Difference In Search Time Research Articles

No evidence for spatial suppression due to across-trial distractor learning in visual search

Previous studies have shown that during visual search, participants are able to implicitly learn across-trial regularities regarding target locations and use these to improve search performance. The present study asks whether such across-trial visual statistical learning also extends to the location of salient distractors. In Experiments 1 and 2, distractor regularities were paired so that a specific distractor location was 100% predictive of another specific distractor location on the next trial. Unlike previous findings that employed target regularities, the current results show no difference in search times between predictable and unpredictable trials. In Experiments 3–5 the distractor location was presented in a structured order (a sequence) for one group of participants, while it was presented randomly for the other group. Again, there was no learning effect of the across-trial regularities regarding the salient distractor locations. Across five experiments, we demonstrated that participants were unable to exploit across-trial spatial regularities regarding the salient distractors. These findings point to important boundary conditions for the modulation of visual attention by statistical regularities and they highlight the need to differentiate between different types of statistical regularities.

How does the number of targets affect visual search performance in visuospatial neglect?

ABSTRACT Introduction Impairments in visual search are a common symptom in visuospatial neglect (VSN). The severity of the lateralized attention bias in visual search tasks can vary depending on the number of distractors: the more distractors, the more targets are missed. However, little is known about how the number of targets affect search performance in VSN. The aim of the current study was to examine the effect of the number of targets on hit rate in VSN. Methods We included 23 stroke patients with right-brain damage and VSN, 55 with right-brain damage without VSN, and 49 with left-brain damage without VSN, all admitted for inpatient rehabilitation. In a visual search task, patients had to find and tap targets, presented along with non-targets. The location and number of targets varied from trial to trial, allowing the evaluation of the effects of number and location of targets on hit rate. Results VSN patients detected a lower percentage of targets when more targets were present. For patients with right-brain damage without VSN, adding targets only reduced the hit rate of the most contralesional target. No effect of number of targets on hit rate was seen in patients with left-brain damage. Additionally, VSN patients found less contralesional targets than ipsilesional targets, made more delayed revisits, and had an initial rightward bias when compared to the other groups. There were no differences in search time, search consistency, or immediate revisits between groups. There was a moderate positive relation between the hit rate asymmetry score in our search task and conventional paper-and-pencil VSN tasks, and neglect behavior in daily life. Conclusions In VSN patients, a higher number of targets reduces the hit rate. The reduced hit rate in visual search evoked by additional targets should be taken into account when assessing visual search in VSN.

A cat in paradise: hunting and feeding behaviour of Eurasian lynx among abundant naive prey

Kill rates of predators typically increase when they come into contact with naive and abundant prey. Such a situation can lead to surplus killing or the occurrence of parallel kills (i.e. additional kills that predator makes while still consuming the carcass from the previous kill). However, there is limited information on the feeding behaviour of predators during such events and how they affect kill rates. Here we report on hunting and feeding behaviour of a male Eurasian lynx (Lynx lynx) that dispersed into a region where this apex predator had been absent for several decades. We also report on the kleptoparasitism by wild boar (Sus scrofa), which effects on lynx prey consumption have not yet been explored. We found 66 ungulates killed by the lynx, among which 39% were part of parallel kills. Compared to the single kills, lynx fed on parallel kills for 2.7-times longer, while the kill rate was 37% higher, resulting in one of the highest kill rates reported so far for male lynx in Europe. We did not detect differences in search times following single or parallel kills and the average distance between consecutive kills was similar in both kill types. We also recorded the highest kleptoparasitism rate by dominant scavengers on Eurasian lynx, as 48% of kills were usurped and consumed by the wild boars. Kleptoparasitism reduced the average time lynx was able to feed on prey for 52% compared to kills not found by wild boars. However, the lynx did not compensate for these losses by increasing the hunting effort, probably due to abundant naive prey available in the area.

A Framework for Privacy Preserving, Distributed Search Engine Using Topology of DLT and Onion Routing

Risks regarding Internet privacy and security have been identified as issues for both new and experienced users of Internet technology. This paper explores the privacy and security threats in centralized search engines and proposes a decentralized search system. The proposed decentralized search system provides privacy and security for its users. The decentralized nature also provides transparency, distributed search and community-driven decisions in the proposed framework. We compare the proposed framework with the existing centralized approach. Our analysis shows that (1) there is no significant difference in search time between the centralized and proposed framework, and (2) the proposed framework is more efficient by providing search results with fewer search resources compared to the centralized approach.

