A detection task was performed using different pictographic representations of objects in order to test the hypothesis that high-level information (familiarity) may influence detection thresholds. The stimuli were five versions of forms: outline drawings of objects, silhouettes, and three fragmented versions of forms derived from the outlines. The stimuli varied on two parameters: their nameability (easily nameable, hardly nameable, and not nameable) as assessed by a naming task, and their energy content as assessed by a two-dimensional fast-Fourier transform. The greatest (...) amount of energy was observed for silhouettes, and the amount of energy contained in the vertical and horizontal spatial frequency components was equivalent for outlines and the three versions of fragmented forms. Luminance thresholds for the detection of the forms were measured by means of an adaptive method. The results show that thresholds were determined only by the energy content of the stimuli. High-level semantic or name information had no influence on the detectability of the visual signal. The results are discussed in terms of the visibility of spatial frequency components at detection threshold. (shrink)

Several authors have characterized a striking phenomenon of perceptual learning in visual discrimination tasks. This learning process is selective for the stimulus characteristics and location in the visual field. Since the human visual system exploits symmetry for object recognition we were interested in exploring how it learns to use preattentive symmetry cues for discriminating simple, meaningless, forms. In this study, similar to previous studies of perceptual learning, we asked whether the effects of practice acquired in the discrimination of pairs (...) of shape with a specific orientation of the symmetry axis would transfer to the discrimination of shapes with different orientation of symmetry axis, or to shapes presented in different areas of the visual field. We found that there was no learning transfer between forms with very different axes of symmetry (90° apart). Interestingly, however, we found a transfer of learning effect to horizontally oriented symmetry axis from a condition with an axis of symmetry differing by 45°. Also it appears that some subjects took a longer time to learn than the typical fast learning paradigm would predict. Data showed that when observers practice discrimination of meaningless symmetric forms, consistent improvement in the performance occurs. This improvement is lasting over days, and it tends to be specific for the area of the visual field trained. We will discuss results from some of the observers whose learning was not fast, but who actually improved with more practice and with large time intervals (1 day) between training sessions. (shrink)

Past research shows that the bilingual experience may enhance cognitive executive function. In this experiment, we evaluated cognitive control in bilinguals relative to monolinguals by using a dimensional overlap model to predict performance in a task composed of Stroop and Simon stimuli. A group of 24 Spanish monolinguals and 24 bilinguals with differing first languages and all having Spanish as a second language did a picture naming task and a task composed of Stroop and Simon stimuli, where the effect of (...) different overlap conditions between stimuli and responses were examined. The tasks were performed in Spanish for both groups and performance was indexed with behavioral and electrophysiological measures. We hypothesized that the bilinguals’ daily language practice in L2 reflected overlap conditions similar to the Simon task. Both naming a picture in L2 and the Simon task would involve conflict at the response level. L2 picture naming entails interference between two potential oral responses, to name in L2 vs. L1. Similarly, incongruent stimuli in the Simon task produce interference because the irrelevant dimension overlap with an incorrect response. In contrast, the manual Stroop task involves a different type of conflict between two overlapping stimulus dimensions. We predicted for these reasons a superior performance in Simon tasks over Stroop tasks for bilinguals, while monolinguals were expected to have a similar performance in both tasks. We also expected to see a correlation between the performance on the picture naming task and the Simon task in bilinguals. However, the behavioral results did not confirm these hypotheses. In fact, both groups had similar congruency effects as measured by reaction times and error rates, and there was no correlation between the picture naming and Simon task in bilinguals. Despite this, the electrophysiological data suggested a relationship between the picture naming task and the P300 congruency effect in bilinguals. Our findings provide insights into the neurocognitive bases of language and serve as a research avenue for language behaviors in bilinguals. (shrink)

