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1.
Psychol Methods ; 2023 Dec 14.
Artículo en Inglés | MEDLINE | ID: mdl-38095989

RESUMEN

Meta-d'/d' has become the quasi-gold standard to quantify metacognitive efficiency because meta-d'/d' was developed to control for discrimination performance, discrimination criteria, and confidence criteria even without the assumption of a specific generative model underlying confidence judgments. Using simulations, we demonstrate that meta-d'/d' is not free from assumptions about confidence models: Only when we simulated data using a generative model of confidence according to which the evidence underlying confidence judgments is sampled independently from the evidence utilized in the choice process from a truncated Gaussian distribution, meta-d'/d' was unaffected by discrimination performance, discrimination task criteria, and confidence criteria. According to five alternative generative models of confidence, there exist at least some combination of parameters where meta-d'/d' is affected by discrimination performance, discrimination criteria, and confidence criteria. A simulation using empirically fitted parameter sets showed that the magnitude of the correlation between meta-d'/d' and discrimination performance, discrimination task criteria, and confidence criteria depends heavily on the generative model and the specific parameter set and varies between negligibly small and very large. These simulations imply that a difference in meta-d'/d' between conditions does not necessarily reflect a difference in metacognitive efficiency but might as well be caused by a difference in discrimination performance, discrimination task criterion, or confidence criteria. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

2.
Psychol Rev ; 130(6): 1521-1543, 2023 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-36913292

RESUMEN

How can choice, confidence, and response times be modeled simultaneously? Here, we propose the new dynamical weighted evidence and visibility (dynWEV) model, an extension of the drift-diffusion model of decision-making, to account for choices, reaction times, and confidence simultaneously. The decision process in a binary perceptual task is described as a Wiener process accumulating sensory evidence about the choice options bounded by two constant thresholds. To account for confidence judgments, we assume a period of postdecisional accumulation of sensory evidence and parallel accumulation of information about the reliability of the present stimulus. We examined model fits in two experiments, a motion discrimination task with random dot kinematograms and a postmasked orientation discrimination task. A comparison between the dynWEV model, two-stage dynamical signal detection theory, and several versions of race models of decision-making showed that only dynWEV produced acceptable fits of choices, confidence, and reaction time. This finding suggests that confidence judgments depend not only on choice evidence but also on a parallel estimate of stimulus discriminability and postdecisional accumulation of evidence. (PsycInfo Database Record (c) 2024 APA, all rights reserved).


Asunto(s)
Toma de Decisiones , Percepción de Movimiento , Humanos , Tiempo de Reacción/fisiología , Toma de Decisiones/fisiología , Reproducibilidad de los Resultados , Percepción Visual/fisiología , Juicio/fisiología , Percepción de Movimiento/fisiología
3.
Atten Percept Psychophys ; 83(8): 3311-3336, 2021 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-34089166

RESUMEN

How can we explain the regularities in subjective reports of human observers about their subjective visual experience of a stimulus? The present study tests whether a recent model of confidence in perceptual decisions, the weighted evidence and visibility model, can be generalized from confidence to subjective visibility. In a postmasked orientation identification task, observers reported the subjective visibility of the stimulus after each single identification response. Cognitive modelling revealed that the weighted evidence and visibility model provided a superior fit to the data compared with the standard signal detection model, the signal detection model with unsystematic noise superimposed on ratings, the postdecisional accumulation model, the two-channel model, the response-congruent evidence model, the two-dimensional Bayesian model, and the constant noise and decay model. A comparison between subjective visibility and decisional confidence revealed that visibility relied more on the strength of sensory evidence about features of the stimulus irrelevant to the identification judgment and less on evidence for the identification judgment. It is argued that at least two types of evidence are required to account for subjective visibility, one related to the identification judgment, and one related to the strength of stimulation.


Asunto(s)
Toma de Decisiones , Juicio , Teorema de Bayes , Humanos
4.
Neuroimage ; 218: 116963, 2020 09.
Artículo en Inglés | MEDLINE | ID: mdl-32461149

RESUMEN

Is confidence in perceptual decisions generated by the same brain processes as decision itself, or does confidence require metacognitive processes following up on the decision? In a masked orientation task with varying stimulus-onset-asynchrony, we used EEG and cognitive modelling to trace the timing of the neural correlates of confidence. Confidence reported by human observers increased with stimulus-onset-asynchrony in correct and to a lesser degree in incorrect trials, a pattern incompatible with established models of confidence. Electrophysiological activity was associated with confidence in two different time periods, namely 350-500 â€‹ms after stimulus onset and 250-350 â€‹ms after the response. Cognitive modelling revealed that only the activity following on the stimulus exhibited the same statistical regularities as confidence, while the statistical pattern of the activity following the response was incompatible with confidence. It is argued that electrophysiological markers of confidence and error awareness are at least in parts distinct.