A novel method for assessing patients with schizophrenia and their first-degree relatives by increasing cognitive load of visuo-spatial working memory.

In patients with schizophrenia, social and functional outcome is determined by the cognitive impairment. Assessment of visuo-spatial working memory (VSWM) which can simulate the day-to-day activities by simultaneous involvement of various elements of working memory may reflect disorganized thinking and fragmentation of thoughts in schizophrenia. Thirty-six patients with schizophrenia, 29 first-degree relatives of patients, and 25 healthy controls performed a VSWM task with three memory loads (comprising three pairs, six pairs, and eight pairs of abstract pictures). They were administered Hindi version of the Mini Mental State Examination, Scale for the Assessment of Negative Symptoms and Scale for the Assessment of Positive Symptoms, and Edinburgh handedness inventory. Patients (mean age 27.29(5.98) years) committed significantly higher number of errors than healthy controls (mean age 26.76(6.08) years) in load 3 (P=0.012) and total errors (P=0.018). Within all the groups, errors in load 3 were significantly higher than in load 2. Significant correlation was observed between years of education (r=-0.388, P=0.021), treatment duration (r=-0.880, P<0.001), negative symptoms scores (r=0.345, P=0.039), and the total errors committed by patients. Visuo-spatial working memory was impaired in schizophrenia with increasing cognitive load with no difference in search time between the groups.

Survival Processing Enhances Visual Search Efficiency.

Words rated for their survival relevance are remembered better than when rated using other well-known memory mnemonics. This finding, which is known as the survival advantage effect and has been replicated in many studies, suggests that our memory systems are molded by natural selection pressures. In two experiments, the present study used a visual search task to examine whether there is likewise a survival advantage for our visual systems. Participants rated words for their survival relevance or for their pleasantness before locating that object's picture in a search array with 8 or 16 objects. Although there was no difference in search times among the two rating scenarios when set size was 8, survival processing reduced visual search times when set size was 16. These findings reflect a search efficiency effect and suggest that similar to our memory systems, our visual systems are also tuned toward self-preservation.

Self association facilitates attentional inhibition in human visual search

PURPOSE: Previous research on attentional priority of self-associated stimuli mostly focused on the advantage in attentional attraction. The characteristics of self-associated stimuli in attentional inhibition remained unclear. The purpose of this research was to investigate whether self-associated information can facilitate inhibition compared with other information in human visual search. METHODS: Firstly participants completed an associative-learning task to associate color with label (e.g., green-self, blue-stranger). After that, they would finish a WM-guided visual search task. In this task, they were presented with several items to identify an unique target among the items. Participants were noted a specific color (e.g., red) in advance that need to be recalled and the items with the informed color could be excluded as distracters in the search display. This resulted in three conditions that the informed distracter color was either self-associated, stranger-associated, or neutral (no established association). RESULTS: The response times of the search task were significantly shorter when the informed distracter color was self-associated (i.e., green) compared with when the informed distracter color was stranger-associated (i.e., blue) or neutral (i.e., red). There was no significant difference in search time between stranger-associated color and neural color condition. The results suggested that when the distracters link to self, participants could inhibit the distracters rapidly and search faster. CONCLUSIONS: The present study provided an evidence that the active inhibition of a self-associated stimulus improves visual search performance. This study also furthered our understanding about attentional priority of self-associated stimuli and extended the self attention network (SAN) model.

Consumer Decision-Making Based on Review Websites: Are There Differences Between Choosing a Hotel and Choosing a Physician?

BackgroundWeb users are increasingly encouraged to rate and review consumer services (eg, hotels, restaurants) and, more recently, this is also the case for physicians and medical services. The resemblance in the setup and design of commercial rating websites (CRWs) and Web-based physician rating websites (PRWs) raises the question of whether choice-making processes based on the two types of websites could also be similar.ObjectiveThis qualitative study sought to explore the extent to which consumer decision making based on Web-based reviews is the same for consumer services (ie, choice of a hotel) and health services (ie, choice of a pediatrician), while providing an in-depth understanding of potential differences or similarities.MethodsBetween June and August 2015, we carried out a total of 22 qualitative interviews with young parents residing in the German-speaking part of Switzerland. Participants were invited to complete 2 choice tasks, which involved (1) choosing a hotel based on the commercial Web-based rating website TripAdvisor and (2) selecting a pediatrician based on the PRW Jameda. To better understand consumers’ thought processes, we instructed participants to “think aloud”, namely to verbalize their thinking while sorting through information and reaching decisions. Using a semistructured interview guide, we subsequently posed open-ended questions to allow them to elaborate more on factors influencing their decision making, level of confidence in their final choice, and perceived differences and similarities in their search for a hotel and a physician. All interviews were recorded, transcribed, and analyzed using an inductive thematic approach.ResultsParticipants spent on average 9:57 minutes (standard deviation=9:22, minimum=3:46, maximum=22:25) searching for a hotel and 6:17 minutes (standard deviation=4:47, minimum=00:38, maximum=19:25) searching for a pediatrician. Although the choice of a pediatrician was perceived as more important than the choice of a hotel, participants found choosing a physician much easier than selecting an appropriate accommodation. Four main themes emerged from the analysis of our interview data that can explain the differences in search time and choice confidence: (1) trial and error, (2) trust, (3) competence assessment, and (4) affect and likeability.ConclusionsOur results suggest that, despite congruent website designs, individuals only trust review information to choose a hotel, but refuse to fully rely on it for selecting a physician. The design and content of Web-based PRWs need to be adjusted to better address the differing information needs of health consumers.

