Visual and acoustic confusability a visual search task

Visual and acoustic confusability between a target item and background items was varied in a visual search task. Visual confusability was a highly significant source of difficulty while acoustic confusability had no effect. The results do not seem to be interpretable within a theory which assumes compulsory auditory encoding of visual information.     

Visual and acoustic confusability a visual search task

Visual and acoustic confusability between a target item and background items was varied in a visual search task. Visual confusability was a highly significant source of difficulty while acoustic confusability had no effect. The results do not seem to be interpretable within a theory which assumes compulsory auditory encoding of visual information.     

Global statistical learning in a visual search task

Locating a target in a visual search task is facilitated when the target location is repeated on successive trials. Global statistical properties also influence visual search, but have often been confounded with local regularities (i.e., target location repetition). In two experiments, target locations were not repeated for four successive trials, but with a target location bias (i.e., the target appeared on one half of the display twice as often as the other). Participants quickly learned to make more first saccades to the side more likely to contain the target. With item-by-item search first saccades to the target were at chance. With a distributed search strategy first saccades to a target located on the biased side increased above chance. The results confirm that visual search behavior is sensitive to simple global statistics in the absence of trial-to-trial target location repetitions.     

An informational analysis of a visual search task

An earlier paper examined a visual-search task that required a S to locate a two-digit symbol from an array of digits. The results were not subjected to a detailed theoretical analysis. The present paper suggests an information-theory analysis of the data and shows that all of the data can be reduced to a consistent format. It is also argued that such an analysis may prove fruitful in the investigation of search strategies.     

Feature or location? Infants and adults adopt different strategies to search for a hidden toy in an ambiguous task

Evidence suggests that infants and adults attribute different importance to certain object properties when performing object-directed actions. Namely, infants tend to rely on information about an object's location, whereas adults are more likely to base their actions on its features. In this study, we tested whether the strategic choices of infants (aged 13 months) and adults would be modified by the context of the demonstration. Participants watched as an experimenter hid a ball under one of two different coloured containers, using either a communicative or a non-communicative manner. Then, the locations of the two containers were changed out of sight of the participant. During the test, participants were encouraged to look for the ball under one of the containers. We found that adults were more likely to follow a feature-based strategy than infants. However, there was no effect of the context of the demonstration, suggesting that communication may play different roles in encoding object properties and directing overt behaviour.     

Attention capacity and task difficulty in visual search

When a visual search task is very difficult (as when a small feature difference defines the target), even detection of a unique element may be substantially slowed by increases in display set size. This has been attributed to the influence of attentional capacity limits. We examined the influence of attentional capacity limits on three kinds of search task: difficult feature search (with a subtle featural difference), difficult conjunction search, and spatial-configuration search. In all 3 tasks, each trial contained sixteen items, divided into two eight-item sets. The two sets were presented either successively or simultaneously. Comparison of accuracy in successive versus simultaneous presentations revealed that attentional capacity limitations are present only in the case of spatial-configuration search. While the other two types of task were inefficient (as reflected in steep search slopes), no capacity limitations were evident. We conclude that the difficulty of a visual search task affects search efficiency but does not necessarily introduce attentional capacity limits.     

Stimulus segmentation in the visual search task

Four experiments were conducted in order to study the segmentation process in a visual search task with relevant stimuli (target and distractors) randomly distributed among textural elements. The basic idea was that a parallel segmentation process of the relevant stimuli would contribute to the overall reaction time independently of the contribution of the number of relevant stimuli. In the first experiment, with relevant stimuli and textural elements that differed in the orientation of their component lines, texture presence interacted with number of relevant stimuli and with target presence. These results were not favorable to the parallel segmentation hypothesis. In the second and third experiments, in which the relevant and the textural stimuli differed in orientation and in the luminance contrast of their component lines, the results support a parallel segmentation process for the higher contrast conditions. In these experiments, the effect of texture presence was greater on target-absent than on target-present trials. Experiment 4 shows that the search can be restricted to the high-contrast relevant stimuli when the number of these stimuli is constant and the number of textural stimuli changes from trial to trial. The present results suggest that the relevant stimuli can be segmented in parallel and then submitted to a restricted analysis, even when they are scattered among textural stimuli.     