Asunto(s)
Toma de Decisiones/fisiología , Metacognición/fisiología , Modelos Psicológicos , Desempeño Psicomotor/fisiología , Adolescente , Adulto , Algoritmos , Electroencefalografía , Fenómenos Electrofisiológicos , Potenciales Evocados , Femenino , Fijación Ocular , Humanos , Masculino , Orientación , Estimulación Luminosa , Autoimagen , Adulto Joven
5.
PLoS Comput Biol ; 15(10): e1007456, 2019 10.
Artículo en Inglés | MEDLINE | ID: mdl-31634359

RESUMEN

Recent studies have traced the neural correlates of confidence in perceptual choices using statistical signatures of confidence. The most widely used statistical signature is the folded X-pattern, which was derived from a standard model of confidence assuming an objective definition of confidence as the posterior probability of making the correct choice given the evidence. The folded X-pattern entails that confidence as the subjective probability of being correct equals the probability of 0.75 if the stimulus in neutral about the choice options, increases with discriminability of the stimulus in correct trials, and decreases with discriminability in incorrect trials. Here, we show that the standard model of confidence is a special case in which there is no reliable trial-by-trial evidence about discriminability itself. According to a more general model, if there is enough evidence about discriminability, objective confidence is characterised by different pattern: For both correct and incorrect choices, confidence increases with discriminability. In addition, we demonstrate the consequence if discriminability is varied in discrete steps within the standard model: confidence in choices about neutral stimuli is no longer .75. Overall, identifying neural correlates of confidence by presupposing the folded X-pattern as a statistical signature of confidence is not legitimate.


Asunto(s)
Interpretación Estadística de Datos , Conducta de Elección/fisiología , Simulación por Computador , Toma de Decisiones/fisiología , Aprendizaje Discriminativo/fisiología , Modelos Teóricos , Probabilidad , Autoimagen
6.
Neurosci Conscious ; 2018(1): niy001, 2018.
Artículo en Inglés | MEDLINE | ID: mdl-30042854

RESUMEN

Visual search is facilitated when display configurations are repeated over time, showing that memory of spatio-configural context can cue the location of the target. The present study investigates whether memory of the search target in relation to the configuration of distractors alters subjective experience of the visual search target and/or the subjective experience of the display configuration. Observers performed a masked localization task for targets embedded in repeated vs. non-repeated (baseline) arrays of distractors items. After the localization response, observers reported their subjective experience of either the target or the display configuration. Bayesian analysis revealed that repeated displays resulted in a stronger visual experience of both targets and display configurations. However, subsequent analysis showed that repeated search displays increased the correlation between the experience of the display configuration and localization accuracy, but there was no such effect on experience of the target stimulus. We suggest that memory of visual context enhances the representation of the current visual search display. This representation improves visual search and at the same time increases observers' subjective experience of the display configuration.

7.
Atten Percept Psychophys ; 80(3): 622-642, 2018 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-29299850

RESUMEN

Shielding visual search against interference from salient distractors becomes more efficient over time for display regions where distractors appear more frequently, rather than only rarely Goschy, Bakos, Müller, & Zehetleitner (Frontiers in Psychology 5: 1195, 2014). We hypothesized that the locus of this learned distractor probability-cueing effect depends on the dimensional relationship of the to-be-inhibited distractor relative to the to-be-attended target. If the distractor and target are defined in different visual dimensions (e.g., a color-defined distractor and orientation-defined target, as in Goschy et al. (Frontiers in Psychology 5: 1195, 2014), distractors may be efficiently suppressed by down-weighting the feature contrast signals in the distractor-defining dimension Zehetleitner, Goschy, & Müller (Journal of Experimental Psychology: Human Perception and Performance 38: 941-957, 2012), with stronger down-weighting being applied to the frequent- than to the rare-distractor region. However, given dimensionally coupled feature contrast signal weighting (cf. Müller J, Heller & Ziegler (Perception & Psychophysics 57:1-17, 1995), this dimension-(down-)weighting strategy would not be effective when the target and the distractors are defined within the same dimension. In this case, suppression may operate differently: by inhibiting the entire frequent-distractor region on the search-guiding master saliency map. The downside of inhibition at this level is that, although it reduces distractor interference in the inhibited (frequent-distractor) region, it also impairs target processing in that region-even when no distractor is actually present in the display. This predicted qualitative difference between same- and different-dimension distractors was confirmed in the present study (with 184 participants), thus furthering our understanding of the functional architecture of search guidance, especially regarding the mechanisms involved in shielding search from the interference of distractors that consistently occur in certain display regions.


