Serial and Parallel Search in Pattern Vision?

Perception ◽  
1987 ◽  
Vol 16 (3) ◽  
pp. 389-398 ◽  
Author(s):  
Scott B Steinman
Keyword(s):  
Visual Search ◽  
Visual Field ◽  
Reaction Times ◽  
Positional Information ◽  
Human Vision ◽  
The Other ◽  
Parallel Search ◽  
Lateral Separation ◽  
Serial Search ◽  
Initial Results

The nature of the processing of combinations of stimulus dimensions in human vision has recently been investigated. A study is reported in which visual search for suprathreshold positional information—vernier offsets, stereoscopic disparity, lateral separation, and orientation—was examined. The initial results showed that reaction times for visual search for conjunctions of stereoscopic disparity and either vernier offsets or orientation were independent of the number of distracting stimuli displayed, suggesting that disparity was searched in parallel with vernier offsets or orientation. Conversely, reaction times for detection of conjunctions of vernier offsets and orientation, or lateral separation and each of the other positional judgements, were related linearly to the number of distractors, suggesting serial search. However, practice has a significant effect upon the results, indicative of a shift in the mode of search from serial to parallel for all conjunctions tested as well as for single features. This suggests a reinter-pretation of these and perhaps other studies that use the Treisman visual search paradigm, in terms of perceptual segregation of the visual field by disparity, motion, color, and pattern features such as colinearity, orientation, lateral separation, or size.

scholarly journals Attention and the motion after effect: New measurements with visual search reveal important individual differences in adaptability

2018 ◽  
Author(s):  
Michael J. Morgan ◽  
Joshua A. Solomon
Keyword(s):  
Reaction Times ◽  
Visual Pathway ◽  
Human Vision ◽  
The Other ◽  
Test Array ◽  
Mouse Click ◽  
Search Speed ◽  
After Effect ◽  
The One ◽  
Do So

AbstractIt is usually assumed that sensory adaptation is a universal property of human vision. However, in two experiments designed to measure adaptation without bias, we have discovered a minority of participants who were unusual in the extent of their adaptation to motion. One experiment was designed so that targets would be invisible without adaptation; the other, so that adaptation would interfere with target detection. In the first, participants adapted to a spatial array of moving Gabor patches. On each trial the adapting array was followed by a test array in which but all of the test patches except one were identical to their spatially corresponding adaptors; the target moved in the opposite direction to its adaptor. Participants were required to identify the location of the changed target with a mouse click. The ability to do so increased with the number of adapting trials. Neither search speed nor accuracy was affected by an attentionally-demanding conjunction task at the fixation point during adaptation, suggesting low-level (pre-attentive) sites in the visual pathway for the adaptation. However, a minority of participants found the task virtually impossible. In the second experiment the same participants were required to identify the one element in the test array that was slowly moving: reaction times in this case were elevated following adaptation. The putatively weak adapters from the first experiment found this task easier than the strong adapters.

scholarly journals Reliance on central vs. peripheral vision for visual search in younger and older adults

2020 ◽  
Author(s):  
Anne-Sophie Laurin ◽  
Julie Ouerfelli-Éthier ◽  
Laure Pisella ◽  
Aarlenne Zein Khan
Keyword(s):  
Older Adults ◽  
Visual Search ◽  
Peripheral Vision ◽  
Reaction Times ◽  
Central Vision ◽  
Younger Adults ◽  
Serial Search ◽  
Attentional Resources ◽  
Search Tasks ◽  
Fixation Durations

