The effect of attentional demands on the antisaccade cost

In the present study, we examined the effect of attentional demands on the antisaccade cost (the latency difference between antisaccades and prosaccades). Participants performed a visual search for a target digit and were required to execute a saccade toward (prosaccade) or away from (antisaccade) the target. The results of Experiment 1 revealed that the antisaccade cost was greater when the target was premasked (i.e., presented through the removal of line segments) than when it appeared as an onset. Furthermore, in premasked target conditions, the antisaccade cost was increased by the presentation of onset distractors. The results of Experiment 2 revealed that the antisaccade cost was greater in a difficult search task (a numeral 2 among 5s) than in an easy one (a 2 among 7s). The findings provide evidence that attentional demands increase the antisaccade cost. We propose that the attentional demands of the search task interfere with the attentional control required to select the antisaccade goal.     

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.     

Unexpected Costs of High Working Memory Capacity Following Directed Forgetting and Contextual Change Manipulations

Greater working memory capacity is usually associated with greater ability to maintain information in the face of interruptions. In two experiments, we found that some types of interruptions actually lead to greater forgetting among high-span people than among low-span people. Specifically, an instruction designed to change mental context resulted in significant forgetting for high-span people but minimal forgetting among the low-span people. Intentional forgetting instructions also resulted in greater forgetting among higher working memory capacity participants than among lower working memory capacity participants. A candidate explanation called the intensified context shift hypothesis is proposed which suggests that high-span people are more context dependent than low-span people.     

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.     

Individual differences in syntactic ambiguity resolution: Readers vary in their use of plausibility information

Two experiments investigated the relation between individual differences in working memory capacity and differences in the efficiency of syntactic processing. In one experiment, readers comprehended sentences containing main-verb/reduced-relative ambiguities that all resolved to the reduced-relative interpretation. High-span (but not low-span) readers processed sentences more slowly when the sentences were biased to the preferred, main-verb interpretation than when they were biased to the reduced-relative interpretation. Moreover, high-span (but not low-span) readers used information about the plausibility of the different interpretations even though low-span readers appeared to possess the requisite knowledge. In Experiment 2, readers received intensive exposure to sentences with main-verb/reduced-relative ambiguities. Exposure enhanced low-span readers' use of plausibility information. Moreover, the effect of exposure generalized to sentences that were not included in the training materials.     

Antisaccade costs with static and dynamic targets

In the present study we examined the antisaccade cost (latency difference between antisaccades and prosaccades) in a variety of search tasks. In a series of experiments participants searched for a target and were required to execute a saccade toward (prosaccade) or aw ay (antisaccade) from the target. The results revealed that the antisaccade cost was greater for static targets than for dynamic targets, and it was greater for onset targets than for offset targets. Furthermore, the offset of an onset target interfered with prosaccades, but facilitated antisaccades, resulting in a reduction of the antisaccade cost. To account for the data a model is presented, in which attentional control and working memory processes play an important role in the generation of antisaccades.     

Processing Italian Relative Clauses: Working Memory Span and Word Order Effects on RTs

In this study, the authors aim to clarify whether the subject–object asymmetry in relative clause comprehension is due to the use of parsing strategies (Active Filler Theory) or to a greater memory load generated by object sentences. Two experiments investigate how individual differences in working memory span may influence the reading times of relative sentences in Italian, a language characterized by a flexible structure. The results of Experiment 1 indicate that object extraction is more complex than subject extraction when sentences have a canonical structure. Furthermore, low-span participants have particular difficulties with object relative sentence comprehension. The results of Experiment 2 show that subject-relative clauses with uncanonical structures are more complex to understand than object-relative clauses, and low-span participants have more difficulties than high-span participants in elaborating both subject and object relative clauses. These data seem to be coherent with the Active Filler Theory.     

反向眼跳的实验范式、机制及影响因素

反向眼跳任务是研究内源性眼跳的主要方法。1978年,Hallett在研究中首次使用了反向眼跳的实验任务。实验中要求被试抑制对外围目标的注视,并注视它的相反位置。反向眼跳任务是研究行为控制以及注意功能的有效范式。目前认为反向眼跳任务中的朝向眼跳和反向眼跳计划是同时加工并相互竞争的,并且反向眼跳的产生与额顶叶皮层下组织有关。反向眼跳会受到多种因素的影响,例如,空白效应、工作记忆、认知老化、目标离心率等。     

Effects of the Central Executive on Postural Control

The authors focused on individual working memory (WM) capacity and examined its effect on postural control. Participants were 79 young volunteers split into two groups of low- and high WM span, based on scores from the Reading Span Test. The length of unrest was measured in the following conditions: double-leg standing as a single (D-S) task, single-leg standing as a single (S-S) task, double-leg standing as a dual (D-D) task, and single-leg standing as a dual (S-D) task. Regarding inte-group comparisons, total length was prolonged significantly between the low- and the high-span groups but only on the S-D task. The present results revealed that dual-task interference emerged in the low-span group when in a more unstable posture.     

