Determinants of central processing order in psychological refractory period paradigms: central arrival times, detection times, or preparation?

Three psychological refractory period (PRP) experiments were conducted to assess the effect of central arrival times at the bottleneck on task order scheduling. In Experiment 1, a visual first task (plus-minus symbol discrimination) was combined with an auditory second task (left-right tone judgement) in a standard PRP paradigm with constant task order. In Experiment 2, the order of the tasks varied unpredictably. In Experiment 3, visual-auditory dual-task trials were randomly mixed with single-task trials. To dissociate central arrival times from stimulus detection times, the perceptual stage of the visual task was extended using stimulus degradation. Most importantly, no evidence for a first-come, first-served principle at the central bottleneck was found with the employed paradigms. Instead, the results indicated that preparation (Experiment 1) and the detection times of the stimuli (Experiments 2 and 3) were the main determinants of central processing order in the present study. In the light of previous research, the results indicate that central processing order can be influenced by various factors. The interplay between these factors seems to depend highly on the conditions and requirements of the employed experimental paradigm.     

Flanker and Simon effects interact at the response selection stage

The present study aimed at investigating the processing stage underlying stimulus–stimulus (S–S) congruency effects by examining the relation of a particular type of congruency effect (i.e., the flanker effect) with a stimulus–response (S–R) spatial correspondence effect (i.e., the Simon effect). Experiment 1 used a unilateral flanker task in which the flanker also acted as a Simon-like accessory stimulus. Results showed a significant S–S Congruency × S–R Correspondence interaction: An advantage for flanker–response spatially corresponding trials was observed in target–flanker congruent conditions, whereas, in incongruent conditions, there was a noncorresponding trials' advantage. The analysis of the temporal trend of the correspondence effects ruled out a temporal-overlap account for the observed interaction. Moreover, results of Experiment 2, in which the flanker did not belong to the target set, demonstrated that this interaction cannot be attributed to perceptual grouping of the target–flanker pairs and referential coding of the target with respect to the flanker in the congruent and incongruent conditions, respectively. Taken together, these findings are consistent with a response selection account of congruency effects: Both the position and the task-related attribute of the flanker would activate the associated responses. In noncorresponding-congruent trials and corresponding-incongruent trials, this would cause a conflict at the response selection stage.     

On the nonautomaticity of visual word processing: electrophysiological evidence that word processing requires central attention

The present study used event-related potentials (ERPs) to determine the degree to which people can process words while devoting central attention to another task. Experiments 1-4 measured the N400 effect, which is sensitive to the degree of mismatch between a word and the current semantic context. Experiment 5 measured the P3 difference between low- and high-frequency words. Because these effects can occur only if a word has been identified, both ERP components index word processing. The authors found that the N400 effect (Experiments 1, 3, and 4) and the P3 difference (Experiment 5) were strongly attenuated for Task 2 words presented nearly simultaneously with Task 1. No such attenuation was found when the Task 1 stimulus was presented but required no response (Experiment 2). Strong attenuation was also evident when the Task 2 word was presented before the Task 1 stimulus (Experiment 4), suggesting that central resources are not allocated to stimuli first-come, first-served but rather are strategically locked to Task 1. The authors conclude that visual word processing is not fully automatic but rather requires access to limited central attentional resources.     