According to one productive and influential approach to cognition, categorization, object recognition, and higher level cognitive processes operate on a set of fixed features, which are the output of lower level perceptual processes. In many situations, however, it is the higher level cognitive process being executed that influences the lower level features that are created. Rather than viewing the repertoire of features as being fixed by low-level processes, we present a theory in which people create features to subserve the representation (...) and categorization of objects. Two types of category learning should be distinguished. Fixed space category learning occurs when new categorizations are representable with the available feature set. Flexible space category learning occurs when new categorizations cannot be represented with the features available. Whether fixed or flexible, learning depends on the featural contrasts and similarities between the new category to be represented and the individual's existing concepts. Fixed feature approaches face one of two problems with tasks that call for new features: If the fixed features are fairly high level and directly useful for categorization, then they will not be flexible enough to represent all objects that might be relevant for a new task. If the fixed features are small, subsymbolic fragments (such as pixels), then regularities at the level of the functional features required to accomplish categorizations will not be captured by these primitives. We present evidence of flexible perceptual changes arising from category learning and theoretical arguments for the importance of this flexibility. We describe conditions that promote feature creation and argue against interpreting them in terms of fixed features. Finally, we discuss the implications of functional features for object categorization, conceptual development, chunking, constructive induction, and formal models of dimensionality reduction. Key Words: concept learning; conceptual development; features; perceptual learning; stimulus encoding. (shrink)

Intelligent systems are faced with the problem of securing a principled (ideally, veridical) relationship between the world and its internal representation. I propose a unified approach to visual representation, addressing both the needs of superordinate and basic-level categorization and of identification of specific instances of familiar categories. According to the proposed theory, a shape is represented by its similarity to a number of reference shapes, measured in a high-dimensional space of elementary features. This amounts to embedding the stimulus in (...) a low-dimensional proximal shape space. That space turns out to support representation of distal shape similarities which is veridical in the sense of Shepard's (1968) notion of second-order isomorphism (i.e., correspondence between distal and proximal similarities among shapes, rather than between distal shapes and their proximal representations). Furthermore, a general expression for similarity between two stimuli, based on comparisons to reference shapes, can be used to derive models of perceived similarity ranging from continuous, symmetric, and hierarchical, as in the multidimensional scaling models (Shepard, 1980), to discrete and non-hierarchical, as in the general contrast models (Tversky, 1977; Shepard and Arabie, 1979). (shrink)

There have recently been various empirical attempts to answer Molyneux’s question, for example, the experiments undertaken by the Held group. These studies, though intricate, have encountered some objections, for instance, from Schwenkler, who proposes two ways of improving the experiments. One is “to re-run [the] experiment with the stimulus objects made to move, and/or the subjects moved or permitted to move with respect to them” (p. 94), which would promote three dimensional or otherwise viewpoint-invariant representations. The other is “to (...) use geometrically simpler shapes, such as the cube and sphere in Molyneux’s original proposal, or planar figures instead of three-dimensional solids” (p. 188). Connolly argues against the first modification but agrees with the second. In this article, I argue that the second modification is also problematic (though still surmountable), and that both Schwenkler and Connolly are too optimistic about the prospect of addressing Molyneux’s question empirically. (shrink)

Studies on mind-wandering frequently use reading as an experimental task. In these studies, reading is conceived as a cognitive process that potentially offers a contrast to mind-wandering, because it seems to be task-related, goal-directed and stimulus-dependent. More recent work attempts to avoid the dichotomy of successful cognitive processes and processes of mind-wandering found in earlier studies. We approach the issue from the perspective that texts provoke modes of cognitive involvement different from the information processing and recall account that underlies (...) many early mind-wandering studies. After all, reading itself is an umbrella term for activities that are characterized by a variety of phenomenological and functional signatures. We conceptualize reading and mind-wandering in relation to each other through the framework of enculturated predictive processing, which is informed by research in literary studies. Earlier accounts think of reading predominantly in terms of the construction of situation models that organize textual information. By contrast, enculturated predictive processing foregrounds shifting stances readers can take in relation to the text. Characters featuring in literary texts might be mind-wandering themselves, or passages in literary style might make the construction of a clearly defined situational model impossible. Furthermore, we take into account that texts often elicit mind-wandering through the construction of task-relevant and attention-driven virtual scenarios in readers' minds. This more complex account of reading can enrich recent attempts to understand mind-wandering as a complex, multi-dimensional phenomenon. The study of mind-wandering can benefit, we argue, from a closer attention to the process of reading and to the texts it deploys as stimuli. The emerging perspective from enculturated predictive processing and literary studies makes distinctions in reading that in turn enable research on mind-wandering to ask more precise questions about (1) different kinds of mind-wandering, (2) different modes of reading, and (3) how and where they interconnect across time. (shrink)

