Working Memory Capacity and the Antisaccade Task: Individual Differences in Voluntary Saccade Control.

Performance on antisaccade trials requires the inhibition of a prepotent response (i.e., don't look at the flashing cue) and the generation and execution of a correct saccade in the opposite direction. The authors attempted to further specify the role of working memory (WM) span differences in the antisaccade task. They tested high- and low-span individuals on variants of prosaccade and antisaccade trials in which an eye movement is the sole requirement. In 3 experiments, they demonstrated the importance of WM span differences in both suppression of a reflexive saccade and generation of a volitional eye movement. The results support the contention that individual differences in WM span are not exclusively due to differences in inhibition but also reflect differences in directing the focus of attention. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Attentional control and the relatedness proportion effect in semantic priming.

In 2 experiments, participants completed both an attentional control battery (OSPAN, antisaccade, and Stroop tasks) and a modified semantic priming task. The priming task measured relatedness proportion (RP) effects within subjects, with the color of the prime indicating the probability that the to-be-named target would be related. In Experiment 2, participants were cued before each trial with the probability of a related target. Stimulus onset asynchronies traditionally thought to tap automatic processing (267 ms) versus controlled processing (1,240 ms) were used. Across experiments, principal component analysis on the battery revealed a general attentional control component. Moreover, the RP effect increased linearly with attentional control in both experiments. It is concluded that RP effects produced in this paradigm depend purely upon the effortful process of expectancy generation, which renders them sensitive to individual differences in attentional control. (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)     

Working-memory capacity, proactive interference, and divided attention: Limits on long-term memory retrieval.

Two experiments examined how individual differences in working-memory capacity (WM) relate to proactive interference (PI) susceptibility. We tested high and low WM-span participants in a PI-buildup task under single-task or dual-task ("load") conditions. In Experiment 1, a finger-tapping task was imposed during encoding and retrieval of each list; in Experiment 2, tapping was required during encoding or retrieval. In both experiments, low spans showed greater PI than did high spans under no load, but groups showed equivalent PI under divided attention. Load increased PI only for high spans, suggesting they use attention at encoding and retrieval to combat PI. In Experiment 2, only low spans showed a dual-task cost on List 1 memory, before PI built up. Results indicate a role for attentional processing, perhaps inhibitory in nature, at encoding and retrieval, and are discussed with respect to theories of WM and prefrontal cortex function. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of inhibition of return on voluntary and visually guided saccades.

Four experiments examined the effects of exogenously and endogenously activated inhibition of return (IOR) on endogenously generated and visually guided saccades. In Exps 1–3, 37 Ss responded to a peripheral target by making either a prosaccade (toward the target) or an antisaccade (toward the field opposite the target). Results of Exps 1 and 3 suggest that when IOR is activated by a peripheral precue, it functions as a location tagging mechanism that inhibits detection of signals at the tagged location; thus, IOR cannot simply be a motor alternation bias. Exp 2 showed that IOR could be generated by the execution of an endogenous saccade. Unlike Exp 1, however, IOR was manifest only in the prosaccade task. Exp 4, in which 24 Ss made endogenous saccades in response to a central arrow target, provided some evidence that IOR can influence the latency of endogenously generated saccades to the precued location. (French abstract) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The adaptive character of the attentional system: Statistical sensitivity in a target localization task.

A localization task required participants to indicate which of 4 locations contained a briefly displayed target. Most displays also contained a distractor that was not equally probable in these locations, affecting performance dramatically. Responses were faster when a display had no distractor and almost as fast when the distractor was in its frequent location. Conversely, responses were slower when targets appeared in frequent-distractor locations, even though targets were equally likely in each location. Negative-priming effects were reliably smaller when targets followed distractors in the frequent-distractor location compared to the rare-distractor location, challenging the episodic-retrieval account. Experiment 2 added a 5th location that rarely displayed distractors and never targets, yet responses slowed most when distractors appeared there. The results confirmed that the attentional system is sensitive to first- and higher-order statistical patterns and can make short- and long-term adjustments in preferences based on prior history of inspecting unsuccessful locations. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Perceptual representation as a mechanism of lexical ambiguity resolution: An investigation of span and processing time.

