scholarly journals Grasping Discriminates between Object Sizes Less Not More Accurately than the Perceptual System

Vision ◽  
2019 ◽  
Vol 3 (3) ◽  
pp. 36
Author(s):  
Frederic Göhringer ◽  
Miriam Löhr-Limpens ◽  
Constanze Hesse ◽  
Thomas Schenk
Keyword(s):  
Continuous Variable ◽  
Perceptual System ◽  
Perceptual Task ◽  
Size Discrimination ◽  
Size Information ◽  
Visuomotor Task ◽  
System A ◽  
Dichotomous Variable ◽  
Visual Size ◽  
Maximum Grip

Ganel, Freud, Chajut, and Algom (2012) demonstrated that maximum grip apertures (MGAs) differ significantly when grasping perceptually identical objects. From this finding they concluded that the visual size information used by the motor system is more accurate than the visual size information available to the perceptual system. A direct comparison between the accuracy in the perception and the action system is, however, problematic, given that accuracy in the perceptual task is measured using a dichotomous variable, while accuracy in the visuomotor task is determined using a continuous variable. We addressed this problem by dichotomizing the visuomotor measures. Using this approach, our results show that size discrimination in grasping is in fact inferior to perceptual discrimination therefore contradicting the original suggestion put forward by Ganel and colleagues.

Size Discrimination with Low Spatial Frequencies

Perception ◽  
1982 ◽  
Vol 11 (6) ◽  
pp. 707-720 ◽  
Author(s):  
Robert A Smith
Keyword(s):  
Fourier Spectrum ◽  
Low Frequency ◽  
Current Theory ◽  
Size Perception ◽  
Size Discrimination ◽  
Low Frequencies ◽  
Spatial Frequencies ◽  
Vertical Bars ◽  
The Fourier Transform ◽  
Visual Size

The hypothesis that visual size is determined from the low-frequency Fourier spectrum of the image has been tested in a variety of ways. The fact that size discrimination of vertical bars is unimpaired when high spatial frequencies are filtered out of the image by blurring, and the fact that spatial-frequency adaptation alters perceived size, argue in favor of such hypothesis. However, the hypothesis is weakened by the observation that discrimination is also unimpaired by filtering low frequencies out of the image and by the observation that some manipulations which alter the Fourier transform produce no corresponding perceptual change. No current theory of size perception appears to fit all of these data.

scholarly journals Patient Satisfaction in Outpatient Radiology: Effects of Modality and Patient Demographic Characteristics

2021 ◽  
Vol 8 ◽  
pp. 237437352110496
Author(s):  
Amna A. Ajam ◽  
Bin Xing ◽  
Arham Siddiqui ◽  
Joseph S. Yu ◽  
Xuan V. Nguyen
Keyword(s):  
Patient Satisfaction ◽  
Continuous Variable ◽  
Demographic Variables ◽  
Outpatient Services ◽  
Point Scale ◽  
Contributing Factors ◽  
Demographic Groups ◽  
Dichotomous Variable ◽  
Composite Scores ◽  
Improve Patient

Objective: To characterize predictors of patient satisfaction in outpatient radiology, we examined whether patient satisfaction differs across radiology modalities and demographic groups. Methods: A random sampling of Press-Ganey outpatient services surveys for radiology and non-radiology visits from September 2008 to September 2017 were retrospectively analyzed. Composite scores averaged across all Likert items were analyzed as both a continuous variable and a dichotomous variable of dissatisfaction (defined as ≤3 on the 5-point scale). Results: Among 9983 radiology surveys, mammography had higher composite scores than MRI, CT, radiography, US, and NM/PET (p < 0.001) and lower dissatisfaction (3.9%) than CT (6.7%), MRI (7.3%), and radiography (8.2%). Low-scoring responses were most common in the Facilities domain (7.8%) and least common in Overall Assessment (3.8%). Satisfaction metrics were lowest for ages 20–29 and highest for ages 70–79. Lower dissatisfaction rates were seen among Hispanics (3%) and whites (6%), compared to blacks (10%) and Asians (18%). Conclusion: Significant differences in patient satisfaction were found across imaging modalities and demographic variables. Further investigations to identify contributing factors may help improve patient experiences.

scholarly journals Haptic feedback overrides visual size information during repeated grasping

2015 ◽  
Vol 15 (12) ◽  
pp. 1149
Author(s):  
Carlo Campagnoli ◽  
Evan Cesanek ◽  
Fulvio Domini
Keyword(s):  
Haptic Feedback ◽  
Size Information ◽  
Visual Size

Stereopsis and the Representation of Space

Perception ◽  
1977 ◽  
Vol 6 (3) ◽  
pp. 327-332 ◽  
Author(s):  
Raymond Klein
Keyword(s):  
Dimensional Space ◽  
Three Dimensional ◽  
Normal Subjects ◽  
Picture Plane ◽  
Perceptual System ◽  
System A ◽  
Mental Rotations ◽  
Important Input ◽  
Better Than ◽  
Three Dimensional Space