This article seeks the origin, in the theories of Ibn al-Haytham (Alhazen), Descartes, and Berkeley, of two-stage theories of spatial perception, which hold that visual perception involves both an immediate representation of the proximal stimulus in a two-dimensional ‘‘sensory core’’ and also a subsequent perception of the three dimensional world. The works of Ibn al-Haytham, Descartes, and Berkeley already frame the major theoretical options that guided visual theory into the twentieth century. The field of visual perception was the first (...) area of what we now call psychology to apply mathematics, through geometrical models as used by Euclid, Ptolemy, Ibn al-Haytham, and Descartes (among others). The article shows that Kepler’s discovery of the retinal image, which revolutionized visual anatomy and entailed fundamental changes in visual physiology, did not alter the basic structure of theories of spatial vision. These changes in visual physiology are advanced especially in Descartes' Dioptrics and his L'Homme. Berkeley develops a radically empirist theory vision, according to which visual perception of depth is learned through associative processes that rely on the sense of touch. But Descartes and Berkeley share the assertion that there is a two-dimensional sensory core that is in principle available to consciousness. They also share the observation that we don't usually perceived this core, but find depth and distance to be phenomenally immediate, a point they struggle to accommodate theoretically. If our interpretation is correct, it was not a change in the theory of the psychology of vision that engendered the idea of a sensory core, but rather the introduction of the theory into a new metaphysical context. (shrink)

Visualizing and mental imagery are thought to be cognitive states by all sides of the imagery debate. Yet the phenomenology of those states has distinctly visual ingredients. This has potential consequences for the hypothesis that vision is cognitively impenetrable, the ability of visual processes to ground perceptual warrant and justification, and the distinction between cognitive and perceptual phenomenology. I explore those consequences by describing two forms of visual ambiguity that involve visualizing: the ability to visually experience a picture surface as (...) flat after it has caused volumetric nonconceptual contents, and the ability to use a surface initially perceived as flat to visualize three-dimensional scenes. In both cases, the visual processes which extract viewer-centered volumetric shapes have to rely solely on monocular depth cues in the absence of parallax and stereopsis. Those processes can be cognitively penetrated by acts of visualizing, including ones that draw on conceptual information about kinds. However, the penetrability of the visual processes does not weaken their ability to provide perceptual warrant and justification for beliefs. The reason is that picture perceptions—whether they are stimulus -driven or based on acts of visualizing—are different to object perceptions both phenomenologically and in terms of their functional roles as states. Thus, although the penetrability of the visual processes does mean that subjects can have visual experiences with contradictory contents, perceptual belief is adopted at most towards one set of contents, and questions of warrant and justification are raised only for those contents. A rule-proving exception is provided by trompe-l’oeils. (shrink)

Psychology and philosophy have long reflected on the role of perspective in vision. Since the dawn of modern vision science—roughly, since Helmholtz in the late 1800s—scientific explanations in vision have focused on understanding the computations that transform the sensed retinal image into percepts of the three-dimensional environment. The standard view in the science is that distal properties—viewpoint-independent properties of the environment (object shape) and viewpoint-dependent relational properties (3D orientation relative to the viewer)–are perceptually represented and that properties of the proximal (...) stimulus (in vision, the retinal image) are not. This view is woven into the nature of scientific explanation in perceptual psychology, and has guided impressive advances over the past 150 years. A recently published article suggests that in shape-perception, the standard view must be revised. It argues, on the basis of new empirical data, that a new entity—perspectival shape—should be introduced into scientific explanations of shape perception. Specifically, the article’s centrally advertised claim is that, in addition to distal shape, perspectival shape is perceived. We argue that this claim rests on a series of mistakes. Problems in experimental design entail that the article provides no empirical support for any claims regarding either perspective or the perception of shape. There are further problems in scientific reasoning and conceptual development. Detailing these criticisms and explaining how science treats these issues is meant to clarify method and theory, and to improve exchanges between the science and philosophy of perception. (shrink)

