Consciousness wanted,attention found: Reasons for the advantage of the left visual field in identifying T2 among rapidly presented series

Everyday experience suggests that people are equally aware of events in both hemi-fields. However, when two streams of stimuli are rapidly presented left and right containing two targets, the second target is better identified in the left than in the right visual field.This might be considered evidence for a right-hemisphere advantage in generating conscious percepts. However, this putative asymmetry of conscious perception cannot be measured independently of participants’ access to their conscious percepts, and there is actually evidence from split-brain patients for the reverse, left-hemisphere advantage in having access to conscious percepts. Several other topics were studied in search of the responsible mechanism, among others: Mutual inhibition of hemispheres, cooperation of hemispheres in perceiving midline stimuli, and asymmetries in processing various perceptual inputs. Directing attention by salient cues turned out to be one of the few mechanisms capable of modifying the left visual-field advantage in this paradigm. Thus, this left visual-field advantage is best explained by the notion of a right-hemisphere advantage in directing attention to salient events. Dovetailing with the pathological asymmetries of attention after right-hemisphere lesions and with asymmetries of brain activation when healthy participants shift their attention, the present results extend that body of evidence by demonstrating unusually large and reliable behavioral asymmetries for attention-directing processes in healthy participants.     

Using afterimages for orientation and color to explore mechanisms of visual filling-in

Simulations of Grossberg's FACADE model of visual perception have previously been used to explain afterimage percepts produced by viewing a sequence of orthogonally oriented gratings. Additional simulations of the model are now used to predict new afterimage percepts. One simulation emphasizes that the afterimage percepts are the result of orientation afterresponses and color afterresponses that interact at a filling-in stage. We report experimental data that agree with FACADE's prediction. A second simulation emphasizes the properties of the model's filling-in stage and predicts a situation where the afterimage percept should not appear. We report experimental data indicating that this model prediction is incorrect. We argue that the model is unable to account for this result unless the filling-in stage mechanisms are different from a diffusive-type process. We propose an alternative mechanism, and simulations demonstrate the system's ability to account for the afterimage data.     

The link between brain learning, attention, and consciousness

The processes whereby our brains continue to learn about a changing world in a stable fashion throughout life are proposed to lead to conscious experiences. These processes include the learning of top-down expectations, the matching of these expectations against bottom-up data, the focusing of attention upon the expected clusters of information, and the development of resonant states between bottom-up and top-down processes as they reach an attentive consensus between what is expected and what is there in the outside world. It is suggested that all conscious states in the brain are resonant states and that these resonant states trigger learning of sensory and cognitive representations. The models which summarize these concepts are therefore called Adaptive Resonance Theory, or ART, models. Psychophysical and neurobiological data in support of ART are presented from early vision, visual object recognition, auditory streaming, variable-rate speech perception, somatosensory perception, and cognitive-emotional interactions, among others. It is noted that ART mechanisms seem to be operative at all levels of the visual system, and it is proposed how these mechanisms are realized by known laminar circuits of visual cortex. It is predicted that the same circuit realization of ART mechanisms will be found in the laminar circuits of all sensory and cognitive neocortex. Concepts and data are summarized concerning how some visual percepts may be visibly, or modally, perceived, whereas amodal percepts may be consciously recognized even though they are perceptually invisible. It is also suggested that sensory and cognitive processing in the What processing stream of the brain obey top-down matching and learning laws that are often complementary to those used for spatial and motor processing in the brain's Where processing stream. This enables our sensory and cognitive representations to maintain their stability as we learn more about the world, while allowing spatial and motor representations to forget learned maps and gains that are no longer appropriate as our bodies develop and grow from infanthood to adulthood. Procedural memories are proposed to be unconscious because the inhibitory matching process that supports these spatial and motor processes cannot lead to resonance.     

