Attentional selection by distractor suppression

Selective attention was studied in displays containing singletons popping out for their odd form or color. The target was defined as the form-singleton, the distractor as the color-singleton. The task was to discriminate the length of a longer line inside the target. Target-distractor similarity was controlled using a threshold measurement as dependent variable in experiments in which distractor presence vs absence, bottom-up vs top-down selection (through knowledge of target features), and target-distractor distance were manipulated. The results in the bottom-up condition showed that length threshold was elevated when a distractor was present and that this elevation progressively increased as the number of distractors was increased from one to two. This set-size effect was not accounted by the hypothesis that selective attention intervenes only at the stage of decision before response. Selective attention produced a suppressive surround in which discriminability of neighboring objects was strongly reduced, and a larger surround in which discriminability was reduced by an approximately constant amount. Different results were found in the top-down condition in which target discriminability was unaffected by distractor presence and no effect of target-distractor distance was found. On the other hand, response times in both bottom-up and top-down conditions were slower the shorter the target-distractor distance was. On the basis of the experimental results, selective attention is a parallel process of spatial filtering at an intermediate processing level operating after objects have been segmented. This filtering stage explores high level interactions between objects taking control on combinatorial explosion by operating over only a limited spatial extent: it picks out a selected object and inhibits the neighboring objects; then, non-selected objects are suppressed across the overall image. When no feature-based selection is available in the current behavior, this filtering influences perception in decreasing discriminability of non-selected objects. When feature-based selection is available, spatial interactions are set before stimulus arrival, hence only the unmatching objects have their discriminability diminished.     

Attentional modulation of visual processes in motion perception.

Examined the effects of spatially directed attention on the temporal characteristics of information transmission in the visual system. A 2-stimulus, 2-flash, long-range motion display was used. The results showed that attending to 1 of the 2 stimuli altered the perceived direction of motion, the pattern of motion and no-motion responses, and ratings of motion quality. The results were compared with predictions derived from 2 conceptual frameworks of attention: a temporal-profile model and an additive account. The results support the temporal-profile model. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Attentional selection is biased toward mood-congruent stimuli.

One can exert significant volitional control over the attentional filter so that stimuli that are consistent with one's explicit goals are more likely to receive attention and become part of one's conscious experience. Here we pair a mood induction procedure with an inattentional blindness task to show that one's current mood has a similar influence on attention. A positive, negative, or neutral mood manipulation was followed by an attentionally demanding multiple-object tracking task. During the tracking task, participants were more likely to notice an unexpected face when its emotional expression was congruent with participants' mood. This was particularly true for the frowning face, which was detected almost exclusively by participants in the sad mood induction condition. This attentional bias toward mood-congruent stimuli provides evidence that one's temporary mood can influence the attentional filter, thereby affecting the information that one extracts from, and how one experiences the world. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Attentional control of spatial scale: effects on self-organized motion patterns

Prior to the presentation of a test stimulus, subjects' attentional state was either narrowly focused on a particular location or broadly spread over a large spatial region. In previous studies, it was found that broadly spread attention enhances the sensitivity of relatively large spatial filters (increasing the perceiver's spatial scale), thereby diminishing spatial resolution and enhancing sensitivity to global stimulus structure. In this study it is shown that attentional spread also affects the self-organization of unidirectional versus oscillatory motion patterns for the directionally ambiguous, counterphase presentation of rows of evenly-spaced visual elements (lines segments; dots); i.e. qualitatively different motion patterns can be formed for the same stimulus at different spatial scales. Although the degree to which attention is spread along a spatial axis can be controlled by the perceiver, the effects of spread attention are not limited to a single axis. These results, as well as previously observed effects of attentional spread on spatial resolution, are accounted for by a neural model involving large, foveally-centered receptive fields with co-operatively interacting subunits (probably at the level of MST or higher).     

Attentional modulation of visual motion processing in cortical areas MT and MST

The visual system is constantly inundated with information received by the eyes, only a fraction of which seems to reach visual awareness. This selection process is one of the functions ascribed to visual attention. Although many studies have investigated the role of attention in shaping neuronal representations in the visual cortex, few have focused on attentional modulation of neuronal signals related to visual motion. Here we report that the responses of direction-selective neurons in monkey visual cortex are greatly influenced by attention, and that this modulation occurs as early in the cortical hierarchy as the level of the middle temporal visual area (MT). Our finding demonstrates a stronger and earlier influence of attention on motion processing along the dorsal visual pathway than previously recognized.     

Attentional requirements for the selection of words from different grammatical categories.