In the philosophy of perception, olfaction is the perennial problem child, presenting a range of difficulties to those seeking to define its proper referents, and its phenomenological content. Here, we argue that many of these difficulties can be resolved by recognizing the object-like representation of odors in the brain, and by postulating that the basic objects of olfaction are best defined by their biological value to the organism, rather than physico-chemical dimensions of stimuli. Building on this organism-centered account, we speculate (...) that the phenomenological space of olfaction is organized into a number of coarse affective dimensions that apply categorically. This organization may be especially useful for coupling sensation to decision-making and instrumental action in a sensory modality where the stimulus space is especially complex and high-dimensional. (shrink)

Seven studies explored the empirical basis for claims that infants represent cardinal values of small sets of objects. Many studies investigating numerical ability did not properly control for continuous stimulus properties such as surface area, volume, contour length, or dimensions that correlate with these properties. Experiment 1 extended the standard habituation/dishabituation paradigm to a 1 vs 2 comparison with three-dimensional objects and confirmed that when number and total front surface area are confounded, infants discriminate the arrays. Experiment 2 revealed (...) that infants dishabituated to a change in front surface area but not to a change in number when the two variables were pitted against each other. Experiments 3 through 5 revealed no sensitivity to number when front surface area was controlled, and Experiments 6 and 7 extended this pattern of findings to the Wynn (1992) transformation task. Infants’ lack of a response to number, combined with their demonstrated sensitivity to one or more dimensions of continuous extent, supports the hypothesis that the representations subserving object-based attention, rather than those subserving enumeration, underlie performance in the above tasks. (shrink)

The experiments reported herein probe the visual cortical mechanisms that control near–far percepts in response to two-dimensional stimuli. Figural contrast is found to be a principal factor for the emergence of percepts of near versus far in pictorial stimuli, especially when stimulus duration is brief. Pictorial factors such as interposition (Experiment 1) and partial occlusion Experiments 2 and 3) may cooperate, as generally predicted by cue combination models, or compete with contrast factors in the manner predicted by the FACADE (...) model. In particular, if the geometrical conŽ guration of an image favors activation of cortical bipole grouping cells, as at the top of a T-junction, then this advantage can cooperate with the contrast of the conŽ guration to facilitate a near–far percept at a lower contrast than at an X-junction. Varying the exposure duration of the stimuli shows that the more balanced bipole competition in the X-junction case takes longer exposure times to resolve than the bipole competition in the T-junction case (Experiment 3). (shrink)

There is growing interest in the effect of sound on visual motion perception. One model involves the illusion created when two identical objects moving towards each other on a two-dimensional visual display can be seen to either bounce off or stream through each other. Previous studies show that the large bias normally seen toward the streaming percept can be modulated by the presentation of an auditory event at the moment of coincidence. However, no reports to date provide sufficient evidence to (...) indicate whether the sound bounce-inducing effect is due to a perceptual binding process or merely to an explicit inference resulting from the transient auditory stimulus resembling a physical collision of two objects. In the present study, we used a novel experimental design in which a subliminal sound was presented either 150 ms before, at, or 150 ms after the moment of coincidence of two disks moving towards each other. The results showed that there was an increased perception of bouncing when the subliminal sound was presented at or 150 ms after the moment of coincidence compared to when no sound was presented. These findings provide the first empirical demonstration that activation of the human auditory system without reaching consciousness affects the perception of an ambiguous visual motion display. (shrink)

You might reasonably surmise from the title of this paper that I will be discussing a theory of vision. After all, what is a theory of vision but a theory of how the world is connected to our visual representations? Theories of visual perception universally attempt to give an account of how a proximal stimulus (presumably a pattern impinging on the retina) can lead to a rich representation of a three dimensional world and thence to either the recognition of (...) known objects or to the coordination of actions with visual information. Such theories typically provide an effective (i.e., computable) mapping from a 2D pattern to a representation of a 3D scene, usually in the form of a symbol structure. But such a mapping, though undoubtedly the essential purpose of a theory of vision, leaves at least one serious problem that I intend to discuss here. It is this problem, rather than a theory of vision itself, that is the subject of this talk. (shrink)