The functional role of central and peripheral vision in the control of posture

Three experiments were conducted to investigate the role of central and peripheral vision (CV and PV) in postural control. In Experiment 1, either the central or peripheral visual field were selectively stimulated using a circular random dot pattern that was either static or alternated at 5 Hz. Center of foot pressure (CoP) was used to examine postural sway during quiet standing under both CV and PV conditions. The results showed that, when the visual stimulus was presented in the periphery, the CoP area decreased and more so in the anterior-posterior (AP) than in the medio-lateral (ML) direction, indicating a characteristic directional specificity. There was no significant difference between the static and dynamic (alternating) conditions. Experiment 2 investigated the directional specificity of body sway found in Experiment 1 by having the trunk either be faced toward the stimulus display or perpendicularly to it, with the head always facing the display. The results showed that the stabilizing effect of peripheral vision was present in the direction of stimulus observation (i.e., the head/gaze direction), irrespective of trunk orientation. This suggested that head/gaze direction toward the stimulus presentation, rather than a biomechanical factor like greater mobility of the ankle joint in AP direction than in ML direction, was essential to postural stability. Experiment 3 further examined whether the stabilizing effect of peripheral vision found in Experiments 1 and 2 was caused because more dots (500) were presented as visual cues to the peripheral visual field than to the central visual field (20 dots) by presenting the same number of dots (20) in both conditions. It was found that, in spite of the equal number of dots, the postural sway amplitudes were larger for the central vision conditions than for the peripheral vision conditions. In conclusion, the present study showed that peripheral rather than central vision contributes to maintaining a stable standing posture, with postural sway being influenced more in the direction of stimulus observation, or head/gaze direction, than in the direction of trunk orientation, which suggests that peripheral vision operates primarily in a viewer-centered frame of reference characterized by the head/gaze direction rather than in a body-centered frame of reference characterized by the anatomical planes of the body.     

Deeper processing at target selection increases the magnitude of negative priming

Do deeper levels of processing produce equivalent priming effects at all stages of task performance? In Experiment 1, we varied the level of processing factorially across two task stages—target selection and response selection. Each stage required perceptual (e.g., color) or conceptual (e.g., friendliness) processing of stimulus items (i.e., animal names). Negative priming was substantially greater when deeper processing was required at thetarget selection stage, but it was unaffected by the level of processing at the response selection stage. In contrast, positive priming was greater when deeper processing was required at theresponse selection stage, but it was unaffected by processing at the target selection stage. In Experiment 2, we generalized this finding using a task in which numeric targets were selected on the basis of their parity. As in Experiment 1, the deeper level of processing at the target selection stage produced a larger negative priming effect. These results illuminate the role of target selection demands in modulating the strength of negative priming.     

Mechanisms of sentence context effects in reading: Automatic activation and conscious attention

In. Experiment I subjects named target words that were preceded by a congruous sentence context, an incongruous sentence context, or no sentence context, under stimulus conditions that were either normal or degraded by contrast reduction. Under normal stimulus conditions, a contextual facilitation effect, but no contextual inhibition effect, was observed. When the target word was degraded, both contextual facilitation and inhibition were observed. Experiment 2 replicated the increase in contextual inhibition under degraded conditions and also demonstrated that inhibition increased as the interval between contextual processing and target-word onset was lengthened. The results were interpreted within the framework of the Posner and Snyder two-process theory of expectancy. Thus, when target-word recognition is rapid, only the fast-acting automatic activation component of context effects has time to operate. When target-word processing is delayed, the conscious-attention mechanism, which is responsible for inhibition effects, becomes operative. The relevance of these results to developmental investigations of the interaction of word recognition and contextual processing is discussed.     

Seeing changes: How familiarity alters our perception of change

The impact of object familiarity on change blindness was examined. Familiarity was operationalized by manipulating the orientation (upright vs. inverted) of letters: Upright letters formed familiar stimuli whereas inverted letters produced unfamiliar stimuli. Across four experiments, orientation was shown to affect the ability to detect change. In Experiment 1, the orientation effect was independent of the number of distractors (set size), suggesting that orientation and set size affect separate processes. In Experiment 1b, it was shown that the orientation effect did not depend on the alternation of a particular letter pair. In Experiment 2 an interaction between set size and stimulus quality suggests that set size has its effects early in processing, whereas additivity between stimulus quality and orientation suggests that orientation has an effect on later processing. Experiment 3 replicates and extends the findings from Experiments 1 and 2. A stage model of change blindness is proposed and extended by drawing on constructs from Rensink (2000b, 2002, 2005).     

