Results of phase II clinical trial of Tamoxifen and Toremifen in two different doses in advanced breast cancer in postmenopausal women

Previous research has shown that skilled athletes are able to respond faster than novices to skill-specific information. The aim of this study was to ascertain whether expert outfielders are faster than non-experts in acting on information about the flight of a fly ball. It was hypothesized that expert outfielders are better attuned to this information; as a result, faster and more accurate responses were expected. This hypothesis was tested by having non-expert and expert outfielders judge, as quickly as possible, where a ball would land in the front-behind dimension (perceptual condition) and, in another condition, to attempt to catch such balls (catching condition). The results of the perceptual condition do not support the hypothesis that expert outfielders are more sensitive to ball flight information than non-experts, but the results of the catching condition reveal that experts are more likely to initiate locomotion in the correct direction.     

Playing chess unconsciously.

Expertise in a certain stimulus domain enhances perceptual capabilities. In the present article, the authors investigate whether expertise improves perceptual processing to an extent that allows complex visual stimuli to bias behavior unconsciously. Expert chess players judged whether a target chess configuration entailed a checking configuration. These displays were preceded by masked prime configurations that either represented a checking or a nonchecking configuration. Chess experts, but not novice chess players, revealed a subliminal response priming effect, that is, faster responding when prime and target displays were congruent (both checking or both nonchecking) rather than incongruent. Priming generalized to displays that were not used as targets, ruling out simple repetition priming effects. Thus, chess experts were able to judge unconsciously presented chess configurations as checking or nonchecking. A 2nd experiment demonstrated that experts' priming does not occur for simpler but uncommon chess configurations. The authors conclude that long-term practice prompts the acquisition of visual memories of chess configurations with integrated form-location conjunctions. These perceptual chunks enable complex visual processing outside of conscious awareness. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Perceptual repetition blindness effects.

Repetition blindness (RB) may reveal a new limitation on human perceptual processing. Recently, however, researchers have attributed RB to postperceptual processes. The standard rapid serial visual presentation (RSVP) paradigm used in most RB studies is open to such objections. The "single-frame" paradigm introduced by J. C. Johnston and B. L. Hale (1984) allowed investigation of RB with minimal memory demands. Participants made a judgment about whether 1 masked target word was the same or different than a posttarget probe. Confidence ratings permitted use of signal detection methods. In the critical condition for RB, a precue of the posttarget word was provided prior to the target stimulus so that the required judgment amounted to whether the target did or did not repeat the precue word. In control treatments, the precue was an unrelated word or a dummy. Results showed that perceptual sensitivity was significantly reduced in the RB condition relative to baseline control conditions. The data showed that RB can be obtained under conditions in which memory problems are minimal and perceptual sensitivity is assessed independently of biases. RB therefore can be a perceptual phenomenon. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

How is body orientation controlled during somersaulting?

How body orientation is controlled during somersaulting was investigated in 2 experiments that analyzed the kinematics of 223 backward standing somersaults. In Experiment 1, open-loop, initial-condition (flight duration), and prospective (time to contact, or TC?) control strategies were tested as candidates for the regulation of body moment of inertia during the jump. Decreasing between-trials variability of body orientation over time as well as a negative correlation between body angular velocity and TC? suggested that the moment of inertia was regulated prospectively. In Experiment 2, the visual basis for this regulation was examined by asking experts and novices to execute somersaults either with eyes closed or open. Results showed that the prospective regulation observed in the vision condition disappeared in the no-vision condition with the experts, arguing in favor of a visual control during the jump. Such a coupling was absent with the novices, thus illustrating the role played by the perception–action cycle in the learning process. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Working memory enhances visual perception: Evidence from signal detection analysis.

We show that perceptual sensitivity to visual stimuli can be modulated by matches between the contents of working memory (WM) and stimuli in the visual field. Observers were presented with an object cue (to hold in WM or to merely attend) and subsequently had to identify a brief target presented within a colored shape. The cue could be re-presented in the display, where it surrounded either the target (on valid trials) or a distractor (on invalid trials). Perceptual identification of the target, as indexed by A′, was enhanced on valid relative to invalid trials but only when the cue was kept in WM. There was minimal effect of the cue when it was merely attended and not kept in WM. Verbal cues were as effective as visual cues at modulating perceptual identification, and the effects were independent of the effects of target saliency. Matches to the contents of WM influenced perceptual sensitivity even under conditions that minimized competition for selecting the target. WM cues were also effective when targets were less likely to fall in a repeated WM stimulus than in other stimuli in the search display. There were no effects of WM on decisional criteria, in contrast to sensitivity. The findings suggest that reentrant feedback from WM can affect early stages of perceptual processing. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Attention set for number: Expectation and perceptual load in inattentional blindness.