You detect while I search: examining visual search efficiency in a joint search task

Numerous factors impact attentional allocation, with behaviour being strongly influenced by the interaction between individual intent and our visual environment. Traditionally, visual search efficiency has been studied under solo search conditions. Here, we propose a novel joint search paradigm where one individual controls the visual input available to another individual via a gaze contingent window (e.g., Participant 1 controls the window with their eye movements and Participant 2 – in an adjoining room – sees only stimuli that Participant 1 is fixating and responds to the target accordingly). Pairs of participants completed three blocks of a detection task that required them to: (1) search and detect the target individually, (2) search the display while their partner performed the detection task, or (3) detect while their partner searched. Search was most accurate when the person detecting was doing so for the second time while the person controlling the visual input was doing so for the first time, even when compared to participants with advanced solo or joint task experience (Experiments 2 and 3). Through surrendering control of one’s search strategy, we posit that there is a benefit of a reduced working memory load for the detector resulting in more accurate search. This paradigm creates a counterintuitive speed/accuracy trade-off which combines the heightened ability that comes from task experience (discrimination task) with the slower performance times associated with a novel task (the initial search) to create a potentially more efficient method of visual search.     

Sit-and-wait strategies in dynamic visual search

The role of memory in visual search has lately become a controversial issue. Horowitz and Wolfe (1998) observed that performance in a visual search task was little affected by whether the stimuli were static or randomly relocated every 111 ms. Because a memory-based mechanism, such as inhibition of return, would be of no use in the dynamic condition, Horowitz and Wolfe concluded that memory is likewise not involved in the static condition. However, Horowitz and Wolfe could not effectively rule out the possibility that observers adopted a different strategy in the dynamic condition than in the static condition. That is, in the dynamic condition observers may have attended to a subregion of the display and waited for the target to appear there (sit-and-wait strategy). This hypothesis is supported by experimental data showing that performance in their dynamic condition does not differ from performance in another dynamic condition in which observers are forced to adopt a sit-and-wait strategy by being presented with a limited region of the display only.     

Precuing benefits for color and location in a visual search task

Selection in multiple-item displays has been shown to benefit immensely from advance knowledge of target location (e.g., Henderson, 1991), leading to the suggestion that location is completely dominant in visual selective attention (e.g., Tsal & Lavie, 1993). Recently, direct selection by color has been reported in displays in which location does not vary (Vierck & Miller, 2005). The present experiment investigated the possibility of independent selection by color in a task with multiple-item displays and location precues in order to see whether color is also used for selection even when target location does vary and supposedly dominant location precues can be used. Precues provided independent information about the location and color of a target, and each type of precue could be either valid or invalid. The precues were followed by brief displays of six letters in six different colors, and participants had to discriminate the case of a prespecified target letter (e.g., R vs. r). Performance was much better when location cues were valid than when they were invalid, confirming the large advantage associated with valid advance location information. Performance was also better with valid advance color information, however, both when location cues were valid and when they were invalid. But these color benefits were dependent on the closeness of the colored letter to the cued location. Our results thus suggest that selection by color in a multiple-item display, where location and color information are independent from each other and equalized, is mediated by location information.     

Online response preparation in a rapid serial visual search task

Online response preparation was assessed in a visual search task using rapid serial visual presentation. In each trial, a series of letters was presented sequentially, and participants were instructed to make a target-present response if a prespecified target letter was presented or a target-absent response if it was not. Measurements of response preparation using both probe reaction time and the lateralized readiness potential indicated that preparation of the target-absent response increased near the end of the sequence. Most of the increase appeared to be due to direct priming of the target-absent response by nontarget letters, but part was due to the increased conditional probability of this response near the end of the sequence. These results extend previous studies of response preparation by showing online response preparation during a temporally extended reaction time task.     