Two grammatical classes are commonly distinguished in psycholinguistic research. The open-class includes content words such as nouns, whereas the closed-class includes function words such as determiners. A standing issue is to identify whether these words are retrieved through similar or distinct selection mechanisms. We report a comparative investigation of the allocation of attentional resources during the retrieval of words from these 2 classes. Previous studies used a psychological-refractory-period paradigm to establish that open-class word retrieval is supported by central attention mechanisms. We applied the same logic to closed-class word retrieval. French native speakers named pictures with determiner noun phrases while they concurrently identified the pitch of an auditory tone. The ease of noun and determiner retrieval was manipulated independently. Results showed that both manipulations affected picture naming and tone discrimination responses in similar ways. This suggests the involvement of central attentional resources in word production, irrespective of word class. These results argue against the commonly held hypothesis that closed-class retrieval is an automatic consequence of syntactic specific processes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Attentional selection and attentional gradients: an alternative method for studying transient visual-spatial attention

Event-related potential (ERP) effects of transient and sustained non-spatial visual attention were investigated in an experiment where subjects were instructed to attend to the color or form of visual stimuli in order to detect infrequently presented targets with the relevant feature. The to-be-attended feature was either varied in a trial-by-trial fashion (transient attention) or was kept constant for an entire experimental block (sustained attention). Both transient and sustained attention resulted in a larger negativity for attended as compared to unattended stimuli between 200 and 300 ms post-stimulus. This effect was more pronounced for sustained attention than for transient attention and larger for attention to color than for attention directed to stimulus form. In the sustained, but not in the transient attention condition, color attention resulted in larger positivities for attended stimuli between 150 and 200 ms and in the P3 time range. These effects are interpreted as evidence for the existence of non-spatial attentional selection processes that are more effective under sustained than under transient attention conditions and are different from processes of visual-spatial attention. Moreover, the results indicate a special status for sustained attention to stimulus color.     

Delayed Attentional Engagement in the Attentional Blink.

Observers often miss the 2nd of 2 visual targets (first target [T1] and second target [T2]) when these targets are presented closely in time; the attentional blink (AB). The authors hypothesized that the AB occurs because the attentional response to T2 is delayed by T1 processing, causing T2 to lose a competition for attention to the item that follows it. The authors investigated this hypothesis by determining whether the AB is attenuated when T2 is precued. The results from 4 experiments showed that the duration and magnitude of the AB were substantially reduced when T2 was precued. The observed improvement in T2 report did not occur at the expense of T1 report, suggesting that processing of T1 was already completed or was at least protected when the cue was presented. The authors conclude that, during the AB, there is a delay between detection and the selection of target candidates for consolidation in short-term memory. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The speed of feature-based attention: Attentional advantage is slow, but selection is fast.

When paying attention to a feature (e.g., red), no attentional advantage is gained in perceiving items with this feature in very brief displays. Therefore, feature-based attention seems to be slow. In previous feature-based attention studies, attention has often been measured as the difference in performance in a secondary task. In our recent work on Boolean map theory (Huang & Pashler, 2007), we distinguished between 2 concepts that are often conflated with the term attention, namely the selection of information from stimulus and the following processing optimization (i.e., attentional advantage) of the selected stimulus. Attention, as examined in previous feature-based attention studies, only fits the definition of processing optimization, but does not fit the definition of selection of information. Therefore, it is open to question whether feature-based attention, when defined as selection, is fast or slow. In this study, I systematically measured the speed of feature-based attention in relation to both definitions. Attention was found to be slow (~100 ms) in terms of processing optimization (i.e., attentional advantage) but fast in terms of the selection of information (     

Attentional modulation of central odor processing

As long ago as 1931 Fisher outlined the reasons for the accumulation of male 'benefit genes' (e.g. male fertility factors) on the Y chromosome, but it was over four decades later that a study of men with partial Y chromosome deletions revealed that a factor essential for male fertility was present on the human Y. Today, the Y deletion interval containing this 'Azoospermia Factor' (AZF) has been subdivided into three subintervals associated with different degrees of spermatogenic impairment. Furthermore, three deletion intervals have been identified on the mouse Y that impact on the spermatogenic process. This review examines these deletion intervals in mouse and man and summarises progress towards identifying candidate genes for their respective spermatogenic functions.     

Attentional blink for color.

Colored letters were presented by means of rapid serial visual presentation (RSVP). Two letters (T1 and T2) were targets that required a speeded (T1) or delayed (T2) response. T1 was shown on half of the trials. Two tasks were performed in the experimental conditions. Task1 required a discrimination between 2 letters (when T1 was shown) or an indication that T1 was absent. In Experiment 1, Task2 was to detect the presence of a unique color in the RSVP stream (e.g., green in a stream of alternating red and gray). In Experiment 2, Task2 was to report the color of the first colored letter to appear in the RSVP stream. The lag between T1 and T2 in the RSVP stream was manipulated. Accuracy of color reports in Task2 was poor at shorter lags and improved as the lag was lengthened in both experiments, demonstrating an attentional blink for chromatic information. Theoretical implications of the results are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Attentional effects of single dose triazolam

1. While the effects of benzodiazepines on human memory have been extensively studied little is known about the effects of these agents on attentional processes. The authors studied the effects of a single dose of triazolam on selective visual-spatial attention using a double blind, placebo controlled design. 2. In each of 2 sessions 12 normal volunteers ingested either 0.25 mg of triazolam or placebo. Attentional performance was evaluated using two versions of the covert orienting paradigm which measured automatic (exogenous) and controlled (endogenous) aspects of attentional orienting, respectively. 3. Triazolam selectively modified performance on automatic orienting to exogenous cues. Specifically, triazolam increased the facilitation of target detection seen at shorter (150 msec) SOA's. This may indicate an increase in facilitation and a reduction in inhibition or a slowing of the time course of the biphasic attentional effect normally resulting from exogenous cuing. 4. These results indicate the importance of using experimental paradigms which effectively dissociate endogenous and exogenous mechanisms of spatial orienting in studies evaluating the effects of pharmacological agents on visual-spatial attention.     