Inattentional blindness is the failure to detect unexpected events when attention is otherwise engaged. Previous research indicates that inattentional blindness increases as perceptual demands intensify. The authors present 6 cuing experiments that manipulated both the perceptual demands of a primary letter-naming task and the expectations of the individual. Inattentional blindness was greatest for individuals who held a numerical expectation that was consistent with the number of primary-task items presented. Expectation also affected detection differentially at various levels of perceptual load: Detection at moderate and high perceptual load was significantly affected by expectation, whereas detection at low perceptual load was not. The authors suggest that at moderate to high levels of perceptual load, individuals whose numerical expectations are fulfilled terminate processing when the primary task is complete, at the expense of the unexpected visual event. These experiments provide compelling evidence that expectations do affect detection of an unexpected stimulus, and they are the first to demonstrate that individuals set their attention for the number of items to be detected and are vulnerable to inattentional blindness whenever their primary-task numerical expectation is fulfilled. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Multisensory cues capture spatial attention regardless of perceptual load.

We compared the ability of auditory, visual, and audiovisual (bimodal) exogenous cues to capture visuo-spatial attention under conditions of no load versus high perceptual load. Participants had to discriminate the elevation (up vs. down) of visual targets preceded by either unimodal or bimodal cues under conditions of high perceptual load (in which they had to monitor a rapidly presented central stream of visual letters for occasionally presented target digits) or no perceptual load (in which the central stream was replaced by a fixation point). The results of 3 experiments showed that all 3 cues captured visuo-spatial attention in the no-load condition. By contrast, only the bimodal cues captured visuo-spatial attention in the high-load condition, indicating for the first time that multisensory integration can play a key role in disengaging spatial attention from a concurrent perceptually demanding stimulus. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Biological movements look uniform: Evidence of motor-perceptual interactions.

Demonstrated a visual dynamic illusion in 6 experiments. Previous work has shown that in 2-dimensional (2-D) drawing movements, tangential velocity and radius of curvature covary in a constrained manner. The velocity of point stimuli is perceived as uniform if and only if this biological constraint is satisfied. The illusion is conspicuous: The variations of velocity in the stimuli exceed 200%. Yet movements are perceived as uniform. Conversely, 2-D stimuli moving at constant velocity are perceived as strongly nonuniform. The illusion is robust: Exposure to true constant velocity fails to suppress it. Results cannot be explained entirely by the kinetic depth effect. The illusion is evidence of a coupling between motor and perceptual processes: Even in the absence of any intention to perform a movement, certain properties of the motor system implicitly influence perceptual interpretation of the visual stimulus. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Cellular basis for the negative dromotropic effect of adenosine on rabbit single atrioventricular nodal cells

Detection and resolution of square patches of sinusoidal gratings were measured in central and peripheral vision (30 degrees horizontal temporal visual field) for high-contrast gratings as a function of the number of cycles in the stimulus. We determined performance in a forced-choice paradigm for a fixed number of stimulus cycles by arranging for stimulus diameter to vary inversely with spatial frequency. For both psychophysical tasks and for both target locations, the psychometric function relating performance to log spatial frequency shifted to higher frequencies without changing slope significantly as the number of cycles in the stimulus was increased. Thus the entire effect could be captured by an analysis of spatial acuity, which increased with increasing number of grating cycles over the range 0.5-6 cycles but remained constant over the range 6-14 cycles. In the central field, resolution acuity and detection acuity were equal regardless of the number of cycles in the stimulus. In the peripheral field, detection acuity exceeded resolution acuity and perceptual aliasing occurred for stimuli in the range 1-14 cycles. From this result we conclude that resolution acuity is sampling limited in the periphery, provided that the stimulus contains at least one full cycle of the grating. Essential features of the results could be accounted for by Fourier analysis of the stimulus.     

Bothered by abstraction: The effect of expertise on knowledge transfer and subsequent novice performance.

Although experts should be well positioned to convey their superior knowledge and skill to novices, the organization of that knowledge, and particularly its level of abstraction, may make it difficult for them to do so. Using an electronic circuit-wiring task, the authors found that experts as compared with beginners used more abstract and advanced statements and fewer concrete statements when providing task instructions to novices. In a 2nd study, the authors found that beginner-instructed novices performed better than expert-instructed novices and reported fewer problems with the instructions when performing the same task. In Study 2, the authors found that although novices performed better on the target task when instructed by beginners, they did better on a different task within the same domain when instructed by experts. The evidence suggests that the abstract, advanced concepts conveyed by experts facilitated the transfer of learning between the different tasks. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Repetition blindness has a perceptual locus: Evidence from online processing of targets in RSVP streams.