In 2 experiments, the authors investigated the ability of high- and low-span comprehenders to construe subtle shades of meaning through perceptual representation. High- and low-span comprehenders responded to pictures that either matched or mismatched a target object's shape as implied by the preceding sentence context. At 750 ms after hearing the sentence describing the target object, both high- and low-span comprehenders had activated a contextually appropriate perceptual representation of the target object. However, only high-span comprehenders had perceptually represented the contextually appropriate meaning immediately upon hearing the sentence, whereas low-span comprehenders required more processing time before the perceptual representation was activated. The results are interpreted in a framework of co-occurring lexical representations and perceptual-motor representations. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Antisaccade task performance in questionnaire-identified schizotypes

Individuals who scored high on Perceptual Aberration-Magical Ideation Scales (Per-Mag; n = 90), the Social Anhedonia Scale (SocAnh; n = 39), and control participants (n = 89) were administered saccadic refixation (prosaccade) and saccadic suppression (antisaccade) tasks. Eye movements were scored in terms of error rates and latency. None of the groups differed in terms of their performance on the prosaccade task. Both the Per-Mag (p < 0.01) and SocAnh (p < 0.05) groups exceeded the controls in terms of mean antisaccade errors. The high-risk groups did not differ from each other. Eighteen of the Per-Mag individuals and 10 of the SocAnh individuals displayed deviant antisaccade performance. These findings are particularly interesting in light of suggestive evidence that antisaccade task deficits may serve as a marker of susceptibility to schizophrenia. It is hypothesized that the individuals who scored aberrantly on the Chapman scales and displayed antisaccade performance deficits are most likely to be at risk for the development of psychosis.     

Apparent decrease in population clearance of theophylline: implications for dosage

Tthe antisaccade eye movement task, which has been linked to frontal lobe function, presents a target in one visual field and asks subjects to move their eyes to the same location in the opposite field. The task requires inhibition of the reflexive prosaccade to the cue, initiation of the antisaccade to the opposite field, and visuo-spatial memory of the cue location. Forty-two subjects from 19-79 years of age performed this task and a control task, visually guided saccades to the cue itself, to determine which functions are affected by aging. The time to initiate antisaccades increased linearly with age at a rate greater than the time to initiate visually guided saccades. This difference suggests that the processing time to inhibit the incorrect movement to the cue is selectively increased with age. Older subjects also made more incorrect prosaccadic movements to the cue, a finding consistent with the loss of inhibitory processing capacity. The accuracy of movements did not change, which suggests that visuo-spatial memory is unaffected by aging.     

Ten years of experience with the modified Ross procedure

BACKGROUND: Abnormal performance on the antisaccade task suggests that patients with schizophrenia have difficulty with the inhibition of reflexive attentional shifts. The aim of the study was to investigate whether deficits in the inhibition of reflexive attentional shifts were specific to the oculomotor modality or whether they could also occur when attentional shifts were made without eye movements (e.g. covert attentional shifts). METHODS: Fifteen medicated patients with chronic schizophrenia and 15 matched controls performed the antisaccade task and the covert orientating task (COVAT) where the probability of targets appearing at the same location of a peripheral cue was varied so that voluntary and reflexive orientating systems had the same goal (80% probability of target and cued condition) or opposite goals (20% probability of target at cued location). A condition where only reflexive orientating was initiated was also included (50% probability of target at cued location). For each of these conditions the stimulus onset asynchrony (SOA) varied between 150 and 350 ms. RESULTS: Patients with schizophrenia showed normal latency and accuracy for visually guided saccades but increased error rates and latency on the antisaccade task. For the COVAT, patients with schizophrenia were unable to use voluntary orientating strategies to inhibit reflexive shifts of covert attention. On conditions where only reflexive orientating was required or when the goals of the reflexive and voluntary orientating systems were the same, patients with schizophrenia showed normal performance. CONCLUSIONS: These results suggest the reflexive orientating mode is normal in patients with chronic schizophrenia. However, these patients have a reduced ability to utilize the voluntary orientating mode to control or inhibit reflexive orientating. This impairment of voluntary control is evident for both overt and covert attentional shifts.     

Mood-Congruent Attentional Bias in Dysphoria: Maintained Attention to and Impaired Disengagement From Negative Information.