相似性判断和差异性判断的不对称性及其机制探索

本文阐述了相似性判断和差异性判断不对称性的相关研究。首先介绍了不对称性的发展及理论解释。其次,根据事件相关电位的研究结果,阐述了图-词信息的双编码模型对相似性判断的影响。接着分析和介绍了相似性判断的双编码过程及其时间进程。最后,作者提出有待深入研究的几个问题：（1）差异性策略在分类和推理中的应用;（2）相似性双编码过程的实证研究及其应用;（3）从发展认知神经科学的角度探讨不对称的认知神经机制。     

Categories and percepts: a bi-directionnal framework for categorization

Categorization is a fundamental process whereby variable perceptual inputs are reduced progressively to a small number of equivalence classes, called 'categories'. How do theorists frame the categorization problem so that variable face, object and scene information is stabilized for higher-level processing? One approach suggests that perception delivers a fixed set of features that are treated as inputs to categorization processes. This paper questions this unidirectionality and argues instead that perceptual organization is linked intimately with the categorization being accomplished. An example is presented where it can be shown that the history of categorization changes the featural analysis and the perception of identical, but unfamiliar, inputs. Flexible percepts are then generalized to real-world scene categorization in the space of multiple spatial scales. This evidence suggests that a bidirectional framework, with direct interactions between concepts and percepts, is a more appropriate framework for categorization.     

Reexamining the possible benefits of visual crowding: dissociating crowding from ensemble percepts

Peripheral objects and their features become indistinct when closely surrounding but nonoverlapping objects are present. Most models suggest that this phenomenon, called crowding, reflects limitations of visual processing, but an intriguing idea is that it may be, in part, adaptive. Specifically, the mechanism generating crowding may simultaneously facilitate ensemble representations of features, leaving meaningful information about clusters of objects. In two experiments, we tested whether visual crowding and the perception of ensemble features share a common mechanism. Observers judged the orientation of a crowded bar, or the ensemble orientation of all bars in the upper and lower visual fields. While crowding was predictably stronger in the upper relative to the lower visual field, the ensemble percept did not vary between the visual fields. Featural averaging within the crowded region does not always scale with the resolution limit defined by crowding, suggesting that dissociable processes contribute to visual crowding and ensemble percepts.     

The multisensory perception of flavor

Following on from ecological theories of perception, such as the one proposed by [Gibson, J. J. (1966). The senses considered as perceptual systems. Boston: Houghton Mifflin] this paper reviews the literature on the multisensory interactions underlying the perception of flavor in order to determine the extent to which it is really appropriate to consider flavor perception as a distinct perceptual system. We propose that the multisensory perception of flavor may be indicative of the fact that the taxonomy currently used to define our senses is simply not appropriate. According to the view outlined here, the act of eating allows the different qualities of foodstuffs to be combined into unified percepts; and flavor can be used as a term to describe the combination of tastes, smells, trigeminal, and tactile sensations as well as the visual and auditory cues, that we perceive when tasting food.     

As the cube turns: Evidence for two processes in the perception of a dynamic reversible figure

The reported reversals of a rotating Necker cube, which changes direction of rotation when a perspective reversal occurs, were examined under a number of conditions. These permitted comparisons of reversal rates within viewing periods, across successive viewing periods within an experimental session, and across successive weekly sessions. In addition, observers viewed either one or two rotating cubes simultaneously within each of the various viewing periods. Clear evidence for a learning effect was obtained in the form of significant savings across successive viewing periods and sessions. At the same time, results from the multiple-cube conditions and from the pattern of reversals within individual viewing periods appeared to be more consistent with a process of neural fatigue. A two-stage model of reversible-figure perception is proposed which is characterized by (1) fatiguing with extended viewing of the two sets of neural channels that underlie the two percepts of the reversible figure, and (2) learning, which helps to establish the organization of the cortical channels as well as moderate channel activity via such processes as attention and strategy.     

