多目标追踪的任务难度对不同类型非目标选择性抑制的影响

采用多目标追踪（MOT）与点探测刺激觉察任务相结合的实验范式,分别通过改变运动与静止非目标数量,考察追踪难度变化对不同类型非目标选择性抑制的影响。实验一通过改变运动非目标数量为4、5、6,发现当运动非目标数量为6时,追踪难度显著增加,静止非目标上的抑制量也显著增加,而运动非目标上的抑制量则不随追踪难度的变化而变化;实验二改变静止非目标数量为4、5、6,同样发现当静止非目标数量为6时,追踪难度显著增加,静止非目标上的抑制量也显著增加,而运动非目标上的抑制量仍不随追踪难度的变化而变化,且当静止非目标数量为6时,静止非目标上的抑制量显著大于运动非目标,出现了反转现象,其原因可能是视野范围内总的对象数量超出了视觉索引容量,被试改变了对静止与运动非目标的抑制策略。综合实验结果表明,静止非目标上的抑制程度随追踪难度的提高而增加;而运动非目标上的抑制程度对追踪难度的变化不敏感,在不同难度水平上保持相对稳定。     

动态非注意盲中的分心物加工机制：是否存在抑制

系统考察在控制目标与非目标颜色特征属性的条件下, 动态非注意盲中视觉系统是否存在对分心物的抑制机制。实验一为基线实验, 将目标与非目标设置为相同的白色圆形, 考察被试对不同颜色特征(白色或者黑色)新异刺激的觉察情况; 实验二和实验三通过改变目标与非目标的颜色特征, 进一步探讨视觉系统对分心物(包括非目标和新异刺激)的抑制机制。结果发现, 视觉系统对干扰目标追踪(并计数)任务的分心物均产生抑制作用, 并且不同颜色特征的分心物受到的抑制作用不同, 与目标颜色特征相同的分心物受到的抑制作用较大, 相应新异刺激的觉察率低; 与目标颜色特征区分明显的分心物受到的抑制作用较小, 相应新异刺激的觉察率较高。     

目标与非目标数量变化对多目标追踪的选择性抑制效应

采用多目标追踪和点探测刺激觉察任务相结合的实验范式,考察目标和非目标数量变化对多目标追踪的选择性抑制效应。实验一设置非目标恒定而变化目标数量,结果发现：随着目标数量的增加,目标与非目标间的抑制差异量不随目标数量变化而变化。实验二设置目标恒定而变化非目标数量,结果发现：在非目标数量变化的三种水平下,目标与非目标间的抑制差异量也无显著差异。综合实验结果表明：在多目标追踪的追踪容量或抑制容量范围内,抑制差异量对目标数量或非目标数量变化是不敏感的;注意资源分配方式在一定范围内保持相对稳定。     

工作记忆表征对视觉注意的影响:基于非目标模板的视角

储存在工作记忆中的视觉表征会影响注意选择过程。其中,与目标有关的工作记忆表征(靶子模板)对视觉注意起到自上而下的引导作用,而与目标无关的工作记忆表征(非目标模板)亦会对注意分配产生影响。本文通过系统分析非目标工作记忆表征影响视觉搜索过程的相关研究,发现非目标模板在视觉搜索任务中既存在自动化的注意捕获,也会形成主动抑制以提高目标搜索绩效。进一步地,对非目标模板的注意捕获或抑制受实验范式、任务难度、刺激材料特征以及认知控制水平等因素的影响。未来研究应该在不断深入细化变量操纵、完善变量控制的同时,进一步扩展应用领域的研究。     

工作记忆内容对空间返回抑制的影响

工作记忆内容能够以相对自动化的方式引导视觉选择性注意。研究的目的在于考察工作记忆内容对空间返回抑制的影响。实验一要求被试在客体工作记忆保持阶段完成返回抑制任务,结果发现无论返回抑制任务目标是否与工作记忆内容匹配都出现了返回抑制效应。实验二要求被试在空间工作记忆保持阶段完成返回抑制任务,结果发现当目标落在记忆空间上时返回抑制效应消失。因此,空间返回抑制仅会受到基于空间工作记忆的视觉注意引导的影响。     

目标数量与运动框架旋转角度对不同场认知风格个体多目标追踪表现的影响

通过改变目标数量、运动框架突变旋转角度探究不同场认知风格被试在多目标追踪任务中的表现。结果发现：(1)在任务难度较低(运动参考框架稳定, 目标数量为3和4)和任务难度中等(运动参考框架突变向右旋转20°, 目标数量为4)条件下, 场独立型被试的多目标追踪表现均显著好于场依存型被试。在任务难度较高(运动框架稳定, 目标数量为5以及运动参考框架突变向右旋转40°, 目标数量为4)条件下, 两组被试差异不显著。表明不同场认知风格被试追踪表现受任务难度影响; (2)随着目标数量由3至5增多, 追踪负荷增大使被试的追踪成绩显著下降; (3)相比运动框架稳定, 运动框架向右突变旋转20°和40°均显著削弱了被试的追踪表现。旋转角度变化破坏了场景连续性, 影响了追踪表现。     

