Word Length and Visual-Noise Texture in Backward Masking

Perception ◽  
1976 ◽  
Vol 5 (2) ◽  
pp. 211-215 ◽  
Author(s):  
Harold S Zamansky ◽  
Thomas R Corwin
Keyword(s):  
Present Experiment ◽  
Visual Angle ◽  
Word Length ◽  
Visual Noise ◽  
Backward Masking ◽  
Stroke Width ◽  
Letter Array ◽  
Feature Similarity ◽  
The One

Visual-noise masks composed of randomly scattered letter fragments disrupt the recognition of briefly viewed letter arrays when the masks are presented immediately after these arrays. According to the feature-similarity assumption, maximal disruption should occur when the target letters and the letter fragments comprising the mask share a common stroke width. This assumption was disconfirmed in the present experiment. Two-, four-, and six-letter arrays, whose stroke width subtended a visual angle of 3·8′, were viewed tachistoscopically in conjunction with visual-noise masks whose letter fragments subtended visual angles of 1·2′, 1·9′, 3·8′, 6·6′, or 9·7′. The most effective mask for all three letter-array lengths was the one composed of letter fragments subtending 6·6′. The results, together with those of previous experiments, are accounted for in terms of a neural line-detecting mechanism.

scholarly journals Sense of Agency in Multi-Step Actions

2019 ◽  
Author(s):  
Patricia Garrido-Vásquez ◽  
Tanja Rock
Keyword(s):  
Present Experiment ◽  
Sense Of Agency ◽  
Implicit Measure ◽  
Opposite Pattern ◽  
Daily Lives ◽  
Perception Of Causality ◽  
Sensory Effects ◽  
One Step ◽  
Sensory Attenuation ◽  
The One

In our daily lives, we frequently execute actions that require several steps to bring about the outcome. However, investigations on how the sense of agency—the sense of controlling our actions and their outcomes—evolves in multi-step actions are still lacking. The purpose of the present research is to fill this gap. In the present study, the participants executed one-step, two-step, and three-step actions in which one, two, or three keys had to be pressed consecutively to generate a tone. We used sensory attenuation as an implicit measure of the sense of agency. Sensory attenuation means that self-produced sensory effects are perceived as less intense than externally generated effects. In the present experiment, sensory attenuation was measured in a psychophysical paradigm and increased in multi-step actions compared to the one-step action. We also asked the participants to explicitly rate the amount to which they felt that they had generated the tone. Ratings were highest in the one-step condition and dropped for multi-step actions, thus showing the opposite pattern of the sensory attenuation data. We assume that enhanced sensory attenuation in multi-step actions could be due to increased effort or more accurate sensorimotor predictions of action effects. The decrease in explicit ratings for multi-step actions might be attributed to reduced perception of causality.

The Relationship between Time of Arrival of Nontargets and Their Spatial Location: Evidence for Asymmetries in Visual Attentional Processing

Perception ◽  
1994 ◽  
Vol 23 (7) ◽  
pp. 849-856 ◽  
Author(s):  
Kieran Coyle
Keyword(s):  
Present Experiment ◽  
Visual Angle ◽  
Time Lag ◽  
Spatial Location ◽  
Time Of Arrival ◽  
Attentional Processing ◽  
Subsequent Period ◽  
Additional Processing ◽  
The Relationship

A brief advance of the presentation of distant nontargets has previously been shown to secure them an analysis, suggesting that even stimuli beyond the putative ‘spotlight’ of attention are analysed. In the present experiment nontargets were presented near to fixation or peripherally (at 0.6 or 1.9 deg of visual angle) for a duration of 17, 33, or 67 ms before being masked. After a subsequent period (SOA) of 0, 20, 40, 60, or 80 ms the target was presented at fixation. The results from the shortest nontarget duration show a time lag in the development of the effect of far nontargets on response to the target. At durations of 33 and 67 ms the identity of far nontargets has been established before masking takes place, since their effect is observable at zero SOA. However, while this effect remains relatively constant over SOAs of 20 to 80 ms it increases wth SOA in the near condition, suggesting that, although both near and far nontargets have been identified, it is only the near nontargets which are subject to further processing during the interval between nontarget and target presentations. The results favour a model of attention in which stimuli are passively selected and subject to additional processing on the basis of their spatial location rather than that the location or representation of distractor items are actively suppressed.

