scholarly journals The influence of search termination with correct "target absent" response

2018 ◽  
Vol 18 (10) ◽  
pp. 280
Author(s):  
Jieun Cho ◽  
Sang Chul Chong
Keyword(s):  
Search Termination ◽  
Correct Target

Selective Attention and Error Processing in an Illusory Conjunction Task

2005 ◽  
Vol 19 (3) ◽  
pp. 216-231 ◽  
Author(s):  
Albertus A. Wijers ◽  
Maarten A.S. Boksem
Keyword(s):  
Target Detection ◽  
Event Related Potentials ◽  
Illusory Conjunction ◽  
Conjunction Error ◽  
Error Related Negativity ◽  
Display Element ◽  
Related Potentials ◽  
Feature Error ◽  
High Level ◽  
Correct Target

Abstract. We recorded event-related potentials in an illusory conjunction task, in which subjects were cued on each trial to search for a particular colored letter in a subsequently presented test array, consisting of three different letters in three different colors. In a proportion of trials the target letter was present and in other trials none of the relevant features were present. In still other trials one of the features (color or letter identity) were present or both features were present but not combined in the same display element. When relevant features were present this resulted in an early posterior selection negativity (SN) and a frontal selection positivity (FSP). When a target was presented, this resulted in a FSP that was enhanced after 250 ms as compared to when both relevant features were present but not combined in the same display element. This suggests that this effect reflects an extra process of attending to both features bound to the same object. There were no differences between the ERPs in feature error and conjunction error trials, contrary to the idea that these two types of errors are due to different (perceptual and attentional) mechanisms. The P300 in conjunction error trials was much reduced relative to the P300 in correct target detection trials. A similar, error-related negativity-like component was visible in the response-locked averages in correct target detection trials, in feature error trials, and in conjunction error trials. Dipole modeling of this component resulted in a source in a deep medial-frontal location. These results suggested that this type of task induces a high level of response conflict, in which decision-related processes may play a major role.

Anticipatory saccades in sequential procedural learning in monkeys

1996 ◽  
Vol 76 (2) ◽  
pp. 1361-1366 ◽  
Author(s):  
K. Miyashita ◽  
M. K. Rand ◽  
S. Miyachi ◽  
O. Hikosaka
Keyword(s):  
Time Course ◽  
Preceding Paper ◽  
Button Press ◽  
Visually Guided ◽  
Short Term ◽  
Skilled Performance ◽  
Opposite Hand ◽  
Sequential Procedures ◽  
Correct Target

1. In a preceding paper we examined the short-term and long-term processes of learning of sequential procedures in monkeys. We now report that the pattern of eye movements changed along with the long-term learning. 2. The monkey's task was to press five consecutive pairs of target buttons (indicated by illumination) in the correct order for every pair, which the monkey had to find by trial and error (2 x 5 task). The whole sequence was called the "hyperset"; each pair was called the "set." 3. Initially, the saccade toward the correct target occurred after illumination of the targets (visually guided saccade). After sufficient learning, the saccade tended to occur before the target illumination (anticipatory saccade). This was true only for the hyperset that had been learned. 4. The likelihood of anticipatory saccade increased gradually over 20-30 days of practice of the particular hyperset. The time course was similar to how the hand learned (button press latency). 5. The monkeys were required to use the same hand for each hyperset throughout learning, except when we asked them to use the opposite hand. The nearly perfect performance due to the extensive practice was then deteriorated by the use of the opposite hand. We found, in addition, that anticipatory saccades became much less frequent. This finding suggests that critical for the skilled performance was the combination of the eyes and the side of the hand that was used for the practice of a given sequence.

scholarly journals Mechanisms of membrane protein biogenesis

2014 ◽  
Vol 70 (a1) ◽  
pp. C1161-C1161
Author(s):  
Irmgard Sinning
Keyword(s):  
Membrane Proteins ◽  
Signal Sequence ◽  
Signal Recognition Particle ◽  
Signal Recognition ◽  
Protein Biogenesis ◽  
Cargo Proteins ◽  
Target Membrane ◽  
Hydrophobic Nature ◽  
Correct Target ◽  
Srp Rna

More than 25% of the cellular proteome comprise membrane proteins that have to be inserted into the correct target membrane. Most membrane proteins are delivered to the membrane by the signal recognition particle (SRP) pathway which relies on the recognition of an N-terminal signal sequence. In contrast to this co-translational mechanism, which avoids problems due to the hydrophobic nature of the cargo proteins, tail-anchored (TA) membrane proteins utilize a post-translational mechanism for membrane insertion – the GET pathway (guided entry of tail-anchored membrane proteins). The SRP and GET pathways are both regulated by GTP and ATP binding proteins of the SIMIBI family. However, in the SRP pathway the SRP RNA plays a unique regulatory role. Recent insights into eukaryotic SRP will be discussed.

scholarly journals Interlaboratory Study on Thermal Cycler Performance in Controlled PCR and Random Amplified Polymorphic DNA Analyses

2001 ◽  
Vol 47 (1) ◽  
pp. 47-55 ◽  
Author(s):  
Ginny C Saunders ◽  
Juliet Dukes ◽  
Helen C Parkes ◽  
Johanne H Cornett
Keyword(s):  
Random Amplified Polymorphic Dna ◽  
Positive Sample ◽  
Interlaboratory Study ◽  
Pcr Assay ◽  
Single Product ◽  
The United Kingdom ◽  
Rapd Pcr ◽  
Block Temperature ◽  
Thermal Cycler ◽  
Correct Target

