Low target prevalence is a stubborn source of errors in visual search tasks

In visual search tasks, observers look for targets in displays containing distractors. Likelihood that targets will be missed varies with target prevalence, the frequency with which targets are presented across trials. Miss error rates are much higher at low target prevalence (1%-2%) than at high prevalence (50%). Unfortunately, low prevalence is characteristic of important search tasks such as airport security and medical screening where miss errors are dangerous. A series of experiments show this prevalence effect is very robust. In signal detection terms, the prevalence effect can be explained as a criterion shift and not a change in sensitivity. Several efforts to induce observers to adopt a better criterion fail. However, a regime of brief retraining periods with high prevalence and full feedback allows observers to hold a good criterion during periods of low prevalence with no feedback.     

Effects of secondary tasks on search performance

Summary Two experiments studied the effect of secondary task load on continuous visual search. Two effects were observed when a secondary task was applied. Search speed (which is assumed to reflect the efficiency of nontarget rejection) was impaired, whereas target detection distance (which presumably reflects the efficiency of target detection) increased. These findings are explained in the framework of a two-process model of visual search which assumes that two operations are performed simultaneously during each fixation, that is, automatic detection and controlled search. The secondary task interferes with the operation of controlled search which reacts to this impairment by way of a compensatory slow-down of search speed. This gain in time also benefits the operation of automatic detection which converts the temporal gain into a spatial extension of the area under its control.     

Debtor education, financial literacy, and pending bankruptcy legislation

This paper reports on an evaluation of a financial education-training program for residents of New York who had filed for bankruptcy. Over 400 individuals divided into three groups (trained debtors, untrained debtors, and non-debtors) completed identical questionnaires approximately three months apart. Trained debtors took the pretest before training and the post-test after training. Results revealed that trained debtors' financial knowledge increased after training compared with untrained and non-debtors. Trained debtors showed more negative attitudes towards unnecessary spending compared with the other two groups and reported less intention to buy than non-debtors reported. Self-reported behaviors showed significant changes in the desired direction for trained debtors' use of credit cards (i.e. number owned, purchases, and balance amount), paying bills, budgeting, and borrowing from predatory lenders. Implications for pending legislation are discussed.     

Effects of focusing strategy on speeded classification with grouping,filtering, and condensation tasks

Speeded classification was studied with three tasks varying in the way in which extra stimuli are provided for a single class:grouping, with additional levels on a single relevant dimension;filtering, with additional levels on an irrelevant dimension; andcondensation, with additional levels on a second relevant dimension. (Both relevant dimensions must be processed for correct classification.) For the dimensions used (color and form), filtering was easiest, followed by grouping and condensation. In the latter two cases, asymmetric classifications, in which one class had a single member, eliminated the difficulty of classification. The presumed mechanism is focusing, in which the single stimulus is seen as a positive set and all other stimuli as negative.     

Infants' search for visible objects: implications for the interpretation of early search errors

This study examined the error patterns of 9-month-old infants searching for hidden objects and objects that were visible within a container. Although errors occurred in both conditions, there were important differences between them. When the object was hidden, infants showed significant perseveration in that they searched more often at the object's previous hiding place than at a control location. When the object was visible, however, they made fewer errors and the errors they did make were as likely to be to the control location as to the previous hiding place. These results suggest that infants' errors in searching for a visible object reflect lapses of attention rather than systematic misunderstandings of objects or space and so are not incompatible with an information-processing account of early search.     

The relations between knowledge,search strategy,and performance in unaided and aided information search

Information search is a critical step in resolving complex issues in many different decision-making domains. This study examines the relations between knowledge, search strategy, and performance in both unaided and aided information search. The results of an experiment indicates that (a) task-relevant knowledge is directly related to performance in aided but not in unaided information search; (b) in unaided information search, search strategy mediates the relation between knowledge and performance; that is, knowledge indirectly affects performance through its effect on search strategy; and (c) an information search aid moderates both the relation between knowledge and search strategy and the relation between search strategy and performance. These findings highlight the importance and the roles of task-relevant technical knowledge and search strategy in explaining information search performance and are most likely to apply to complex, knowledge-intensive domains in which decision makers search large databases to resolve issues.     

Types and frequency of errors in visual search

The experimental method allowed false-positive as well as false-negative errors to be measured during visual search. Data were collected from eight Ss on four target-set size conditions on each of 25 days in order to determine whether the finding that search rate is independent of target-set size after practice might be attributable to a systematic variation in total error rate with set size. Even after practice, these Ss continued to search significantly faster for a single target than for target sets which were composed of five or more characters. Further, the incidence of total errors was much lower than in those studies in which search rate had been found to be independent of set size (i.e., parallel processing), even though these latter studies considered only the occurrence of false-negative errors. Additional analysis strongly suggests that: (1) attainment of parallel processing and a highly accurate performance are incompatible, and (2) verbal instructions alone are not sufficient to control the accuracy levels.     