Four experiments tested whether repetition blindness (RB; reduced accuracy reporting repetitions of briefly displayed items) is a perceptual or a memory-recall phenomenon. RB was measured in rapid serial visual presentation (RSVP) streams, with the task altered to reduce memory demands. In Experiment 1 only the number of targets (1 vs. 2) was reported, eliminating the need to remember target identities. Experiment 2 segregated repeated and nonrepeated targets into separate blocks to reduce bias against repeated targets. Experiments 3 and 4 required immediate "online" buttonpress responses to targets as they occurred. All 4 experiments showed very strong RB. Furthermore, the online response data showed clearly that the 2nd of the repeated targets is the one missed. The present results show that in the RSVP paradigm, RB occurs online during initial stimulus encoding and decision making. The authors argue that RB is indeed a perceptual phenomenon. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Temporal limitations in the effective binding of attended target attributes in the mutual masking of visual objects.

The problem of feature binding has been examined under conditions of distributed attention or with spatially dispersed stimuli. We studied binding by asking whether selective attention to a feature of a masked object enables perceptual access to the other features of that object using conditions in which spatial attention was directed at a single location where all objects appeared. In an identification condition, the task required reporting the same property of each object. High rates of identification showed good perceptual availability. In a search condition, the task required reporting the property (e.g., shape) that was associated with a specific value of the searched property (e.g., surface texture) of the same object. Focusing of attention on a target’s searched property value did not result in a high rate of identifying the target’s other property, and strong object masking was found. Backward masking between spatially superimposed visual objects appears to be primarily due to a difficulty in feature binding of a target object rather than to a substitution of an integrated object by the following stimulus. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The role of temporal cortical areas in perceptual organization

The visual areas of the temporal lobe of the primate are thought to be essential for the representation of visual objects. To examine the role of these areas in the visual awareness of a stimulus, we recorded the activity of single neurons in monkeys trained to report their percepts when viewing ambiguous stimuli. Visual ambiguity was induced by presenting incongruent images to the two eyes, a stimulation condition known to instigate binocular rivalry, during which one image is seen at a given time while the other is perceptually suppressed. Previous recordings in areas V1, V2, V4, and MT of monkeys experiencing binocular rivalry showed that only a small proportion of striate and early extrastriate neurons discharge exclusively when the driving stimulus is seen. In contrast, the activity of almost all neurons in the inferior temporal cortex and the visual areas of the cortex of superior temporal sulcus was found to be contingent upon the perceptual dominance of an effective visual stimulus. These areas thus appear to represent a stage of processing beyond the resolution of ambiguities--and thus beyond the processes of perceptual grouping and image segmentation--where neural activity reflects the brain's internal view of objects, rather than the effects of the retinal stimulus on cells encoding simple visual features or shape primitives.     

Mechanisms and neural basis of object and pattern recognition: A study with chess experts.

Comparing experts with novices offers unique insights into the functioning of cognition, based on the maximization of individual differences. Here we used this expertise approach to disentangle the mechanisms and neural basis behind two processes that contribute to everyday expertise: object and pattern recognition. We compared chess experts and novices performing chess-related and -unrelated (visual) search tasks. As expected, the superiority of experts was limited to the chess-specific task, as there were no differences in a control task that used the same chess stimuli but did not require chess-specific recognition. The analysis of eye movements showed that experts immediately and exclusively focused on the relevant aspects in the chess task, whereas novices also examined irrelevant aspects. With random chess positions, when pattern knowledge could not be used to guide perception, experts nevertheless maintained an advantage. Experts' superior domain-specific parafoveal vision, a consequence of their knowledge about individual domain-specific symbols, enabled improved object recognition. Functional magnetic resonance imaging corroborated this differentiation between object and pattern recognition and showed that chess-specific object recognition was accompanied by bilateral activation of the occipitotemporal junction, whereas chess-specific pattern recognition was related to bilateral activations in the middle part of the collateral sulci. Using the expertise approach together with carefully chosen controls and multiple dependent measures, we identified object and pattern recognition as two essential cognitive processes in expert visual cognition, which may also help to explain the mechanisms of everyday perception. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Quantitative theories of metacontrast masking.

In metacontrast masking, the effect of a visual mask stimulus on the perceptual strength of a target stimulus varies with the stimulus-onset asynchrony (SOA) between them. As SOA increases, the target percept first becomes weaker, bottoms out at an intermediate SOA, and then increases for still larger SOAs. As a result, a plot of target percept strength against SOA produces a U-shaped masking curve. Theories have proposed special mechanisms to account for this curve, but new mathematical analyses indicate that it is a robust characteristic of a large class of neurally plausible systems. The author describes 3 quantitative methods of accounting for the U-shaped masking effect and analyzes previously published mathematical models of masking. The models produce the masking curve through mask blocking, whereby a strong internal representation of the target blocks the mask's effects. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The influence of degree of expertise and objective task complexity on perceived task complexity and performance.

