Working memory and target-related distractor effects on visual search

We examined two forms of top-down effects on visual selection: (1) information held in working memory (WM) and (2) the semantic relations between targets and distractors. We found that items held in WM affected search for a different target. This WM-based interference effect generalized across different exemplars, even though participants could remember the specific exemplar on the trial. This argues against a memory top-up account of performance. In addition, there was interference from distractors that were not held in WM but were semantically related to the target. The effects of WM capture and the effects of capture by a distractor related to the target combined additively. The data suggest that task-irrelevant information in WM and task-relevant templates for targets compete separately for selection. The implications for understanding top-down processes in search are discussed.     

Rater information acquisition processes: Tracing the effects of prior knowledge, performance level, search constraint, and memory demand

Research on performance ratings has tended to neglect factors affecting raters' acquisition of ratee performance information. The present research examined the dynamic effects of this rater information acquisition process. Study 1 examined the effects of prior ratee knowledge (familiarity) and ratee performance level on subsequent acquisition of ratee performance information under varying levels of constraint. After exposure to prior ratee information, raters acquired additional information concerning a set of ratees using a computer controlled information board procedure. The results indicated significant effects on the amount of search for prior knowledge, search constraint, and the interaction between prior knowledge and performance level. Study 2 extended the research by including a memory component (time delay) between the exposure to prior information and subsequent search. Results were congruent with Study 1. They indicated significant main effects on the amount of search for prior knowledge, ratee performance level, search constraint, and on the interaction between prior knowledge and performance level. In addition, the results indicated a significant interaction between memory demand and prior knowledge. Implications of these results, limitations, and extensions of this research approach are discussed.     

任务维度和任务无关维度干扰信息的同质性影响视觉搜索的神经机制

在三个实验中, 我们利用功能性磁共振成像(functional magnetic resonance imaging, fMRI)技术考察了在简单特征搜索任务和客体内联合搜索任务中任务维度干扰项的同质性(或称一致性, homogeneity)和任务无关维度干扰信息的同质性对视觉搜索行为的影响及其神经机制。主要探讨了三个问题：(1) 任务维度干扰信息的同质性与目标存在性之间交互作用的神经机制; (2) 任务维度干扰信息的同质性与任务无关维度干扰信息的同质性之间的交互作用及其神经机制; (3) 上述神经机制在不同类型的视觉搜索(特征搜索和联合搜索)中的异同。     

Strategies in the information search process: interaction among task structure, knowledge, and source

The authors explored the information search strategies of 145 individuals in the predecisional stage. Decision-making participants selected pieces of information from a list including relevant and irrelevant data. The authors investigated the influence of the individual's knowledge and information source. In Experiment 1, the authors experimentally manipulated the information source reliability. The results revealed that participants tended to use a sequential strategy when the authors presented information as supplied by a reliable source. In Experiment 2, the authors analyzed the interaction between information source and the individuals' knowledge. When participants believed the source to be reliable, even knowledgeable participants adopted a strategy as sequential as that chosen by naive individuals. In Experiment 3, a mediational model corroborated the hypothesis that the search strategy affects the final judgment. The results were consistent with the constructivist framework, which emphasizes the role of individual, task, and context in the decision-making process.     

Distractor interference in focused attention tasks is not mediated by attention capture

Distractor stimuli possessing information that is relevant for a task (henceforth, task-relevant distractors) often interfere with task performance. The interference by task-relevant distractors is observed even when distractors are positioned outside the main attentional focus. We investigated whether such interference is due to an attention capture by the distractors. Participants responded to a target colour while ignoring word distractors positioned within (Experiment 1) or outside (Experiments 2 and 3) the attentional focus. The words carried task-relevant information in their colour and personally significant information in their content. Because personally significant information affects performance only when positioned in an attended region, it was used as a marker for the locus of the attentional focus. As expected, when distractors were attended, both task-relevant and personally significant information affected performance. However, when distractors were unattended, only task-relevant information caused interference, suggesting that attention did not shift to the distractors’ location. We discuss possible accounts for interference effects in focused-attention tasks.     