Four stereoblind and four normal subjects were tested on a mental rotation task. It was hypothesized that, if stereopsis is an important input for building up the perceptual system that represents three-dimensional space, then subjects lacking it ought to be deficient at mental rotations in depth. Stereoblind subjects were equally efficient at picture-plane and depth rotations, and were nonsignificantly better than normal subjects at rotations in depth. It was concluded that in the absence of stereopsis other cues are sufficient for the development of the ‘three-dimensional’ perceptual system. A puzzling paradox was raised, however, by the finding that the introspections of the two groups differed markedly.

scholarly journals Visual information gleaned by observing grasping movement in allocentric and egocentric perspectives

2010 ◽  
Vol 278 (1715) ◽  
pp. 2142-2149 ◽  
Author(s):  
Francesco Campanella ◽  
Giulio Sandini ◽  
Maria Concetta Morrone
Keyword(s):  
Visual Information ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Size Discrimination ◽  
Reach And Grasp ◽  
Visual Size ◽  
Point Light ◽  
Point Light Display ◽  
Active Interaction ◽  
Three Dimensional Space

One of the major functions of vision is to allow for an efficient and active interaction with the environment. In this study, we investigate the capacity of human observers to extract visual information from observation of their own actions, and those of others, from different viewpoints. Subjects discriminated the size of objects by observing a point-light movie of a hand reaching for an invisible object. We recorded real reach-and-grasp actions in three-dimensional space towards objects of different shape and size, to produce two-dimensional ‘point-light display’ movies, which were used to measure size discrimination for reach-and-grasp motion sequences, release-and-withdraw sequences and still frames, all in egocentric and allocentric perspectives. Visual size discrimination from action was significantly better in egocentric than in allocentric view, but only for reach-and-grasp motion sequences: release-and-withdraw sequences or still frames derived no advantage from egocentric viewing. The results suggest that the system may have access to an internal model of action that contributes to calibrate visual sense of size for an accurate grasp.

scholarly journals Real-world size is automatically encoded in preschoolers’ object representations

2018 ◽  
Author(s):  
Bria Long ◽  
Mariko Moher ◽  
Susan Carey ◽  
Talia Konkle
Keyword(s):  
Real World ◽  
Life Experience ◽  
Object Representations ◽  
Item Pair ◽  
The Real ◽  
Size Information ◽  
Similar Item ◽  
Big Picture ◽  
Visual Size ◽  
Stroop Effects

When adults see a picture of an object, they automatically process how big the object typically is in the real world (Konkle &amp; Oliva, 2012a). How much life experience is needed for this automatic size processing to emerge? Here, we ask whether preschoolers show this same signature of automatic size processing. We showed 3- and 4-year-olds displays with two pictures of objects and asked them to touch the picture that was smaller on the screen. Critically, the relative visual sizes of the objects could either be congruent with their relative real-world sizes (e.g., a small picture of a shoe next to a big picture of a car) or incongruent with their relative real-world sizes (e.g., a big picture of a shoe next to a small picture of a car). Across two experiments, we found that preschoolers were worse at making visual size judgments on incongruent trials, suggesting that real-world size was automatically activated and interfered with their performance. In a third experiment, we found that both 4-year-olds and adults showed similar item-pair effects (i.e., showed larger Size-Stroop effects for the pairs of items, relative to other pairs). Furthermore, the magnitude of the item-pair Stroop effects in 4-year-olds did not depend on whether they could recognize the pictured objects, suggesting that the perceptual features of these objects were sufficient to trigger the processing of real-world size information. These results indicate that, by 3–4 years of age, children automatically extract real-world size information from depicted objects.

Cognitive Complexity and Ego Identity in Talented Israeli Adolescent Boys

2001 ◽  
Vol 15 (3) ◽  
pp. 291-301 ◽  
Author(s):  
Shraga Fisherman
Keyword(s):  
Cognitive Complexity ◽  
Continuous Variable ◽  
Ego Identity ◽  
Two Dimensions ◽  
Adolescent Boys ◽  
Moral Issues ◽  
Adolescent Identity ◽  
One Dimensional ◽  
Regular School ◽  
Dichotomous Variable

Ego identity was defined by Erikson as a one-dimensional and continuous variable. The concept was expanded by Marcia, becoming a two-factor dichotomous variable which yields a typology. Tzuriel went a step further, constructing a complex, multi-factor continuous variable. It seems that, in order to consolidate so complex an identity, an adolescent must have many cognitive and combined abilities, such as processing and organization of information, induction and deduction, and decision-making. The assumption underlying the present study is that gifted adolescent boys with high levels of cognitive complexity will have consolidated and complex ego identities. Eighty-five adolescent boys studying at a school for the talented, and 27 adolescent boys studying at a regular school filled out ego identity questionnaires and cognitive complexity questionnaires. The results showed that the talented boys had higher cognitive complexity scores than the others. Furthermore, relative to the regular-school pupils, the talented boys scored higher on two dimensions of ego identity: (a) meaningfulness versus alienation and (b) naturalness and truthfulness. No significant differences were found on the other dimensions of identity. Meaningfulness and truthfulness are the most ideological and central dimensions of male adolescent identity, especially at age 15. At this age, a boy's moral development and interest in moral issues peaks. He is less interested in issues of vocational commitment. This explains why significant differences were found on the two cited dimensions only. There is reason to expect that, at later stages of adolescence differences would be found on additional dimensions of identity.