Asunto(s)
Atención/fisiología , Adulto , Percepción de Color/fisiología , Señales (Psicología) , Femenino , Humanos , Masculino , Orientación , Adulto Joven
8.
Atten Percept Psychophys ; 80(1): 134-154, 2018 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-29043657

RESUMEN

How do human observers determine their degree of belief that they are correct in a decision about a visual stimulus-that is, their confidence? According to prominent theories of confidence, the quality of stimulation should be positively related to confidence in correct decisions, and negatively to confidence in incorrect decisions. However, in a backward-masked orientation task with a varying stimulus onset asynchrony (SOA), we observed that confidence in incorrect decisions also increased with stimulus quality. Model fitting to our decision and confidence data revealed that the best explanation for the present data was the new weighted evidence-and-visibility model, according to which confidence is determined by evidence about the orientation as well as by the general visibility of the stimulus. Signal detection models, postdecisional accumulation models, two-channel models, and decision-time-based models were all unable to explain the pattern of confidence as a function of SOA and decision correctness. We suggest that the metacognitive system combines several cues related to the correctness of a decision about a visual stimulus in order to calculate decision confidence.


Asunto(s)
Toma de Decisiones/fisiología , Juicio/fisiología , Orientación/fisiología , Detección de Señal Psicológica/fisiología , Percepción Visual/fisiología , Adolescente , Adulto , Señales (Psicología) , Femenino , Humanos , Masculino , Metacognición/fisiología , Estimulación Luminosa/métodos , Adulto Joven
9.
J Exp Psychol Gen ; 146(5): 651-671, 2017 05.
Artículo en Inglés | MEDLINE | ID: mdl-28368190

RESUMEN

Pop-out search implies that the target is always the first item selected, no matter how many distractors are presented. However, increasing evidence indicates that search is not entirely independent of display density even for pop-out targets: search is slower with sparse (few distractors) than with dense displays (many distractors). Despite its significance, the cause of this anomaly remains unclear. We investigated several mechanisms that could slow down search for pop-out targets. Consistent with the assumption that pop-out targets frequently fail to pop out in sparse displays, we observed greater variability of search duration for sparse displays relative to dense. Computational modeling of the response time distributions also supported the view that pop-out targets fail to pop out in sparse displays. Our findings strongly question the classical assumption that early processing of pop-out targets is independent of the distractors. Rather, the density of distractors critically influences whether or not a stimulus pops out. These results call for new, more reliable measures of pop-out search and potentially a reinterpretation of studies that used relatively sparse displays. (PsycINFO Database Record


Asunto(s)
Atención/fisiología , Reconocimiento Visual de Modelos/fisiología , Adulto , Simulación por Computador , Femenino , Humanos , Masculino , Tiempo de Reacción/fisiología , Relación Señal-Ruido , Adulto Joven
10.
Conscious Cogn ; 49: 291-312, 2017 03.
Artículo en Inglés | MEDLINE | ID: mdl-28236748

RESUMEN

Are logistic regression slopes suitable to quantify metacognitive sensitivity, i.e. the efficiency with which subjective reports differentiate between correct and incorrect task responses? We analytically show that logistic regression slopes are independent from rating criteria in one specific model of metacognition, which assumes (i) that rating decisions are based on sensory evidence generated independently of the sensory evidence used for primary task responses and (ii) that the distributions of evidence are logistic. Given a hierarchical model of metacognition, logistic regression slopes depend on rating criteria. According to all considered models, regression slopes depend on the primary task criterion. A reanalysis of previous data revealed that massive numbers of trials are required to distinguish between hierarchical and independent models with tolerable accuracy. It is argued that researchers who wish to use logistic regression as measure of metacognitive sensitivity need to control the primary task criterion and rating criteria.


