双任务干扰的注意资源限制机制:来自汉字笔画数效应的证据

该研究的两个实验采用心理不应期范式,探讨了重叠任务情境下双任务的相互干扰机制。实验中被试相继完成高低音的辨别任务(T1)和汉字外在特征(颜色或笔画数)的任务判断(T2),T1和T2间采用变化的SOA。结果发现:(1)T1的反应选择导致T2的加工成绩大幅下降,PRP效应非常显著。(2)当T1占据中枢瓶颈时,T2和T1在中枢瓶颈中并行得到加工并导致T1的加工效率显著下降。(3)由于注意资源的有限性,具有自动激活特征的汉字同样受瓶颈机制的限制。只要存在对注意资源的二次分配就会存在瓶颈的调节机制。     

注意力资源限制与双任务的相互干扰机制

采用心理不应期研究范式, 两个反应时实验检测了注意力资源分配的特征以及双任务的相互干扰机制。每次实验中, 要求被试快速、相继对高低音辨别任务(T1)和Stroop任务(T2)作出选择性反应, T1和T2间采用6种不同的时间间隔(SOA), 以系统考察不同SOA条件下两个任务的反应时走势。结果发现：(1) 在重叠的双任务情境中, T1的中枢加工导致在T2上出现显著的PRP效应, T2的中枢反应选择对T1的反应选择和反应执行加工同样产生显著的影响。SOA以及T2的难度与复杂度实质性地影响了T1的反应选择和反应执行加工。(2) 当两个任务同时需要进行中枢反应选择加工时, 一个任务占用更多的注意资源将导致另一任务获得较少的注意资源, 注意资源量的多寡直接决定了该任务的加工效率。(3) 两个任务的加工相互影响、相互制约, 这种制约机制不仅仅存在于中枢反应选择阶段, 在反应执行阶段仍然存在。     

辨别任务中线索有效性对儿童返回抑制发展的影响

采用辨别任务范式,运用三个3×3×3的混合实验设计(线索有效性、年级、靶子出现位置),考察了3种线索-靶子时间间隔下线索有效性对辨别任务中儿童返回抑制发展的影响。结果表明:(1)随着年龄的增长,儿童完成任务所需的反应时逐渐缩短;(2)随着年龄的增长,儿童出现返回抑制所需的SOA缩短;(3)辨别任务的难度比较大,所需的认知技能和工作记忆更多,因此返回抑制出现的机制也就更复杂,线索有效性对辨别任务下的返回抑制的影响并没有呈现出规律性的变化。     

被试自身人手初始状态对心理旋转加工的影响:眼动研究

利用眼动追踪技术,探讨在左右手判断任务条件下人手心理旋转加工是否受到被试自身人手初始状态的影响.两个实验的反应时数据和眼动数据均发现:(1)心理旋转加工受被试自身人手初始状态的影响,表现出一致性效应;(2)显著的内旋效应;(3)被试心理旋转加工时注视点取样存在着不均衡性.这些结果表明:在左右手判断任务中,心理旋转加工的对象是被试自身人手的表象,是自我参照的心理旋转,并且内旋效应是由被试对自身人手表象进行旋转时受到人手生理机制约束所致,而不是被试旋转刺激图片的表象由"生理机制约束知识"影响所致.     

颜色特征加工任务间的注意瞬脱研究

本研究以两个实验对颜色特征加工任务间的注意瞬脱效应进行探讨。实验一要求被试对首先呈现的两个色块(记忆项)与随后呈现的两个色块(检测项)是否相同进行比较。结果发现,在记忆项与检测项的SOA为220ms的条件下,记忆项加工对认知资源的持续占用使检测项的加工绩效下降。实验二含两个需相继执行的任务(T1和T2),二者均为比较同时呈现在屏幕左右两侧的两色块颜色是否相同。结果发现,对颜色特征的觉察即可产生注意瞬脱效应,其大小及时程与经典的采用字母识别任务的研究获得的注意瞬脱效应相当。上述结果表明,特征搜索的完成需有限认知资源的参与。然而,注意瞬脱过程中,特征加工与需对知觉对象细节信息进行提取的辨别任务(如字母辨别任务)在消耗认知资源的量上并无差别。     

场认知方式对心理旋转影响的实验研究

采用2个2 × 2×6三因素混合设计实验,以图形和数字为实验材料,探讨能反应个体能力水平差异的场认知方式对心理旋转的影响.两个实验结果均表明(1)场认知方式的主效应显著,场独立性的被试比场依存性的被试反应时短,且正确率高;两类被试的反应时、正确率曲线具有一致的变化趋势;(2)图形和数字的心理旋转反应时呈倒"V"形状,反应时随着旋转角度的增加而增加,180°时反应时最长,以180°为界,曲线两侧的变化趋势对称;(3)正确率随着旋转角度的增加而降低,呈现"V"状,180°时正确率最低,曲线两侧的变化趋势对称.     