The role of configuration and target discriminability in a visual search task

Ss sorted through decks of cards bearing five-element patterns, separating those in which all five were identical from those in which one of the five was different from the remaining four. Sorting time depended on the configuration and size of the pattern in which the elements were arranged but was independent of the goodness of these patterns. It was concluded that Ss did not attend to the patterns themselves, but just to the elements comprising them in searching for the discrepant element. The differences owing to the patterns appear to be due in part to the compactness of the configurations.     

Comparison of schizophrenics and normals on a visual search task.

The response times of 16 paranoids, 16 nonparanoids and 16 normals were compared on a search task which required subjects to identify target letters embedded in displays of varying numbers of non-targets. The rate on increase in response times with increased numbers of letters displayed was not markedly different for the various groups, although a derived measure of decision and response-selection time indicated that normals selected responses more rapidly. When compared with normals, schizophrenics seemed to experience more difficulty in response selection and decision than in processing visual stimulus information.     

Instructions,strategies, and pattern uncertainty in a visual discrimination task

A card-sorting task involved discrimination of patterns from the same equivalence set, patterns from different sets of the same size, and patterns from different sets of different sizes. Instructions, experimental conditions, and the number of different patterns to be sorted into two trays were varied in an attempt to change Ss’ strategies from whole-pattern processing to single-element processing. Instructions alone were ineffectual in preventing whole-pattern processing, and physical masks over most of the criterion stimuli (patterns used as guides in sorting) were only somewhat effective. Differences among tasks that were attributable to size of equivalence set were eliminated only by arranging the stimuli so that a whole-pattern strategy required a great deal more information processing, or so that such a strategy could not lead to the required discrimination. The results were interpreted as confirming the influence of the properties of sets of stimuli, as well as the strength of the tendency of human Ss to process and categorize patterns in their entirety. nt]mis|This research was supported in part by a University Research Council grant.     

Intrinsic motivation and attentional capture from gamelike features in a visual search task

In psychology research studies, the goals of the experimenter and the goals of the participants often do not align. Researchers are interested in having participants who take the experimental task seriously, whereas participants are interested in earning their incentive (e.g., money or course credit) as quickly as possible. Creating experimental methods that are pleasant for participants and that reward them for effortful and accurate data generation, while not compromising the scientific integrity of the experiment, would benefit both experimenters and participants alike. Here, we explored a gamelike system of points and sound effects that rewarded participants for fast and accurate responses. We measured participant engagement at both cognitive and perceptual levels and found that the point system (which invoked subtle, anonymous social competition between participants) led to positive intrinsic motivation, while the sound effects (which were pleasant and arousing) led to attentional capture for rewarded colors. In a visual search task, points were awarded after each trial for fast and accurate responses, accompanied by short, pleasant sound effects. We adapted a paradigm from Anderson, Laurent, and Yantis (Proceedings of the National Academy of Sciences 108(25):10367-10371, 2011b), in which participants completed a training phase during which red and green targets were probabilistically associated with reward (a point bonus multiplier). During a test phase, no points or sounds were delivered, color was irrelevant to the task, and previously rewarded targets were sometimes presented as distractors. Significantly longer response times on trials in which previously rewarded colors were present demonstrated attentional capture, and positive responses to a five-question intrinsic-motivation scale demonstrated participant engagement.     

Lifespan changes in attention: The visual search task

There are two popular frameworks for the study of visual attention. Treisman's Feature Integration Theory focuses on the effortful process of binding together the multiple attributes of an object. Posner's Visual Orienting Theory emphasizes the movement of an attentional spotlight across space. Although both aspects are undoubtedly important in any visual search task, it is not clear how each of these aspects changes with age. We tested observers aged 6, 8, 10, 22, and 72 years on visual search tasks designed to isolate these factors. No age-related differences were found in single- or double-feature discrimination, attention movement to a single item, or search for a single-feature target among distractors. Two age-related changes were found: (1) young children were less able than either young adults or seniors to search for targets defined by a conjunction of features, and (2) both children and seniors were less able than young adults to move attention voluntarily from item to item. This implies that feature integration and voluntary movement of attention have different trajectories over the lifespan.