Information search activity: An overview

IntroductionThis article exposes a brief history of information search models, from general and behavioural models to cognitive ones and presents recent theoretical advances in this research field.Literature findingsSince the beginning of 1990s, many theoretical models have tried to describe and predict the human behaviours involved in the information search tasks, and specifically when this activity is performed in computer systems. Some of these models elaborated by psychologists have attempted to infer the cognitive processes involved.DiscussionInformation search can be considered as a complex cognitive activity that involves various individual (cognitive, affective), contextual and social factors.ConclusionWe also suggest research issues to be developed in order to increase our knowledge in this area and we plead for further research on specific concepts depending on future and/or recent areas of interest.     

Learning efficient visual search for stimuli containing diagnostic spatial configurations and color-shape conjunctions

Visual search is often slow and difficult for complex stimuli such as feature conjunctions. Search efficiency, however, can improve with training. Search for stimuli that can be identified by the spatial configuration of two elements (e.g., the relative position of two colored shapes) improves dramatically within a few hundred trials of practice. Several recent imaging studies have identified neural correlates of this learning, but it remains unclear what stimulus properties participants learn to use to search efficiently. Influential models, such as reverse hierarchy theory, propose two major possibilities: learning to use information contained in low-level image statistics (e.g., single features at particular retinotopic locations) or in high-level characteristics (e.g., feature conjunctions) of the task-relevant stimuli. In a series of experiments, we tested these two hypotheses, which make different predictions about the effect of various stimulus manipulations after training. We find relatively small effects of manipulating low-level properties of the stimuli (e.g., changing their retinotopic location) and some conjunctive properties (e.g., color-position), whereas the effects of manipulating other conjunctive properties (e.g., color-shape) are larger. Overall, the findings suggest conjunction learning involving such stimuli might be an emergent phenomenon that reflects multiple different learning processes, each of which capitalizes on different types of information contained in the stimuli. We also show that both targets and distractors are learned, and that reversing learned target and distractor identities impairs performance. This suggests that participants do not merely learn to discriminate target and distractor stimuli, they also learn stimulus identity mappings that contribute to performance improvements.     

Predecisional information acquisition: Effects of task variables on suboptimal search strategies

Effective overall performance in judgment tasks generally involves both acquisition of information and integration of the information acquired. When information is costly the decision maker must balance acquisition costs against improved decisional accuracy, a complex balancing problem in which, laboratory evidence suggests, humans often do poorly. The three experiments reported here extend this earlier evidence to different task structures, subject pools, incentive systems, information volumes, decision aids, and kind of data sources. Though each of these factors was found to affect performance, the general finding was of persistent underpurchase (buying less information overall than is optimal) and mispurchase (buying poor sources when better sources are available at the same cost), with significant inflation of overall costs. It is proposed that unaided human judgment is unequal to the complexity of the cost/benefit trade-offs involved in acquiring costly information, and that formal decision analysis should be preferred whenever the stakes justify.     

Expertise, visual search, and information pick-up in squash

The visual search characteristics of expert and novice squash players were compared in two experiments. In the first experiment subjects were required to predict the forthcoming direction and force of an opponent's stroke from a film display. This film display was designed to simulate the normal display available to the defending player in squash and involved the use of variable temporal cut-offs to force the subjects to use advance cues in their prediction. Systematic differences in the information pick-up of the experts and novices were observed on the film task but these differences were achieved with only relatively minor between-group variations in visual search strategy. In the second experiment, set in the natural field setting, no expert-novice differences in either fixation distribution, order, or duration were observed on a comparable prediction task. This provided further support for the conclusion that the limiting factor in the perceptual performance of the novices is not an inappropriate search strategy but rather an inability to make full use of the information available from fixated display features. Some practical implications of these findings for the squash coach and player are considered.     