复合字母刺激心理旋转加工中的整体优先效应

采用复合字母材料结合正镜像判断任务,首次揭示了心理旋转加工中的整体优先效应。实验一延长复合字母材料的呈现时间,检验心理旋转实验常用的正/镜像判断任务中的视知觉整体优先效应;实验二将实验一的复合字母材料旋转一定角度,考察心理旋转加工中的整体优先效应。结果发现：（1）延长复合字母呈现时间后的字母正镜像判断任务中,被试判断大字母和判断小字母的时间没有显著差异,并且大小字母是否一致对大字母判断和小字母判断的影响无显著差异;（2）在排除了视知觉的整体优先效应存在的情况下,发现心理旋转加工中存在明显的整体优先效应,大字母（整体）旋转条件下的反应时显著短于小字母（局部）旋转条件下的反应时;（3）旋转角度一致性对大字母旋转和小字母旋转条件下的反应时均无显著影响,表明心理旋转的整体优先效应模式可能有别于视知觉加工的整体优先效应模式     

被试自身人手初始状态对心理旋转加工的影响：眼动研

利用眼动追踪技术,探讨在左右手判断任务条件下人手心理旋转加工是否受到被试自身人手初始状态的影响。两个实验的反应时数据和眼动数据均发现：（1）心理旋转加工受被试自身人手初始状态的影响,表现出一致性效应;（2）显著的内旋效应;（3）被试心理旋转加工时注视点取样存在着不均衡性。这些结果表明：在左右手判断任务中,心理旋转加工的对象是被试自身人手的表象,是自我参照的心理旋转,并且内旋效应是由被试对自身人手表象进行旋转时受到人手生理机制约束所致,而不是被试旋转刺激图片的表象由“生理机制约束知识”影响所致     

信息加工速度的年龄差异机制

选择7-19岁的被试140名,对三种不同任务进行操作.结果表明,在心理旋转任务中,儿童青少年的反应时是青年期反应时的函数,指数函数能较好的描述这种共同的发展变化趋势,但在简单反应时和图形匹配任务中,这种线性关系较差;随着年龄的变化,信息加工速度的下降速率是根据不同的加工任务变化的,简单任务(指简单反应时和图形匹配)下降速度快,复杂任务(指心理旋转)下降速度慢;性别差异随着年龄增长逐步缩小,但不同的加工任务其差异缩小的年龄阶段不同,简单反应时在11岁,图形匹配在13岁,心理旋转在17岁;且性别差异量与年龄不完全是一种函数关系;最后,本研究对信息加工速度的年龄差异机制进行了讨论.     

积极情绪对高中生心理旋转范围的影响:趋近动机的调节效应

为考察积极情绪对高中生心理旋转的影响,采用四种体态表情诱发趋近动机不同的积极情绪和中性情绪。结果发现:(1)直立中性时,局部任务反应时显著长于整体任务。(2)前倾微笑时,局部任务正确率显著高于整体任务,其他条件两种任务差异不显著。整体任务中,后倚微笑正确率高于其他体态表情。结果表明,高中生心理旋转存在整体优先效应;趋近动机是积极情绪对高中生心理旋转影响的调节变量,结果符合动机维度模型的假设。     

Stimulus-response compatibility and psychological refractory period effects: implications for response selection

