Perceptual Comparison Research Articles

Visual Search Asymmetry Due to the Relative Magnitude Represented by Number Symbols.

In visual search tasks, physically large target stimuli are more easily identified among small distractors than are small targets among large distractors. The present study extends this finding by presenting preliminary evidence of a new search asymmetry: stimuli that symbolically represent larger magnitude are identified more easily among featurally equivalent distractors that represent smaller magnitude. Participants performed a visual search task using line-segment digits representing the numbers 2 and 5, and the numbers 6 and 9, as well as comparable non-numeric control stimuli. In three experiments, we found that search times are faster when the target is a digit that represents a larger magnitude than the distractor, although this pattern was not evident in one additional experiment. The results provide suggestive evidence that the magnitude of a number symbol can affect perceptual comparisons between number symbols, and that the semantic meaning of a target stimulus can systematically affect visual search.

Videogame and Computer Intervention Effects on Older Adults' Mental Rotation Performance.

Objective: This article examined older adults' performance on two components of a mental rotation task (reaction time and rotation rate) in a home-based intervention study of videogame (Crazy Taxi [CT]) and computerized cognitive training (PositScience InSight). Materials and Methods: Participants were randomized to one of three groups: one group played an off-the-shelf videogame (i.e., CT), the second group engaged in a computerized training program focused on fast perceptual comparisons, visuospatial working memory, rapid scanning of a visual array and pattern recognition, visual discrimination, and selective and divided attention and processing speed (i.e., InSight), and the third (control) group received no training. Training in the two intervention conditions consisted of 60 training sessions of 1 hour each, which were completed in 3 months (5 hours a week). As part of a larger study, participants received mental rotation testing, which was administered immediately before (baseline), after (post-test), and 3 months after (follow-up) training. Results: Although the InSight group showed greater improvements in rotation rate at the immediate post-test, by the 3-month follow-up, the combined treatment groups (CT and InSight) had improved more than controls. Conclusion: The improvements in mental rotation performance found at 3-month follow-up add additional support to previous research, showing visuospatial benefits of both videogame play and cognitive training in older adults. Common elements of both interventions may include expansion of the attentional field of view and faster visual comparison efficiency.

Performance, perceptual and physiological comparison of traditional and small-sided games in youth hockey

This study aimed to determine if children playing field hockey small-sided games (SSG) have different levels of physiological, performance and perceptual responses, compared to traditional hockey. Fifteen school hockey players (10–12 y) played eight matches over four months. Traditional games (n = 4) were played on a full-sized pitch with 11 players per team, and SSG were played as two-separate games (n = 8), with 7 players per team on a half-field pitch. Heart rate, movement data and match involvement were collected during the game. Participants were asked their session rating of perceived exertion (sRPE) and completed an enjoyment questionnaire. There were more possessions per player in the SSG format compared to traditional (53.9 ± 2.5 vs. 36.8 ± 6.5, [ d = 3.83]). Number of shots on goal, total goals, penalty corners and circle penetrations were increased in SSG compared to traditional games ( d = 1.11–1.83). Mean and maximum heart rate, sRPE, enjoyment, total distance run, meters per minute, distance run at low velocity and high velocity were similar for both formats, with no significant difference between them. SSG increased match involvements, allowing more participation than the traditional format, without compromising the physiological (e.g. heart rate), performance (e.g. total distance) and perceptual (e.g. sRPE) workload.

Preliminary Validation of the Global Neuropsychological Assessment in Alzheimer's Disease and Healthy Volunteers.