Effects of anxiety on task switching: Evidence from the mixed antisaccade task

According to the attentional control theory of anxiety (Eysenck, Derakshan, Santos, & Calvo, 2007), anxiety impairs performance on cognitive tasks that involve the shifting function of working memory. This hypothesis was tested using a mixed antisaccade paradigm, in which participants performed single-task and mixed-task versions of the paradigm. The single task involved the completion of separate blocks of anti- and prosaccade trials, whereas in the mixed task, participants completed anti- and prosaccade trials in a random order within blocks. Analysis of switch costs showed that high-anxious individuals did not exhibit the commonly reported paradoxical improvement in saccade latency, whereas low-anxious individuals did. The findings are discussed within the framework of attentional control theory.     

Working memory capacity and time course of predictive inferences

A naming task assessed activation of inference concepts during reading. A predicting, or a control, context sentence was followed by a target word to be named, which represented the predicted event or an inconsistent event. The interval between the end of the context and the onset of the target word varied between 50 and 1050 msec. Individual differences in working memory capacity were assessed by the reading span task. As reflected by facilitation in naming latencies in the predicting condition, relative to the control condition, (a) inferences were not made within the first 50 msec after the context, regardless of reading span; (b) only the high-span participants drew inferences within a 550-msec interval; and, (c) both the high- and the low-span participants generated them within a 1050-msec interval. These results indicate that high working memory capacity accelerates the time course of predictive inferences, although they do not become automatic. We propose that this effect occurs because these inferences involve time-consuming elaborations that place demands on the effortful and limited resources of working memory. Deficiencies in word knowledge, speed of lexical access, or comprehension of explicit information do not account for low-span readers' difficulties in generating predictive inferences.     

Working Memory Capacity and Time Course of Predictive Inferences

A naming task assessed activation of inference concepts during reading. A predicting, or a control, context sentence was followed by a target word to be named, which represented the predicted event or an inconsistent event. The interval between the end of the context and the onset of the target word varied between 50 and 1050-msec. Individual differences in working memory capacity were assessed by the reading span task. As reflected by facilitation in naming latencies in the predicting condition, relative to the control condition, (a) inferences were not made within the first 50-msec after the context, regardless of reading span; (b) only the high-span participants drew inferences within a 550-msec interval; and, (c) both the high-and the low-span participants generated them within a 1050-msec interval. These results indicate that high working memory capacity accelerates the time course of predictive inferences, although they do not become automatic. We propose that this effect occurs because these inferences involve time-consuming elaborations that place demands on the effortful and limited resources of working memory. Deficiencies in word knowledge, speed of lexical access, or comprehension of explicit information do not account for low-span readers' difficulties in generating predictive inferences.     

颜色和形状工作记忆对非空间返回抑制效应的影响

为进一步考察非空间返回抑制效应是否受工作记忆内容的影响,分别采用颜色和形状工作记忆内容,通过两个实验考察了工作记忆对非空间返回抑制效应的影响。实验结果表明,在颜色和形状工作记忆条件下,均产生了颜色或形状返回抑制效应,并且颜色或形状返回抑制效应量之间均无显著差异,颜色和形状工作记忆内容只增加了判断靶刺激的反应时。研究结论对进一步认识工作记忆内容与非空间返回抑制效应之间的关系有重要参考价值。     

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.     

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.     

手机成瘾者抑制控制能力特点：来自反向眼跳任务的证据

为深入研究手机成瘾者的抑制控制能力特点,使用手机成瘾倾向量表筛选34名被试,手机成瘾组与非手机成瘾组各17名被试完成反向眼跳范式测量。结果发现：(1)手机成瘾组反向眼跳错误率显著高于非手机成瘾组。(2)手机成瘾组朝向眼跳潜伏期显著短于非手机成瘾组。结果表明,手机成瘾组抑制控制能力显著低于非手机成瘾组,反向眼跳任务成绩较差。这表明手机成瘾者较容易受自下而上的刺激驱动,较难抑制无关刺激产生的注意干扰。     