The effect of explanation in simple binary decision tasks

Many studies of explanation have focused on higher level tasks and on how explanations draw upon relevant prior knowledge, which then helps in understanding some event or observation. However, explanations may also affect performance in simple tasks even when they include no task-relevant information. In three experiments, we show that explanations adding no task-relevant information alter performance in a sequential binary decision task. Whereas people with no explanation for why two events occurred at different rates tended to predict each outcome in proportion to their probability of occurrence (to "probability match"), people with an explanation tended to predict the more likely event more often (to "overmatch," a better strategy). These results suggest a broader view of explanation, which includes a role in shaping simple tasks outside of higher level reasoning.     

Retroactive and proactive interference effects in dual learning of blissymbolics and manual sign

Nonspeech systems can be either aided or unaided. Each system possesses its unique learning and memory characteristics. One instructional strategy designed to give learners the advantages of both systems is dual instruction in aided and unaided communication. One problem with this approach, however, might be that of retroactive and proactive interference in learning and memory. The current experiment investigated whether dual instruction in Blissymbolics and manual (ASL) sign would lead to retroactive and proactive interference. Lists of sign/symbol referents in the two systems were taught, to nonhandicapped adults in a controlled setting. No effects of retroactive or proactive interference were found. Additionally, a proactive facilitation effect was found for immediate retention. Results are discussed in terms of the nature of the task, the learning memory attributes of the nonspeech systems, and the effects of sign/symbol translucency.     

unemployment,social support,individual resources,and job search behavior

The authors investigated the relation between the social support received by unemployed individuals (N = 104) and their job search behavior. A moderated mediation model demonstrated that the effect of social support on job search behaviors was mediated by self‐esteem but only if adequacy of social support was perceived as low. In addition, the effect of social support on job search behavior was partially mediated by optimistic expectations and resilience. In sum, social support seems to be a resource with complex and partially surprising effects on job search behavior.     

Leader-focused search: The impact of an emerging preference on information search

This article examines the influence an emerging preference (i.e., a leader) has on predecisional information search. We explore two possibilities. First, decision makers may seek information they expect will support their leader (leader-supporting search). Second, decision makers may seek information about their leader, irrespective of the expected valence of the information (leader-focused search). Across various studies, product domains and experimental designs, we consistently find that decision makers engage in leader-focused search, not leader-supporting search. We also find that leader-focused search can steer decision makers towards information sources that are less important, less credible, and objectively suboptimal.     

Aging and guided visual search: the role of visual working memory

In the present study, we examined age-related differences in utilizing learned associations to guide visual search. Participants viewed an object cue that was associated with 1 or 2 target colors, followed by a search array. Older adults showed slower RTs, larger visual search slopes, and reduced cue–target association knowledge than did younger adults. We also found increased search RTs and higher error rates when the cue was associated with 2 colors instead of 1. However, visual search slopes did not vary with the number of associated colors. This indicates that participants could activate multiple templates simultaneously to guide the search or retrieve associative information directly from the long-term memory. Furthermore, regression analyses showed that VWMC can predict both visual search performances and cue–target association knowledge. More broadly, our results demonstrate that VWMC can modify the effects of age on cued visual search performance.     

Selectivity and strategy in early search

Early information-processing strategies were examined in a study of very young children's search for hidden objects. Sixteen younger children (mean age: 1 year; 11 months) and sixteen older children (mean age: 2;6) received search problems in which observational and/or verbal information about an object's location was provided. The question of primary interest was how they would respond when given two conflicting sources of information, which differed in modality (observational vs verbal) and in currentness. Both younger and older children showed some use of an appropriate strategy of relying on the more current information, although they did not follow it consistently. Children also showed preferential use of observational over verbal information and response biases favoring the middle location. Age differences were found in children's use of verbal information, in the degree to which they benefitted from practice, and in response biases. These results suggested a distinction between two aspects of the development of search: the acquisition of new search skills and the establishment of appropriate priorities among skills already in the child's repertoire.     

