. Participants learned through trial and error to classify grapheme pairs that were organized into categories on the basis of their associated synaesthetic colors. The performance of synaesthetes was similar to non-synaesthetes viewing graphemes that were physically colored in the same way. Specifically, synaesthetes learned (...) to categorize stimuli effectively, they were able to transfer this learning to novel stimuli, and they falsely recognized grapheme-pair foils, all like non-synaesthetes viewing colored graphemes. These findings demonstrate that synaesthesia can be exploited when learning the kind of material taught in many classroom settings. (shrink)

We asked whether the influence of an invisible prime on movement is dependent on conscious movement expectations. Participants reached to a central target, which triggered a directional prime–mask arrow sequence. Participants were instructed that the visible arrows would most often signal a movement modification in a specific direction. Kinematic analyses revealed that responses to the visible mask were influenced by participants’ intentional bias, as movements were fastest when the more probable mask was displayed. In addition, responses were influenced by the (...) invisible prime without regard to its relationship to the more probable mask. Analysis of the time of initial trajectory modifications revealed that both primes influenced responses in a similar manner after accounting for participants’ bias. These results imply that invisible stimuli automatically activate their associated responses and that unconscious priming of the motor system is insensitive to the conscious expectations of the participant making the pointing movements. (shrink)

A modified visual search task demonstrates that humans are very good at resuming a search after it has been momentarily interrupted. This is shown by exceptionally rapid response time to a display that reappears after a brief interruption, even when an entirely different visual display is seen during the interruption and two different visual searches are performed simultaneously. This rapid resumption depends on the stability of the visual scene and is not due to display or response anticipations. These results are (...) consistent with the existence of an iterative hypothesis-testing mechanism that compares information stored in short-term memory (the perceptual hypothesis) with information about the display (the sensory pattern). In this view, rapid resumption occurs because a hypothesis based on a previous glance of the scene can be tested very rapidly in a subsequent glance, given that the initial hypothesis-generation step has already been performed. (shrink)

Hemisphere differences in word reading were examined using explicit and implicit processing measures. In an inclusion task, which indexes both conscious and unconscious word reading processes, participants were briefly presented with a word in either the right or the left visual field and were asked to use this word to complete a three-letter word stem. In an exclusion task, which estimates unconscious word reading, participants completed the word stem with any word other than the prime word. Experiment 1 showed that (...) words presented to either visual field were processed in very similar ways in both tasks, with the exception that words in the right visual field were more readily accessible for conscious report. Experiment 2 indicated that unconsciously processed words are shared between the hemispheres, as similar results were obtained when either the same or the opposite visual field received the word stem. Experiment 3 demonstrated that this sharing between hemispheres is cortically mediated by testing a split-brain patient. These results suggest that the left hemisphere advantage for word reading holds only for explicit measures; unconscious word reading is much more balanced between the hemispheres. (shrink)

When we reach to pick up an object, our actions are effortlessly informed by the object’s spatial information, the position of our limbs, stored knowledge of the object’s material properties, and what we want to do with the object. A substantial body of evidence suggests that grasps are under the control of “automatic, unconscious” sensorimotor modules housed in the “dorsal stream” of the posterior parietal cortex. Visual online feedback has a strong effect on the hand’s in-flight grasp aperture. Previous work (...) of ours exploited this effect to show that grasps are refractory to cued expectations for visual feedback. Nonetheless, when we reach out to pretend to grasp an object (pantomime grasp), our actions are performed with greater cognitive effort and they engage structures outside of the dorsal stream, including the ventral stream. Here we ask whether our previous finding would extend to cued expectations for haptic feedback. Our method involved a mirror apparatus that allowed participants to see a “virtual” target cylinder as a reflection in the mirror at the start of all trials. On “haptic feedback” trials, participants reached behind the mirror to grasp a size-matched cylinder, spatially coincident with the virtual one. On “no-haptic feedback” trials, participants reached behind the mirror and grasped into “thin air” because no cylinder was present. To manipulate haptic expectation, we organized the haptic conditions into blocked, alternating, and randomized schedules with and without verbal cues about the availability of haptic feedback. Replicating earlier work, we found the strongest haptic effects with the blocked schedules and the weakest effects in the randomized uncued schedule. Crucially, the haptic effects in the cued randomized schedule was intermediate. An analysis of the influence of the upcoming and immediately preceding haptic feedback condition in the cued and uncued random schedules showed that cuing the upcoming haptic condition shifted the haptic influence on grip aperture from the immediately preceding trial to the upcoming trial. These findings indicate that, unlike cues to the availability of visual feedback, participants take advantage of cues to the availability of haptic feedback, flexibly engaging pantomime, and natural modes of grasping to optimize the movement. (shrink)

