scholarly journals Distractor suppression leads to reduced flanker interference

2020 ◽  
Author(s):  
Yavor Ivanov ◽  
Jan Theeuwes
Keyword(s):  
High Probability ◽  
Congruence Effect ◽  
Top Down ◽  
Search Mode ◽  
Target Feature ◽  
Priority Map ◽  
Feature Search Mode ◽  
Suppression Mechanism ◽  
Target Experiment ◽  
Low Probability

AbstractRecent studies using the additional singleton paradigm have shown that regularities in distractor locations can cause biases in the spatial priority map, such that attentional capture by salient singletons is reduced for locations that are likely to contain distractors. It has been suggested that this type of suppression is proactive (i.e., occurring before display onset). The current study replicated the original findings using an online version of the task. To further assess the suppression of high-probability locations, we employed a congruence manipulation similar to the traditional flanker effect, where distractors could be either congruent or incongruent with the response to the target. Experiment 1 shows that through statistical learning distractor suppression reduces the interference from incongruent distractors, as participants made less errors in high-probability versus low-probability conditions. In Experiment 2, participants were forced to search for a specific target feature (the so-called feature-search mode), which is assumed to allow participants to ignore distractors in a top-down manner. Yet even when this “top-down” search mode was employed, there was still a congruence effect when the distractor singleton was presented at the low-probability but not at the high-probability location. The absence, but not reversal, of a congruence effect at the high-probability location also further indicates that this distractor suppression mechanism is proactive. The results indicate that regardless of the search mode used, there is suppression of the high-probability location indicating that this location competes less for attention within the spatial priority map than all other locations.

scholarly journals Independent effects of statistical learning and top-down attention

2020 ◽  
Vol 82 (8) ◽  
pp. 3895-3906
Author(s):  
Ya Gao ◽  
Jan Theeuwes
Keyword(s):  
Working Memory ◽  
Statistical Learning ◽  
Spatial Working Memory ◽  
Attentional Selection ◽  
Top Down ◽  
Singleton Distractor ◽  
Priority Map ◽  
Implicit Biases ◽  
Target Experiment ◽  
Independent Effects

Abstract It is well known that spatial attention can be directed in a top-down way to task-relevant locations in space. In addition, through visual statistical learning (VSL), attention can be biased towards relevant (target) locations and away from irrelevant (distractor) locations. The present study investigates the interaction between the explicit task-relevant, top-down attention and the lingering attentional biases due to VSL. We wanted to determine the contribution of each of these two processes to attentional selection. In the current study, participants performed a search task while keeping a location in spatial working memory. In Experiment 1, the target appeared more often in one location, and appeared less often in other location. In Experiment 2, a color singleton distractor was presented more often in location than in all other locations. The results show that when the search target matched the location that was kept in working memory, participants were much faster at responding to the search target than when it did not match, signifying top-down attentional selection. Independent of this top-down effect, we found a clear effect of VSL as responses were even faster when target (Experiment 1) or the distractor (Experiment 2) was presented at a more likely location in visual field. We conclude that attentional selection is driven by implicit biases due to statistical learning and by explicit top-down processing, each process individually and independently modulating the neural activity within the spatial priority map.

scholarly journals Proactive distractor suppression elicited by statistical regularities in visual search

2021 ◽  
Author(s):  
Changrun Huang ◽  
Ana Vilotijević ◽  
Jan Theeuwes ◽  
Mieke Donk
Keyword(s):  
Visual Search ◽  
Statistical Learning ◽  
High Probability ◽  
Search Task ◽  
Reaction Times ◽  
Distractor Interference ◽  
Probe Task ◽  
Priority Map ◽  
Statistical Regularities ◽  
Low Probability

AbstractIrrelevant salient objects may capture our attention and interfere with visual search. Recently, it was shown that distraction by a salient object is reduced when it is presented more frequently at one location than at other locations. The present study investigates whether this reduced distractor interference is the result of proactive spatial suppression, implemented prior to display onset, or reactive suppression, occurring after attention has been directed to that location. Participants were asked to search for a shape singleton in the presence of an irrelevant salient color singleton which was presented more often at one location (the high-probability location) than at all other locations (the low-probability locations). On some trials, instead of the search task, participants performed a probe task, in which they had to detect the offset of a probe dot. The results of the search task replicated previous findings showing reduced distractor interference in trials in which the salient distractor was presented at the high-probability location as compared with the low-probability locations. The probe task showed that reaction times were longer for probes presented at the high-probability location than at the low-probability locations. These results indicate that through statistical learning the location that is likely to contain a distractor is suppressed proactively (i.e., prior to display onset). It suggests that statistical learning modulates the first feed-forward sweep of information processing by deprioritizing locations that are likely to contain a distractor in the spatial priority map.