We administered the Global Neuropsychological Assessment (GNA), an abbreviated cognitive battery, to 105 adults aged 73.0 ± 7.1 years, including 28 with probable Alzheimer's disease, 9 with amnestic mild cognitive impairment, and 68 healthy controls. We examined group differences in baseline performance, test-retest reliability, and correlations with other conventional tests. Healthy adults outperformed patients on all five GNA subtests. Test-retest intraclass correlation coefficients were significant for all GNA subtests. Among patients with healthy controls, GNA Story Memory correlated best with Wechsler Memory Scale-Revised (WMS-R) Logical Memory for learning and delayed recall, GNA Digit Span correlated most highly with the Wechsler Adult Intelligence Scale-Third Edition (WAIS-III) Digit Span, GNA Perceptual Comparison correlated most highly with the Trail Making Test, and GNA Animal Naming correlated most highly with Supermarket Item Naming. Preliminary findings suggest that the GNA shows good test-retest validity, clear convergent and discriminant construct validity, and excellent diagnostic criterion validity for dementia and mild cognitive impairment in an American sample.

Toward realistic binaural auralizations – perceptual comparison between measurement and simulation-based auralizations and the real room for a classroom scenario

In order to make full use of their potential to replace experiments in real rooms, auralizations must be as realistic as possible. Recently, it has been shown that for speech, head-tracked binaural auralizations based on measured binaural room impulse responses (BRIRs) can be so realistic, that they become indistinguishable (or nearly so) from the real room [1, 2]. In the present contribution, perceptual comparisons between the auralized and the real room are reported for auralizations based both on measured and simulated BRIRs. In the experiment, subjects sitting in the real room rated the agreement between the real and the auralized room with respect to a number of attributes. The results indicate that for most attributes, the agreement between the auralized and the real room can be very convincing (better than 7.5 on a nine-point scale). This was not only observed for auralizations based on measured BRIRs, but also for those based on simulated BRIRs. In the scenario considered here, the use of individual head-related impulse responses (HRIRs) does not seem to offer any benefit over using HRIRs from a head-and-torso-simulator.

Residual Augmented Attentional U-Shaped Network for Spectral Reconstruction from RGB Images

Deep convolutional neural networks (CNNs) have been successfully applied to spectral reconstruction (SR) and acquired superior performance. Nevertheless, the existing CNN-based SR approaches integrate hierarchical features from different layers indiscriminately, lacking an investigation of the relationships of intermediate feature maps, which limits the learning power of CNNs. To tackle this problem, we propose a deep residual augmented attentional u-shape network (RA2UN) with several double improved residual blocks (DIRB) instead of paired plain convolutional units. Specifically, a trainable spatial augmented attention (SAA) module is developed to bridge the encoder and decoder to emphasize the features in the informative regions. Furthermore, we present a novel channel augmented attention (CAA) module embedded in the DIRB to rescale adaptively and enhance residual learning by using first-order and second-order statistics for stronger feature representations. Finally, a boundary-aware constraint is employed to focus on the salient edge information and recover more accurate high-frequency details. Experimental results on four benchmark datasets demonstrate that the proposed RA2UN network outperforms the state-of-the-art SR methods under quantitative measurements and perceptual comparison.

The basis of report-difference superiority in delayed perceptual comparison tasks.

A major role for visual short-term memory (VSTM) is to mediate perceptual comparisons of visual information across successive glances and brief temporal interruptions. Research that has focused on the comparison process has noted a marked tendency for performance to be better when participants are required to report a difference between the displays rather than report the absence of a difference (i.e. a sameness). We refer to this performance asymmetry as report-difference superiority (RDS). It has been suggested that RDS reflects the operation of a reflexive mechanism that generates a mismatch signal during the comparison of visual input with information maintained in VSTM. This bottom-up mechanism therefore gives evidence for the presence of a feature change but not for the absence of such a change; consequently, a sameness is harder to detect than a difference between two displays. We test this explanation, and determine whether by itself it is a sufficient explanation of the RDS. In a delayed comparison task we find the RDS effect is most prevalent when items retain the same display locations; however, the effect does persist even when compared item locations were scrambled across memory and test arrays. However, with a conjunction task this scrambling of locations was effective in wholly abolishing the RDS effect. We consider that the RDS effect is a consequence of local comparisons of features, as well as global statistical comparisons.