Older adults show declines performing visual search, but their nature is unclear. We propose that it is related to greater attentional reliance on central vision. To investigate this, we tested how occluding central vision would affect younger and older adults in visual search. Participants (14 younger, M = 21.6 years; 16 older, M = 69.6 years) performed pop-out and serial search tasks in full view and with different sized gaze-contingent artificial central scotomas (no scotoma, 3°, 5° or 7° diameter).In pop-out search, older adults showed longer search times for peripheral targets during full viewing. Their reaction times, saccades and fixation durations also increased as a function of scotoma size, contrary to younger adults. These declines may reflect a relative impairment in peripheral visual attention for global processing in aging.In serial search, despite older adults being generally slower, we found no difference between groups in reaction time increases for eccentric targets and for bigger scotomas. These results may come from the difficulty of serial search, in which both groups used centrally limited attentional windows.We conclude that older adults allocate more attentional resources towards central vision compared to younger adults, impairing their peripheral processing primarily in pop-out visual search.

scholarly journals Visual search of illusory contours: an attempt of automatization

Psihologija ◽  
2008 ◽  
Vol 41 (3) ◽  
pp. 295-309 ◽  
Author(s):  
Vasilije Gvozdenovic
Keyword(s):  
Visual Search ◽  
Experimental Research ◽  
Experimental Psychology ◽  
Illusory Contour ◽  
Task Type ◽  
Parallel Search ◽  
Illusory Contours ◽  
Serial Search ◽  
Experimental Trials ◽  
And Task

Laboratory of Experimental Psychology, University of Belgrade Recent research, which was mostly focused on assessing the types of visual search of illusory contours, showed that visual search is dependent on factors like target configuration and task type. Some experimental research supports the theory of parallel search while other research supports the theory of serial search of illusory contours. The inconsistency is most likely due to the fact that various types of illusory contour configurations were used in set creation. Up to this point, our research indicated that the serial search is used in most cases. Some exceptions of search type have been proven in some modification of task type but nevertheless the search profile remained serial. In this article, we are reporting on two visual search experiments. The first experiment was an investigation of a specific feature of a Kanisza type illusory triangle, orientation. The validity of the profile defined in the first experiment was tested in our second experiment with an attempt to automatize the visual search by the multiplication of the initial experimental trials. Our results confirmed that, regardless of the number of experimental trials, the visual search profile remains serial.

Searching for Inefficiency in Visual Search

2015 ◽  
Vol 27 (1) ◽  
pp. 46-56 ◽  
Author(s):  
Gregory J. Christie ◽  
Ashley C. Livingstone ◽  
John J. McDonald
Keyword(s):  
Visual Search ◽  
Visual Field ◽  
Serial Search ◽  
Task Relevance ◽  
Potential Target ◽  
Time Required

The time required to find an object of interest in the visual field often increases as a function of the number of items present. This increase or inefficiency was originally interpreted as evidence for the serial allocation of attention to potential target items, but controversy has ensued for decades. We investigated this issue by recording ERPs from humans searching for a target in displays containing several differently colored items. Search inefficiency was ascribed not to serial search but to the time required to selectively process the target once found. Additionally, less time was required for the target to “pop out” from the rest of the display when the color of the target repeated across trials. These findings indicate that task relevance can cause otherwise inconspicuous items to pop out and highlight the need for direct neurophysiological measures when investigating the causes of search inefficiency.

How Serial is Serial Processing in Vision?

Perception ◽  
1989 ◽  
Vol 18 (2) ◽  
pp. 191-200 ◽  
Author(s):  
Ehud Zohary ◽  
Shaul Hochstein
Keyword(s):  
Visual Search ◽  
Parallel Processing ◽  
Processing Speed ◽  
Processing Time ◽  
Reaction Times ◽  
Stimulus Presentation ◽  
Serial Search ◽  
Serial Processing ◽  
Processing Task ◽  
Serial Scanning

Visual search for an element defined by the conjunction of its colour and orientation has previously been shown to be a serial processing task since reaction times increase linearly with the number of distractor elements used in the display. Evidence is presented that there are parallel processing constituents to this serial search. Processing time depended on the ratio of the number of the two distractor types used, suggesting that only one type was scanned. Which type was scanned also depended on the distractor ratio, indicating that this decision was made after stimulus presentation and was based on a parallel figure—ground separation of the stimulus elements. Furthermore, in accordance with this serial scanning model, there was an increase in processing speed (elements scanned per second) with increase in number of elements to be scanned. This increased efficiency suggests that clumps of elements were processed synchronously. Under the stimulation conditions used, clumps contained six to sixteen elements and each clump was processed in 50–150 ms.