Letter Interactions in Brief Visual Displays

1980 ◽  
Vol 32 (4) ◽  
pp. 649-668 ◽  
Author(s):  
Grover C. Gilmore
Keyword(s):  
Target Letter ◽  
Target Detection ◽  
Detection Performance ◽  
Visual Displays ◽  
Low Level ◽  
Feature Similarity ◽  
Feature Information ◽  
Inhibitory Potential ◽  
The One

Three experiments were conducted to examine the influence of non-target letters on target detection performance. It was hypothesised that letters which are similar would exert a stronger masking influence on each other than letters which have a low level of feature similarity. The results indicate, however, that every letter has the same inhibitory potential regardless of its similarity rating to other letters. The highly significant letter interactions which did occur in the study were interpreted as evidence for an additive, rather than a subtractive, influence by the non-targets. It is proposed that when a target has an ambiguous identity, due to an impoverished representation, it may be disambiguated by the addition of feature information from the immediate letter context. The effect of filling in the target representation with a feature value from a non-target letter will be to weight the final representation towards the target which has the value most similar to the one substituted. In a sense, then, non-targets which are similar to a target can actually enhance target detection scores.

Are Rats Short-Sighted? Effects of Stimulus Distance and Size on Visual Detection

1981 ◽  
Vol 33 (2b) ◽  
pp. 69-76 ◽  
Author(s):  
Paul Dean
Keyword(s):  
Visual Acuity ◽  
Present Experiment ◽  
Visual Angle ◽  
Visual Detection ◽  
Visual Stimuli ◽  
Good Evidence ◽  
Physical Size ◽  
Stimulus Distance ◽  
Behavioural Evidence

Behavioural evidence concerning short-sightedness in rats is apparently conflicting: in some experiments rats have performed poorly with visual stimuli further than about 60 cm distant, while in others they have made efficient use of more distant cues, for example to find their way through mazes. However, in the experiments suggesting short-sightedness, the physical size of the stimuli was not varied, so that stimulus distance and visual angle were confounded. In the present experiment, therefore, the size and distance of the stimuli to be detected were varied independently. Over the range tested (30–160 cm), distance was found to produce relatively slight effects on the smallest detectable visual angle, and these tended to diminish with practice. Thus, no good evidence was found for short-sightedness in rats up to 160 cm, a finding consistent with current views of the structure and image-forming capacities of the rat's eye. The smallest detectable targets were, however, surprisingly large in view of the rat's visual acuity (which is about 1c/deg): at the distances tested, animals required considerable training to run reliably to targets subtending less than 5–10° of visual angle. Difficulties in responding to stationary stimuli of this size are likely to restrict severely the use that rats make of vision both in the laboratory and in their natural surroundings.

Backward Masking Performance in Schizophrenic Patients and their Healthy Relatives

2009 ◽  
Vol 24 (S1) ◽  
pp. 1-1
Author(s):  
E. Chkonia ◽  
M. Roynishvili ◽  
A. Kezeli ◽  
M.H. Herzog ◽  
A. Brand
Keyword(s):  
Information Processing ◽  
Visual Information ◽  
Control Group ◽  
Backward Masking ◽  
Level Information ◽  
Schizophrenic Patients ◽  
Healthy Control ◽  
Information Processing Deficits ◽  
The One ◽  
Visual Backward Masking

Over the past years, studies of unaffected first-degree relatives of schizophrenic patients have reported cognitive deficits in the domains of executive functions, memory, and attention. However, these deficits may rely on lower level information processing deficits. Here, we investigated visual information processing with a visual backward masking task. A vernier target was followed by a grating mask. Observers had to indicate the offset direction of the vernier. We determined the SOA between the vernier and the grating onset for schizophrenic patients, their healthy first order relatives, and a healthy control group. Schizophrenic patients needed SOAs about three times longer than healthy controls to reach a predefined criterion level. Backward masking performance of unaffected relatives was significantly better than the one of patients but significantly worse than performance of controls. This result adds further evidence that low level deficits as determined by visual backward masking are endophenotypes of schizophrenia.

scholarly journals PRECISÃO DE PLANTAS PLANIALTIMÉTRICAS EM FUNÇÃO DO POSICIONAMENTO DE PONTOS EM IRRADIADAS DE CAMPO.

Irriga ◽  
2006 ◽  
Vol 11 (1) ◽  
pp. 47-54 ◽  
Author(s):  
Luciano Nardini Gomes ◽  
Lincoln Gehring Cardoso ◽  
Zacarias Xavier de Barros ◽  
Sergio Campos ◽  
Vilmar Antônio Rodrigues
Keyword(s):  
Present Experiment ◽  
Treatment Method ◽  
Surface Modeling ◽  
The Third ◽  
Local Topography ◽  
Before And After ◽  
Great Divergence ◽  
Point Positioning ◽  
Longitudinal Profiles ◽  
The One