Methodology for development of airborne sound insulation descriptor valid for light-weight and masonry walls

Evaluating the adequacy of single number quantities that are used to assess the sound insulation performance of walls by listening tests is hampered by the difficulty to perform large numbers of subjective tests, due to the need for combining many stimuli, each representing different source/wall combinations. In this article, this problem is tackled by an alternative approach that makes use of Loudness based validation of proposed single number quantities. The adequacy of the newly proposed method was assessed by comparing wall rankings based on Loudness on one hand, and on laboratory listening tests on the other hand. Perceptual comparison of sounds passing through different types of walls between dwellings was performed by a listening test procedure that focused on differences in perception of sound insulation of a set of real-life heavy weight (HW) and light weight walls (LW), and synthetic variants of those. The latter were upshifted or downshifted versions of real wall insulation spectra. The listening tests were based on a three-alternative forced-choice testing method. Altogether, 40 test subjects with normal hearing ability were asked to rate the loudness of sounds transmitted through different walls, which were simulated by filtering a set of real-life sound stimuli. The resulting ranking of walls in order of isolation performance was compared with rankings based on the Loudness of the transmitted sound, and on the value of single-number quantities, that are commonly used for objective evaluation of the sound insulation i.e., Rw and Rw + C50–5000. Special attention was given to the weight of low frequency isolation values in the subjective assessment and in the calculation of the single number quantities. Two new single-number quantities, Rmod and Rmod,2 are proposed, which are found to fit better to subjective perception of sound insulation than the investigated existing quantities.

Policies or knowledge: priors differ between a perceptual and sensorimotor task.

If the brain abstractly represents probability distributions as knowledge, then the modality of a decision, e.g., movement vs. perception, should not matter. If, on the other hand, learned representations are policies, they may be specific to the task where learning takes place. Here, we test this by asking whether a learned spatial prior generalizes from a sensorimotor estimation task to a two-alternative-forced choice (2-Afc) perceptual comparison task. A model and simulation-based analysis revealed that while participants learn prior distribution in the sensorimotor estimation task, measured priors are consistently broader than sensorimotor priors in the 2-Afc task. That the prior does not fully generalize suggests that sensorimotor priors are more like policies than knowledge. In disagreement with standard Bayesian thought, the modality of the decision has a strong influence on the implied prior distributions. NEW & NOTEWORTHY We do not know whether the brain represents abstract and generalizable knowledge or task-specific policies that map internal states to actions. We find that learning in a sensorimotor task does not generalize strongly to a perceptual task, suggesting that humans learned policies and did not truly acquire knowledge. Priors differ across tasks, thus casting doubt on the central tenet of many Bayesian models, that the brain's representation of the world is built on generalizable knowledge.

Testing of an assistive robot system for haptic exploration of objects

ABSTRACTIntroduction: When children with physical impairments cannot perform hand movements for haptic exploration, they may miss opportunities to learn the properties of objects. Assistive robots may enable them to make manipulation actions. Objective: To examine the differences between using a robotic teleoperation system with haptic feedback and manual exploration when making perceptual comparisons about object properties. Accuracy and exploratory procedures (EP) using the system were compared to those in manual exploration. Method: Twenty adults without physical disabilities and ten typically developing children manipulated four pairs of objects and chose one based on size, roughness, hardness and shape. All participants completed the task with the robotic system (Tech) and manual exploration (No Tech), with the order counterbalanced. Results and conclusion: Participants performed a previously unidentified EP, “tapping”, in the Tech condition. Enclosure was not possible with the robot end effector, but tapping afforded the required perceptual information. Adults’ perceptual comparisons were always accurate and they predominantly performed the optimum EP in both conditions. Even when children performed the optimum EP with the system, their answers were less accurate than with manual exploration. Most gave the correct answer, except for hardness, which was likely due to mechanical flexibility in the robotic system.