Processing of repeated letters in search and matching tasks

Several published experiments have used a variant of the matching or “same”-“different” paradigm in which the subject indicates whether or not all of the items in a visual array are the same. Contrary to the results of most paradigms in which subjects process multiple items, reaction time (RT) in this matching task is independent of the number of items in the display (N). One possible explanation of this independence holds that subjects respond to some overall property of the display, such as its general symmetry, and not to the individual items. I tested this hypothesis with a visual search task in which subjects searched a circular display of N=2, 4, or 6 letters for a specified target letter under three stimulus conditions. In the varied condition, the nontarget letters were all different from each other. In the repeated condition, the nontargets were repetitions of the same letter, but a single discrepant letter was always present in the display. The uniform condition also used repeated nontargets, but the negative (target-absent) displays contained N repetitions of a single nontarget item. I found that RT increased at a rate of 27 msec/item for the varied condition, but at only 13 and 8 msec/item in the repeated and uniform conditions, respectively. The slopes in the latter conditions were significantly lower than the slope for the varied condition, and they also differed significantly from each other. Hence, there was some advantage attributable to properties of the overall patterns associated with positive and negative responses, suggesting that at least some responses were based on these properties. There was a much larger advantage, however, attributable to the use of repeated nontargets, regardless of whether the overall patterns differed. This latter observation implies that the flat RT functions observed in matching studies must be interpreted primarily in terms of responses to individual items rather than to the pattern as a whole.     

Early literacy among Arabic-speaking kindergartners: The role of socioeconomic status,home literacy environment and maternal mediation of writing

We explored the sociocultural context of early literacy development among Arabic-speaking kindergartners in Israel, focusing on the nature of mother–child joint writing. Eighty-nine kindergartners and their mothers participated. Mothers were videotaped in their homes while helping their children write words. Early literacy was evaluated by alphabetic knowledge, concepts about print, phonological awareness, and vocabulary. Kindergartners’ early literacy was related to socioeconomic status (SES), home literacy environment (HLE) and maternal mediation level. Hierarchical regressions indicate that HLE predicted alphabetic knowledge, phonological awareness, and vocabulary beyond SES. Maternal mediation of writing predicted all children's early literacy measures except vocabulary, after controlling for SES and HLE. We discuss maternally mediated joint writing interactions as a possible context for early literacy enhancement among young Arabic-speaking children in Israel.     

Effect of stimulus configuration on spatial judgments in search tasks

Although children over one year of age are able to code spatial information with respect to objects other than the self, there are many instances in which the self is inappropriately used as a spatial referent by children between 2 and 4 years of age. L. G. Braine and R. A. Eder (1983, Developmental Psychology, 19, 45-55) found that, in a search task, the nature of the array influenced the spatial referent used by 2-year-old children. The present work investigated the effect of varying the number, size, and arrangement of boxes in the array. It was found that only the number of boxes defining the left and right sides of the array influenced performance; that is, multiple boxes were associated with the use of external objects as spatial referents. These results were interpreted as stemming from the tendency of young children to code the location of an object with respect to nearby objects. This tendency would lead to the use of adjacent boxes and environmental objects as spatial referents for the multiple-box side, and the use of the self as a spatial referent for the single-box side.     

Visualization,pattern recognition,and forward search: effects of playing speed and sight of the position on grandmaster chess errors

A new approach examined two aspects of chess skill, long a popular topic in cognitive science. A powerful computer‐chess program calculated the number and magnitude of blunders made by the same 23 grandmasters in hundreds of serious games of slow (“classical”) chess, regular “rapid” chess, and rapid “blindfold” chess, in which opponents transmit moves without ever seeing the actual position. Rapid chess led to substantially more and larger blunders than classical chess. Perhaps more surprisingly, the frequency and magnitude of blunders did not differ in rapid versus blindfold play, despite the additional memory and visualization load imposed by the latter. We discuss the involvement of various cognitive processes in human problem‐solving and expertise, especially with respect to chess. Prior opposing views about the basis of general chess skill have emphasized the dominance of either (a) swift pattern recognition or (b) analyzing ahead, but both seem important and the controversy appears currently unresolvable and perhaps fruitless.     