Abstract Background: Intercomparisons of PCR-based data between laboratories require an assurance of assay reproducibility. We performed an interlaboratory study to investigate the contribution made by a variety of thermal cyclers to PCR performance as measured by interblock reproducibility and intrablock repeatability. Methods: Two standardized assays designed to minimize the introduction of non-thermal-cycler-dependent variations were evaluated by 18 laboratories in the United Kingdom, using 33 thermal cyclers of various makes and models. We used a single-product (590 bp) PCR, established in our laboratory as a robust and specific reaction. The second reaction, a multiproduct random amplified polymorphic DNA (RAPD) PCR, was known to be more susceptible to small changes in block temperature and was therefore considered a way of assessing block uniformity with respect to temperature. Assay repeatability data were analyzed with respect to temperature calibration status, the type of temperature control mechanism, thermal cycler age, and the presence of oil overlay or heated lid systems. Results: All (100%) of the laboratories produced the correct target for the single-product PCR assay, although substantial variation in yield in replicate reactions was observed in 9.4% of these. The RAPD reaction generated results that varied extensively both within the same block and between different thermal cyclers. For eight replicates of a positive sample, 88% intrablock repeatability was demonstrated in calibrated thermal cyclers, which decreased to 63% in noncalibrated instruments. Conclusions: Irrespective of the make and model of thermal cycler, temperature-calibrated instruments consistently generated more repeatable RAPD data than noncalibrated instruments. Guidelines are offered on optimizing and monitoring thermal cycler performance.

scholarly journals Evolution of learned strategy choice in a frequency-dependent game

2011 ◽  
Vol 279 (1731) ◽  
pp. 1176-1184 ◽  
Author(s):  
Edith Katsnelson ◽  
Uzi Motro ◽  
Marcus W. Feldman ◽  
Arnon Lotem
Keyword(s):  
Theoretical Analysis ◽  
Strategy Choice ◽  
Model Learning ◽  
Environmental Fluctuation ◽  
Frequency Dependent ◽  
Agent Based ◽  
Learning Rules ◽  
Evolutionary Simulation ◽  
Sufficient Degree ◽  
Correct Target

In frequency-dependent games, strategy choice may be innate or learned. While experimental evidence in the producer–scrounger game suggests that learned strategy choice may be common, a recent theoretical analysis demonstrated that learning by only some individuals prevents learning from evolving in others. Here, however, we model learning explicitly, and demonstrate that learning can easily evolve in the whole population. We used an agent-based evolutionary simulation of the producer–scrounger game to test the success of two general learning rules for strategy choice. We found that learning was eventually acquired by all individuals under a sufficient degree of environmental fluctuation, and when players were phenotypically asymmetric. In the absence of sufficient environmental change or phenotypic asymmetries, the correct target for learning seems to be confounded by game dynamics, and innate strategy choice is likely to be fixed in the population. The results demonstrate that under biologically plausible conditions, learning can easily evolve in the whole population and that phenotypic asymmetry is important for the evolution of learned strategy choice, especially in a stable or mildly changing environment.

scholarly journals Product Lineups: The More You Search, The Less You Find

2020 ◽  
Vol 47 (1) ◽  
pp. 40-55
Author(s):  
Sang Kyu Park ◽  
Aner Sela
Keyword(s):  
Subjective Feeling ◽  
Target Product ◽  
Online Search ◽  
Inference Making ◽  
Search Terms ◽  
True Target ◽  
General Search ◽  
Similar Item ◽  
Correct Target ◽  
Practical Implications

Abstract Consumers often try to visually identify a previously encountered product among a sequence of similar items, guided only by their memory and a few general search terms. What determines their success at correctly identifying the target product in such “product lineups”? The current research finds that the longer consumers search sequentially, the more conservative and—ironically—inaccurate judges they become. Consequently, the more consumers search, the more likely they are to erroneously reject the correct target when it finally appears in the lineup. This happens because each time consumers evaluate a similar item in the lineup, and determine that it is not the option for which they have been looking, they draw an implicit inference that the correct target should feel more familiar than the similar items rejected up to that point. This causes the subjective feeling of familiarity consumers expect to experience with the true target to progressively escalate, making them more conservative but also less accurate judges. The findings have practical implications for consumers and marketers, and make theoretical contributions to research on inference-making, online search, and product recognition.

Comparison of Variable Coded Symbology to a Conventional Tactical Situation Display Method

1996 ◽  
Vol 40 (23) ◽  
pp. 1174-1178 ◽  
Author(s):  
William A. Nugent
Keyword(s):  
Visual Search ◽  
Performance Measures ◽  
The Other ◽  
Sea Surface ◽  
Search Performance ◽  
Elapsed Time ◽  
Display Performance ◽  
Correct Target ◽  
Practical Implications ◽  
First Session

Visual search performance was compared using three variable coded symbology (VCS) methods, which included a mixture of symbol colors and/or shapes on the same tactical situation display, to a single color-coded tactical symbol set. Six participants completed two replications of 12 trials using each method on a combined total of 336 targets. Half the sample viewed visually prominent air targets in VCS methods administered in the first session, with sea surface targets prominent in VCS methods in the second session; the converse for the other half. Performance measures included throughput-an estimate of correct target hits per working minute, and elapsed time to enter selected targets into an on-screen list box. Superior throughput was demonstrated for a VCS method that combined three symbol coding levels on the same display. Performance was generally poorest for a VCS method combining color and monochrome formats within the same symbol set. Practical implications of these findings are discussed.

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