Spatial suppression due to statistical regularities is driven by distractor suppression not by target activation

2018 ◽  
Author(s):  
Michel Failing ◽  
Benchi Wang ◽  
Jan Theeuwes
Keyword(s):  
High Probability ◽  
Target Location ◽  
Target Selection ◽  
Visual Space ◽  
Alternative Interpretation ◽  
Distractor Location ◽  
Target Presentation ◽  
Statistical Regularities ◽  
Low Probability ◽  
Presentation Experiment

Where and what we attend to is not only determined by what we are currently looking for but also by what we have encountered in the past. Recent studies suggest that biasing the probability by which distractors appear at locations in visual space may lead to attentional suppression of high probability distractor locations which effectively reduces capture by a distractor but also impairs target selection at this location. However, in many of these studies introducing a high probability distractor location was tantamount to increasing the probability of the target appearing in any of the other locations (i.e. the low probability distractor locations). Here, we investigate an alternative interpretation of previous findings according to which attentional selection at high probability distractor locations is not suppressed. Instead, selection at low probability distractor locations is facilitated. In two visual search tasks, we found no evidence for this hypothesis: neither when there was only a bias in target presentation but no bias in distractor presentation (Experiment 1), nor when there was only a bias in distractor presentation but no bias in target presentation (Experiment 2). We conclude that recurrent presentation of a distractor in a specific location leads to attentional suppression of that location through a mechanism that is unaffected by any regularities regarding the target location.

Validation of a machine learned model to predict the diagnosis of myocardial infarction

2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
D Doudesis ◽  
J Yang ◽  
A Tsanas ◽  
C Stables ◽  
A Shah ◽  
...  
Keyword(s):  
Myocardial Infarction ◽  
Acute Coronary Syndrome ◽  
Predictive Value ◽  
High Probability ◽  
Cardiovascular Death ◽  
Gradient Boosting ◽  
Funding Source ◽  
Coronary Syndrome ◽  
Low Probability ◽  
One Year

Abstract Introduction The myocardial-ischemic-injury-index (MI3) is a promising machine learned algorithm that predicts the likelihood of myocardial infarction in patients with suspected acute coronary syndrome. Whether this algorithm performs well in unselected patients or predicts recurrent events is unknown. Methods In an observational analysis from a multi-centre randomised trial, we included all patients with suspected acute coronary syndrome and serial high-sensitivity cardiac troponin I measurements without ST-segment elevation myocardial infarction. Using gradient boosting, MI3 incorporates age, sex, and two troponin measurements to compute a value (0–100) reflecting an individual's likelihood of myocardial infarction, and estimates the negative predictive value (NPV) and positive predictive value (PPV). Model performance for an index diagnosis of myocardial infarction, and for subsequent myocardial infarction or cardiovascular death at one year was determined using previously defined low- and high-probability thresholds (1.6 and 49.7, respectively). Results In total 20,761 of 48,282 (43%) patients (64±16 years, 46% women) were eligible of whom 3,278 (15.8%) had myocardial infarction. MI3 was well discriminated with an area under the receiver-operating-characteristic curve of 0.949 (95% confidence interval 0.946–0.952) identifying 12,983 (62.5%) patients as low-probability (sensitivity 99.3% [99.0–99.6%], NPV 99.8% [99.8–99.9%]), and 2,961 (14.3%) as high-probability (specificity 95.0% [94.7–95.3%], PPV 70.4% [69–71.9%]). At one year, subsequent myocardial infarction or cardiovascular death occurred more often in high-probability compared to low-probability patients (17.6% [520/2,961] versus 1.5% [197/12,983], P<0.001). Conclusions In unselected consecutive patients with suspected acute coronary syndrome, the MI3 algorithm accurately estimates the likelihood of myocardial infarction and predicts probability of subsequent adverse cardiovascular events. Performance of MI3 at example thresholds Funding Acknowledgement Type of funding source: Foundation. Main funding source(s): Medical Research Council

scholarly journals Prediction of Patients with Acute Cholecystitis Requiring Emergent Cholecystectomy: A Simple Score

2010 ◽  
Vol 2010 ◽  
pp. 1-5 ◽  
Author(s):  
Wael N. Yacoub ◽  
Mikael Petrosyan ◽  
Indu Sehgal ◽  
Yanling Ma ◽  
Parakrama Chandrasoma ◽  
...  
Keyword(s):  
Heart Rate ◽  
Logistic Regression ◽  
Acute Cholecystitis ◽  
High Probability ◽  
Acute Inflammation ◽  
Gallbladder Wall ◽  
Cutoff Score ◽  
Gangrenous Cholecystitis ◽  
Pathological Review ◽  
Low Probability