Jacob Klapwijk’s book Purpose in the Living World? (Cambridge 2998) is examined with special attention given to the scholarly background from out of which it emerges as a significant contribution to reformational philosophical reflection. As an initial step to clarify some important issues raised by Klapwijk’s critical comments about Dooyeweerd’s “essentialist” concept of species, the article probes facets of the way Jan Lever incorporated reformational philosophical concepts into his biological theory and considers the 1959 review written by Herman Dooyeweerd of (...) Lever’s Creation and Evolution. The analysis focuses specifically upon the social responsibilities of these two scholars and the confrontation of their respective views. With the work of Lever and Dooyeweerd we sense something of the ambiguities when reformational philosophy confronts an evangelical scholasticism. This confrontation is an important facet of the context in which Klapwijk has set forth his discussion of creation and emergent evolution. Purpose is also the fruit of scholarly collaboration across disciplines, providing a welcome stimulus for a deepened understanding of the corporate character of the student vocation. (shrink)

Contrasting brain states when subjects are aware compared to unaware of a presented stimulus has allowed researchers to isolate candidate neural correlates of consciousness. Here we propose that an important next step in this research program is to investigate, perhaps paradoxically, brain states that covary with reports of absences of awareness. Specifically, we propose that in order to distinguish content-specific and content-invariant neural correlates of consciousness, a distinction needs to be made between the neural correlates of awareness of (...) class='Hi'>stimulus absence, and the neural correlates of absence of awareness. We ground this distinction in higher-order computational models of consciousness, where the state of higher-order nodes is invariant to the specific contents of awareness. To map the different levels of these models to neurophysiological correlates, we suggest two empirical approaches – inverted designs and two-dimensional awareness reports – in which reports about awareness and stimulus presence can be dissociated. (shrink)

A method of generating synonyms for a stimulus word using a computer is proposed. Vector Space Model, where words in text data are arranged in a multi-dimensional space and degree of similarity between two words of them is calculated from how close the words are in the space, may be available to the method. However, it is not easy to optimize parameters in the method because there is no appropriate standard synonym database where proper synonyms for a stimulus (...) word are thoroughly collected. Therefore, we first built such a standard database employing two steps of human subjects expriments, and optimized the parameters of the method of generating synonyms. As the result, it was found that the Vector Space Model-based method using an electronic dictionary as source is better to generate synonyms than the one using a text corpus and an ordinal method using a thesaurus. (shrink)

The ability to imagine objects undergoing rotation (mental rotation) improves markedly with practice, but an explanation of this plasticity remains controversial. Some researchers propose that practice speeds up the rate of a general-purpose rotation algorithm. Others maintain that performance improvements arise through the adoption of a new cognitive strategy—repeated exposure leads to rapid retrieval from memory of the required response to familiar mental rotation stimuli. In two experiments we provide support for an integrated explanation of practice effects in mental rotation (...) by combining behavioral and EEG measures in a way that provides more rigorous inference than is available from either measure alone. Before practice, participants displayed two well-established signatures of mental rotation: Both response time and EEG negativity increased linearly with rotation angle. After extensive practice with a small set of stimuli, both signatures of mental rotation had all but disappeared. In contrast, after the same amount of practice with a much larger set both signatures remained, even though performance improved markedly. Taken together, these results constitute a reversed association, which cannot arise from variation in a single cause, and so they provide compelling evidence for the existence of two routes to expertise in mental rotation. We also found novel evidence that practice with the large but not the small stimulus set increased the magnitude of an early visual evoked potential, suggesting increased rotation speed is enabled by improved efficiency in extracting three-dimensional information from two-dimensional stimuli. (shrink)

Consciousness is seen as a difficult “binding” problem. Binding, a process where different sensations evoked by an item are associated in the nervous system, can be viewed as a process similar to associative learning. Several reports that consciousness is associated with some form of memory imply that different forms of memories have a common feature contributing to consciousness. Based on a proposed synaptic mechanism capable of explaining different forms of memory, we developed a framework for consciousness. It is based on (...) the formation of semblance of sensory stimulus from (1) synaptic semblances when excitatory postsynaptic potentials arrive at functionally LINKed postsynaptic membranes, and (2) network semblances when these potentials summate to elicit action potential initiating activity in a network of neurons. It is then possible to derive a framework for consciousness as a multi-dimensional semblance. According to this framework, a continuum of semblances formed from background sensory stimuli and oscillating neuronal activities serve to maintain consciousness. Feasibility of this framework to explain various physiological and pathological states of consciousness, its subjective nature and qualia is examined. (shrink)