Remembering after a perception of discrepancy: out with the old, in with the two

A surprising validation of expectation experienced during a recognition test induces the perception of discrepancy and a feeling of familiarity. The authors investigated whether that perception also affects memory performance when it is experienced in the original encounter with a stimulus. Target words were presented in a study phase, half in a context thought to induce the perception of discrepancy. In a subsequent recognition test, that earlier experience increased the accuracy of subjects' discrimination. However, when the subsequent task required a once-versus-twice judgment, that experience caused an illusion of reoccurrence for words presented once. The authors concluded that a perception of discrepancy in an initial encounter may be a valuable aid to later recognition but can also cause systematic memory errors under some circumstances.     

Discovering your inner Gibson: Reconciling action-specific and ecological approaches to perception–action

Both the action-specific perception account and the ecological approach to perception–action emphasize the role of action in perception. However, the action-specific perception account demonstrates that different percepts are possible depending on the perceiver’s ability to act, even when the same optical information is available. These findings challenge one of the fundamental claims of the ecological approach—that perception is direct—by suggesting that perception is mediated by internal processes. Here, we sought to resolve this apparent discrepancy. We contend that perception is based on the controlled detection of the information available in a global array that includes higher-order patterns defined across interoceptive and exteroceptive stimulus arrays. These higher-order patterns specify the environment in relation to the perceiver, so direct sensitivity to them would be consistent with the ecological claims that perception of the environment is direct and animal-specific. In addition, the action-specific approach provides further evidence for the theory of affordances, by demonstrating that even seemingly abstract properties of the environment, such as distance and size, are ultimately perceived in terms of an agent’s action capabilities.     

How young children judge whether a word is one they know: a dual criterion account

Word familiarity judgment may be important for word learning, yet little is known about how children make this judgment. We hypothesized that preschool-age children differ in the judgment criteria that they use and that this difference derives from individual differences in basic memory processes. Those who have superior phonological working memory, but who retrieve less semantic information than their peers, base the judgment on whether they recognize a word’s sound form. Those who show the opposite memory profile base the judgment on whether they retrieve a word’s meaning. The results of two studies of 3- and 4-year-olds were consistent with these claims. Among those performing poorly on one memory measure, judgment accuracy was directly related to performance on the other memory measure. These memory-judgment relations were also found to be highly specific. This is the first investigation to demonstrate the usefulness of an individual differences approach for identifying relations between linguistic judgment processes and basic memory processes during early childhood.     

The internal clock: evidence for a temporal oscillator underlying time perception with some estimates of its characteristic frequency

Evidence for the proposition that human time perception is determined by an internal clock is largely indirect. It would strengthen the case for this hypothesis if a model for the internal clock were available from which predictions could be derived and tested, and if the basic parameter of such a model, the frequency at which the clock runs, could be estimated. A model for an internal temporal pacemaker is briefly described and its properties are explored by computer simulation. Results are obtained that provide a basis for predicting that, under appropriate conditions, interference between an imposed rhythm and the frequency of a temporal oscillator may cause perturbations in temporal judgment which are related to the characteristic frequency of that oscillator. Experimental data are reported which appear to demonstrate such an interference pattern. These results allow some estimates of the characteristic frequency of the temporal oscillator to be obtained.     

Psychophysical test for the independence of perception and action

Research has suggested that perception and action are independent (see M. A. Goodale & A. Haffenden, 1998). The authors used the Ebbinghaus illusion to test this hypothesis in 2 experiments. Verbal reports of perceived size were compared with maximum grip aperture during grasping (Experiment 1) and manual reports of perceived size (Experiment 2). A multidimensional signal detection analysis was used to distinguish among the possible interactions between the two processes in each experiment (H. Kadlec & J. T. Townsend, 1992a, 1992b). In Experiment 1, the percepts were independent, and there were no interactions between processes for verbal and visuomotor responses. In Experiment 2, the percepts associated with verbal and manual reports were independent, but the processes interacted at the levels of the stimulus information and the decision rules used to transform each percept into a response.     

