scholarly journals Role of symmetry and simplicity in shape disruption perception tasks

Psihologija ◽  
2012 ◽  
Vol 45 (1) ◽  
pp. 5-22 ◽  
Author(s):  
Marija Milisavljevic ◽  
Slobodan Markovic ◽  
Vasilije Gvozdenovic
Keyword(s):  
Visual Search ◽  
Reaction Time ◽  
Visual Perception ◽  
Reaction Times ◽  
Dominant Effect ◽  
Set Size ◽  
Dependent Variables ◽  
Search Experiment ◽  
And Performance

Purpose of the present research was further examination of roles of symmetry and complexity in visual perception tasks. We tested hypothesis from perceptual economy theory, and since we used shape disruptions as one of the stimulus characteristics we could also address Luccio?s two step theory concerning perception of shape disruptions on good forms. Four experiments were conducted, visual search and simultaneous and delayed matching. Symmetry and complexity were varied, as well as set size in visual search experiment. Dependent variables were reaction time and error number. In all four experiments, symmetry had dominant effect, while significant effect of complexity was registered only in Experiment 1. However, in first three experiments interaction of symmetry and complexity was also significant. Analysis of reaction times and performance suggested that our results follow the pattern suggested by perceptual economy, i.e. that symmetry is dominant in easier tasks, while complexity was significant in most difficult task. Our results couldn?t completely support Luccio?s assumption that shape disruption is better perceived on good forms, although it can?t be completely discarded.

Evidence for Attentional Capture by a Surprising Color Singleton in Visual Search

2002 ◽  
Vol 13 (6) ◽  
pp. 499-505 ◽  
Author(s):  
Gernot Horstmann
Keyword(s):  
Visual Search ◽  
Reaction Time ◽  
Target Letter ◽  
Attentional Capture ◽  
Search Task ◽  
Color Singleton ◽  
Conjunction Search ◽  
Feature Search ◽  
Set Size ◽  
And Performance

Three experiments were conducted to investigate whether surprising color singletons capture attention. Participants performed a visual search task in which a target letter had to be detected among distractor letters. Experiments 1 and 2 assessed accuracy as the dependent variable. In Experiment 1, the unannounced presentation of a color singleton 500 ms prior to the letters (and in the same position as the target letter) resulted in better performance than in the preceding conjunction search segment, in which no singleton was presented, and performance was as good in this surprise-singleton trial as in the following feature search segment, in which the singleton always coincided with the target. In contrast, no improvement was observed when the color singleton was presented simultaneously with the letters in Experiment 2, indicating that attentional capture occurred later in the surprise trial than in the feature search segment. In Experiment 3, set size was varied, and reaction time was the dependent variable. Reaction time depended on set size in the conjunction search segment, but not in the surprise trial nor in the feature search segment. The results of the three experiments support the view that surprising color singletons capture attention independently of a corresponding attentional set.

scholarly journals What Can 1 Million Trials Tell Us About Visual Search?

1998 ◽  
Vol 9 (1) ◽  
pp. 33-39 ◽  
Author(s):  
Jeremy M. Wolfe
Keyword(s):  
Retrospective Study ◽  
Visual Search ◽  
Reaction Time ◽  
Search Behavior ◽  
Set Size ◽  
Search Tasks ◽  
Search Processes ◽  
Search Experiment

In a typical visual search experiment, observers look through a set of items for a designated target that may or may not be present. Reaction time (RT) is measured as a function of the number of items in the display (set size), and inferences about the underlying search processes are based on the slopes of the resulting RT x Set Size functions. Most search experiments involve 5 to 15 subjects performing a few hundred trials each. In this retrospective study, I examine results from 2,500 experimental sessions of a few hundred trials each (approximately 1 million total trials). These data represent a wide variety of search tasks. The resulting picture of human search behavior requires changes in our theories of visual search.

scholarly journals Expectancy of Stress-Reducing Aromatherapy Effect and Performance on a Stress-Sensitive Cognitive Task

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Irina Chamine ◽  
Barry S. Oken
Keyword(s):  
Task Performance ◽  
Stress Reduction ◽  
Cognitive Task ◽  
Reaction Times ◽  
Event Related Potentials ◽  
Specific Effects ◽  
N200 Amplitude ◽  
Related Potentials ◽  
And Performance

Objective. Stress-reducing therapies help maintain cognitive performance during stress. Aromatherapy is popular for stress reduction, but its effectiveness and mechanism are unclear. This study examined stress-reducing effects of aromatherapy on cognitive function using the go/no-go (GNG) task performance and event related potentials (ERP) components sensitive to stress. The study also assessed the importance of expectancy in aromatherapy actions.Methods. 81 adults were randomized to 3 aroma groups (active experimental, detectable, and undetectable placebo) and 2 prime subgroups (prime suggesting stress-reducing aroma effects or no-prime). GNG performance, ERPs, subjective expected aroma effects, and stress ratings were assessed at baseline and poststress.Results. No specific aroma effects on stress or cognition were observed. However, regardless of experienced aroma, people receiving a prime displayed faster poststress median reaction times than those receiving no prime. A significant interaction for N200 amplitude indicated divergent ERP patterns between baseline and poststress for go and no-go stimuli depending on the prime subgroup. Furthermore, trends for beneficial prime effects were shown on poststress no-go N200/P300 latencies and N200 amplitude.Conclusion. While there were no aroma-specific effects on stress or cognition, these results highlight the role of expectancy for poststress response inhibition and attention.

