scholarly journals The Aftereffects of Müller-Lyer and Ponzo Illusions: Differences Revealed in Sensorimotor Domain

2017 ◽  
Vol 71 (5) ◽  
pp. 352-358
Author(s):  
Vsevolod Lyakhovetskii ◽  
Valeriia Karpinskaia
Keyword(s):  
Visual System ◽  
Visual Illusion ◽  
Ponzo Illusion ◽  
Touch Screen ◽  
Visual Illusions ◽  
Motor Tasks ◽  
Right Hand ◽  
Long Time ◽  
Visual Domain ◽  
Different Levels

Abstract Either effects or aftereffects of visual illusions are well studied at the visual domain while there are few studies of aftereffects at the motor tasks such as grasping or pointing at the illusory. The aftereffects of Müller-Lyer and Ponzo illusions in the sensorimotor domain were studied. We used four illusions: two versions of Müller-Lyer illusions (upper/bottom shafts appear longer) and two versions of Ponzo illusions (classical and inverted, upper/bottom shafts appear longer). They were presented to four experimental groups, each type to one of the groups. A fifth group was shown neutral stimuli (two horizontal lines, one under another). At first, one of the above described stimuli was presented ten times. Then, for testing the aftereffect, the neutral stimuli were presented thirty times. After the disappearance of each stimulus, the participant moved his/her right hand across the touch screen along its upper and lower shafts. The participants of all experimental groups experienced significant illusions, but only the classical Ponzo illusion caused significant long-time assimilative aftereffect. These results reveal the existence of an illusory aftereffect in the sensorimotor domain. Moreover, it depends on the type of visual illusion, thereby supporting the hypothesis of origin of the different visual illusions at different levels of the visual system.

scholarly journals Number is not just an illusion: Discrete numerosity is encoded independently from perceived size

2021 ◽  
Author(s):  
Andrea Adriano ◽  
Luisa Girelli ◽  
Luca Rinaldi
Keyword(s):  
Convex Hull ◽  
Visual System ◽  
Object Segmentation ◽  
Ponzo Illusion ◽  
Visual Illusions ◽  
Continuous Variables ◽  
Discrete Elements ◽  
Comparison Task ◽  
Low Level ◽  
Number Comparison

AbstractWhile seminal theories suggest that nonsymbolic visual numerosity is mainly extracted from segmented items, more recent views advocate that numerosity cannot be processed independently of nonnumeric continuous features confounded with the numerical set (i.e., such as the density, the convex hull, etc.). To disentangle these accounts, here we employed two different visual illusions presented in isolation or in a merged condition (e.g., combining the effects of the two illusions). In particular, in a number comparison task, we concurrently manipulated both the perceived object segmentation by connecting items with Kanizsa-like illusory lines, and the perceived convex-hull/density of the set by embedding the stimuli in a Ponzo illusion context, keeping constant other low-level features. In Experiment 1, the two illusions were manipulated in a compatible direction (i.e., both triggering numerical underestimation), whereas in Experiment 2 they were manipulated in an incompatible direction (i.e., with the Ponzo illusion triggering numerical overestimation and the Kanizsa illusion numerical underestimation). Results from psychometric functions showed that, in the merged condition, the biases of each illusion summated (i.e., largest underestimation as compared with the conditions in which illusions were presented in isolation) in Experiment 1, while they averaged and competed against each other in Experiment 2. These findings suggest that discrete nonsymbolic numerosity can be extracted independently from continuous magnitudes. They also point to the need of more comprehensive theoretical views accounting for the operations by which both discrete elements and continuous variables are computed and integrated by the visual system.

Visual control of orientation behaviour in the fly: Part I. A quantitative analysis

1976 ◽  
Vol 9 (3) ◽  
pp. 311-375 ◽  
Author(s):  
Werner Reichardt ◽  
Tomaso Poggio
Keyword(s):  
Information Processing ◽  
Quantitative Analysis ◽  
Visual System ◽  
Sensory Information ◽  
Model Systems ◽  
Suitable Model ◽  
Logical Organization ◽  
Integrative Level ◽  
Processing Properties ◽  
Different Levels

An understanding of sensory information processing in the nervous system will probably require investigations with a variety of ‘model’ systems at different levels of complexity.Our choice of a suitable model system was constrained by two conflicting requirements: on one hand the information processing properties of the system should be rather complex, on the other hand the system should be amenable to a quantitative analysis. In this sense the fly represents a compromise.In these two papers we explore how optical information is processed by the fly's visual system. Our objective is to unravel the logical organization of the fly's visual system and its underlying functional and computational principles. Our approach is at a highly integrative level. There are different levels of analysing and ‘understanding’ complex systems, like a brain or a sophisticated computer.