Principles of cognitive science in education: The effects of generation,errors, and feedback

Principles of cognitive science hold the promise of helping children to study more effectively, yet they do not always make successful transitions from the laboratory to applied settings and have rarely been tested in such settings. For example, self-generation of answers to questions should help children to remember. But what if children cannot generate anything? And what if they make an error? Do these deviations from the laboratory norm of perfect generation hurt, and, if so, do they hurt enough that one should, in practice, spurn generation? Can feedback compensate, or are errors catastrophic? The studies reviewed here address three interlocking questions in an effort to better implement a computer-based study program to help children learn: (1) Does generation help? (2) Do errors hurt if they are corrected? And (3) what is the effect of feedback? The answers to these questions are: Yes, generation helps; no, surprisingly, errors that are corrected do not hurt; and, finally, feedback is beneficial in verbal learning. These answers may help put cognitive scientists in a better position to put their well-established principles in the service of children’s learning.     

Comparison of intrusion errors and serial position curves on monaural and dichotic listening tasks: A developmental analysis

Based on a repeated measurement study of 7-, 10-, 14-, and 17-year-olds with monaural and dichotic presentations of word lists varying in associative structure and presentation rate, intrusion and serial position dependent variables were analyzed. Intrusion analyses supported previous reports on word list recall; vis, 7- and 10-year-olds recalled fewer words from monaural and dichotic lists and had more intrusive errors than adolescents. Based on similar orders of report (strategies) for monaural and dichotic word presentations, serial position curves for the two types of presentation were compared. Within-age comparisons were strikingly similar. Between-age comparisons of monaural and dichotic presentation serial position curves support the notion that there are ontogenetic limitations in memory structure and control processes.     

Sources of performance on theory of mind tasks in right hemisphere-damaged patients

Patients with right hemisphere (RHD) or left hemisphere brain damage (LHD) were tested on Theory of Mind (ToM) tasks presented with visual aids that illustrated the relevant premises. As a measure of pragmatic ability, patients were also asked to judge replies in conversation that violated Gricean maxims. Both RHD and LHD patients performed well on the ToM tasks presented with visual aids, but RHD patients displayed difficulty when the same tasks were presented only verbally. In addition, RHD patients showed reduced sensitivity to pragmatic violations. These findings point to the role of right hemisphere structures in processing information relevant to conversations. They indicate that a crucial source of RHD patients' errors in ToM tasks may involve difficulties in utterance interpretation owing to impairments of visuospatial processing required for the representation of textual information.     

Parallel processing of park-whole information in visual search tasks

Combination of information from the parallel processing of different basic features (color, size, etc.) can be used to guide attention to targets defined by conjunctions of those features. Wolfe et al. (1990) argued that, although it was possible to guide attention to the conjunction of, for instance, color and orientation, it was not possible to guide attention to targets defined by conjunctions of two colors or two orientations. The present experiments demonstrate an exception to this rule. Although it is true that attention cannot be guided to a target that hasred and green parts, attention can be guided to an item that can be described as awhole red target with agreen part. In Experiments 1 and 2, we illustrate this point. In Experiments 3 and 4, we rule out some simple size-based accounts of this finding- In Experiments 5 and 6, we begin to explore the nature of these first steps toward dividing the visual scene into parts and wholes.     

Impact of physical fitness on strategy development in decision-making tasks

Data from 30 female subjects indicated that a 17.3% increase in a physical fitness index improved by 12% to 68% the information processing and decision-making capabilities of the subjects. The changes in physical fitness did not affect the performance on a variety of other tasks.     

Contribution of strategy use to performance on complex and simple span tasks

Simple and complex span tasks are widely thought to measure related but separable memory constructs. Recently, however, research has demonstrated that simple and complex span tasks may tap, in part, the same construct because both similarly predict performance on measures of fluid intelligence (Gf) when the number of items retrieved from secondary memory (SM) is equated (Unsworth & Engle, Journal of Memory and Language 54:68–80 2006). Two studies (n = 105 and n = 152) evaluated whether retrieval from SM is influenced by individual differences in the use of encoding strategies during span tasks. Results demonstrated that, after equating the number of items retrieved from SM, simple and complex span performance similarly predicted Gf performance, but rates of effective strategy use did not mediate the span-Gf relationships. Moreover, at the level of individual differences, effective strategy use was more highly related to complex span performance than to simple span performance. Thus, even though individual differences in effective strategy use influenced span performance on trials that required retrieval from SM, strategic behavior at encoding cannot account for the similarities between simple and complex span tasks.     

Search, enumeration, and aging: eye movement requirements cause age-equivalent performance in enumeration but not in search tasks

Response time (RT) and fixation frequency were measured for young and older adults in search and enumeration tasks under high- and low-attentional competition conditions. There was an age-related decrement in search rates for single targets both for RT and fixation frequency, but there was no deficit in enumeration rates either with or without distractors even though serial enumeration rates were much slower than single target search rates. Fixation frequency per item in serial enumeration was much greater than in serial visual search for a single target. Enumerating targets with distractors produced an overall increase in RT and fixation frequency that was greater for older adults. The data are contrary to a generalized slowing account, and an alternative is proposed on the basis of the need to make eye movements in enumeration but not in search tasks.