Attentional bias to negative information has been proposed to be a cognitive vulnerability factor for the development of depression. In 2 experiments, the authors examined mood-congruent attentional bias in dysphoria. In both experiments, dysphoric and nondysphoric participants performed an attentional task with negative, positive, and neutral word cues preceding a target. Targets appeared either at the same or at the opposite location of the cue. Overall, results indicate that dysphoric participants show maintained attention for negative words at longer stimulus presentations, which is probably caused by impaired attentional disengagement from negative words. Furthermore, nondysphoric participants maintain their attention more strongly to positive words. These results are discussed in relation to recent developments in the pathogenesis and treatment of depression. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Antisaccade performance predicted by neuronal activity in the supplementary eye field

The voluntary control of gaze implies the ability to make saccadic eye movements specified by abstract instructions, as well as the ability to repress unwanted orientating to sudden stimuli. Both of these abilities are challenged in the antisaccade task, because it requires subjects to look at an unmarked location opposite to a flashed stimulus, without glancing at it. Performance on this task depends on the frontal/prefrontal cortex and related structures, but the neuronal operations underlying antisaccades are not understood. It is not known, for example, how excited visual neurons that normally trigger a saccade to a target (a prosaccade) can activate oculomotor neurons directing gaze in the opposite direction. Visual neurons might, perhaps, alter their receptive fields depending on whether they receive a pro- or antisaccade instruction. If the receptive field is not altered, the antisaccade goal must be computed and imposed from the top down to the appropriate oculomotor neurons. Here we show, using recordings from the supplementary eye field (a frontal cortex oculomotor centre) in monkeys, that visual and movement neurons retain the same spatial selectivity across randomly mixed pro- and antisaccade trials. However, these neurons consistently fire more before antisaccades than prosaccades with the same trajectories, suggesting a mechanism through which voluntary antisaccade commands can override reflexive glances.     

Saccadic system functioning among schizophrenia patients and their first-degree biological relatives.

In Study 1, 30 schizophrenia Ss and 27 nonpsychiatric comparison Ss were presented with a fixation task, a visually guided reflexive saccade (prosaccade) task, a predictive tracking task (0.4-Hz square wave), and an antisaccade task. The 2 groups did not differ on either the fixation or prosaccade tasks. Schizophrenia Ss had an increased number of errors on the antisaccade task and had decreased rightward visually guided saccade amplitudes during the predictive tracking task. In Study 2, 13 psychiatric comparison Ss and 32 1st-degree biological relatives of the schizophrenia Ss were compared with the schizophrenia Ss and a larger and older sample of nonpsychiatric Ss (n?=?33) on the predictive tracking and antisaccade tasks. The groups did not differ on predictive saccadic tracking. The schizophrenia Ss and their 1st-degree biological relatives made more errors on the antisaccade task than both the nonpsychiatric and psychiatric comparison groups (who did not significantly differ). Results are consistent with the notion that dysfunction of dorsolateral prefrontal cortex, caudate nucleus, or both is related to liability for schizophrenia. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

When danger lurks in the background: Attentional capture by animal fear-relevant distractors is specific and selectively enhanced by animal fear.

Across 2 experiments, a new experimental procedure was used to investigate attentional capture by animal fear-relevant stimuli. In Experiment 1 (N = 34), unselected participants were slower to detect a neutral target animal in the presence of a spider than a cockroach distractor and in the presence of a snake than a large lizard distractor. This result confirms that phylogenetically fear-relevant animals capture attention specifically and to a larger extent than do non-fear-relevant animals. In Experiment 2 (N = 86), detection of a neutral target animal was slowed more in the presence of a feared fear-relevant distractor (e.g., a snake for snake-fearful participants) than in presence of a not-feared fear-relevant distractor (e.g., a spider for snake-fearful participants). These results indicate preferential attentional capture that is specific to phylogenetically fear-relevant stimuli and is selectively enhanced in individuals who fear these animals. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

"Big" versus "little" science: comparative analysis of program projects and individual research grants

The verbal fluency task requires generation of category exemplars and appears to be an example of what M. Moscovitch (1995) calls a strategic test of memory retrieval. Four experiments explored the role of individual differences in working memory (WM) capacity on verbal fluency under various secondary load conditions. High WM participants consistently recalled more exemplars. However, load conditions caused a decline in recall only for high WM participants. Low WM participants showed no effect of secondary workload on exemplar generation. WM group differences and load effects were observed even in the 1st min of retrieval, which suggests that differences were not due to differences in knowledge. A model of retrieval is supported that relies on cue-based-automatic activation, monitoring of output for errors, controlled suppression of previously recalled items, and controlled strategic search.     