scholarly journals Computation of vortex sheet roll-up in the Trefftz plane

1987 ◽  
Vol 184 ◽  
pp. 123-155 ◽  
Author(s):  
Robert Krasny
Keyword(s):  
Mesh Size ◽  
Vortex Sheet ◽  
Smoothing Parameter ◽  
Tip Vortex ◽  
Tip Vortices ◽  
Time Calculation ◽  
Long Time ◽  
Principal Value ◽  
Different Levels ◽  
Good Agreement

Two vortex-sheet evolution problems arising in aerodynamics are studied numerically. The approach is based on desingularizing the Cauchy principal value integral which defines the sheet's velocity. Numerical evidence is presented which indicates that the approach converges with respect to refinement in the mesh-size and the smoothing parameter. For elliptic loading, the computed roll-up is in good agreement with Kaden's asymptotic spiral at early times. Some aspects of the solution's instability to short-wavelength perturbations, for a small value of the smoothing parameter, are inferred by comparing calculations performed with different levels of computer round-off error. The tip vortices’ deformation, due to their mutual interaction, is shown in a long-time calculation. Computations for a simulated fuselage-flap configuration show a complicated process of roll-up, deformation and interaction involving the tip vortex and the inboard neighbouring vortices.

scholarly journals Protein malnutrition in the rat induced by protein-calorie imbalance

1966 ◽  
Vol 20 (3) ◽  
pp. 641-648 ◽  
Author(s):  
T. W. Wikramanayake
Keyword(s):  
Amino Acids ◽  
High Carbohydrate Diet ◽  
The Body ◽  
Carbohydrate Diet ◽  
High Carbohydrate ◽  
Growing Rats ◽  
Low Protein ◽  
Long Time ◽  
Different Levels ◽  
Effect Of Feeding

1. A study has been made of the effect of feeding growing rats for a long time on a low-protein, high-carbohydrate diet given at two different levels of energy. 2. When the proteins of the diet provided o or 5% of the calories the body-weight fell rapidly and fat accumulated in the liver. Addition of carbohydrate (glucose) to the diets increased the amount of fat in the liver. 3. It is suggested that a deficiency of protein retards the synthesis in the liver of lipoproteins required for removal of triglyceride from the liver. Additional carbohydrate diverts amino acids from the amino acid pool to tissues such as muscles, increasing the liver damage.

Archaeology and ideological propaganda in annexed Alsace (1940–1944)

Antiquity ◽  
1999 ◽  
Vol 73 (279) ◽  
pp. 184-190 ◽  
Author(s):  
Jean-Pierre Legendre
Keyword(s):  
Everyday Life ◽  
Archaeological Research ◽  
Long Time ◽  
The Media ◽  
Different Levels

In June 1940, following the signature of the Rethondes armistice, the French province of Alsace was joined to Germany and integrated with the neighbouring German province of Baden, into the Gau Baden-Elsass, later known as Gau Oberrhein. A period of more than four years began, when the Nazi authorities resorted to any means to Germanize the province and its inhabitants as quickly as possible. Various measures were taken as early as 1940, such as a ban on the speaking of French and even the wearing of the Basque beret. Those measures were backed up with the use of propaganda at different levels in everyday life. One of the favourite themes of the media consisted in trying to demonstrate that Alsatians were descendants of ‘Germanic’ populations who settled a long time ago in this country, and that those origins justified their integration into the Reich (FIGURE 1). Local archaeological research was especially favoured by the Nazis to further this theory.

De (on) Verklaarbaarheid Van Fossilisatie

1998 ◽  
Vol 58 ◽  
pp. 101-109
Author(s):  
Elisabeth van der Linden
Keyword(s):  
Learning Process ◽  
Past Tense ◽  
Advanced Learners ◽  
Syntactic Structures ◽  
The Past ◽  
Knowledge Based ◽  
Long Time ◽  
Past Tenses ◽  
Different Levels

In the literature about fossilization, several definitions have been given and several explanations have been suggested for this phenomenon. I see fossilization as a long-time stagnation in the T2 learning process, leading to errors based on transfer. Fossilization is caused by sociolinguistic, pyscholinguistic and purely linguistic factors. In this paper I concentrate on the acquisition of syntactic structures and on the role of input and instruction in that process. I argue that, although in the acquisition of some syntactic structures, UG plays an important role, this does not account for the whole learning process: learners have not only to reset parameters when acquiring T2 but have to proceduralize knowledge based on the surface structure of sentences. In the case of the use of past tenses in French, many of the Dutch advanced learners of three different levels of proficiency do not acquire native-like intuitions about the use of these tenses, although input as well as instruction are thorough on this point. I suggest that the past tense system is not UG-dependent and that the instruction does not allow proceduralization of the knowledge.