面孔方位对返回抑制的影响

采用辨别任务探讨了正立与倒立的中性面孔线索对返回抑制的影响。实验一采用同时线索化范式考察了正立与倒立面孔线索对靶刺激反应的影响,结果发现,两种面孔线索对随后靶刺激的反应没有影响。实验二采用单线索范式考察正立与倒立面孔对返回抑制的影响,结果发现,两种线索条件下均产生了返回抑制,而且返回抑制量没有显著差异。实验三,正立与倒立面孔作为靶刺激呈现,得到与实验二相同的结果。这些结果表明当采用中性面孔为线索时,返回抑制的产生并不受线索与靶刺激显著性的影响,而且返回抑制这种盲目机制不受任务难度的影响。     

视觉观点采择需要抑制控制的参与：一项负启动研究

从抑制控制模型出发,采用负启动范式考察视觉观点采择的认知机制。实验1采用自身体转换任务(N=35) 、实验2采用圆点数量判断任务(N=33)分别考察成人在完成二级和一级视觉观点采择任务时是否需要抑制控制的参与。结果发现,成人在完成两类视觉观点采择任务时均出现了负启动效应,说明当他人观点和自我观点不一致时,个体需要抑制自我的观点才能成功采择他人的观点。     

情绪和时间辨别任务中视听整合与预先准备效应

本研究分别在时间和情绪认知维度上考察预先准备效应对情绪视听整合的影响。时间辨别任务(实验1)发现视觉引导显著慢于听觉引导,并且整合效应量为负值。情绪辨别任务(实验2)发现整合效应量为正值;在负性情绪整合中,听觉引导显著大于视觉引导;在正性情绪整合中,视觉引导显著大于听觉引导。研究表明,情绪视听整合基于情绪认知加工,而时间辨别会抑制整合;此外,跨通道预先准备效应和情绪预先准备效应都与引导通道有关。     

客体运动方向的视觉工作记忆存储方式

采用变化觉察范式,以独立运动的客体为对象,通过两个实验,探讨多个客体的运动方向在视觉工作记忆中的存储机制,即单个对象独立存储,抑或其存储受多个客体构型的影响。实验一和实验二相继考察了非目标客体运动方向变化,以及是否存在非目标客体对觉察目标客体运动方向的影响。结果发现,非目标客体运动方向变化条件下的觉察正确率显著低于不变的条件,然而只呈现目标客体条件下的觉察正确率与同时呈现目标和非目标条件无显著差异。该结果与前人在静态条件下对目标客体的觉察受目标客体和非目标客体整体构型影响的结论不一致。本研究的结果支持多个客体的运动方向信息在工作记忆中是以独立方式存储的假设。     

Some puzzling findings in multiple object tracking (MOT): II. Inhibition of moving nontargets

We present three studies examining whether multiple object tracking (MOT) benefits from the active inhibition of nontargets, as proposed in Pylyshyn (2004, Visual Cognition). Using a probe-dot technique, the first study showed poorer probe detection on nontargets than on either the targets being tracked or in the empty space between objects. The second study used a matching nontracking task to control for possible masking of probes, independent of target tracking. The third study examined how localized the inhibition is to individual nontargets. The result of these three studies led to the conclusion that nontargets are subject to a highly localized object-based inhibition. Implications of this finding for the FINST visual index theory are discussed. We suggest that we need to distinguish between the differentiation (or individuation) of enduring token objects and the process of making the objects accessible through indexes, with only the latter being limited to 4 or 5 objects.     

Perceptual integration of motion and form information: evidence of parallel-continuous processing

In three visual search experiments, the processes involved in the efficient detection of motion-form conjunction targets were investigated. Experiment 1 was designed to estimate the relative contributions of stationary and moving nontargets to the search rate. Search rates were primarily determined by the number of moving nontargets; stationary nontargets sharing the target form also exerted a significant effect, but this was only about half as strong as that of moving nontargets; stationary nontargets not sharing the target form had little influence. In Experiments 2 and 3, the effects of display factors influencing the visual (form) quality of moving items (movement speed and item size) were examined. Increasing the speed of the moving items (> 1.5 degrees/sec) facilitated target detection when the task required segregation of the moving from the stationary items. When no segregation was necessary, increasing the movement speed impaired performance: With large display items, motion speed had little effect on target detection, but with small items, search efficiency declined when items moved faster than 1.5 degrees/sec. This pattern indicates that moving nontargets exert a strong effect on the search rate (Experiment 1) because of the loss of visual quality for moving items above a certain movement speed. A parallel-continuous processing account of motion-form conjunction search is proposed, which combines aspects of Guided Search (Wolfe, 1994) and attentional engagement theory (Duncan & Humphreys, 1989).     