The objective was to develop a score, to stratify patients with acute cholecystitis into high, intermediate, or low probability of gangrenous cholecystitis. The probability of gangrenous cholecystitis (score) was derived from a logistic regression of a clinical and pathological review of 245 patients undergoing urgent cholecystectomy. Sixty-eight patients had gangrenous inflammation, 132 acute, and 45 no inflammation. The score comprised of: age > 45 years (1 point), heart rate > 90 beats/min (1 point), male (2 points), Leucocytosis > 13,000/mm3(1.5 points), and ultrasound gallbladder wall thickness>4.5 mm (1 point). The prevalence of gangrenous cholecystitis was 13% in the low-probability (0–2 points), 33% in the intermediate-probability (2–4.5 points), and 87% in the high probability category (>4.5 points). A cutoff score of 2 identified 31 (69%) patients with no acute inflammation (PPV 90%). This scoring system can prioritize patients for emergent cholecystectomy based on their expected pathology.

Frequency of enforcement is more important than the severity of punishment in reducing violation behaviors

2021 ◽  
Vol 118 (42) ◽  
pp. e2108507118
Author(s):  
Kinneret Teodorescu ◽  
Ori Plonsky ◽  
Shahar Ayal ◽  
Rachel Barkan
Keyword(s):  
High Probability ◽  
Real Life ◽  
Expected Value ◽  
Relative Importance ◽  
Decisions From Experience ◽  
High Severity ◽  
Low Probability ◽  
Violation Rate ◽  
Severity Of Punishment ◽  
Enforcement Policies

External enforcement policies aimed to reduce violations differ on two key components: the probability of inspection and the severity of the punishment. Different lines of research offer different insights regarding the relative importance of each component. In four studies, students and Prolific crowdsourcing participants (Ntotal = 816) repeatedly faced temptations to commit violations under two enforcement policies. Controlling for expected value, we found that a policy combining a high probability of inspection with a low severity of fines (HILS) was more effective than an economically equivalent policy that combined a low probability of inspection with a high severity of fines (LIHS). The advantage of prioritizing inspection frequency over punishment severity (HILS over LIHS) was greater for participants who, in the absence of enforcement, started out with a higher violation rate. Consistent with studies of decisions from experience, frequent enforcement with small fines was more effective than rare severe fines even when we announced the severity of the fine in advance to boost deterrence. In addition, in line with the phenomenon of underweighting of rare events, the effect was stronger when the probability of inspection was rarer (as in most real-life inspection probabilities) and was eliminated under moderate inspection probabilities. We thus recommend that policymakers looking to effectively reduce recurring violations among noncriminal populations should consider increasing inspection rates rather than punishment severity.

Portable Ventilation/Perfusion Scanning is Useful for Evaluating Clinically Significant Pulmonary Embolism in the ICU Despite Abnormal Chest Radiography

2018 ◽  
Vol 35 (10) ◽  
pp. 1032-1038 ◽  
Author(s):  
Aaron S. Weinberg ◽  
William Chang ◽  
Grace Ih ◽  
Alan Waxman ◽  
Victor F. Tapson
Keyword(s):  
Pulmonary Embolism ◽  
Chest Radiograph ◽  
High Probability ◽  
Hemodynamic Instability ◽  
X Rays ◽  
X Ray ◽  
Abnormal Chest ◽  
Chest X Ray ◽  
Low Probability ◽  
Clinically Significant