PRECISÃO DE PLANTAS PLANIALTIMÉTRICAS EM FUNÇÃO DO POSICIONAMENTO DE PONTOS EM IRRADIADAS DE CAMPO.  Luciano Nardini Gomes; Lincoln Gehring Cardoso; Zacarias Xavier de Barros; Sergio Campos; Vilmar Antônio RodriguesDepartamento de Engenharia Rural, Faculdade de Ciências Agronômicas, Universidade Estadual Paulista, Botucatu, SP, [email protected]  1 RESUMO O presente trabalho teve como objetivo estudar a influência do posicionamento de pontos em visadas irradiadas, na geração de uma planta planialtimétrica. Em uma área teste de14 hectarese com nítidas variações de relevo foi realizado um levantamento planialtimétrico por taqueometria, lançando-se poligonais abertas e irradiadas, cobrindo todas as feições do relevo. Os mapas planialtimetricos foram obtidos pelo programas Datageosis, Topoesalq e por procedimento manual. No programa Datageosis a obtenção da planta foi totalmente automatizada visto que esse programa realiza modelagem numérica de superfície. O programa Topoesalq, por não oferecer o mesmo recurso do Datageosis, forneceu apenas relatório de cotas inteiras necessitando traçado manual de curvas. Para o terceiro método todo o processamento, desde cálculos até a representação final foi considerado o procedimento manual. Nos locais com diferenças de representação da planialtimetria, foram lançados perfis longitudinais. As plantas geradas foram confrontadas com os perfis de referência, constatando-se que a planialtimetria obtida pelo sistema Datageosis melhor representou o relevo local. Posteriormente foram consideradas apenas as visadas irradiadas que apresentavam, numa mesma visada, leituras posicionadas antes e após cada variação de relevo. O processamento pelos três métodos resultou em plantas representativas da planialtimetria local comprovadas também pelos perfis. Conclui-se que, para a elaboração de planta planialtimétrica compatível com o relevo local levantado, o planejamento do procedimento de campo deve estar em conformidade com o método de tratamento posterior dos dados obtidos. UNITERMOS: Planialtimetria, modelagem numérica da superfície.  GOMES, L. N.; CARDOSO, L. G.; BARROS, Z. X. de; CAMPOS, S.; RODRIGUES, V. A.; ACCURACY OF PLANIALTIMETRIC PLANTS ACCORDING TO POINT POSITIONING IN AN IRRADIATED FIELD.  2 ABSTRACT The present experiment aimed to study the influence of point positioning in an irradiated field to produce a planialtimetric plant. A planialtimetric evaluation was carried out in a 14-acre experimental area with well-defined topographic variations. Planialtimetric maps were designed using manual procedures, Datageosis and Topoesalq. Datageosis built all the curves after numerical surface modeling. Topoesalq provided only height reports and the drawing of curves was done manually. The third method was a manual procedure. Because there were planialtimetry representation differences, longitudinal profiles were used in the sites where there was a great divergence among plants. When obtained profiles and plants were compared, it was verified that the one produced by Datageosis represented the relief plant better. Later, only the irradiated field points were evaluated and each point presented positioned readings before and after each relief map variation. The processing through the three methods resulted in significant plants of the local planialtimetry, according to the control profiles. It was concluded that the planning of the field procedure should be suitable to the posterior treatment method of obtained data in order to make a planialtimetric plant to accord to the evaluated local topography. KEYWORDS: planialtimetry, numerical surface modeling

scholarly journals Emergent faithfulness to morphological and semantic heads in lexical blends

2014 ◽  
Vol 1 (1) ◽  
Author(s):  
Katherine E. Shaw ◽  
Andrew M. White ◽  
Elliott Moreton ◽  
Fabian Monrose
Keyword(s):  
Stress Analysis ◽  
Experimental Evidence ◽  
Word Length ◽  
Privileged Position ◽  
Word Stress ◽  
Main Stress ◽  
The One ◽  
Positional Faithfulness ◽  
Source Word ◽  
Marked Structure

In many languages, sounds in certain "privileged" positions preserve marked structure which is eliminated elsewhere (Positional Faithfulness, Beckman 1998).  This paper presents new corpus and experimental evidence that faithfulness to main-stress location and segmental content of morpho-semantic heads emerges in English blends. The study compared right-headed (subordinating) blends, like motor + hotel -&gt; motel (a kind of hotel) with coordinating blends like spoon + fork -&gt; spork (equally spoon and fork).<br /><br />Stress: Analysis of 1095 blends from Thurner (1993) found that right-headed blends were more faithful to stress location of the second source word than were coordinating blends.  Given source words with conflicting stress (e.g., FLOUNder + sarDINE), participants preferentially matched the blend that preserved second-word stress (flounDINE) to a right-headed definition.<br /><br />Segmental content: When source-word length was controlled, segments from right-headed blends were more likely to survive than those from coordinating blends.  Given source words that could be spliced at two points (e.g., flaMiNGo + MoNGoose), participants preferentially matched the one that preserved more of the second word (flamongoose) to a right-headed definition.<br /><br />These results support the hypotheses that Positional Faithfulness constraints are universally available, that heads are a privileged position, and that blend phonology is sensitive to headedness.<br /><br />

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