The purpose of this paper was to provide insight into the nature of response selection by reviewing the literature on stimulus-response compatibility (SRC) effects and the psychological refractory period (PRP) effect individually and jointly. The empirical findings and theoretical explanations of SRC effects that have been studied within a single-task context suggest that there are two response-selection routes—automatic activation and intentional translation. In contrast, all major PRP models reviewed in this paper have treated response selection as a single processing stage. In particular, the response-selection bottleneck (RSB) model assumes that the processing of Task 1 and Task 2 comprises two separate streams and that the PRP effect is due to a bottleneck located at response selection. Yet, considerable evidence from studies of SRC in the PRP paradigm shows that the processing of the two tasks is more interactive than is suggested by the RSB model and by most other models of the PRP effect. The major implication drawn from the studies of SRC effects in the PRP context is that response activation is a distinct process from final response selection. Response activation is based on both long-term and short-term task-defined S-R associations and occurs automatically and in parallel for the two tasks. The final response selection is an intentional act required even for highly compatible and practiced tasks and is restricted to processing one task at a time. Investigations of SRC effects and responseselection variables in dual-task contexts should be conducted more systematically because they provide significant insight into the nature of response-selection mechanisms.     

Concurrent deployment of visual attention and response selection bottleneck in a dual-task: Electrophysiological and behavioural evidence

Visual attention and response selection are limited in capacity. Here, we investigated whether visual attention requires the same bottleneck mechanism as response selection in a dual-task of the psychological refractory period (PRP) paradigm. The dual-task consisted of an auditory two-choice discrimination Task 1 and a conjunction search Task 2, which were presented at variable temporal intervals (stimulus onset asynchrony, SOA). In conjunction search, visual attention is required to select items and to bind their features resulting in a serial search process around the items in the search display (i.e., set size). We measured the reaction time of the visual search task (RT2) and the N2pc, an event-related potential (ERP), which reflects lateralized visual attention processes. If the response selection processes in Task 1 influence the visual attention processes in Task 2, N2pc latency and amplitude would be delayed and attenuated at short SOA compared to long SOA. The results, however, showed that latency and amplitude were independent of SOA, indicating that visual attention was concurrently deployed to response selection. Moreover, the RT2 analysis revealed an underadditive interaction of SOA and set size. We concluded that visual attention does not require the same bottleneck mechanism as response selection in dual-tasks.     

Backward crosstalk effects in psychological refractory period paradigms: effects of second-task response types on first-task response latencies

Three experiments using psychological refractory period (PRP) tasks documented backward crosstalk effects in which the nature of the second-task response influenced the first-task response latencies. Such effects are difficult to explain within currently popular bottleneck models, according to which second-task response selection does not begin until first-task response selection has finished. In Experiments 1 and 2, the first of the PRP tasks required a choice reaction time (RT) response, whereas the second task required a go/no-go decision. Task 1 responses were faster when the second task required a go response than when it required a no-go response. Experiment 3 showed that Task 1 RTs were also influenced by the complexity of second-task responses. These backward crosstalk effects indicate that significant second-task processing is carried out in time to influence first-task responses and thus challenge strictly serial bottleneck models.     

Age differences in overlapping-task performance: evidence for efficient parallel processing in older adults

Two psychological refractory period (PRP) experiments were conducted to examine overlapping processing in younger and older adults. A shape discrimination task (triangle or rectangle) for Task 1 (T1) and a lexical-decision task (word or nonword) for Task 2 (T2) were used. PRP effects, response time for T2 increasing as stimulus onset synchrony (SOA) decreased, were obtained for both age groups. The effect of word frequency on T2 was smaller at the short SOA than at the long SOA, reflecting slack effects, which were larger for older than younger adults in both experiments. These results suggest that older adults can perform lexical access of T2 in parallel with the processing of T1 at least as efficiently as younger adults.     

Multiple bottlenecks in information processing? An electrophysiological examination

When two stimuli are to be processed in rapid succession, reaction time (RT) to the second stimulus is delayed. The slowing of RT has been attributed to a single processing bottleneck at response selection (RS) or to a central bottleneck following the initiation of the first response. The hypothesis of a response initiation bottleneck is mainly based on reports of underadditive interactions between stimulus onset asynchrony (SOA) and the number of stimulus—response alternatives (simple vs. two-choice response). The present study tested the hypothesis of a response initiation bottleneck by recording the lateralized readiness potential (LRP), a brain wave, emerging during or immediately following RS. The LRP findings were consistent with a central bottleneck but did not support the late bottleneck hypothesis. Instead, the LRP provided direct evidence that the underadditive interaction of number of alternatives and SOA is due to an increase of response anticipations in the simple response condition.     