Asunto(s)
Metacognición/fisiología , Modelos Teóricos , Análisis de Regresión , Detección de Señal Psicológica/fisiología , Humanos , Modelos Logísticos , Pruebas Neuropsicológicas
11.
Psychol Methods ; 22(2): 322-339, 2017 06.
Artículo en Inglés | MEDLINE | ID: mdl-26651986

RESUMEN

Unplanned optional stopping rules have been criticized for inflating Type I error rates under the null hypothesis significance testing (NHST) paradigm. Despite these criticisms, this research practice is not uncommon, probably because it appeals to researcher's intuition to collect more data to push an indecisive result into a decisive region. In this contribution, we investigate the properties of a procedure for Bayesian hypothesis testing that allows optional stopping with unlimited multiple testing, even after each participant. In this procedure, which we call Sequential Bayes Factors (SBFs), Bayes factors are computed until an a priori defined level of evidence is reached. This allows flexible sampling plans and is not dependent upon correct effect size guesses in an a priori power analysis. We investigated the long-term rate of misleading evidence, the average expected sample sizes, and the biasedness of effect size estimates when an SBF design is applied to a test of mean differences between 2 groups. Compared with optimal NHST, the SBF design typically needs 50% to 70% smaller samples to reach a conclusion about the presence of an effect, while having the same or lower long-term rate of wrong inference. (PsycINFO Database Record


Asunto(s)
Teorema de Bayes , Proyectos de Investigación , Tamaño de la Muestra , Interpretación Estadística de Datos , Humanos , Probabilidad
12.
Front Psychol ; 7: 591, 2016.
Artículo en Inglés | MEDLINE | ID: mdl-27242566

RESUMEN

In several visual tasks, participants report that they feel confident about discrimination responses at a level of stimulation at which they would report not seeing the stimulus. How general and reliable is this effect? We compared subjective reports of discrimination confidence and subjective reports of visibility in an orientation discrimination task with varying stimulus contrast. Participants applied more liberal criteria for subjective reports of discrimination confidence than for visibility. While reports of discrimination confidence were more efficient in predicting trial accuracy than reports of visibility, only reports of visibility but not confidence were associated with stimulus contrast in incorrect trials. It is argued that the distinction between discrimination confidence and visibility can be reconciled with both the partial awareness hypothesis and higher order thought theory. We suggest that consciousness research would benefit from differentiating between subjective reports of visibility and confidence.

13.
J Exp Psychol Hum Percept Perform ; 42(6): 821-36, 2016 06.
Artículo en Inglés | MEDLINE | ID: mdl-26727018

RESUMEN

Searching for an object among distracting objects is a common daily task. These searches differ in efficiency. Some are so difficult that each object must be inspected in turn, whereas others are so easy that the target object directly catches the observer's eye. In 4 experiments, the difficulty of searching for an orientation-defined target was parametrically manipulated between blocks of trials via the target-distractor orientation contrast. We observed a smooth transition from inefficient to efficient search with increasing orientation contrast. When contrast was high, search slopes were flat (indicating pop-out); when contrast was low, slopes were steep (indicating serial search). At the transition from inefficient to efficient search, search slopes were flat for target-present trials and steep for target-absent trials within the same orientation-contrast block-suggesting that participants adapted their behavior on target-absent trials to the most difficult, rather than the average, target-present trials of each block. Furthermore, even when search slopes were flat, indicative of pop-out, search continued to become faster with increasing contrast. These observations provide several new constraints for models of visual search and indicate that differences between search tasks that were traditionally considered qualitative in nature might actually be due to purely quantitative differences in target discriminability. (PsycINFO Database Record


Asunto(s)
Reconocimiento Visual de Modelos/fisiología , Desempeño Psicomotor/fisiología , Percepción Espacial/fisiología , Adulto , Femenino , Humanos , Masculino , Adulto Joven
14.
Psychon Bull Rev ; 23(5): 1300-1315, 2016 10.
Artículo en Inglés | MEDLINE | ID: mdl-26635097