Formative evaluation of a patient-specific clinical knowledge summarization tool

ObjectiveTo iteratively design a prototype of a computerized clinical knowledge summarization (CKS) tool aimed at helping clinicians finding answers to their clinical questions; and to conduct a formative assessment of the usability, usefulness, efficiency, and impact of the CKS prototype on physicians’ perceived decision quality compared with standard search of UpToDate and PubMed. Materials and methodsMixed-methods observations of the interactions of 10 physicians with the CKS prototype vs. standard search in an effort to solve clinical problems posed as case vignettes. ResultsThe CKS tool automatically summarizes patient-specific and actionable clinical recommendations from PubMed (high quality randomized controlled trials and systematic reviews) and UpToDate. Two thirds of the study participants completed 15 out of 17 usability tasks. The median time to task completion was less than 10s for 12 of the 17 tasks. The difference in search time between the CKS and standard search was not significant (median=4.9 vs. 4.5min). Physician’s perceived decision quality was significantly higher with the CKS than with manual search (mean=16.6 vs. 14.4; p=0.036). ConclusionsThe CKS prototype was well-accepted by physicians both in terms of usability and usefulness. Physicians perceived better decision quality with the CKS prototype compared to standard search of PubMed and UpToDate within a similar search time. Due to the formative nature of this study and a small sample size, conclusions regarding efficiency and efficacy are exploratory.

Testing Different Search Methods for Recovering Scattered and Scavenged Remains

ABSTRACTVertebrate scavengers are primary mechanisms for scatter and disarticulation of human remains in rural habitats. Because recovery of the body can be hampered by the degree of scatter due to scavengers, the methods used to search for body parts will influence how much is found and the length of time taken to recover the body. We compared the frequency of scavenging by vertebrates in two different habitats, a deciduous forest and a tall grass meadow, and measured the time taken to search for scattered remains within a designated search area using four methods. Freshly killed 23 kg pigs were placed in either a forest or tall grass meadow habitat, and scavenging by vertebrates was observed over a 5–6 day period. Subsequently, the link, line, zone, and spiral methods were used to search for remains within a 21 m2 search area. Three of 5 pigs in the forest and 4 of 5 pigs in the meadow habitat were scavenged by a variety of vertebrates. Mean time to search the designated area around each pig differed between the forest and the meadow, but not by search method. Mobility within each habitat likely explains the difference in search times, and also accounts for some of the variability between search methods.

Effects of navigation aids on web performance in younger and older adults

Age-related differences in web navigation were examined in two experiments, one (N=44) examining search performance and memory for site structure and a second (N=61) investigating search and memory for site content. Participants searched a large website under one of two experimental conditions; a control condition with only basic navigation aids or a condition with more enhanced navigation aids available. In Experiment 1, the enhanced navigation aids were breadcrumbs and a dynamic side-tree (BC-DST), whereas in Experiment 2 only the dynamic side-tree (DST) was available. In Experiment 1, search was more efficient for both age groups in the BC-DST condition. Age differences in search time and recall of the website’s structure could be eliminated by controlling for working memory and processing speed. In Experiment 2, navigation speed improved with practice and there were larger improvements observed for older adults. Navigation tools did not improve performance in either age group. Younger adults had better memory for content than their older counterparts. Contrary to the hypothesis that older adults are more frequently ‘lost’ in their search, age was not associated with the number of pages or repeat pages visited. Future research should focus on alleviating cognitive demands of search in more representative groups of older users.