Decision and Response in Dual-Task Interference

Experiments with two stimuli (S₁and S₂) and two responses suggest the existence of a stage of processing that cannot be shared between two concurrent tasks. Widespread support has been found for the hypothesis that response selection for Task₂is postponed when the S₁to S₂stimulus onset asynchrony (SOA) is short (Pashler, 1994a). At short SOAs, manipulations which impact Task₂processing prior to response selection (e.g., degradation of stimulus quality) have little effect on Task₂response times (RTs). On the other hand, manipulations which are thought to impact response selection or execution (e.g., Stroop interference) always impact Task₂RTs. There is, however, one particularly compelling demonstration that appears to be inconsistent with the response selection bottleneck hypothesis: Karlin and Kestenbaum (1968) report that the RT difference between detection (i.e., 1-choice) and 2-choice discrimination dramatically decreases with decreasing SOA. Given that the primary difference between detection and discrimination is believed to be at response selection, their result may indicate a processing bottleneck at response execution (Keele, 1973). We fail to replicate the Karlin and Kestenbaum result in two substantive replications of Karlin and Kestenbaum's tasks and procedures. In the single experiment in which Karlin and Kestenbaum's result is replicated, a simple response execution bottleneck account is ruled out by the stability of the difference between 2-choice and 3-choice discrimination times across SOA. Two additional experiments demonstrate that response preparation and task strategy do not substantially contribute to the attenuation of response selection-level effects with decreasing SOA.     

A central capacity sharing model of dual-task performance

The authors present the central capacity sharing (CCS) model and derive equations describing its behaviors to explain results from dual-task situations. The predictions of the CCS model are contrasted with those of the central bottleneck model. The CCS model predicts all of the hallmark effects of the psychological refractory period (PRP) pardigm: -1 slope of the PRP effect at short stimulus onset asynchronies (SOAs), underadditivity of precentral Task 2 manipulations, additivity of central or postcentral Task 2 manipulations with SOA, and carry forward to Task 2 of Task 1 precentral or central manipulations at short SOAs. The CCS model also predicts that Task 1 response times increase with decreasing SOA. The model is a viable alternative to the central bottleneck model.     

Information continuity across the response selection bottleneck: Early parallel Task 2 response activation contributes to overt Task 2 performance

Several studies of dual-task performance have demonstrated Task 2 to Task 1 response priming (backward compatibility effects), indicating some degree of parallel response computation for concurrent tasks and suggesting that the well-established response selection bottleneck (RSB) model may be incomplete. However, the RSB might be considered to remain informationally intact if this early parallel Task 2 response information does not persist across the attentional shift between tasks to contribute to overt Task 2 performance. We used an adapted psychological refractory period paradigm with an additional early transient Task 2 stimulus to examine whether response information generated for Task 2 in parallel with overt Task 1 response selection could persist across the bottleneck to influence eventual overt Task 2 performance. After controlling for potential indirect effects of Task 1 processing stage variability propagating onto Task 2 reaction time via locus of slack effects, we observed reliable and consistent effects of early Task 2 response information facilitating Task 2 reaction times. These effects were observed only when the responses to both tasks of the dual-task pair were compatible, under both univalent and bivalent response mappings across tasks. These findings may represent evidence of a variably sensitive response gating or suppression mechanism in dual-task performance and support the idea that backward response compatibility effects represent transient informational influences on central response codes, rather than later postbottleneck response execution processes.     

Dissociating sources of dual-task interference using human electrophysiology

In the psychological refractory period (PRP) paradigm, two unmasked targets are presented, each of which requires a speeded response. Response times to the second target (T2) are slowed when T2 is presented shortly after the first target (T1). Electrophysiological studies have previously shown that the P3 event-related potential component is not delayed during T2 response slowing in the PRP paradigm, but that the lateralized readiness potential is delayed, which suggests a bottleneck on response selection operations but not on stimulus identification. Recently, researchers (Arnell & Duncan, 2002; Jolicoeur & Dell'Acqua, 1999) observed T2 response slowing in an encoding-speeded response (ESR) paradigm where T2 followed a masked T1 that required identification but not a speeded response. T2 response slowing in the ESR paradigm is often indistinguishable from that in the PRP paradigm, prompting some researchers to postulate a common processing bottleneck for the two paradigms. With the use of the ESR paradigm, we observed T2 response slowing and, in contrast to the PRP paradigm, we also observed corresponding P3 delays. The results suggest that dissociable bottlenecks underlie the dual-task costs from the two paradigms.