Handedness in Relation to Measures of Motor and Tactile-Perceptual Functions in Normal Children

1976 ◽  
Vol 43 (2) ◽  
pp. 475-481 ◽  
Author(s):  
M. Alan J. Finlayson ◽  
Ralph M. Reitan
Keyword(s):  
Educational Attainment ◽  
Full Scale ◽  
Symbol Recognition ◽  
Motor Tasks ◽  
Normal Children ◽  
Right Hand ◽  
The Right ◽  
Right And Left Hands

10 boys and 10 girls were tested at each of six age levels (6, 7, 8, 12, 13, and 14 yr.). All of the children were right-handed, and at each age level the groups did not differ in age, WISC Full Scale IQ, or educational attainment. The groups were compared on motor tasks (strength and speed) and tactile-perceptual tasks (finger localization and symbol recognition). The performances of the right and left hands were compared. The results indicated clear right-hand motor superiority, but no “sidedness” effect for the tactile-perceptual measures. The implication of these results for brain-behaviour relationships was discussed.

Semantics of Hawrami Body Part Terms

2012 ◽  
Vol 16 (3) ◽  
pp. 319-335
Author(s):  
Bistoon Abasi ◽  
Amer Gheitury
Keyword(s):  
Native Speakers ◽  
Body Part ◽  
Field Work ◽  
The Body ◽  
Body Parts ◽  
Human Beings ◽  
Long Time ◽  
Semantic Properties ◽  
Different Levels ◽  
Internal Body

Human body as a universal possession of human beings constitutes an interesting domain where questions regarding semantic categorisations might be sought crosslinguistically. In the following, we will attempt to describe the terms used to refer to the body in Hawrami, an Iranian language spoken in Paveh, a small township in the western province of Kermanshah near Iraqi borders. Due to the scarcity of written material, the inventory of 202 terms referring to external and internal body parts were obtained through a field work, which took a long time, and techniques, such as the “colouring task”, observation and recording the terms as used in ordinary conversations and informal interviews with native speakers. The semantic properties of the terms and the way they are related in a partonymy or locative relationship were also investigated. As far as universals of body part terms are concerned, while conforming to ‘depth principle’ concerning the number of levels each partonomy may consist of, Hawrami violates an important feature of this principle by not allowing transitive relations between different levels of partonomic hierarchies. In addition, Hawrami lacks a term for labelling the ‘whole’.

Long-Time Voice Accumulation During Work, Leisure, and a Vocal Loading Task in Groups With Different Levels of Functional Voice Problems

2017 ◽  
Vol 31 (2) ◽  
pp. 246.e1-246.e10 ◽  
Author(s):  
Susanna Whitling ◽  
Viveka Lyberg-Åhlander ◽  
Roland Rydell
Keyword(s):  
Long Time ◽  
Different Levels

Novel Visual Illusions Related to Vasarely's ‘Nested Squares’ Show That Corner Salience Varies with Corner Angle

Perception ◽  
10.1068/p5383 ◽  
2005 ◽  
Vol 34 (4) ◽  
pp. 409-420 ◽  
Author(s):  
Xoana G Troncoso ◽  
Stephen L Macknik ◽  
Susana Martinez-Conde
Keyword(s):  
Discrimination Task ◽  
Computational Models ◽  
Visual Illusion ◽  
Human Subjects ◽  
Brightness Discrimination ◽  
Receptive Fields ◽  
Visual Illusions ◽  
Corner Angle ◽  
Brightness Discrimination Task ◽  
Sharp Corners

Vasarely's ‘nested-squares’ illusion shows that 90° corners can be more salient perceptually than straight edges. On the basis of this illusion we have developed a novel visual illusion, the ‘Alternating Brightness Star’, which shows that sharp corners are more salient than shallow corners (an effect we call ‘corner angle salience variation’) and that the same corner can be perceived as either bright or dark depending on the polarity of the angle (ie whether concave or convex: ‘corner angle brightness reversal’). Here we quantify the perception of corner angle salience variation and corner angle brightness reversal effects in twelve naive human subjects, in a two-alternative forced-choice brightness discrimination task. The results show that sharp corners generate stronger percepts than shallow corners, and that corner gradients appear bright or dark depending on whether the corner is concave or convex. Basic computational models of center – surround receptive fields predict the results to some degree, but not fully.

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