Studies on mind-wandering frequently use reading as an experimental task. In these studies, reading is conceived as a cognitive process that potentially offers a contrast to mind-wandering, because it seems to be task-related, goal-directed and stimulus-dependent. More recent work attempts to avoid the dichotomy of successful cognitive processes and processes of mind-wandering found in earlier studies. We approach the issue from the perspective that texts provoke modes of cognitive involvement different from information processing and recall account that underlies many (...) early mind-wandering studies. After all, reading itself is an umbrella term for activities that are characterised by a variety of phenomenological and functional signatures. We conceptualise reading and mind-wandering in relation to each other through the framework of enculturated predictive processing, which is informed by research in literary studies. Earlier accounts think of reading predominantly in terms of the construction of situation models to organise textual information. By contrast, enculturated predictive processing foregrounds shifting stances readers can take in relation to the text. Characters featuring in literary texts might be mind-wandering themselves, or passages in literary style might make the construction of a clearly defined situational model impossible. Furthermore, we take into account that texts often elicit mind-wandering through the construction of task-relevant and attention-driven virtual scenarios in readers’ minds. This more complex account of reading can enrich recent attempts to understand mind-wandering as a complex, multi-dimensional phenomenon. The study of mind-wandering can benefit, we argue, from a closer attention to the process of reading and to the texts it deploys as stimuli. The emerging perspective from enculturated predictive processing and literary studies makes distinctions in reading that in turn enable research on mind-wandering to ask more precise questions about (1) different kinds of mind-wandering, (2) different modes of reading, and (3) how and where they interconnect across time. (shrink)

Consciousness is seen as a difficult “binding” problem. Binding, a process where different sensations evoked by an item are associated in the nervous system, can be viewed as a process similar to associative learning. Several reports that consciousness is associated with some form of memory imply that different forms of memories have a common feature contributing to consciousness. Based on a proposed synaptic mechanism capable of explaining different forms of memory, we developed a framework for consciousness. It is based on (...) the formation of semblance of sensory stimulus from (1) synaptic semblances when excitatory postsynaptic potentials arrive at functionally LINKed postsynaptic membranes, and (2) network semblances when these potentials summate to elicit action potential initiating activity in a network of neurons. It is then possible to derive a framework for consciousness as a multi-dimensional semblance. According to this framework, a continuum of semblances formed from background sensory stimuli and oscillating neuronal activities serve to maintain consciousness. Feasibility of this framework to explain various physiological and pathological states of consciousness, its subjective nature and qualia is examined. (shrink)

The aim of the present study was to investigate the effect of observing other’s movements on subsequent performance in bottlenose dolphins. The imitative ability of non-human animals has intrigued a number of researchers. So far, however, studies in dolphins have been confined to intentional imitation concerned with the explicit request to imitate other agents. In the absence of instruction to imitate, do dolphins (un)intentionally replicate other’s movement features? To test this, dolphins were filmed while reaching and touching a stimulus (...) before and after observing another dolphin (i.e., model) performing the same action. All videos were reviewed and segmented in order to extract the relevant movements. A marker was inserted post-hoc via software on the videos upon the anatomical landmark of interest (i.e. rostrum) and was tracked throughout the time course of the movement sequence. The movement was analyzed using an in-house software developed to perform two-dimensional (2D) post-hoc kinematic analysis. The results indicate that dolphins’ kinematics is sensitive to other’s movement features. Movements performed for the ‘visuomotor priming’ condition were characterized by a kinematic pattern similar to that performed by the observed dolphin (i.e., model). Addressing the issue of spontaneous imitation in bottlenose dolphins might allow ascertaining whether the potential or impulse to produce an imitative action is generated, not just when they intend to imitate, but whenever they watch another conspecific’s behavior. In closing, this will clarify whether motor representational capacity is a by-product of factors specific to humans or whether more general characteristics such as processes of associative learning prompted by high level of encephalization could help to explain the evolution of this ability. (shrink)