Repetitive antisaccade execution does not increase the unidirectional prosaccade switch-cost

An antisaccade is the execution of a saccade to the mirror-symmetrical location (i.e., same amplitude but opposite visual field) of a single and exogenously presented visual target. Such a response requires top-down decoupling of the normally direct spatial relations between stimulus and response and results in increased planning times and directional errors compared to their spatially compatible prosaccade counterparts. Moreover, antisaccades are associated with diffuse changes in cortical and subcortical saccade networks: a finding that has, in part, been attributed to pre-setting the oculomotor system to withhold a stimulus-driven prosaccade. Moreover, recent work has shown that a corollary cost of oculomotor pre-setting is that the planning time for a to-be-completed prosaccade is longer when preceded by an antisaccade (i.e., the unidirectional prosaccade switch-cost). Notably, this result has been attributed to antisaccades imparting a residual inhibition of the oculomotor networks that support the planning of stimulus-driven prosaccades. In the current investigation, we sought to determine if the number of antisaccades preceding a prosaccade increases this residual inhibition and thus influences the magnitude of the unidirectional prosaccade switch-cost. To that end, participants alternated between pro- and antisaccades after every second (i.e., AABB schedule) and every fourth (i.e., AAAABBBB schedule) trial. In addition, participants completed pro- and antisaccades in separate blocks of trials. Results demonstrated that task-switch prosaccades produced longer reaction times than their task-repetition and blocked condition counterparts, whereas antisaccade reaction times did not vary across task-repetition, task-switch and blocked condition trials. Most notably, the magnitude of the unidirectional prosaccade switch-cost was not modulated across the different task-switching schedules. Thus, we propose that the top-down requirements of the antisaccade task do not produce additive inhibition of stimulus-driven saccade networks.     

Control of reflexive and voluntary saccades in the gap effect

In two experiments, we examined whether voluntary and reflexive saccades shared a common fixation disengagement mechanism, Participants were required to perform a variety of tasks, each requiring a different level of information processing of the display prior to execution of the saccade. In Experiment 1, participants executed either a prosaccade or an antisaccade upon detecting a stimulus array. In Experiment 2, participants executed a prosaccade to a stimulus array only if the array contained a target item. The target could be a line (easy search) or a digit (difficult search). The critical manipulation in both experiments was the relative timing between the removal of the fixation stimulus and the onset of the stimulus array. In both experiments, it was found that saccadic latencies were shortest when the fixation stimulus was removed before the onset of the stimulus array—a gap effect. It was concluded that reflexive and voluntary saccades share a common fixation disengagement mechanism that is largely independent of higher level cognitive processes.     

Control' of reflexive and voluntary saccades in the gap effect.

In two experiments, we examined whether voluntary and reflexive saccades shared a common fixation disengagement mechanism. Participants were required to perform a variety of tasks, each requiring a different level of information processing of the display prior to execution of the saccade. In Experiment 1, participants executed either a prosaccade or an antisaccade upon detecting a stimulus array. In Experiment 2, participants executed a prosaccade to a stimulus array only if the array contained a target item. The target could be a line (easy search) or a digit (difficult search). The critical manipulation in both experiments was the relative timing between the removal of the fixation stimulus and the onset of the stimulus array. In both experiments, it was found that saccadic latencies were shortest when the fixation stimulus was removed before the onset of the stimulus array--a gap effect. It was concluded that reflexive and voluntary saccades share a common fixation disengagement mechanism that is largely independent of higher level cognitive processes.     

Attention control and the antisaccade task: a response time distribution analysis

In three experiments response time (RT) differences between correct prosaccade and antisaccade trials were examined via distribution analyses by fitting an ex-Gaussian function to individual RT distributions. Experiment 1 demonstrated that antisaccades are slower than prosaccades and this difference is due to both a shift in the overall distribution as well as a lengthening of the tail of the distribution. Experiment 2 demonstrated that manipulating foreperiod duration led to changes in both accuracy and RT for antisaccades but not prosaccades. Furthermore, the change in RT for antisaccades resulted in a lengthening in the tail of the distribution but not a shift in the distribution. Finally, Experiment 3 demonstrated that with sufficient practice performance on antisaccades was equated with performance on prosaccades in terms of both accuracy and RT. An examination of the RT distributions suggested that practice led to parallel changes in both the mean of the distribution and the tail of the antisaccade distribution. These results are interpreted within a two-factor theory of attention control that suggests that performance on antisaccades is driven by both competition resolution and goal-maintenance abilities.