Wyniki wyszukiwania - Biblioteka Nauki

1

What determines the direction of subliminal priming

100%

Jaśkowski P. , Verleger R.

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2007

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tom 3

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nr 1-2

181-192

EN

Masked stimuli (primes) can affect the preparation of a motor response to subsequently presented target stimuli. Reactions to the target can be facilitated (straight priming) or inhibited (inverse priming) when preceded by a compatible prime (calling for the same response) and also when preceded by an incompatible prime. Several hypotheses are currently under debate. These are the self-inhibition (SI) hypothesis, the object-updating (OU) hypothesis, and mask-triggered inhibition (MTI) hypothesis. All assume that the initial activation of the motor response is elicited by the prime according to its identity. This activation inevitably leads to straight priming in some cases and the mechanisms involved are undisputed. The hypotheses differ, however, as to why inverse priming occurs. The self-inhibition (SI) hypothesis assumes that the motor activation elicited by a prime is automatically followed by an inhibition phase, leading to inverse priming if three conditions are fulfilled: perceptual evidence for the prime has to be sufficiently strong, it has to be immediately removed by the mask, and the delay between the prime and target has to be long enough for inhibition to become effective. The object-updating (OU) hypothesis assumes that inverse priming is triggered by the mask, provided that it contains features calling for the alternative response (i.e. the one contrasting with the response induced by the prime). The MTI hypothesis assumes that the inhibitory phase is triggered by each successive stimulus which does not support the perceptual hypothesis provided by the prime. Based mostly on our own experiments, we argue that (1) attempts to manipulate the three factors required by the SI hypothesis imply changes of other variables and that (2) indeed, other variables seem to affect priming: prime-mask perceptual interaction and temporal position of the mask. These observations are in favor of the MTI hypothesis. A limiting factor for all three hypotheses is that inverse priming is larger for arrows than for other shapes, making it doubtful as to what extent the majority of studies on inverse priming, due to their use of arrows, can be generalized to other stimuli.

2

What should a quantitative model of masking look like and why would we want it?

100%

Francis G.

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2007

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tom 3

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nr 1-2

21-31

EN

Quantitative models of backward masking appeared almost as soon as computing technology was available to simulate them; and continued interest in masking has lead to the development of new models. Despite this long history, the impact of the models on the field has been limited because they have fundamental shortcomings. This paper discusses these shortcomings and outlines what future quantitative models should look like. It also discusses several issues about modeling and how a model could be used by researchers to better explore masking and other aspects of cognition.

3

Visual masking and the dynamics of human perception, cognition, and consciousness:A century of progress, a contemporary synthesis, and future directions

100%

Ansorge U. , Francis G. , Herzog M. , Öğmen H.

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2007

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tom 3

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nr 1-2

1-8

EN

The 1990s, the "decade of the brain," witnessed major advances in the study of visual perception, cognition, and consciousness. Impressive techniques in neurophysiology, neuroanatomy, neuropsychology, electrophysiology, psychophysics and brain-imaging were developed to address how the nervous system transforms and represents visual inputs. Many of these advances have dealt with the steady-state properties of processing. To complement this "steady-state approach," more recent research emphasized the importance of dynamic aspects of visual processing. Visual masking has been a paradigm of choice for more than a century when it comes to the study of dynamic vision. A recent workshop (http://lpsy.epfl.ch/VMworkshop/), held in Delmenhorst, Germany, brought together an international group of researchers to present state-of-the-art research on dynamic visual processing with a focus on visual masking. This special issue presents peer-reviewed contributions by the workshop participants and provides a contemporary synthesis of how visual masking can inform the dynamics of human perception, cognition, and consciousness.

4

Psychophysical evidence for distinct contributions in processing low and high spatial frequencies of fearful facial expressions in backward masking task

75%

Szczepanowski R. , Sobków A.

Polish Psychological Bulletin

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2012

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tom 43

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nr 3

167-172

EN

The present report examined the hypothesis that two distinct visual routes contribute in processing low and high spatial frequencies of fearful facial expressions. Having the participants presented with a backwardly masked task, we analyzed conscious processing of spatial frequency contents of emotional faces according to both objective and subjective taskrelevant criteria. It was shown that fear perception in the presence of the low-frequency faces can be supported by stronger automaticity leading to less false positives. In contrary, the detection of high-frequency fearful faces was more likely supported by conscious awareness leading to more true positives.

5

The power of the feed-forward sweep

75%

VanRullen R.

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2007

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tom 3

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nr 1-2

167-176

EN

Vision is fast and efficient. A novel natural scene can be categorized (e.g. does it contain an animal, a vehicle?) by human observers in less than 150 ms, and with minimal attentional resources. This ability still holds under strong backward masking conditions. In fact, with a stimulus onset asynchrony of about 30 ms (the time between the scene and mask onset), the first 30 ms of selective behavioral responses are essentially unaffected by the presence of the mask, suggesting that this type of "ultra-rapid" processing can rely on a sequence of swift feed-forward stages, in which the mask information never "catches up" with the scene information. Simulations show that the feed-forward propagation of the first wave of spikes generated at stimulus onset may indeed suffice for crude recognition or categorization. Scene awareness, however, may take significantly more time to develop, and probably requires feed-back processes. The main implication of these results for theories of masking is that pattern or metacontrast (backward) masking do not appear to bar the progression of visual information at a low level. These ideas bear interesting similarities to existing conceptualizations of priming and masking, such as Direct Parameter Specification or the Rapid Chase theory.

6

Psychophysical evidence for distinct contributions in processing low and high spatial frequencies of fearful facial expressions in backward masking task

75%

Szczepanowski R. , Sobków A.

Polish Psychological Bulletin

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2012

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tom 43

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nr 3

167-172

EN

The present report examined the hypothesis that two distinct visual routes contribute in processing low and high spatial frequencies of fearful facial expressions. Having the participants presented with a backwardly masked task, we analyzed conscious processing of spatial frequency contents of emotional faces according to both objective and subjective taskrelevant criteria. It was shown that fear perception in the presence of the low-frequency faces can be supported by stronger automaticity leading to less false positives. In contrary, the detection of high-frequency fearful faces was more likely supported by conscious awareness leading to more true positives.

7

Common-onset masking simulated with a distributed-code model

63%

Bridgeman B.

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2007

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tom 3

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nr 1-2

33-40

EN

A distributed-coding model incorporating lateral inhibition in a simulated nerve network has been successful in accounting for many properties of backward masking (Bridgeman, 1971, 1978), linking modeling with neurophysiology and psychophysics. Metacontrast is a variety of backward masking that is of particular interest in uncovering properties of visual coding because target and mask do not overlap in time or space, and it is the first stimulus that is reduced in visibility, not the second. The lateral inhibitory model can also simulate common-onset masking, where a target and mask appear simultaneously but the mask disappears after a variable delay, and it can reproduce qualitatively the effects of attention on object substitution by varying the time interval over which sensory codes are analyzed.