Previous research has successfully used feature integration theory to operationalise the predictions of Perceptual Load Theory, while simultaneously testing the predictions of both models. Building on this work, we test the extent to which these models hold up in a 3D world. In two experiments, participants responded to a target stimulus within an array of shapes whose apparent depth was manipulated using a combination of monoscopic and stereoscopic cues. The search task was designed to test the predictions of feature (...) integration theory, as the target was identified by a single feature or a conjunction of features and embedded in search arrays of varying size, and perceptual load theory, as the task included congruent and incongruent distractors presented alongside search tasks imposing high or low perceptual load. Findings from both experiments upheld the predictions of feature integration theory, regardless of 2D/3D condition. Longer search times in conditions with a combination of monoscopic and stereoscopic depth cues suggests that binding features into three-dimensional objects requires greater attentional effort. This additional effort should have implications for perceptual load theory, yet our findings did not uphold its predictions; the effect of incongruent distractors did not differ between conjunction search trials and feature search trials. Individual differences in susceptibility to the effects of perceptual load were evident and likely explain the absence of load effects. Overall, our findings suggest that feature integration theory may be useful for predicting attentional performance in a 3D world. (shrink)

Mammalian outer hair cells generate mechanical forces at acoustic frequencies and can thus amplify the sound stimulus within the inner ear. The mechanism of force generation depends upon the plasma membrane potential but not upon either calcium or ATP. Forces are generated in the lateral cortex along the full length of the cell. The cortex includes a two‐dimensional cytoskeletal lattice composed of circumferential filaments 6–7 nm thick that are cross‐linked by filaments 3–4 nm thick and 40–60 nm long. The (...) two filament types may, respectively, be actin and some form of spectrin. The lattice reinforces the cylindrical shape of the cell and permits limited changes in length. Beneath it lie the lateral cisternae, a regular system of multi‐layered membranes. Force–generation may depend upon voltage‐dependent shape changes in proteins that lie either in the plasma membrane or in the cytoskeletal lattice. (shrink)

Biological motion is the phenomenon of recognizing a human form out of moving point-light dots, where both bottom–up and top–down processing mechanisms have been reported. This study reviews available psychological and neuroscientific evidence, and it assesses attempts either to assimilate biological motion to other structure-from-motion cases or to include biological motion into a visual “social cognition” subsystem . While neither theoretical option seems to accommodate all relevant psychological results, the study proposes that biological motion may be an object recognition task, (...) inside the framework of Pylyshyn’s sequence of data-driven and cognitive mechanisms. This implies that a bottom–up object construction out of two-dimensional stimulus information precedes a top–down, but emotionally significant categorization of a particular human movement. Recognition of biological motion may be an example of visual processing in general. (shrink)

That conditional, if-then reasoning does not emerge until 4–5 years has long been accepted. Here we show that children barely 3 years old can do conditional reasoning. All that was needed was a superficial change to the stimuli: When color was a property of the shapes rather than of the background, 3-year-olds could succeed. Three-year-olds do not seem to use color to inform them which shape is correct unless color is a property of the shapes themselves. While CD requires integrating (...) color and shape information, the dimensional change card sort task requires keeping those dimension cognitively separate – inhibiting attention to one when sorting by the other. For DCCS, a superficial change to the stimuli that is the inverse of what helps on CD enables 3-year-olds to succeed when normally they do not until ∼4⁤12 years. As we and others have previously shown, 3-year-olds can succeed at DCCS when color is a property of the background, instead of a property of the stimulus. Our findings on CD and DCCS suggest that scaffolding preschoolers’ emerging conceptual skills by changing the way stimuli look enables 3-year-olds to demonstrate reasoning abilities long thought beyond their grasp. Evidently, children of 3 years have difficulty mentally separating dimensions of the same object and difficulty mentally integrating dimensions not part of the same object. Our present CD findings plus our earlier DCCS findings provide strong evidence against prominent cognitive complexity, conditional reasoning, and graded memory theories for why 3-year-olds fail these two tasks. The ways we have traditionally queried children may have obscured the budding reasoning competencies present at 3 years of age. (shrink)

Previous research found that application of eyeshadow on the upper eyelids induces overestimation of eye size. The present study examined whether this eyeshadow illusion is dependent on or independent of viewpoint. We created a three-dimensional model of a female face and manipulated the presence/absence of eyeshadow and face orientation around the axis of yaw (Experiment 1) or pitch (Experiment 2) rotation. Using the staircase method, we measured perceived eye size for each face stimulus. Results showed that the eyeshadow illusion (...) occurred regardless of face orientation around axes of both yaw and pitch rotations. Crucially, the illusion’s magnitude did not vary across face orientations; lack of interaction between the illusion’s magnitude and face orientation was confirmed by small values of Bayes factors. These findings ruled out the hypothesis that eyeshadow serves as a depth cue and leads to overestimation of eye size due to size-distance scaling. Alternatively, the present findings suggest that the eyeshadow illusion can be well explained by the assimilation between the eyes and eyeshadow, which also facilitates assimilation between the eyes and eyebrows. Practical implications and the present findings’ generalizability are also discussed. (shrink)

For the faithful there is much to ponder. In this short book, based on lectures delivered in Spain in 1990, Quine begins by locating his work historically.

