Banishing Illusory Contours: A New Possibility

Perception ◽  
1997 ◽  
Vol 26 (6) ◽  
pp. 753-754 ◽  
Author(s):  
Theodore E Parks
Keyword(s):  
Harmful Effect ◽  
Illusory Figure ◽  
Illusory Contours

As an alternative to an earlier hypothesis, it may be that the harmful effect of certain modifications to a pattern which would otherwise produce an illusory figure may be due to excessive coincidences that would be present if an illusory figure were to be seen.

Illusory Contours from Pictorially Three-Dimensional Inducing Elements: Counterevidence for Parks and Rock's Example

Perception ◽  
1993 ◽  
Vol 22 (7) ◽  
pp. 809-818 ◽  
Author(s):  
Franco Purghé
Keyword(s):  
Three Dimensional ◽  
Illusory Figure ◽  
Illusory Contours ◽  
Line Elements

In 1990 Parks and Rock claimed that, in pictorially three-dimensional (3-D) inducing patterns, an illusory figure does not emerge if a clear occlusion event is not present. A new pictorially 3-D pattern is presented which contradicts this claim. Two experiments were carried out. The first was aimed at ascertaining the presence of an illusory figure in the new 3-D pattern; the second was aimed at offering evidence that in Parks and Rock's pattern the disappearance of the illusory figure could be due to local interferences caused by the line elements in contact with the inducing borders. The results tend to contradict Parks and Rock's conclusions.

On the Microgenesis of Illusory Figures: A Failure to Replicate

Perception ◽  
1994 ◽  
Vol 23 (7) ◽  
pp. 857-862 ◽  
Author(s):  
Theodore E Parks
Keyword(s):  
Problem Solving ◽  
Viewing Time ◽  
Illusory Figure ◽  
Illusory Contours ◽  
Do So

Reynolds found in 1981 that with increased viewing time of a pattern which may or may not produce illusory contours there were: first, reports of the pattern without an illusory figure; then, at longer exposures, an increase in the frequency with which illusory figures were reported; and then, with still longer exposures, a decrease in such reports if the pattern contained elements which tended to contradict the possibility of such a figure. Unfortunately, however, three attempts to replicate these potentially very important findings—with the aid of substantially improved methodology—consistently failed to do so. It is suggested that this failure, although it is disappointing to those who subscribe to a ‘problem solving’ explanation of illusory contours, may not constitute a strong refutation of such a theory. Regardless, the purpose in the report is to clarify and rectify the published record concerning this part of the evidential underpinnings of that theory.

Amodal Completion versus Induced Inhomogeneities in the Organization of Illusory Figures

Perception ◽  
1992 ◽  
Vol 21 (5) ◽  
pp. 627-636 ◽  
Author(s):  
Marco Davi ◽  
Baingio Pinna ◽  
Marco Sambin
Keyword(s):  
Phenomenological Model ◽  
Control Experiment ◽  
Amodal Completion ◽  
Brightness Contrast ◽  
Primary Factor ◽  
Paired Comparisons ◽  
Illusory Figure ◽  
Illusory Contours ◽  
Energetic Model ◽  
Method Of Paired Comparisons

An analysis is presented of a phenomenological model of illusory contours. The model is based on amodal completion as the primary factor giving rise to the illusory figure. In the experiment, conducted by the method of paired comparisons, the same parameter was manipulated in two series of equivalent configurations. The first series yielded examples of amodal completion, the second examples of illusory figures. Three groups of subjects evaluated the magnitude of completion, the brightness contrast of the illusory figure, and the contour clarity of the illusory figure. A control experiment was conducted, which demonstrated that in these configurations amodal completion and amodal continuation behave in the same way. Line displacement did not influence the brightness or the contour clarity of the illusory figures, though it influenced the magnitude of amodal completion. These results are in agreement with the energetic model developed by Sambin.

Illusory Contours Do Not Capture Stereopsis—They Just Constrain the Depth Spreading

Perception ◽  
1997 ◽  
Vol 26 (1_suppl) ◽  
pp. 182-182
Author(s):  
J Häkkinen ◽  
I Kojo ◽  
M Liinasuo ◽  
G Nyman
Keyword(s):  
Central Area ◽  
Stereoscopic Depth ◽  
Illusory Figure ◽  
Illusory Contours ◽  
Background Texture ◽  
Background Pattern