Effects of computer icons and figure/background area ratios and color combinations on visual search performance on an LCD monitor

This study investigated the effects of figure/background color combinations, the type of computer icon and the figure/background area ratio on visual search performance on a liquid crystal display (LCD) screen. Participants had to search for the target item in a circle stimulus array, which had a diameter of 20 cm and included one target and 19 distracters. Results showed that these three independent variables significantly affected the visual search performance. The search times for EMAIL and SAVE computer icons were significantly shorter than that for a PRINT computer icon. Visual search performance was better for computer icons with a 90% figure/background area ratio than for a 70% ratio. However, no difference in search time between 90% and 50% ratios or between 70% and 50% ratios was observed. Color combinations also significantly affected the visual search performance and white/yellow and white/blue color combinations for the figure/background resulted in better performance than black/blue and black/yellow combinations. However, no difference in search time was observed for participants with and without esthetic training. The implications of the results are applicable to design icons for the interfacing of computers and communication information.

Interaction between seed crypsis and habitat structure influence patch choice in a granivorous bird, the chaffinch Fringilla coelebs

Food abundance is an important determinant in habitat and patch selection but food accessibility and detectability is less often considered. Foraging on more cryptic seeds may increase predation risk by increasing the length of head down periods. Habitat structure may interact with this as birds are less able to detect predators with their head lowered in riskier obstructed habitats. We investigated patch choice in chaffinches Fringilla coelebs foraging in obstructed and open habitats and artificially manipulated the search times of seeds by colouring them either yellow or black. One trial consisted of a choice between the conspicuous seed in the open patch, and the cryptic seed in the obstructed patch; in the second trial the treatments were reversed. Individuals were more willing to forage in the obstructed habitat when the yellow seeds were present (43% of pecks made in the obstructed patch) than when the black seeds were present (18% of pecks in the obstructed patch). Differences in search time are likely to explain this result: yellow seeds were located almost twice as fast (1.26±0.60 seconds) as black ones (2.36±0.88 seconds). This experiment shows that individual foraging decisions may be influenced not only by food abundance but by the properties of individual food items (in this case seed crypsis) and the structure of the habitat they are present in.

Effects of manganese on chemically induced food search behaviour of the Norway lobster, Nephrops norvegicus (L.)

The decapod Norway lobster, Nephrops norvegicus (L.), lives on muddy sediments rich in manganese (Mn). In hypoxic conditions, manganese is reduced and released from the sediment, so increased concentrations of dissolved Mn 2+ become bioavailable. In excess, manganese acts as a neurotoxin and may inhibit vital functions of benthic organisms, such as muscle contraction. We investigated in a laboratory flume experiment, the effect of environmentally realistic concentrations of manganese (0.1 and 0.2 mM for 12 days) on the food search behaviour of N. norvegicus. We found that lobsters exposed to manganese had a more than doubled reaction time to food odour stimuli compared to the controls ( p < 0.05). In addition, manganese exposure reduced the number of N. norvegicus reaching the food stimuli source. Compared to the controls where 86% reached the stimuli source, only about half of the lobsters exposed to 0.1 mM Mn and one-third of the lobsters exposed to 0.2 mM Mn reached the stimuli source ( p < 0.05 and 0.001, respectively). There was no significant difference between treatments in the number of lobsters leaving their shelter or in the time from reaction until leaving the shelter and there was no difference in search time for those animals that eventually did locate the stimuli source. This study shows that environmentally realistic manganese concentrations affect parts of the food search behaviour of N. norvegicus, likely due to impaired chemosensory ability or reduced motivation for feeding. Thus, the ability of N. norvegicus to detect and find food can be reduced in areas with high manganese concentrations, with possible consequences on individual and population levels.

Age Differences in Search Time for Two Over-Thecounter (OTC) Drug Label Formats

This study compared older and younger adults' knowledge acquisition and search times for information on older and newer over-the-counter (OTC) drug label formats. The results showed that younger adults were faster than older adults. The younger group performed significantly faster with the newer formatted labels than the older formatted labels, whereas the older adults yielded no difference between the two formats. Potential directions for future research are discussed.

Comparing Cascading and Indexed Menu Designs for Differences in Performance and Preference

Three menu layouts were compared for objective and subjective performance, as well as overall preference. The menus structures consisted of an index layout, a vertical cascading layout, and a horizontal cascading layout. Significant differences in search time were revealed between the three menu item layouts that favored the index menu layout. In addition, there was a non-reliable trend that favored the subjective opinion that the index layout was less disorientating than the other two layouts. Moreover, participants selected the index layout as their first preference choice more than the other two layouts. The poorest performer, both objectively and subjectively, was the horizontal layout. Possible reasons for these outcomes are discussed.