Face to Face: Evaluating Visual Comparison.

Data are often viewed as a single set of values, but those values frequently must be compared with another set. The existing evaluations of designs that facilitate these comparisons tend to be based on intuitive reasoning, rather than quantifiable measures. We build on this work with a series of crowdsourced experiments that use low-level perceptual comparison tasks that arise frequently in comparisons within data visualizations (e.g., which value changes the most between the two sets of data?). Participants completed these tasks across a variety of layouts: overlaid, two arrangements of juxtaposed small multiples, mirror-symmetric small multiples, and animated transitions. A staircase procedure sought the difficulty level (e.g., value change delta) that led to equivalent accuracy for each layout. Confirming prior intuition, we observe high levels of performance for overlaid versus standard small multiples. However, we also find performance improvements for both mirror symmetric small multiples and animated transitions. While some results are incongruent with common wisdom in data visualization, they align with previous work in perceptual psychology, and thus have potentially strong implications for visual comparison designs.

Ratios and differences in perceptual comparison: A reexamination of Torgerson’s conjecture

How do we compare stimuli that vary in magnitude? According to a well-known conjecture by Torgerson (1961), observers perceive only a single relation between stimuli, that is either a ratio or difference, but which one cannot be determined empirically. Previous research has used direct scaling procedures in which observers have judged ratios and differences numerically, but with mixed results. We used a novel behavioral task in which observers learned to produce non-symbolic ratios and differences by feedback and without explicit instruction. In two sets of experiments, observers viewed pairs of stimuli that varied in brightness, number of dots, or circle areas, and responded by clicking along a bar. Feedback was provided based on either the stimulus ratios or differences and the response location. Observers produced ratios and differences accurately, with average individual correlations of r=.94 and .95 across experiments, respectively. Regressions showed that responding was controlled jointly by ratios and differences, with the untrained relation predicting significant variance in approximately half of individual cases. Results were further supported by rank-order analyses, non-metric scaling analyses, and Monte Carlo simulations. Although Torgerson’s conjecture was originally proposed in explicit tasks in which observers were required to use their mathematical knowledge, our results show that the perceptual system automatically computes both differences and ratios when comparing stimuli in a non-symbolic, implicit learning task. Thus Torgerson’s conjecture, as applied to our task, is fundamentally false. Evidence for two operations rather than one suggests that the perceptual system might represent elements of an algebraic field, which could support adaptive behavior such as spatial navigation that appears to be computationally complex.

Endoscopic Partial Arytenoidectomy for Bilateral Vocal Fold Paralysis: Medially Based Mucosal Flap Technique

Endoscopic partial arytenoidectomy (EPA) is one of the static operations for treatment of bilateral vocal fold paralysis (BVFP). Improvement in airway may cause voice loss and aspiration. The author reports his experience on EPA using medially based mucosal flap to enlarge posterior glottis without removing any part of membranous vocal fold. Sixty-four consecutive patients with BVFP underwent EPA. Pre- and postoperative evaluations included Voice Handicap Index-30, aerodynamic and acoustic analysis, flow volume loops, perceptual evaluation of pre- and postoperative voice using grade, roughness, breathiness, asthenia, strain (GRBAS) scale, speech intensity, breathing ability evaluation, and functional outcome swallowing scale. Nine patients had preoperative tracheotomy and one patient required postoperative tracheotomy. All tracheotomized patients were decannulated 1 month after surgery. Fifty-six patients (88%) did not report dyspnea in their daily activities and were considered satisfied with their postoperative airway; eight patients required revision: seven total arytenoidectomy and one posterior cricoid split with costal cartilage grafting. All Voice Handicap Index-30 results and all acoustic results (except fundamental frequency) increased significantly after surgery (P < 0.05). All aerodynamic analysis results (except mean airflow rate) decreased significantly after EPA (P < 0.05). Mean airflow rate increased significantly after EPA (P < 0.05). All flow volume loop parameters increased significantly after EPA (P < 0.05). Perceptual comparison of pre- and postoperative voice revealed similar grade and roughness (P > 0.05); however, increased breathiness (P < 0.05) was observed. Mean speech intensity decreased from 67 dB to 61 dB (P < 0.05). Postoperative breathing ability was significantly better. Pre- and postoperative functional outcome swallowing scales were not significantly different (P > 0.05). EPA is a very successful static surgical option for BVFP. It results in comfortable airway with mild voice handicap. Postoperatively, it does not increase aspiration significantly. Endoscopic total arytenoidectomy is reserved for revision of failures.