The Dynamics of Perceptual Learning in Different Visual Search Tasks: Psychophysics and Psychophysiology

Perception ◽  
1997 ◽  
Vol 26 (1_suppl) ◽  
pp. 232-232 ◽  
Author(s):  
U Leonards ◽  
R Rettenbach ◽  
R Sireteanu
Keyword(s):  
Visual Search ◽  
Reaction Time ◽  
Error Rate ◽  
Parallel Search ◽  
Additional Line ◽  
Serial Search ◽  
Search Tasks ◽  
Attentional Load ◽  
Skin Response ◽  
Perceptual Changes

Serial visual search can become parallel with practice (Sireteanu and Rettenbach, 1995 Vision Research35 2037 – 2043). Our purpose was to examine whether psychophysiological indices reflect the changes in reaction time during training. We used targets and distractors that differed either in orientation (‘tilt’), or in local brightness: closed circles with or without an additional line element (‘added line’), or circles with gaps of different width (‘gap’). The subjects’ task was to indicate the presence or absence of a target on a computer screen by immediately pressing a button and pointing to the location of the target if the trial was positive, or raise the hand if negative. No feedback was given. Response time and error rate were recorded. In addition, electrocardiograms, galvanic skin response, respiration rate and amplitude, horizontal eye movements, and electromyograms were monitored. Two naive and two experienced subjects participated in at least 16 experimental sessions. Before training, slopes differed for the three tasks, ranging from parallel search for the feature ‘tilt’ to a very steep serial search for the feature ‘gap’. These differences were reflected in the psychophysiological parameters. Reaction time and error rate decreased continuously with learning, leading to parallel search after prolonged practice for all three tasks (see Nase et al, 1995 Perception24 Supplement, 84). Preliminary results indicate that the psychophysiological measures do not follow the perceptual changes during learning. We conclude that, despite the perceptual parallelisation with practice, the attentional load remains high for initially serial tasks.

Varieties of Binocular Interaction in Human Vision

1998 ◽  
Vol 9 (1) ◽  
pp. 53-60 ◽  
Author(s):  
H. C. Hughes ◽  
J. T. Townsend
Keyword(s):  
Lower Bound ◽  
Stereo Vision ◽  
Response Times ◽  
Reaction Times ◽  
Human Vision ◽  
The Other ◽  
Binocular Fusion ◽  
Probability Summation ◽  
Serial Processing ◽  
On And Off Pathways

Binocular processing was investigated using a quantitative, process-oriented metatheory of response times. The analyses are not confined to particular distributional assumptions or specific models. Upper and lower performance boundaries for probability summation in parallel processing are defined and compared with observed distributions of reaction times using a variety of dichoptic stimuli. Performance that exceeds the upper bound strongly suggests facilitatory convergence between the two eyes (binocular channel summation). Performance below the lower bound suggests that inputs to the two eyes are processed serially. The results indicate that binocular channel summation in subjects with normal stereo vision requires targets of the same luminance polarity (paired increments or decrements) in corresponding retinal locations. When corresponding retinal locations are stimulated with opposing luminance polarities (increment to one eye, decrement to the other), performance is consistent with probability summation, indicating that parallel ON and OFF pathways remain segregated at least to the level of binocular fusion. Further analyses of data from a stereo-blind observer suggest serial processing of binocular inputs.