Objective: Computed tomography angiography is limited in the intensive care unit (ICU) due to renal insufficiency, hemodynamic instability, and difficulty transporting unstable patients. A portable ventilation/perfusion (V/Q) scan can be used. However, it is commonly believed that an abnormal chest radiograph can result in a nondiagnostic scan. In this retrospective study, we demonstrate that portable V/Q scans can be helpful in ruling in or out clinically significant pulmonary embolism (PE) despite an abnormal chest x-ray in the ICU. Design: Two physicians conducted chart reviews and original V/Q reports. A staff radiologist, with 40 years of experience, rated chest x-ray abnormalities using predetermined criteria. Setting: The study was conducted in the ICU. Patients: The first 100 consecutive patients with suspected PE who underwent a portable V/Q scan. Interventions: Those with a portable V/Q scan. Results: A normal baseline chest radiograph was found in only 6% of patients. Fifty-three percent had moderate, 24% had severe, and 10% had very-severe radiographic abnormalities. Despite the abnormal x-rays, 88% of the V/Q scans were low probability for a PE despite an average abnormal radiograph rating of moderate. A high-probability V/Q for PE was diagnosed in 3% of the population despite chest x-ray ratings of moderate to severe. Six patients had their empiric anticoagulation discontinued after obtaining the results of the V/Q scan, and no anticoagulation was started for PE after a low-probability V/Q scan. Conclusion: Despite the large percentage of moderate-to-severe x-ray abnormalities, PE can still be diagnosed (high-probability scan) in the ICU with a portable V/Q scan. Although low-probability scans do not rule out acute PE, it appeared less likely that any patient with a low-probability V/Q scan had severe hypoxemia or hemodynamic instability due to a significant PE, which was useful to clinicians and allowed them to either stop or not start anticoagulation.

Enhancement and Suppression Flexibly Guide Attention

2019 ◽  
Vol 30 (12) ◽  
pp. 1724-1732 ◽  
Author(s):  
Seah Chang ◽  
Howard E. Egeth
Keyword(s):  
Color Singleton ◽  
Top Down ◽  
Target Feature ◽  
Attentional Guidance ◽  
Feature Enhancement ◽  
Letter Target ◽  
Irrelevant Color

Previous research suggests that observers can suppress salient-but-irrelevant stimuli in a top-down manner. However, one question left unresolved is whether such suppression is, in fact, solely due to distractor-feature suppression or whether it instead also reflects some degree of target-feature enhancement. The present study ( N = 60) addressed this issue. On search trials (70% of trials), participants searched for a shape target when an irrelevant color singleton was either present or absent; performance was better when a color singleton was present. On interleaved probe trials (30% of trials), participants searched for a letter target. Responses were faster for the letter on a target-colored item than on a neutral-colored item, whereas responses were slower for the letter on a distractor-colored item than on a neutral-colored item. The results demonstrate that target-feature enhancement and distractor-feature suppression contribute to attentional guidance independently; enhancement and suppression flexibly guide attention as the occasion demands.

scholarly journals Analysis of the disc components of our galaxy via kinematic and spectroscopic procedures

2019 ◽  
Vol 36 ◽  
Author(s):  
S. Karaali ◽  
S. Bilir ◽  
E. Yaz Gökçe ◽  
O. Plevne
Keyword(s):  
High Probability ◽  
Space Velocity ◽  
Total Space ◽  
Apparent Magnitude ◽  
Galactic Latitude ◽  
Thick Disc ◽  
Thin Disc ◽  
Different Populations ◽  
Low Probability ◽  
The Rich

Abstract We used the spectroscopic and astrometric data provided from the GALactic Archaeology with HERMES (GALAH) Data Release (DR2) and Gaia DR2, respectively, for a large sample of stars to investigate the behaviour of the [ $\alpha$ /Fe] abundances via two procedures, that is, kinematically and spectroscopically. With the kinematical procedure, we investigated the distribution of the [ $\alpha$ /Fe] abundances into the high-/low-probability thin disc, and high-/low-probability thick-disc populations in terms of total space velocity, [Fe/H] abundance, and age. The high-probability thin-disc stars dominate in all sub-intervals of [ $\alpha$ /Fe], including the rich ones: [ $\alpha$ /Fe] $\,>\,0.3$ dex, where the high-probability thick-disc stars are expected to dominate. This result can be explained by the limiting apparent magnitude of the GALAH DR2 ( $V \lt 14$ mag) and intermediate galactic latitude of the star sample. Stars in the four populations share equivalent [ $\alpha$ /Fe] and [Fe/H] abundances, total space velocities, and ages. Hence, none of these parameters can be used alone for separation of a sample of stars into different populations. High-probability thin-disc stars with abundance $-1.3 \lt {\rm[Fe/H]}\leq -0.5$ dex and age $9 \lt \tau\leq13$ Gyr are assumed to have different birth places relative to the metal-rich and younger ones. With the spectroscopic procedure, we separated the sample stars into $\alpha$ -rich and $\alpha$ -poor categories by means of their ages as well as their [ $\alpha$ /Fe] and [Fe/H] abundances. Stars older than 8 Gyr are richer in [ $\alpha$ /Fe] than the younger ones. We could estimate the abundance [ $\alpha$ /Fe] = 0.14 dex as the boundary separating the $\alpha$ -rich and $\alpha$ -poor sub-samples in the [ $\alpha$ /Fe] $\,\times\,$ [Fe/H] plane.

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