The role of “chirp” identification in duplex perception

Duplex perception occurs when the phonetically distinguishing transitions of a syllable are presented to one ear and the rest of the syllable (the “base”) is simultaneously presented to the other ear. Subjects report hearing both a nonspeech “chirp” and a speech syllable correctly cued by the transitions. In two experiments, we compared phonetic identification of intact syllables, duplex percepts, isolated transitions, and bases. In both experiments, subjects were able to identify the phonetic information encoded into isolated transitions in the absence of an appropriate syllabic context. Also, there was no significant difference in phonetic identification of isolated transitions and duplex percepts. Finally, in the second experiment, the category boundaries from identification of isolated transitions and duplex percepts were not significantly different from each other. However, both boundaries were statistically different from the category boundary for intact syllables. Taken together, these results suggest that listeners do not need to perceptually integrate F2 transitions or F2 and F3 transition pairs with the base in duplex perception. Rather, it appears that listeners identify the chirps as speech without reference to the base.     

Stereovision: beyond disparity computations

One of the most powerful sources of information about three-dimensional (3-D) structure is provided by stereovision (or stereopsis). For over a century, theoretical and empirical investigations into this ability have focused on the role of binocular disparity in generating percepts of 3-D structure. Recent work in image segmentation demonstrates that stereovision can cause large changes in perceptual organization that cannot be understood on the basis of binocular disparity alone. It is argued that these phenomena reveal the need for theoretical tools beyond those that have dominated the study of visual perception over the past three decades.     

On the refractoriness of somesthetic temporal acuity

Preconditioning, with a burst of electrical pulse stimuli elevates the threshold for temporal acuity as measured with a technique requiring the S to detect a short gap in an otherwise regular burst of similar stimuli. Only a small amount of backward inhibition can be observed. The temporal duration of the inhibitory effect (up to 700 msec.) suggests that repetitive after-discharges of second-order afferents in Ike spinal cord may underlie this behavioral measure by actually filling in the intervals which are used by the S to make the judgment. The phenomenon is thus thought to be a disruption of a true temporal judgment rather than one indirectly mediated by an amplitude judgment, and as such it represents a significant datum on the temporal resolving power of time dimensions of neural coding.     

Is Perception the Canonical Route to Aesthetic Judgment?

It is commonplace amongst philosophers of art to make claims that postulate important links between aesthetics and perception. In this paper, I focus on one such claim—that perception is the canonical route to aesthetic judgment. I consider a range of prima facie plausible interpretations of this claim, and argue that each fails to identify any important link between aesthetic judgment and perception. Given this, I conclude that we have good reason to be sceptical of the claim that perception is in any way privileged as a source of aesthetic judgment.     

What is primed in priming from imagery?

Priming from imagery is typically weaker than that from perception. This has been interpreted as resulting from weaker activation of perceptual processes. However, for imagery and perception, commonality is only half the story: Each is also characterized by specific processes. If priming can be due to both unshared and shared components of imagery and perception, then it should be possible to observe greater priming from imagery than from perception. Two new priming experiments were designed to test this hypothesis, while controlling incidental task differences. In both experiments, participants studied objects by counting their parts (from a mental image or a picture). Experiment 1 used a word-picture matching test task, which was hypothesized to depend on stimulus processing specific to perception, and Experiment 2 a size judgment test task, which was hypothesized to depend on retrieval and generation processes specific to imagery. As predicted, priming for perceived objects was greater than priming for imagined objects in the word-picture matching task. Conversely, in the size judgment task, more priming from imagery than from perception was observed. These results support the conclusions that (a) imagery and perception have substantial unshared processes, and (b) these processes contribute to priming.     

Nonparametric Calibration of Item-by-Attribute Matrix in Cognitive Diagnosis

A nonparametric technique based on the Hamming distance is proposed in this research by recognizing that once the attribute vector is known, or correctly estimated with high probability, one can determine the item-by-attribute vectors for new items undergoing calibration. We consider the setting where Q is known for a large item bank, and the q-vectors of additional items are estimated. The method is studied in simulation under a wide variety of conditions, and is illustrated with the Tatsuoka fraction subtraction data. A consistency theorem is developed giving conditions under which nonparametric Q calibration can be expected to work.