Explanation and verbalization in a computer-assisted search task

Three experiments examine the effects of two different forms of explanation on assisted performance on a complex search task. The task involves determining which of a set of factories is responsible for polluting a river by testing the river for the presence or absence of various pollutants. All subjects receive computer suggestions as to which pollutants they should test for. In addition, some subjects receive an explanation of the principle according to which the advice program works. Two forms of explanation are compared. Experiment 1 shows that subjects who are allowed to ask “why” each computer recommendation is made perform significantly better than those who are provided with a block text of explanation at the start of each trial. Experiment 2 shows that the latter type of explanation is not completely ineffective, however. Subjects who are required to verbalize following the single explanation perform significantly better than do subjects who are required to verbalize but who have not received any form of explanation. Finally, Experiment 3 shows that subjects who receive the multiple “why” explanations or the explanation/verbalization combination maintain a superior performance level on subsequent unaided trials.     

Information search and choice accuracy as a function of task complexity and task structure

Previous research has consistently shown that subjects switch to noncompensatory information search behaviour when task complexity increases. However, a rather specific class of tasks was used in these studies for which complete information search is not necessary to attain accurate task performance. In the present study information search behaviour, choice accuracy, subjective difficulty and confidence were registered under various task complexity conditions in two different task environments. In the first task, subjects had to make a choice between apartments; in the second task, a choice was required between baskets containing groceries of different prices. Forty subjects made choices by means of computerized information boards. The results showed effects of both complexity and type of task on information search behaviour. The lowest proportion of requested information and the most variable search pattern was observed for the apartments task in the complex task condition. However, accuracy remained constant over all complexity conditions. Together, the results suggest that under high task complexity levels subjects try to work smarter rather than harder. In the context of a choice requirement the specific task structure may allow them to switch to noncompensatory strategies while maintaining accuracy and avoiding the integration of large amounts of information.     

Multi-attribute sequential search

This article describes empirical and theoretical results from two multi-attribute sequential search tasks. In both tasks, the DM sequentially encounters options described by two attributes and must pay to learn the values of the attributes. In the continuous version of the task the DM learns the precise numerical value of an attribute when she pays to view it. In the threshold version the DM learns only whether the value of an attribute is above or below a threshold that she sets herself. Results from the continuous condition reveal that DMs tended to terminate their searches too early relative to the optimal policy. The pattern reversed in the threshold condition: DMs searched for too long. Maximum likelihood comparisons of two different stochastic decision models showed that DMs under both information conditions performed in ways consistent with the optimal policies. Those offered continuous-valued attribute information did not, however, spontaneously degrade this information into binary (acceptable/unacceptable) form, despite the theoretical finding that satisficing can be a very effective and efficient search strategy.     

Person perception informs understanding of cognition during visual search

Does person perception—the impressions we form from watching others—hold clues to the mental states of people engaged in cognitive tasks? We investigated this with a two-phase method: In Phase 1, participants searched on a computer screen (Experiment 1) or in an office (Experiment 2); in Phase 2, other participants rated the searchers’ video-recorded behavior. The results showed that blind raters are sensitive to individual differences in search proficiency and search strategy, as well as to environmental factors affecting search difficulty. Also, different behaviors were linked to search success in each setting: Eye movement frequency predicted successful search on a computer screen; head movement frequency predicted search success in an office. In both settings, an active search strategy and positive emotional expressions were linked to search success. These data indicate that person perception informs cognition beyond the scope of performance measures, offering the potential for new measurements of cognition that are both rich and unobtrusive.     

Assessing visual search performance differences between Transportation Security Administration Officers and nonprofessional visual searchers

Some visual searches depend upon accuracy (e.g., radiology, airport security screening), and it is important for both theoretical and applied reasons to understand what factors best predict performance. The current study administered a visual search task to both professional (Transportation Security Administration Officers) and nonprofessional (members of Duke University) searchers to examine group differences in which factors predict accuracy. Search speed—time taken to terminate search—was the primary predictor for nonprofessional searchers (accounting for 59% of their accuracy variability) and for the least experienced professional searchers (37% of variability). In contrast, consistency—how similarly (in terms of search speed) an individual spent searching from trial to trial—was the primary predictor for the most experienced professional visual searchers (39% of variability). These results inform cognitive theory by illuminating factors that differentially affect search performance between participants, and real-world issues by identifying search behaviours (consistency in particular) important to experienced professional searchers.