scholarly journals Context-based Sound and the Ecological Theory of Perception

2017 ◽  
Vol 22 (1) ◽  
pp. 42-50
Author(s):  
David Chapman
Keyword(s):  
Ecological Model ◽  
Ecological Theory ◽  
Analytical Framework ◽  
Perceptual System ◽  
Environmental Sound ◽  
Affective Dimension ◽  
Sonic Art ◽  
System A ◽  
Sonic Environment

This article aims to investigate the ways in which context-based sonic art is capable of furthering a knowledge and understanding of place based on the initial perceptual encounter. How might this perceptual encounter operate in terms of a sound work’s affective dimension? To explore these issues I draw upon James J. Gibson’s ecological theory of perception and Gernot Böhme’s concept of an ‘aesthetic of atmospheres’.Within the ecological model of perception, an individual can be regarded as a ‘perceptual system’: a mobile organism that seeks information from a coherent environment. I relate this concept to notions of the spatial address of environmental sound work in order to explore (a) how the human perceptual apparatus relates to the sonic environment in its mediated form and (b) how this impacts on individuals’ ability to experience such work as complex sonic ‘environments’. Can the ecological theory of perception aid the understanding of how the listener engages with context-based work? In proposing answers to this question, this article advances a coherent analytical framework that may lead us to a more systematic grasp of the ways in which individuals engage aesthetically with sonic space and environment. I illustrate this methodology through an examination of some of the recorded work of sound artist Chris Watson.

Continuous Variable Transmission With an Inertia-Regulating System

2010 ◽  
Vol 132 (5) ◽  
Author(s):  
G. Centeno ◽  
F. Morales ◽  
F. B. Perez ◽  
F. G. Benitez
Keyword(s):  
Angular Velocity ◽  
Power Transmission ◽  
Continuous Variable ◽  
Transmission System ◽  
Computational Simulations ◽  
Efficient Manner ◽  
Additional Degree ◽  
System A ◽  
Continuous Variable Transmission ◽  
Variable Transmission

This article describes a power transmission system applicable to vehicles. It consists of an oscillating, ratcheting-type, continuously variable transmission (CVT) system governed by an inertia mechanism. The inertia-regulating mechanism adds an additional degree of freedom and gives the system a dynamic character. The transmission consists of three different subsystems. The first of these converts the rotation of the engine or motor into an oscillating angular velocity movement and regulates the amplitude of this movement. The oscillating rotation from the first subsystem is used to drive a second subsystem, which acts as a regulating device by means of an inertial mechanism. The oscillating movement at the output of the second subsystem is rectified in the third, resulting in a unidirectional angular velocity. As a result, a unidirectional torque is generated at the output of the CVT, commensurate with the operating condition of the transmission, and this is capable of overcoming a torque resistance. A prototype of this transmission was built and tested to check the experimental results against those predicted by a series of computational simulations. As a result, the experimental graphs that characterize the operation of this type of transmission system were obtained, demonstrating its ability to function in an efficient manner.

scholarly journals A Computable Gaussian Quantum Correlation for Continuous-Variable Systems

Entropy ◽  
2021 ◽  
Vol 23 (9) ◽  
pp. 1190
Author(s):  
Liang Liu ◽  
Jinchuan Hou ◽  
Xiaofei Qi
Keyword(s):  
Quantum Correlation ◽  
Quantum Discord ◽  
Continuous Variable ◽  
Gaussian State ◽  
Product State ◽  
Gaussian States ◽  
System A ◽  
Gaussian Channels ◽  
The Mean ◽  
Gaussian Quantum Discord

Generally speaking, it is difficult to compute the values of the Gaussian quantum discord and Gaussian geometric discord for Gaussian states, which limits their application. In the present paper, for any (n+m)-mode continuous-variable system, a computable Gaussian quantum correlation M is proposed. For any state ρAB of the system, M(ρAB) depends only on the covariant matrix of ρAB without any measurements performed on a subsystem or any optimization procedures, and thus is easily computed. Furthermore, M has the following attractive properties: (1) M is independent of the mean of states, is symmetric about the subsystems and has no ancilla problem; (2) M is locally Gaussian unitary invariant; (3) for a Gaussian state ρAB, M(ρAB)=0 if and only if ρAB is a product state; and (4) 0≤M((ΦA⊗ΦB)ρAB)≤M(ρAB) holds for any Gaussian state ρAB and any Gaussian channels ΦA and ΦB performed on the subsystem A and B, respectively. Therefore, M is a nice Gaussian correlation which describes the same Gaussian correlation as Gaussian quantum discord and Gaussian geometric discord when restricted on Gaussian states. As an application of M, a noninvasive quantum method for detecting intracellular temperature is proposed.

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