Research on expertise has shown that nonexperts may sometimes outperform experts. Some researchers have suggested that superior performance by experts depends on the match between the experts' cognition and the demands of the task. The authors explored this issue using a quasi-experiment set in an organization. They examined how 3 sets of similar tasks that differ in their type of complexity can lead to differences in task perceptions and performance among experts, intermediates, and novices. The results suggest that experts and novices pay attention to different aspects of a task and that this affects both their perceptions of task complexity (i.e., task analyzability and variability) and their performance on the task. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Trust my face: Cognitive factors of head fakes in sports.

In many competitive sports, players try to deceive their opponents about their behavioral intentions by using specific body movements or postures called fakes. For example, fakes are performed in basketball when a player gazes in one direction but passes or shoots the ball in another direction to avert efficient defense actions. The present study aimed to identify the cognitive processes that underlie the effects of fakes. The paradigmatic situation studied was the head fake in basketball. Observers (basketball novices) had to decide as quickly as possible whether a basketball player would pass a ball to the left or to the right. The player's head and gaze were oriented in the direction of an intended pass or in the opposite direction (i.e., a head fake). Responding was delayed for incongruent compared to congruent directions of the player's gaze and the pass. This head fake effect was independent of response speed, the presence of a fake in the immediately preceding trial, and practice with the task. Five further experiments using additive-factors logic and locus-of-slack logic revealed a perceptual rather than motor-related origin of this effect: Turning the head in a direction opposite the pass direction appears to hamper the perceptual encoding of pass direction, although it does not induce a tendency to move in the direction of the head's orientation. The implications of these results for research on deception in sports and their relevance for sports practice are discussed. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Perceptual organization of moving stimuli modulates the flash-lag effect.

When a visual stimulus is flashed at a given location the moment a second moving stimulus arrives at the same location, observers report the flashed stimulus as spatially lagging behind the moving stimulus (the flash-lag effect). The authors investigated whether the global configuration (perceptual organization) of the moving stimulus influences the magnitude of the flash-lag effect. The results indicate that a flash presented near the leading portion of a moving stimulus lags significantly more than a flash presented near the trailing portion. This result also holds for objects consisting of several elements that group to form a unitary percept of an object in motion. The present study demonstrates a novel interaction between the global configuration of moving objects and the representation of their spatial position and may provide a new and useful tool for the study of perceptual organization. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Illusory conjunctions of forms, objects, and scenes during rapid serial visual search.

"Temporal migration" describes a situation in which subjects viewing rapidly presented stimuli (e.g., 9–20 items/s) confidently report a target element as having been presented in the same display as a previous or following stimulus in the sequence. Four experiments tested a short-term buffer model of this phenomenon. Experiments 1 and 4 tested the hypothesis that subjects' errors are due to the demands of the verbal report procedure rather than to perceptual integration. In Experiment 1, 12 color objects were presented at a rate of 9/s. Prior to each sequence, an object was named and subjects responded "yes" or "no" to indicate whether the target element (a black frame) occurred with that object. Consistent with the perceptual hypothesis, the yes/no procedure yielded the same results as the verbal report procedure. Experiment 2 tested the hypothesis that the direction of migration depends on "frame" detection time. Results showed that reaction time to frame detection was significantly faster in trials in which subjects reported the frame on a preceding rather than a following picture. Experiments 3 and 4 used the standard naming procedure and the yes/no procedure to test temporal migration using more complex, interrelated stimuli (objects and scenes). Implications for the use of the temporal migration effect to study visual integration within eye fixations are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Perceptual load alters visual excitability.

Increasing perceptual load reduces the processing of visual stimuli outside the focus of attention, but the mechanism underlying these effects remains unclear. Here we tested an account attributing the effects of perceptual load to modulations of visual cortex excitability. In contrast to stimulus competition accounts, which propose that load should affect simultaneous, but not sequential, stimulus presentations, the visual excitability account makes the novel prediction that load should affect detection sensitivity for both simultaneous and sequential presentations. Participants fixated a stimulus stream, responding to targets defined by either a color (low load) or color and orientation conjunctions (high load). Additionally, detection sensitivity was measured for a peripheral critical stimulus (CS) presented occasionally. Increasing load at fixation reduced sensitivity to the peripheral CSs; this effect was similar regardless of whether CSs were presented simultaneously with central stimuli or during the (otherwise empty) interval between them. Controls ruled out explanations of the results in terms of strategic task prioritization. These findings support a cortical excitability account for perceptual load, challenging stimulus competition accounts. (PsycINFO Database Record (c) 2011 APA, all rights reserved)