RESUMEN

Visual search is central to the investigation of selective visual attention. Classical theories propose that items are identified by serially deploying focal attention to their locations. While this accounts for set-size effects over a continuum of task difficulties, it has been suggested that parallel models can account for such effects equally well. We compared the serial Competitive Guided Search model with a parallel model in their ability to account for RT distributions and error rates from a large visual search data-set featuring three classical search tasks: 1) a spatial configuration search (2 vs. 5); 2) a feature-conjunction search; and 3) a unique feature search (Wolfe, Palmer & Horowitz Vision Research, 50(14), 1304-1311, 2010). In the parallel model, each item is represented by a diffusion to two boundaries (target-present/absent); the search corresponds to a parallel race between these diffusors. The parallel model was highly flexible in that it allowed both for a parametric range of capacity-limitation and for set-size adjustments of identification boundaries. Furthermore, a quit unit allowed for a continuum of search-quitting policies when the target is not found, with "single-item inspection" and exhaustive searches comprising its extremes. The serial model was found to be superior to the parallel model, even before penalizing the parallel model for its increased complexity. We discuss the implications of the results and the need for future studies to resolve the debate.


Asunto(s)
Atención/fisiología , Modelos Psicológicos , Tiempo de Reacción/fisiología , Percepción Espacial/fisiología , Percepción Visual/fisiología , Humanos
15.
Front Hum Neurosci ; 9: 119, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-25805987

RESUMEN

The redundant-signals paradigm (RSP) is designed to investigate response behavior in perceptual tasks in which response-relevant targets are defined by either one or two features, or modalities. The common finding is that responses are speeded for redundantly compared to singly defined targets. This redundant-signals effect (RSE) can be accounted for by race models if the response times do not violate the race model inequality (RMI). When there are violations of the RMI, race models are effectively excluded as a viable account of the RSE. The common alternative is provided by co-activation accounts, which assume that redundant target signals are integrated at some processing stage. However, "co-activation" has mostly been only indirectly inferred and the accounts have only rarely been explicitly modeled; if they were modeled, the RSE has typically been assumed to have a decisional locus. Yet, there are also indications in the literature that the RSE might originate, at least in part, at a non-decisional or motor stage. In the present study, using a distribution analysis of sequential-sampling models (ex-Wald and Ratcliff Diffusion model), the locus of the RSE was investigated for two bimodal (audio-visual) detection tasks that strongly violated the RMI, indicative of substantial co-activation. Three model variants assuming different loci of the RSE were fitted to the quantile reaction time proportions: a decision, a non-decision, and a combined variant both to vincentized group as well as individual data. The results suggest that for the two bimodal detection tasks, co-activation has a shared decisional and non-decisional locus. These findings point to the possibility that the mechanisms underlying the RSE depend on the specifics (task, stimulus, conditions, etc.) of the experimental paradigm.

16.
Conscious Cogn ; 35: 192-205, 2015 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-25758187

RESUMEN

Previous studies provided contradicting results regarding metacognitive sensitivity estimated from subjective reports of confidence in comparison to subjective reports of visual experience. We investigated whether this effect of content of subjective reports is influenced by the statistical method to quantify metacognitive sensitivity. Comparing logistic regression and meta-d in a masked orientation task, a masked shape task, and a random-dot motion task, we observed metacognitive sensitivity of reports regarding decisional confidence was greater than of reports about visual experience irrespective of mathematical procedures. However, the relationship between subjective reports and the logistic transform of accuracy was often not linear, implying that logistic regression is not a consistent measure of metacognitive sensitivity. We argue that a science of consciousness would benefit from the assessment of both visual experience and decisional confidence, and recommend meta-d as measure of metacognitive sensitivity for future studies.


Asunto(s)
Estado de Conciencia , Toma de Decisiones , Metacognición , Detección de Señal Psicológica , Percepción Visual , Humanos , Modelos Logísticos , Enmascaramiento Perceptual , Autoinforme
17.
Front Psychol ; 5: 1195, 2014.
Artículo en Inglés | MEDLINE | ID: mdl-25414676

RESUMEN

Targets in a visual search task are detected faster if they appear in a probable target region as compared to a less probable target region, an effect which has been termed "probability cueing." The present study investigated whether probability cueing cannot only speed up target detection, but also minimize distraction by distractors in probable distractor regions as compared to distractors in less probable distractor regions. To this end, three visual search experiments with a salient, but task-irrelevant, distractor ("additional singleton") were conducted. Experiment 1 demonstrated that observers can utilize uneven spatial distractor distributions to selectively reduce interference by distractors in frequent distractor regions as compared to distractors in rare distractor regions. Experiments 2 and 3 showed that intertrial facilitation, i.e., distractor position repetitions, and statistical learning (independent of distractor position repetitions) both contribute to the probability cueing effect for distractor locations. Taken together, the present results demonstrate that probability cueing of distractor locations has the potential to serve as a strong attentional cue for the shielding of likely distractor locations.