En enero de 1974 Zubiri dio un breve curso en la Sociedad de Estudios y Publicaciones de Madrid sobre el tema Tres dimensiones del ser humano: individual, social e histórica. Meses después publicó la última de esas lecciones bajo el título de La dimensión histórica del ser humano. El presente volumen recoge el texto de las tres conferencias, más la versión escrita de la última de ellas. La tesis que Zubiri desarrolla en estas lecciones es que el ser humano es (...) a la vez y necesariamente individual, social e histórico, y que estas dimensiones vienen exigidas por su propia realidad específica, que es pluralizante, continuante y prospectiva. (shrink)

Over the last twenty years, in all of these neighbouring fields, modal systems have been developed that we call multi-dimensional. (Our definition of multi ...

Two-dimensional approaches to semantics, broadly understood, recognize two "dimensions" of the meaning or content of linguistic items. On these approaches, expressions and their utterances are associated with two different sorts of semantic values, which play different explanatory roles. Typically, one semantic value is associated with reference and ordinary truth-conditions, while the other is associated with the way that reference and truth-conditions depend on the external world. The second sort of semantic value is often held to play a distinctive role in (...) analyzing matters of cognitive significance and/or context-dependence. (shrink)

Perceptual processes differ from cognitive, this paper argues, in functioning to be causally controlled by proximal stimuli, and being modular, at least in a modest sense that excludes their being isotropic in Jerry Fodor's sense. This claim agrees with such theorists as Jacob Beck and Ben Phillips that a function of stimulus-control is needed for perceptual status. In support of this necessity claim, I argue, inter alia, that E.J. Green's recent architectural account misclassifies processes deploying knowledge of grammar as (...) perceptual. _Pace_ Beck and Phillips, however, I argue a function of stimulus-control is insufficient for perceptual as opposed to cognitive status. One consideration in favour of such insufficiency, noted but (I argue) not convincingly rebutted by these theorists, concerns perpetually grounded demonstrative thought. Two other considerations trade on the fact that a function of stimulus-control can arise not from blind nature but intentional design or social institutions, where so-functioning processes may but need not be perceptual. I offer two cases where such processes are cognitive, viz. skilful play-by-play announcing of ongoing events, and voluntary visualizing of ongoing events under the guidance of apt play-by-play announcements, dubbed announcement-driven visualizing (ADV). The cognitive status of these three diverse phenomena cannot be explained by an absence of a perception-like representational format or content (for ADV has such) or by a presence of personal-level mental states causally mediating between stimuli and outputs (for perception has such). A bettter explanation invokes, I argue, the non-modular character of the generating process. (shrink)

Graeme Forbes (2011) raises some problems for two-dimensional semantic theories. The problems concern nested environments: linguistic environments where sentences are nested under both modal and epistemic operators. Closely related problems involving nested environments have been raised by Scott Soames (2005) and Josh Dever (2007). Soames goes so far as to say that nested environments pose the “chief technical problem” for strong two-dimensionalism. We call the problem of handling nested environments within two-dimensional semantics “the nesting problem”. We show that the two-dimensional (...) semantics for attitude ascriptions developed in Chalmers (2011a) has no trouble accommodating certain forms of the nesting problem that involve factive verbs such as “know” or “establish”. A certain form of the nesting problem involving apriority and necessity operators does raise an interesting puzzle, but we show how a generalized version of the nesting problem arises independently of two-dimensional semantics—it arises, in fact, for anyone who accepts the contingent a priori. We, then, provide a two-dimensional treatment of the apriority operator that fits the two-dimensional treatment of attitude verbs and apply it to the generalized nesting problem. We conclude that two-dimensionalism is not seriously threatened by cases involving the nesting of epistemic and modal operators. (shrink)