EFFECT OF REACTION TRAINING ON DURATION AND REACTION TIMES

2021 ◽  
Vol 7 (27) ◽  
pp. 86-92
Author(s):  
Tülin ATAN
Keyword(s):  
Reaction Time ◽  
Normal Distribution ◽  
Training Program ◽  
Reaction Times ◽  
Rank Test ◽  
Tennis Players ◽  
Before And After ◽  
Speed Performance ◽  
And Performance ◽  
Training Exercises

In this study, it was aimed to examine the effects of reaction training on reaction time and speed in tennis players. For this purpose a total of 18 tennis players; 9 male (age; 13.33 ± 1.80 years) and 7 female (13.85 ± 2.19 years) were voluntarily participated the study. In this study, the reaction training program, which was applied for 2 days a week for 12 weeks, was prepared in addition to tennis training. In the reaction training, exercises suitable for visual and auditory reaction were used. Before and after the 12-week reaction training, a 30 m speed running test and reaction time tests were performed. Whether the data showed normal distribution was analyzed with the Shapiro Wilk test and it was determined that the data did not show normal distribution. Mann Whitney U test was used in comparisons between the two groups. Wilcoxan Signd Rank test was used in the comparisons made before and after the training. As a result of the statistical analysis, it was seen that both the physical characteristics and performance parameters of males and females in our study group were not statistically different (p>0.05). For this reason, all subjects were taken into consideration regardless of gender in comparisons before and after tennis training. After the reaction training program applied to the subjects, it was determined that the 30 m speed performance values were shortened in duration compared to the pre-training period, that is, the speed improved (p <0.01). When the reaction time values were compared before and after the training program applied, it was seen that the reaction time values improved significantly after the training (p <0.01). As a result, reaction training performed in tennis players’ increases speed and reaction time performance. Reaction training is recommended in sports branches where this type of motor is important.

Some Factors Affecting Reaction Times to Auditory Stimuli in Mental Patients

1954 ◽  
Vol 100 (419) ◽  
pp. 462-477 ◽  
Author(s):  
K. R. L. Hall ◽  
E. Stride
Keyword(s):  
Reaction Time ◽  
Visual Perception ◽  
Visual Stimuli ◽  
Reaction Times ◽  
Auditory Stimuli ◽  
Factors Affecting ◽  
Mental Patients ◽  
Personal Equation ◽  
Work Up

A number of studies on reaction time (R.T.) latency to visual and auditory stimuli in psychotic patients has been reported since the first investigations on the personal equation were carried out. The general trends from the work up to 1943 are well summarized by Hunt (1944), while Granger's (1953) review of “Personality and visual perception” contains a summary of the studies on R.T. to visual stimuli.

Effects of Uncertainties of Time and Occurrence on Reaction Time of Mentally Handicapped Students

1981 ◽  
Vol 53 (2) ◽  
pp. 355-360 ◽  
Author(s):  
Paul R. Surburg
Keyword(s):  
Reaction Time ◽  
Reaction Times ◽  
Reaction Time Task ◽  
Mentally Handicapped ◽  
Treatment Groups ◽  
Time Task

The purpose of this study was to determine the effects of uncertainties of time and occurrence on reaction time of mildly handicapped students. 33 students were randomly assigned to the following treatment groups: no catch-trials, 10% catch-trials, and 20% catch-trials. Randomly varied foreperiods of 1.5, 3.0, and 4.5 sec. were used in a reaction time task. The role of catch-trials varied over four days of testing. Reaction times following 3.0- and 4.5-sec. were significantly faster than measurements following a 1.5-sec. foreperiod.