If vertical cut-out sectors defining a Kanizsa square are given crossed disparity, the illusory figure appears in depth. Such an illusory figure can pull the background pattern inside the illusory figure to the same depth. It has been assumed that illusory contours are necessary for this phenomenon, which is called stereo capture (Ramachandran, 1986 Perception & Psychophysics39 361 – 373). However, we noticed that the vertical cut-out sectors of the inducing figures (‘pacmen’) are not the only structures that can capture the background texture. The rows of background dots that are enclosed between the disparate vertical cut-out sectors also have unambiguous stereoscopic depth. Thus it might be possible that the disparate rows alone capture the background texture. To investigate our hypothesis we created a stereogram in which the inducing figures were removed. It consisted of a dotted background texture and four areas devoid of dots. The dotless areas corresponded to the areas which were occluded by the original inducing figures. Because of this, the top and bottom rows inside the central area were in crossed disparity. According to our results (a) depth capture also occurred without illusory contours; (b) when illusory contours were not present, the depth of the disparate rows spread more often to other areas. Usually the depth spread first to the central area of the figure and after that horizontally to other areas of the figure. Therefore, we conclude that illusory contours do not capture stereopsis—they just constrain the depth spreading.

Human Capital Accumulation and Resource Abundance

2011 ◽  
pp. 66-77
Author(s):  
O. Vasilieva
Keyword(s):  
Economic Growth ◽  
Human Capital ◽  
Capital Accumulation ◽  
Relevant Literature ◽  
Harmful Effect ◽  
Human Capital Accumulation ◽  
Resource Abundance ◽  
Empirical Results ◽  
Theoretical Predictions ◽  
Crowd Out

Does resource abundance positively affect human capital accumulation? Or, alternatively, does it «crowd out» the human capital leading to the deterioration of economic growth? The paper gives an overview of the relevant literature and discusses both theoretical and empirical results obtained regarding the connection between human capital accumulation and resource abundance. It shows that despite some theoretical predictions about the harmful effect of resource abundance on human capital accumulation, unambiguous evidence of such impact that would be robust with respect to the change of resource abundance parameter has not been obtained yet.

Addiction and Liver Disease

2014 ◽  
Vol 25 (2) ◽  
pp. 75-83
Author(s):  
Md Akmat Ali ◽  
Farida Yeasmin ◽  
MN Nag
Keyword(s):  
Liver Disease ◽  
Liver Diseases ◽  
Drug Users ◽  
Harmful Effect ◽  
Main Role ◽  
Drug Induced ◽  
Mortality And Morbidity ◽  
Other Substances ◽  
Excessive Alcohol ◽  
Medicine Today

Drug induced liver disease is a global problem. The aims of the study are to know the recreational drugs causing harmful effect on liver, epidemiology of addiction; pathophysiology and their consequences. The major findings published to date concerning different agents causing addiction and liver disease, their implications with regard to understanding disease mechanisms and their amplitude or spectrum are described. Addiction not only invites lot of sufferings to the family and the country, but also responsible for different types of liver disease including fatty liver, hepatitis and liver failure; responsible for mortality and morbidity. Among the addiction causing substances alcohol playing the main role for liver disease worldwide. Indirect effects of addiction on liver are hepatitis B, hepatitis C and their complication, mainly due to contamination of sharing needle. Majority of people in Bangladesh are life long abstainer. Excessive alcohol beverages and other substances like heroin, amphetamine are not harmless, rather they can cause serious liver diseases. There are some differences in prevalence of addiction and liver diseases among countries. Intravenous drug users are affected both directly and indirectly due to contaminated needle sharing . DOI: http://dx.doi.org/10.3329/medtoday.v25i2.17926 Medicine Today 2013 Vol.25(2): 75-83

Improvement Of The Method Of Winter Concreting With The Use Of Heating Wires

2019 ◽  
pp. 51-58
Keyword(s):  
Harmful Effect ◽  
Electric Heating ◽  
Strength Development ◽  
Construction Sites ◽  
Dominant Position ◽  
Heating Wire ◽  
Hands On ◽  
Basic Parameters ◽  
Monolithic Structures

Long-term experience of application of a method of electric heating by heating wires of the monolithic concrete and reinforced concrete structures erected in winter conditions is analyzed. This method, developed by the author of the article, took a dominant position on the construction sites due to the simplicity and efficiency in comparison with the mass applied in those years, the method of electric heating of concrete with steel round and strip electrodes. The data on labor intensity, material and energy costs in comparison with the method of rod electric heating are presented. Step-by-step technological operations on preparatory works and electric heating of monolithic structures with the use of extensive hands-on material, which formed the basis for the development of technological regulations, supplemented by a number of new proposals to improve the technology of works, are concretized. In order to work out the optimal mode of heat treatment, the studies of the concrete thermal conductivity factor in the process of its heating and strength development were carried out. The method for calculation of the basic parameters of concrete electric heating is presented. For simplification of calculations, for a wide contingent of masters, superintendents and technical personnel, the nomogram , making it possible with sufficient accuracy under the construction conditions to calculate the necessary heating parameters, was developed. The necessity of grounding the heating wire remaining in the concrete to reduce the harmful effect of magnetic radiation from various appliances and household appliances on the human body is noted.

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