The role of working memory capacity in retrieval.

The verbal fluency task that requires generation of category exemplars and appears to be an example of what M. Moscovitch (1995) calls a strategic test of memory retrieval. Four experiments explored the role of individual differences in working memory (WM) capacity on verbal fluency under various secondary load conditions. High WM participants consistently recalled more exemplars. However, load conditions caused a decline in recall only for high WM participants. Low WM participants showed no effect of secondary workload on exemplar generation. WM group differences and load effects were observed even in the 1st min of retrieval, which suggests that differences were not due to differences in knowledge. A model of retrieval is supported that relies on cue-based-automatic activation, monitoring of output for errors, controlled suppression of previously recalled items, and controlled strategic search. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Emotional attention set-shifting and its relationship to anxiety and emotion regulation.

Attentional deployment is a primary strategy individuals use to regulate emotion. In 2 experiments, a measure of an individual’s ability to deploy attention toward and away from emotional mental representations was developed. This measure of attentional control capacity for emotion adapted an explicit-cuing task switching paradigm in which participants had to shift between emotional and neutral mental sets. Experiment 1 (N = 118) showed that those higher in trait anxiety and worrisome thoughts took longer to switch from a neutral to an emotional mental set. In Experiment 2 (N = 42), participants were given a stressful anagram task, and those who switched more efficiently from a neutral set to an emotional set were more frustrated by the stressful task. In addition, those who switched more efficiently from an emotional set to a neutral set persisted longer on the stressful task. These findings provide an initial step toward identifying possible mechanisms through which individuals apply attentional control to emotional mental representations to regulate emotion. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Working memory and retrieval: A resource-dependent inhibition model.

Four experiments examined individual differences in working memory (WM) capacity and how those differences affect performance on retrieval from both primary and secondary memory. The results showed that WM differences appear only in retrieval from primary memory and then only under conditions that lead to interference or response competition within the task. This suggests that WM capacity is important to retrieval that is based on controlled effortful search but not search that is based on automatic activation. A view is presented suggesting that individual differences in attentional resources lead to differences in the ability to inhibit or suppress irrelevant information. The paradigm also allowed more general comparisons between the processes involved in retrieval from primary and secondary memory. As expected, it was found that retrieval from primary memory was a function of set size. However, for sets larger than 2 items, retrieval from secondary memory was independent of set size. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The combined effect of gaze direction and facial expression on cueing spatial attention.

Empirical evidence shows an effect of gaze direction on cueing spatial attention, regardless of the emotional expression shown by a face, whereas a combined effect of gaze direction and facial expression has been observed on individuals' evaluative judgments. In 2 experiments, the authors investigated whether gaze direction and facial expression affect spatial attention depending upon the presence of an evaluative goal. Disgusted, fearful, happy, or neutral faces gazing left or right were followed by positive or negative target words presented either at the spatial location looked at by the face or at the opposite spatial location. Participants responded to target words based on affective valence (i.e., positive/negative) in Experiment 1 and on letter case (lowercase/uppercase) in Experiment 2. Results showed that participants responded much faster to targets presented at the spatial location looked at by disgusted or fearful faces but only in Experiment 1, when an evaluative task was used. The present findings clearly show that negative facial expressions enhance the attentional shifts due to eye-gaze direction, provided that there was an explicit evaluative goal present. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Anxiety-related attentional biases and their regulation by attentional control.

This study examined the role of self-reported attentional control in regulating attentional biases related to trait anxiety. Simple detection targets were preceded by cues labeling potential target locations as threatening (likely to result in negative feedback) or safe (likely to result in positive feedback). Trait anxious participants showed an early attentional bias favoring the threatening location 250 ms after the cue and a late bias favoring the safe location 500 ms after the cue. The anxiety-related threat bias was moderated by attentional control at the 500-ms delay: Anxious participants with poor attentional control still showed the threat bias, whereas those with good control were better able to shift from the threatening location. Thus, skilled control of voluntary attention may allow anxious persons to limit the impact of threatening information. (PsycINFO Database Record (c) 2010 APA, all rights reserved)