The Effect of Symbol Background Color on the Speed of Locating Targets by Adults Without Disabilities: Implications for Augmentative and Alternative Communication Display Design

2019 ◽  
Vol 4 (6) ◽  
pp. 1482-1488
Author(s):  
Jennifer J. Thistle
Keyword(s):  
Augmentative And Alternative Communication ◽  
Reaction Times ◽  
The Other ◽  
Background Color ◽  
Alternative Communication ◽  
Display Design ◽  
Line Drawings ◽  
Research With Children ◽  
Study Participants ◽  
Perceptual Factors

Purpose Previous research with children with and without disabilities has demonstrated that visual–perceptual factors can influence the speech of locating a target on an array. Adults without disabilities often facilitate the learning and use of a child's augmentative and alternative communication system. The current research examined how the presence of symbol background color influenced the speed with which adults without disabilities located target line drawings in 2 studies. Method Both studies used a between-subjects design. In the 1st study, 30 adults (ages 18–29 years) located targets in a 16-symbol array. In the 2nd study, 30 adults (ages 18–34 years) located targets in a 60-symbol array. There were 3 conditions in each study: symbol background color, symbol background white with a black border, and symbol background white with a color border. Results In the 1st study, reaction times across groups were not significantly different. In the 2nd study, participants in the symbol background color condition were significantly faster than participants in the other conditions, and participants in the symbol background white with black border were significantly slower than participants in the other conditions. Conclusion Communication partners may benefit from the presence of background color, especially when supporting children using displays with many symbols.

Items’ Cross-Category Associations as a Confounding Factor in the Implicit Association Test

2001 ◽  
Vol 48 (2) ◽  
pp. 123-134 ◽  
Author(s):  
Melanie C. Steffens ◽  
Inga Plewe
Keyword(s):  
Implicit Association Test ◽  
Confounding Factor ◽  
Reaction Times ◽  
Association Test ◽  
The Other ◽  
Reaction Time Difference ◽  
Implicit Association ◽  
Male And Female ◽  
Research Activities ◽  
Degree Of Association

Abstract. The introduction of the Implicit Association Test (IAT; Greenwald, McGhee, & Schwartz, 1998 ) has stimulated numerous research activities. The IAT is supposed to measure the degree of association between concepts. Instances have to be assigned to these concepts by pressing appropriate keys as quickly as possible. The reaction time difference between certain conditions, termed the IAT effect, is used as an indicator of the degree of the concepts’ association. We tested the hypothesis that the degree of association between one concept (or category) and the instances of the other presented concept also influences reaction times. In our experiment, the instances in the target categories, male and female names, were kept constant. The adjectives in the evaluative categories were manipulated: Either the pleasant adjectives were female-associated and the unpleasant adjectives were male-associated, or vice versa. These stereotypic associations were indeed found to exert a substantial influence on the size of the IAT effect. This finding casts doubt on the assumption that the IAT effect may be interpreted as a pure measure of the degree of association between concepts.

Visual asymmetries during face encoding Increased dwell time and fixations in the upper and left hemifields

2018 ◽  
Author(s):  
Fatima Maria Felisberti
Keyword(s):  
Face Recognition ◽  
Eye Movements ◽  
Visual Field ◽  
Face Processing ◽  
Dwell Time ◽  
The Other ◽  
Environmental Cues ◽  
Reading Habits ◽  
The Right

Visual field asymmetries (VFA) in the encoding of groups rather than individual faces has been rarely investigated. Here, eye movements (dwell time (DT) and fixations (Fix)) were recorded during the encoding of three groups of four faces tagged with cheating, cooperative, or neutral behaviours. Faces in each of the three groups were placed in the upper left (UL), upper right (UR), lower left (LL), or lower right (LR) quadrants. Face recognition was equally high in the three groups. In contrast, the proportion of DT and Fix were higher for faces in the left than the right hemifield and in the upper rather than the lower hemifield. The overall time spent looking at the UL was higher than in the other quadrants. The findings are relevant to the understanding of VFA in face processing, especially groups of faces, and might be linked to environmental cues and/or reading habits.

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