Shapes that are rendered invisible through backward masking are still able to influence motor responses: this is called masked priming. Yet it is unknown whether this influence is on the control of ongoing action, or whether it merely influences the initiation of an already-programmed action. We modified a masked priming procedure such that the critical prime-mask sequence was displayed during the execution of an already-initiated goal-directed pointing movement. Psychophysical tests of prime visibility indicated that the identity of the prime shapes (...) were not accessible to participants for conscious report. Yet detailed kinematic analysis of the finger in motion revealed that masked primes had an influence on the pointing trajectories within 277 ms of their appearance, 56 ms earlier than the trajectory deviations observed in response to the visible masks. These results indicate that subliminal shapes can indeed influence the control of ongoing motor activity. (shrink)

Empirical adequacy, formal explanation and understanding are distinct goals of science. While no a priori criterion for understanding should be laid down, there may be inherent limitations on the way we are able to understand explanations of physical phenomena. I examine several recent contributions to the exercise of fashioning an explanatory discourse to mold the formal explanation provided by quantum mechanics to our modes of understanding. The question is whether we are capable of truly understanding (or comprehending) quantum phenomena, as (...) opposed to simply accepting the formalism and certain irreducible quantum correlations. The central issue is that of understanding versus merely redefining terms to paper over our ignorance. (shrink)

Darwin and the Art of Science will consist of excerpts from six of Darwin's books, chosen and introduced by James Costa. The excerpts will be arranged by plant (rather than according to which book they're from) in order to make the most of extraordinary images provided by the Oak Springs Garden Foundation library. As a group, they will provide unparalleled access to Darwin's fascinating observations and musings about the world of plants and how their distinctive features have evolved.

Meaning systems and psychological suffering -- Conceptualizations of meaning system -- Meaning systems and mental health culture -- Contemporary culture and objectification -- Training for talk therapists.

Why does one theory "succeed" while another, possibly clearer interpretation, fails? By exploring two observationally equivalent yet conceptually incompatible views of quantum mechanics, James T. Cushing shows how historical contingency can be crucial to determining a theory's construction and its position among competing views. Since the late 1920s, the theory formulated by Niels Bohr and his colleagues at Copenhagen has been the dominant interpretation of quantum mechanics. Yet an alternative interpretation, rooted in the work of Louis de Broglie in (...) the early 1920s and reformulated and extended by David Bohm in the 1950s, equally well explains the observational data. Through a detailed historical and sociological study of the physicists who developed different theories of quantum mechanics, the debates within and between opposing camps, and the receptions given to each theory, Cushing shows that despite the preeminence of the Copenhagen view, the Bohm interpretation cannot be ignored. Cushing contends that the Copenhagen interpretation became widely accepted not because it is a better explanation of subatomic phenomena than is Bohm's, but because it happened to appear first. Focusing on the philosophical, social, and cultural forces that shaped one of the most important developments in modern physics, this provocative book examines the role that timing can play in the establishment of theory and explanation. (shrink)

Alexis de Tocqueville, a French aristocrat paradoxically famous for his insights into democracy and equality, is one of history’s greatest analysts of American society and politics. His contributions to political theory and sociology are of enduring significance. This book, from one of the world’s leading experts, is a clearly written and accessible introduction to Tocqueville’s social and political theories. Schleifer guides readers through his two major works, Democracy in America (1835/40) and The Old Regime and the Revolution (1856), as well (...) as his working papers, correspondence, and other writings. Schleifer examines Tocqueville’s essential themes and explores the various meanings of his key terms, including equality, democracy, liberty, and revolution. He combines a skillful exposition of Tocqueville’s analysis of the beneficial and harmful consequences of democracy with a crystal clear discussion of his often overlooked economic ideas and social reform proposals. Schleifer traces both the overall unity and the significant changes in Tocqueville’s ideas, demonstrating the complexity and subtlety of his thought and the importance of his legacy. It will be essential reading for all scholars, students, and general readers interested in the history of political thought, political theory, American politics, and sociology. (shrink)