Interactive Generation of Time‐evolving, Snow‐Covered Landscapes with Avalanches

AbstractWe introduce a novel method for interactive generation of visually consistent, snow‐covered landscapes and provide control of their dynamic evolution over time. Our main contribution is the real‐time phenomenological simulation of avalanches and other user‐guided events, such as tracks left by Nordic skiing, which can be applied to interactively sculpt the landscape. The terrain is modeled as a height field with additional layers for stable, compacted, unstable, and powdery snow, which behave in combination as a semi‐viscous fluid. We incorporate the impact of several phenomena, including sunlight, temperature, prevailing wind direction, and skiing activities. The snow evolution includes snow‐melt and snow‐drift, which affect stability of the snow mass and the probability of avalanches. A user can shape landscapes and their evolution either with a variety of interactive brushes, or by prescribing events along a winter season time‐line. Our optimized GPU‐implementation allows interactive updates of snow type and depth across a large (10 × 10 km) terrain, including real‐time avalanches, making this suitable for visual assets in computer games. We evaluate our method through perceptual comparison against exiting methods and real snow‐depth data.

Perceptual Comparison of Source-Code Plagiarism within Students from UK, China, and South Cyprus Higher Education Institutions

Perspectives of students on what constitutes source-code plagiarism may differ based on their educational background. Surveys have been conducted with home students undertaking computing and joint computing subject degrees at higher education institutions throughout the UK, China, and South Cyprus, and a total of 984 responses have been statistically analysed to determine the common areas of understanding and misunderstanding among students on various topics related to source-code plagiarism. The study identifies those topics which are well understood, and those topics which are not properly understood across the different groups of students, and is the first study which specifically discusses Cypriot student perceptions on source-code plagiarism. This study provides useful information to educators (teaching home and international students) who wish to better inform their students on the issues of plagiarism and source-code plagiarism. Finally, the survey results revealed that although students who were informed about plagiarism better understood what actions constitute plagiarism, some topics were still unclear among students regardless of the students’ educational background and whether they had been previously informed about plagiarism.

Maximum likelihood difference scales represent perceptual magnitudes and predict appearance matches.

One central problem in perception research is to understand how internal experiences are linked to physical variables. Most commonly, this relationship is measured using the method of adjustment, but this has two shortcomings: The perceptual scales that relate physical and perceptual variables are not measured directly, and the method often requires perceptual comparisons between viewing conditions. To overcome these problems, we measured perceptual scales of surface lightness using maximum likelihood difference scaling, asking observers only to compare the lightness of surfaces presented in the same context. Observers were lightness constant, and the perceptual scales qualitatively and quantitatively predicted perceptual matches obtained in a conventional adjustment experiment. Additionally, we show that a contrast-based model of lightness perception predicted 98% of the variance in the scaling and 88% in the matching data. We suggest that the predictive power was higher for scales because they are closer to the true variables of interest.