Effect of Attention on the Detection and Identification of Masked Spatial Patterns

Perception ◽  
10.1068/p5276 ◽  
2005 ◽  
Vol 34 (3) ◽  
pp. 305-318 ◽  
Author(s):  
Endel Põder
Keyword(s):  
Visual Search ◽  
Spatial Patterns ◽  
Signal Detection Theory ◽  
Detection Task ◽  
Small Target ◽  
Crowding Effect ◽  
Identification Task ◽  
Set Size ◽  
Detection And Identification ◽  
Search Experiment

The effect of attention on the detection and identification of vertically and horizontally oriented Gabor patterns in the condition of simultaneous masking with obliquely oriented Gabors was studied. Attention was manipulated by varying the set size in a visual-search experiment. In the first experiment, small target Gabors were presented on the background of larger masking Gabors. In the detection task, the effect of set size was as predicted by unlimited-capacity signal detection theory. In the orientation identification task, increasing the set size from 1 to 8 resulted in a much larger decline in performance. The results of the additional experiments suggest that attention can reduce the crowding effect of maskers.

scholarly journals Zinc Removal from ZnO Industrial Wastewater by Hydroxide Precipitation and Coagulation Methods: The Role of pH and Coagulant Dose

2020 ◽  
Vol 11 (2) ◽  
pp. 35-42
Author(s):  
Ratnawati Ratnawati
Keyword(s):  
Reaction Time ◽  
Industrial Wastewater ◽  
Waste Treatment ◽  
Liquid Waste ◽  
Reaction Times ◽  
Quality Standards ◽  
Government Regulations ◽  
Zinc Removal ◽  
Zn Concentration

Liquid waste from the ZnO industry must be treated to meet the quality standards of wastewater into water bodies, according to the Minister of Environment Regulations No.5, 2014. It still contains 79 mg/L of Zn metal, cloudy with turbidity above 500 NTU, and COD value around 222 mg/L. This study aims to determine the effect of pH on reducing Zn metal and the coagulant dose to minimize turbidity and COD in liquid waste produced by the ZnO factory in Depok, West Java. The waste treatment has been carried out by adding alkaline to neutralize the acid conditions in the equalization basin. However, the results have not met the requirements. It is necessary to vary the pH (8.5; 9.0; 9.5; 10.0 and 10.5) to precipitate of Zn optimally, modify the dose of coagulants (50; 100 and 150 mg/L) and reaction times (10; 15 and 20 minutes) to reduce its turbidity and COD concentration. The best results were obtained at a pH of 9.5 with a coagulant dose of 50 mg/L and a reaction time of 10 minutes. This condition can reduce Zn concentration (79 to 3.71 mg/L), turbidity (557 to 1.42 NTU), COD (222 to 68 mg/L) with a removal efficiency of 95.3%; 99.7%; and 69.4% respectively. These values have met the standard requirements according to government regulations.

scholarly journals Interference in Geometrical Stoop like Task among Different Handed Persons

2017 ◽  
Vol 5 (1) ◽  
Author(s):  
Ashwini Kumar
Keyword(s):  
Reaction Time ◽  
Visual Perception ◽  
Congruency Effect ◽  
Visual Fields ◽  
Reaction Times ◽  
Stroop Interference ◽  
Reaction Time Analysis ◽  
Time Analysis ◽  
Interference Condition ◽  
Accuracy Rates

The Geometrical Stroop like task was administered to study the amount of interference in different handed persons in naming geometrical word and their shape when stimuli were presented in two different conditions congruent and incongruent in two visual fields (RVF and LVF). It was hypothesized that, the ability of visual perception can be differing of a person in terms of their handedness. 149 subjects were voluntary participated in this study in which 80 subjects were predominantly Right handed and rest of them were non-right handed, between 17 and 21 years old. Each pair of stimulus was presented for 180msec preceded by a fixation dot for 2000msec. Subjects were asked to respond as fast and as accurately as they could either the geometrical words or the shape or both, depending upon the conditions. Reaction times of correct responses were analyzed. As expected, the results of this study on the basis of Stroop-like experiment give us enough findings in support of hypothesis. The findings of current study indicate that congruency effect in both of the groups. A significantly higher accuracy rates were obtained in non right handed person under the Stroop interference condition. Under this same condition, reaction time analysis yielded also significant differences between two groups.

scholarly journals Learning to search. The importance of eye movements in the decrease of response times during a visual choice reaction time task

2016 ◽  
Vol 9 (5) ◽  
Author(s):  
Aleksandra Kroll ◽  
Monika Mak ◽  
Jerzy Samochowiec
Keyword(s):  
Eye Movements ◽  
Reaction Time ◽  
Choice Reaction Time ◽  
Visual Target ◽  
Response Times ◽  
Reaction Times ◽  
Reaction Time Task ◽  
Visual Tasks ◽  
Target Searching

Reaction times are often used as an indicator of the efficiency of the processes in thecentral nervous system. While extensive research has been conducted on the possibleresponse time correlates, the role of eye movements in visual tasks is yet unclear. Here wereport data to support the role of eye movements during visual choice reaction time training.Participant performance, reaction times, and total session duration improved. Eyemovementsshowed expected changes in saccade amplitude and resulted in improvementin visual target searching.

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