The Handbook of Roman Catholic Moral Terms contains more than 800 moral terms, offering concise definitions, historical context, and illustrations of how these terms are used in the Catholic tradition, including Church teaching and documents. James T. Bretzke, SJ, places Catholic tradition in a contemporary context in order to illuminate the continuities as well as discontinuities of Church teaching and key directions of Catholic thought. The author also provides extensive cross-referencing and bibliographic suggestions for further research. Designed to serve (...) as a vital reference work for libraries, students and scholars of theology, priests and pastoral ministers, as well as all adults interested in theological enrichment or continuing education, the Handbook of Roman Catholic Moral Terms is the most comprehensive post–Vatican II work of its kind available in English. (shrink)

From the beginning, the implications of quantum theory for our most general understanding of the world have been a matter of intense debate. Einstein argues that the theory had to be regarded as fundamentally incomplete. Its inability, for example, to predict the exact time of decay of a single radioactive atom had to be due to a failure of the theory and not due to a permanent inability on our part or a fundamental indeterminism in nature itself. In 1964, John (...) Bell derived a theorem which showed that any deterministic theory which preserved locality would have certain consequences for measurements performed at a distance from one another. An experimental check seems to show that these consequences are not, in fact, realized. The correlation between the sets of events is much stronger than any local deterministic theory could allow. What is more, this stronger correlation is precisely that which is predicted by quantum theory. The astonishing result is that local deterministic theories of the classical sort seem to be permanently excluded. Not only can the individual decay not be predicted, but no future theory can ever predict it. The contributors in this volume wrestle with this conclusion. Some welcome it; others leave open a return to at lease some kind of deterministic world, one which must however allow something like action-at-a distance. How much lit it? And how can one avoid violating relativity theory, which excludes action-at-a-distance? How can a clash between the two fundamental theories of modern physics, relativity and quantum theory, be avoided? What are the consequences for the traditional philosophic issue of causality explanation and objectivity? One thing is certain; we can never return to the comfortable Newtonian world where everything that happened was, in principle, predictable and where what happened at one measurement site could not affect another set of measurements being performed light-years away, at a distance that a light-signal could not bridge. Contributors: James T. Cushing, Abner Shimony, N. David Mermin, Jon P. Jarrett, Linda Wessels, Bas C. van Fraassen, Jeremy Butterfield, Michael L. G. Redhead, Henry P. Stapp, Arthur Fine, R. I. G. Hughes, Paul Teller, Don Howard, Henry J. Folse, and Ernan McMullin. (shrink)

This book examines a selection of philosophical issues in the context of specific episodes in the development of physical theories. Advances in science are presented against the historical and philosophical backgrounds in which they occurred. A major aim is to impress upon the reader the essential role that philosophical considerations have played in the actual practice of science. The book begins with some necessary introduction to the history of ancient and early modern science, with major emphasis being given to the (...) two great watersheds of twentieth-century physics: relativity and, especially, quantum mechanics. At times the term 'construction' may seem more appropriate than 'discovery' for the way theories have developed and, especially in the later chapters, the question of the influence of historical, philosophical and even social factors on the very form and content of scientific theories is discussed. (shrink)

We are often told that quantum phenomena demand radical revisions of our scientific world view and that no physical theory describing well defined objects, such as particles described by their positions, evolving in a well defined way, let alone deterministically, can account for such phenomena. The great majority of physicists continue to subscribe to this view, despite the fact that just such a deterministic theory, accounting for all of the phe nomena of nonrelativistic quantum mechanics, was proposed by David Bohm (...) more than four decades ago and has arguably been around almost since the inception of quantum mechanics itself. Our purpose in asking colleagues to write the essays for this volume has not been to produce a Festschrift in honor of David Bohm or to gather together a collection of papers simply stating uncritically Bohm's views on quantum mechanics. The central theme around which the essays in this volume are arranged is David Bohm's version of quantum mechanics. It has by now become fairly standard practice to refer to his theory as Bohmian mechanics and to the larger conceptual framework within which this is located as the causal quantum theory program. While it is true that one can have reservations about the appropriateness of these specific labels, both do elicit distinc tive images characteristic of the key concepts of these approaches and such terminology does serve effectively to contrast this class of theories with more standard formulations of quantum theory. (shrink)