Evaluating expectations about negative emotional states of aggressive boys using Bayesian model selection.

Researchers often have expectations about the research outcomes in regard to inequality constraints between, e.g., group means. Consider the example of researchers who investigated the effects of inducing a negative emotional state in aggressive boys. It was expected that highly aggressive boys would, on average, score higher on aggressive responses toward other peers than moderately aggressive boys, who would in turn score higher than nonaggressive boys. In most cases, null hypothesis testing is used to evaluate such hypotheses. We show, however, that hypotheses formulated using inequality constraints between the group means are generally not evaluated properly. The wrong hypotheses are tested, i.e.. the null hypothesis that group means are equal. In this article, we propose an innovative solution to these above-mentioned issues using Bayesian model selection, which we illustrate using a case study. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Attentional and ocular movements.

The relationship between eye movements and movements of attention was examined in a series of 6 experiments. A temporal order judgment technique was used to index attentional allocation. The results showed that endogenous movements of attention were slower than movements of the eyes and that the participants were able to hold attention at one location while executing an eye movement to another location. Under conditions of exogenous cueing, attention moved rapidly to the cued location, in advance of the eyes. These findings challenge the prevailing view that ocular movements must necessarily be preceded by a movement of attention. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Attentional strategies in dichotic listening.

Describes 2 experiments in which a total of 48 college students heard series of 3 dichotic word-digit pairs and were instructed to recall them either by ears or by types. Recall instructions were given before each block of 12 series, before each individual series, or after each series. With preinstruction, serial position effects were rather flat for the 1st-reported channel but showed a marked recency effect for the 2nd-reported channel, suggesting that the Ss attended mainly to the lst channel. With postinstruction, serial position effects were parallel for the 2 channels. Results were practically the same whether channels represented ears or types, suggesting that attention played the same role in each case. (French summary) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Attentional demands of visual word recognition.

Becker's (1976, 1979, 1980, 1985; Becker & Killion, 1977; Eisenberg & Becker, 1982) verification model was used as a framework to investigate the attentional demands of word recognition. In two experiments, a lexical decision task and an auditory probe task were performed in single- and dual-task conditions. Responses to probes were divided into detection and movement measures that indexed the demands of recognition and response output, respectively. In Experiment 1, single- to dual-task decrements in probe detection performance were larger during low-frequency as compared with high-frequency trials. This finding indicates that the attentional demands of word recognition vary with word frequency. These findings were replicated in Experiment 2, which was designed to separate a response compatibility and a capacity interpretation of the results. The findings are interpreted within Becker's verification model. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Suppression of Attentional Bias in PTSD.

Sixty combat veterans with posttraumatic stress disorder performed an emotional Stroop task under 1 of 4 contextual conditions designed to test theoretical explanations for an attentional bias suppression effect. Results revealed that when the emotional Stroop task was performed under conditions involving a future threat of either watching a combat video or giving a speech, attentional bias was inhibited. There was limited support for the prediction that the suppression effect was strongest when stressor content matched word content on the Stroop. In contrast to participants in the threat conditions, veterans who believed that they would receive additional compensation for speeded color naming or who believed that they would have no other experimental demands were slower when color naming combat-threat words. Potential theoretical explanations of the findings are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Development of Attentional and Oculomotor Control.

The present study was conducted to examine the development of attentional and oculomotor control. More specifically, the authors were interested in the development of the ability to inhibit an incorrect but prepotent response to a salient distractor. Participants, who ranged in age from 8 to 25 years, performed 3 different eye movement tasks: a prosaccade, an antisaccade, and an oculomotor capture task. The time required to initiate a saccade decreased with age across all 3 tasks. Consistent with previous reports, accuracy was relatively age invariant in the prosaccade task. Performance improved with age, asymptoting at 16 years in the antisaccade task. It is interesting to note that despite the superficial similarity of the antisaccade and oculomotor capture tasks, performance was relatively age invariant in the latter. These results are discussed in terms of developmental differences in the interaction of goal-directed and stimulus-driven processes in the control of attention and action. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Attentional bias in emotional disorders.

Tested a visual attention paradigm with 16 Ss referred by general practitioners for anxiety management training and 16 undergraduate controls. Ss were administered the State–Trait Anxiety Inventory and the Beck Depression Inventory. Words (either threat related or neutral) were simultaneously presented on 2 areas of the screen of a microcomputer. The ensuing distribution of visual attention was measured. Findings indicate that clinically anxious (but not clinically depressed) Ss consistently shifted attention toward threat words, resulting in reduced detection latencies for probes appearing in the vicinity of such stimuli. Control Ss, on the other hand, tended to shift attention away from such material. Results support the existence of anxiety-related encoding bias. It is suggested that this cognitive mechanism may contribute to the maintenance of such mood disorders. (27 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)