Physical and Perceptual Comparison of Real and Focused Sound Sources in a Concert Hall

Physical and Perceptual Comparison of Real and Focused Sound Sources in a Concert Hall

The influence of posterior visual pathway damage on visual information processing speed in multiple sclerosis

Background: The injury of visual pathway and abnormalities of visual processing speed (VPS) are frequent in MS, but their association remains unexplored. Objective: To evaluate the impact of posterior visual pathway structural and functional integrity on VPS of MS patients. Methods: Cross-sectional study of 30 MS patients and 28 controls, evaluating the association of a VPS tests composite (Salthouse Perceptual Comparison test, Trail Making Test A and Symbol Digit Modalities Test) with 3T MRI visual cortex thickness, optic radiations (OR) diffusion tensor imaging indexes, and medial visual component (MVC) functional connectivity (FC) (MVC-MVC FC (iFC) and MVC-brain FC (eFC)) by linear regression, removing the effect of premorbid IQ, fatigue, and depression. Results: V2 atrophy, lower OR fractional anisotropy (FA) and MVC FC significantly influenced VPS in MS (at none or lesser extent in controls), even after removing the effect of Expanded Disability Status Scale and previous optic neuritis (V2 (r2 = 0.210): β = +0.366, p = 0.046; OR FA (r2 = 0.243): β = +0.378, p = 0.034; MVC iFC, for example, left cuneus (r2 = 0.450): β = −0.613, p < 0.001; MVC eFC, for example, right precuneus-postcentral gyrus (r2 = 0.368): β = −0.466, p = 0.002). Conclusion: Posterior visual pathway integrity, structural (V2 thickness and OR FA) and functional (MVC FC), may explain respectively up to 24% and 45% of VPS variability in MS.

Real‐time video chroma keying: a parallel approach based on local texture and global colour distribution

This study presents an automatic, human perception based chroma-keying algorithm that extracts the objects of interest (i.e. foreground) from monochromatic background. Given an image to be chroma keyed, the global colour distribution and the local texture property are analysed in CIECAM02 colour appearance model. After the analysis, input image is automatically segmented into three parts: foreground, background, and uncertain regions. Afterwards, the background colour is propagated from known background to uncertain region by using interpolation functions; and the foreground colour is estimated based on global colour distribution and a linear cost criteria. The quantitative and perceptual comparisons on the matting results show that the proposed method can reliably remove the background region, correctly restore the intrinsic foreground colour, and accurately keep the fine details. In addition, the authors implement the proposed method on a heterogeneous parallel computing architecture which efficiently distributes the workload among different processors. The simulation results show that the foreground objects can be accurately extracted from high-definition and/or ultra-high-definition videos in real time.

Objective and perceptual comparisons of two bluetooth hearing aid assistive devices

Purpose: With the advent of Bluetooth technology, many of the assistive listening devices for hearing have become manufacturer specific, with little objective information about the performance provided.Method: Thirty native English-speaking adults (mean age 29.8) with normal hearing were tested pseudo-randomly with two major hearing aid manufacturers’ proprietary Bluetooth connectivity devices paired to the accompanying manufacturer’s specific hearing aids. Sentence recognition performance was objectively measured for each system with signals transmitted via a land-line to the same iPhone in two conditions.Results: There was a significant effect of participant’s performance according to listening condition. There was no significant effect between device manufacturers according to listening condition, but there was a significant effect in participant’s perception of “quality of sound”.Conclusions: Despite differences in signal transmission for each devise, when worn by participants both the systems performed equally. In fact, participants expressed personal preferences for specific technology that was largely due to their perceived quality of sound while listening to recorded signals. While further research is necessary to investigate other measures of benefit for Bluetooth connectivity devices, preliminary data suggest that in order to ensure comfort and compatibility, not only should objective measures of the patient benefit be completed, but also assessing the patient’s perception of benefit is equally important.Implications for RehabilitationAll professionals who work with individuals with hearing loss, become aware of the differences in the multiple choices for assistive technology readily available for hearing loss.With the ever growing dispensing of Bluetooth connectivity devices coupled to hearing aids, there is an increased burden to determine whether performance differences could exist between manufacturers.There is a growing need to investigate other measures of benefit for Bluetooth hearing aid connectivity devices that not only include objective measures, but also patient perception of benefit.