One of the major philosophical problems in physical sciences is what criteria should determine how scientific theories are selected and justified in practice and whether, in describing observable physical phenomena, such theories are effectively constrained to be unique. This book studies the example of a particular theory, the S-matrix theory. The S-matrix program was initiated by Heisenberg to deal with difficulties encountered in quantum field theories in describing particular phenomena. Since then, each theory has at different times been favored as (...) the explanation of observed phenomena. Certainly the S-matrix theory was adequate, feasible and fertile. However, the quantum field theory interpretation is now widely accepted and the study of alternative theories is all but abandoned. By examining the philosophy which influenced the turns in this story, the author explains how an adequate and viable theory fell out of favor and concludes with a critique of different methodologies in the history of science. (shrink)

The T&T Clark Handbook of Analytic Theology provides theological and philosophical resources that demonstrate analytic theology's unique contribution to the task of theology. Analytic theology is a recent movement at the nexus of theology, biblical studies, and philosophy that marshals resources from the analytic philosophical tradition for constructive theological work. Paying attention to the Christian tradition, the development of doctrine, and solid biblical studies, analytic theology prizes clarity, brevity, and logical rigour in its exposition of Christian teaching. Each contribution in (...) this volume offers an overview of specific doctrinal and dogmatic issues within the Christian tradition and provides a constructive conceptual model for making sense of the doctrine. Additionally, an extensive bibliography serves as a valuable resource for researchers wishing to address issues in theology from an analytic perspective. (shrink)

A case study of the development of quantum field theory and of S-matrix theory, from their inceptions to the present, is presented. The descriptions of science given by Kuhn and by Lakatos are compared and contrasted as they apply to this case study. The episodes of the developments of these theories are then considered as candidates for competing research programs in Lakatos' methodology of scientific research programs. Lakatos' scheme provides a reasonable overall description and a plausible assessment of the relative (...) value of these two programs in terms of progressive and degenerating problem shifts. Also discussed are the roles of various types of models as they have been used in these areas of theoretical high-energy physics. (shrink)

American intellectual history in the future will be embodied, embedded, and extended. Building on a sturdy foundation of past practices, intellectual historians will consolidate the advances of the last half-century and continue to study ideas articulated in multiple registers, by multiple historical actors, for multiple purposes.

Intellectual history and the history of political thought are siblings, perhaps even twins. They have similar origins and use similar materials. They attract many of the same friends and make some of the same enemies. Yet like most siblings, they have different temperaments and ambitions. This essay explores the family resemblances and draws out the contrasts by examining two major works by one of the most prominent political theorists of the past half-century, Alan Ryan, who has recently published two big (...) books that intellectual historians will find rewarding and provocative. (shrink)

The Catholic Church in the United States provides extensive health care service through its more than 600 health facilities. The Church, on the basis of its moral teaching, sees health care as a basic human right and supports universal coverage. At the same time, the Church considers abortion morally wrong and opposes coverage of abortion as a health service in a national health plan. Mandated coverage of abortion would violate the moral commitments of Catholic hospitals and the consciences of Catholics (...) who would be required to financially support provision of abortion services. Keywords: abortion, Catholic hospitals, Clinton health plan, health care reform CiteULike Connotea Del.icio.us What's this? (shrink)

I don’t think Lynne Rudder Baker’s constitution view can account for personal identity problems of a synchronic or diachronic nature. As such, it cannot accommodate the Christian’s claim of eschatological bodily resurrection-a principle reason for which she gives this account. In light of this, I press objections against her constitution view in the following ways: First, I critique an analogy she draws between Aristotle’s “accidental sameness” and constitution. Second, I address three problems for Baker’s constitution view [‘Constitution Problems’ ], each (...) more problematic than the next: CP1: Her definition of constitution lacks explanatory power; CP2: If there is a plausible definition of constitution, constitution implies either too many persons or no human persons at all; CP3: Constitution yields no essential distinction between human and divine persons. If my argument go through, her constitution view has neither an explanation for diachronic personal identity nor personal identity through resurrection. (shrink)