18.
Conscious Cogn ; 28: 126-40, 2014 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-25058629

RESUMEN

Can participants make use of the large number of response alternatives of visual analogue scales (VAS) when reporting their subjective experience of motion? In a new paradigm, participants adjusted a comparison according to random dot kinematograms with the direction of motion varying between 0° and 360°. After each discrimination response, they reported how clearly they experienced the global motion either using a VAS or a discrete scale with four scale steps. We observed that both scales were internally consistent and were used gradually. The visual analogue scale was more efficient in predicting discrimination error but this effect was mediated by longer report times and was no longer observed when the VAS was discretized into four bins. These observations are consistent with the interpretation that VAS and discrete scales are associated with a comparable degree of metacognitive sensitivity, although the VAS provides a greater amount of information.


Asunto(s)
Estado de Conciencia , Percepción de Movimiento , Escala Visual Analógica , Adulto , Estado de Conciencia/fisiología , Discriminación en Psicología , Femenino , Humanos , Masculino , Pruebas Neuropsicológicas , Estimulación Luminosa , Sensibilidad y Especificidad , Adulto Joven
19.
Atten Percept Psychophys ; 76(3): 669-74, 2014 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-24664853

RESUMEN

The influence of reward on cognitive processes including visual perception, spatial attention, and perceptual learning has become an increasingly important field of study in recent years. For example, Tseng and Lleras (Attention, Perception, & Psychophysics, 75(2), 287-298, 2013) investigated whether reward has an effect on implicit learning of target-distractor arrangements in visual search-that is, contextual cueing (Chun & Jiang Cognitive Psychology, 36(1), 28-71, 1998). They found that reward expedited the development of the cueing effect-that is, the reaction time difference between repeated and nonrepeated displays. However, their analysis did not account for potential effects of reward on the learning of individual target locations-that is, probability cueing (Jiang, Swallow, & Rosenbaum Journal of Experimental Psychology. Human Perception and Performance, 39, 285-297, 2013). The present study was a replication of Tseng and Lleras (Attention, Perception, & Psychophysics, 75(2), 287-298, 2013) that took into account reward effects on configural and locational learning, as well. We found that reward led to performance gains even in baseline ("new") displays, which contained only repeated target, but not distractor, locations. Furthermore, contextual cueing was smaller, and not larger, in high- than in low-reward trials. We concluded that reward modulates probability, and not contextual, cueing, and that this mechanism can account for the findings of Tseng and Lleras.


Asunto(s)
Señales (Psicología) , Discriminación en Psicología/fisiología , Percepción Visual/fisiología , Femenino , Humanos , Masculino
20.
Atten Percept Psychophys ; 76(2): 367-82, 2014 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-24323673

RESUMEN

Previous research on the contribution of top-down control to saccadic target selection has suggested that eye movements, especially short-latency saccades, are primarily salience driven. The present study was designed to systematically examine top-down influences as a function of time and relative salience difference between target and distractor. Observers performed a saccadic selection task, requiring them to make an eye movement to an orientation-defined target, while ignoring a color-defined distractor. The salience of the distractor was varied (five levels), permitting the percentage of target and distractor fixations to be analyzed as a function of the salience difference between the target and distractor. This analysis revealed the same pattern of results for both the overall and the short-latency saccades: When the target and distractor were of comparable salience, the vast majority of saccades went directly to the target; even distractors somewhat more salient than the target led to significantly fewer distractor, as compared with target, fixations. To quantify the amount of top-down control applied, we estimated the point of equal selection probability for the target and distractor. Analyses of these estimates revealed that, to be selected with equal probability to the target, a distractor had to have a considerably greater bottom-up salience, as compared with the target. This difference suggests a strong contribution of top-down control to saccadic target selection-even for the earliest saccades.


Asunto(s)
Atención/fisiología , Fijación Ocular/fisiología , Movimientos Sacádicos/fisiología , Percepción Visual/fisiología , Adulto , Análisis de Varianza , Color , Femenino , Humanos , Masculino , Orientación , Estimulación Luminosa/métodos , Probabilidad , Tiempo de Reacción , Adulto Joven
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