Testing the performance of avalanche transceivers

Avalanche rescue beacons are electronic transmitter–receiver devices designed to locate avalanche victims in avalanche debris. They have become standard equipment for the winter backcountry traveler. With the appearance of digital beacons or transceivers and the growing variety of beacons, the need arose for independent testing of this type of rescue equipment. Although there is a European standard for manufacturing beacons, there are substantial differences not only in how performance is defined between different brands, but also in how performance is best measured. Testing the performance is crucial, but not straightforward. There is no standard test procedure. Therefore, test designs are proposed to comprehensively measure search time and range. They should ensure reproducibility of performance results and were applied in two large field tests in Switzerland. A method recently proposed to define the width of search strip based on maximum range measurements in co-axial antenna orientation was verified by these tests and can be recommended. Results show that the maximal range of different beacons varies between about 25 and 100 m. Differences in search times were significant as well, but these were relatively small compared with the total time for recovery of a buried victim. Theoretical considerations of the relation between search time and range were also confirmed.

Methamphetamine exposure from postnatal day 11 to 20 causes impairments in both behavioral strategies and spatial learning in adult rats

Spatial learning and memory deficits in a water maze have been observed in adult animals exposed to a regimen of 4 daily doses of d-methamphetamine (MA) at 2 h intervals from postnatal day 11 to 20. An interpretational issue for these long-term effects of MA is whether they are truly spatial deficits or are secondary to alterations in sensorimotor systems. In this experiment, we evaluated the effects of a pretraining procedure shown to minimize the influence of drug-induced sensorimotor deficits. Animals within a litter were treated with MA or saline. Animals were either pretrained for nonspatial task requirements in the water maze (i.e., swimming and platform climbing) or were naı̈ve to the task. Animals that received the pretraining did better than the naı̈ve animals. The naı̈ve MA animals performed worse than the naı̈ve control animals as previously observed. By contrast, no difference in search time was noted between pretrained MA- and SAL-treated animals during the acquisition phase of testing. When the platform was relocated in a novel position, spatial learning was impaired for MA animals, regardless of pretraining. No increase in the number of platform nonrecognition events (swimovers, deflections, or jump-offs) occurred among pretrained or naı̈ve groups compared to controls. These data suggest that sensorimotor deficits do not account for the spatial learning and memory deficits in animals exposed neonatally to MA.

Spatial, contextual and working memory are not affected by the absence of mossy fiber long-term potentiation and depression

The mossy fibers of the hippocampus display NMDA-receptor independent long-term plasticity. A number of studies addressed the role of mossy fiber long-term plasticity in memory, but have provided contrasting results. Here, we have exploited a genetic model, the rab3A null-mutant, which is characterized by the absence of both mossy fiber long-term potentiation and long-term depression. This mutant was backcrossed to 129S3/SvImJ and C57Bl/6J to obtain standardized genetic backgrounds. Spatial working memory, assessed in the eight-arm radial maze, was unchanged in rab3A null-mutants. Moreover, one-trial cued and contextual fear conditioning was normal. Long-term spatial memory was tested in the Morris water maze. Two different versions of this task were used, an ‘easy’ version and a ‘difficult’ one. On both versions, no differences in search time and quadrant preferences were observed. Thus, despite the elimination of mossy fiber long-term plasticity, these tests revealed no impairments in mnemonic capabilities. We conclude that spatial, contextual and working memory do not depend on mossy fiber plasticity.

The role of priming in conjunctive visual search

To assess the role of priming in conjunctive visual search tasks, we systematically varied the consistency of the target and distractor identity between different conditions. Search was fastest in the standard conjunctive search paradigm where identities remained constant. Search was slowest when potential target identity varied predictably for each successive trial (the ‘switch’ condition). The role of priming was also demonstrated on a trial-by-trial basis in a ‘streak’ condition where target and distractor identity was unpredictable yet was consistent within streaks. When the target to be found was the same for a few trials in a row, search performance became similar to that when the potential target was the same on all trials. A similar pattern was found for the target absent trials, suggesting that priming is based on the whole search array rather than just the target in each case. Further analysis indicated that the effects of priming are sufficiently strong to account for the advantage seen for the conjunctive search task. We conclude that the role of priming in visual search is underestimated in current theories of visual search and that differences in search times often attributed to top-down guidance may instead reflect the benefits of priming.