Selective nontarget inhibition in Multiple Object Tracking

We previously reported that in the Multiple Object Tracking (MOT) task, which requires tracking several identical targets moving unpredictably among identical nontargets, the nontargets appear to be inhibited, as measured by a probe-dot detection method. The inhibition appears to be local to nontargets and does not extend to the space between objects—dropping off very rapidly away from targets and nontargets. In the present three experiments we show that (1) nontargets that are identical to targets but remain in a fixed location are not inhibited and (2) moving objects that have a different shape from targets are inhibited as much as same-shape nontargets, and (3) nontargets that are on a different depth plane and so are easily filtered out are not inhibited. This is consistent with a task-dependent view of item inhibition wherein nontargets are inhibited if (and only if) they are likely to be mistaken for targets.     

Flexible feature-based inhibition in visual search mediates magnified impairments of selection: evidence from carry-over effects under dynamic preview-search conditions

Evidence for inhibitory processes in visual search comes from studies using preview conditions, where responses to new targets are delayed if they carry a featural attribute belonging to the old distractor items that are currently being ignored-the negative carry-over effect (Braithwaite, Humphreys, & Hodsoll, 2003). We examined whether inhibition was applied in the same manner across different types of displays or whether the inhibitory weighting applied to different features varied with their utility for the search task. To test this, we present the first empirical investigation of negative carry-over effects under the ecologically valid conditions of dynamic visual search. Experiment 1 investigated preview search using dynamic moving and static displays. Detection was very poor when new targets carried the color of the old distractors, and this negative carry-over effect was significantly exaggerated with moving, compared with static, displays. Experiments 2a and 2b demonstrated that this effect could not be attributed to an increased role of preattentive grouping between new and old items for dynamic displays. Collectively, the findings suggest that feature-based inhibition contributes strongly to preview search through dynamic displays, and this leads to an amplified attentional blindness to new targets. The data specifically indicate that inhibitory processes in search differentially weight color and location in moving and static displays, and that feature-based inhibition may underlie many instances of sustained inattentional blindness in everyday life.     

Direct and indirect memory tests: What they reveal about age differences in interference

The effects of interference on memory in younger and older adults were examined in a series of three experiments. In the study task, subjects were presented with a series of sentences, each having both a target, to-be-remembered ending, and a nontarget ending. Older adults showed equal priming of targets and nontargets on an indirect memory test (Experiment 1), whereas younger adults showed greater priming of the targets. In contrast, on direct memory tests (Experiments 2 and 3) both age groups were more accurate for targets than nontargets. This pattern of results is interpreted as evidence that age differences in interference involve selective attention mechanisms, but not elaborative rehearsal processes.     

Perceptual processing of nontargets in an attention task

The capability of nontargets to qualitatively influence the semantic processing of coincident targets was investigated in three experiments. Subjects were aurally presented a series of word pairs and attempted to detect homonymic instances of a predesignated category (e.g., animals). The nontarget with which a target (e.g., ANT) was paired was appropriate (e.g., CRAWLING), inappropriate (e.g., UNCLE), or neutral (e.g., STRAW). Experiments 1 and 2 established that detection of targets can be facilitated by appropriate nontargets and inhibited by inappropriate ones. Thus, nontargets can influence the way in which targets are semantically represented. Experiment 3 showed that this effect is eliminated when subjects are precued as to the ear of entry of targets. Thus, precuing appears to curtail the perceptual processing of nontargets. The data run counter to theories that claim that focused attention does not entail the perceptual suppression of nontargets.     

Nontarget columns and parafoveal target identification: Some limits on previously observed effects

Summary Three experiments were conducted to determine limits to the phenomenon in which a column of nontargets to the foveal side of a parafoveally presented target is more detrimental to identification than a column to the target's peripheral side, while a single nontarget to the peripheral side is more disruptive. Experiments 1 and 2 showed that proximity of nontarget characters in a column is not sufficent to produce the difference in the effect of the position of nontarget columns and single nontargets. Physical features of characters in the column allowing closure emerged as important to the effect of its position on target identification. Experiment 3 confirmed the findings of the first two experiments and showed, in addition, that performance is better with nontarget columns than with single nontargets because characters in the columns exert lateral interference on one another and thereby release such interference on the target.     

What is learned about nontarget items in simple visual search?

Human sensitivity to correlational structure between nontargets and likelihood of target presence in a visual letter-search task were studied in two experiments. In each of these experiments, the performance of subjects for whom the nontarget information was altered in the final trial block was compared with the performance of subjects for whom the nontarget information did not change. When stimulus strings were presented individually on a computer screen and subjects were required to make a yes-no decision about target presence (Experiment 1), the change in nontarget structure resulted in increased reaction times for target-absent trials. When subjects searched simultaneously for three possible targets (Experiment 2), the change in nontarget structure produced increased error rates and increased reaction times for both target-absent and target-present trials. Correlations between the amount of predictive information in individual stimulus strings and reaction times also showed that both switching and nonswitching subjects were sensitive to the nontarget context. However, neither self-reports of strategy nor postexperiment choices between context-consistent and -inconsistent letter strings indicated any explicit knowledge of the predictive information in the nontarget stimuli. Subjects can thus acquire and benefit from, apparently without awareness, information about subtle correlational structure in nontarget elements in simple visual search.