Assessing the effect of sound complexity on the audiotactile cross-modal dynamic capture task

Recent studies have provided evidence that dual-task interference is typically caused by a single-channel bottleneck, but the processing locus of the bottleneck has yet to be pinned down. A bottleneck locus at the response-selection stage is widely advocated, but an earlier locus would be consistent with most previous evidence. Four new experiments used the “locus of slack” method to investigate whether the stages postponed by the central bottleneck include stimulus classification, a very late stage of perceptual processing. The experiments varied stimulus classification difficulty for two different analogueue perceptual judgements. Experiment 1 found only modest absorption into slack for the difficulty of a spatial position judgement. Experiments 2–4 found virtually no absorption into slack for the difficulty of a box-width judgement. These results support a bottleneck locus beginning at or before the stage of stimulus classification and hence prior to the stage of response selection. Other evidence, however, leaves no doubt that response selection is also subject to bottleneck postponement. Two architectures are discussed that can account parsimoniously for both old and new results. One posits a single bottleneck resulting from a unified CPU-like central processor; the other posits multiple bottlenecks resulting from multiple processors accomplishing different substages of central processing.     

Processing order in dual-task situations: The “first-come,first-served” principle and the impact of task order instructions

When two overlapping tasks are processed, they hit a bottleneck at a central processing stage that prevents simultaneous processing of the two tasks. Thus far, however, the factors determining the processing order of the tasks at the bottleneck are unknown. The present study was designed to (re)investigate whether the arrival times of the two tasks at the central bottleneck are a key determinant of the processing order (cf. Sigman & Dehaene, 2006). To this end, we implemented a visual–auditory dual task with a random stimulus order, in which we manipulated arrival time by prolonging the initial, perceptual processing stage (stimulus analysis) of the visual task and compared the effects of this manipulation with those of one impacting the central bottleneck stage of the visual task. Additionally, we implemented two instruction conditions: Participants were told to respond either in the order of stimulus presentation or in the order they preferred. The manipulation of the visual perception stage led to an increase in task response reversals (i.e., the response order was different from the order of stimulus presentation), whereas there was no such increase when the bottleneck stage was manipulated. This pattern provides conclusive evidence that the processing order at the bottleneck is (at least in part) determined by the arrival times of the tasks at that point. Reaction time differences between the two instruction conditions indicated that additional control processes are engaged in determining task processing order when the participants are expressly told to respond in the order of stimulus presentation.     

内倾特质个体的自我参照加工程度效应

采用事件相关电位技术和三类刺激的经典oddball范式,以内隐的方式探讨内倾特质个体的自我参照加工程度效应及其神经机制。实验发现,在P2的波幅上,在电极前部、前中部和中部位置高自我相关的刺激比其它刺激诱发了更大的P2波幅。在P2的潜伏期上,在电极前部、中部、和中后部位置高自我相关的刺激比其它刺激诱发了更短的潜伏期。在N2的波幅上,高自我相关名字比其它刺激在左脑所诱发了更大的P2的波幅;对比内倾型被试,中间型被试的高自我相关名字比其它刺激诱发了更大的N2的波幅。在N2的潜伏期上,高自我相关的刺激在全脑都比其它刺激诱发了更短的N2潜伏期,且中后部电极位置的潜伏期最短;两类人格被试的高自我相关名字比其它刺激诱发了更短的N2潜伏期,但中间型人格被试的潜伏期最短。在P3平均波幅上,高自我相关的刺激在全脑都比其它刺激诱发了更大的P3波幅,其中中部脑区效应最大。研究结果表明内倾特质个体的自我参照加工具有程度效应,但对比中间型个体,内倾特质个体的自我参照加工的程度效应更弱。     

Generalization and response latency

The present experiments investigated generalization in a reaction time situation where the generalization stimulus, a tone, preceded the reaction time signal, a light. The hypotheses under investigation were that the duration of the cue stimulus would determine the degree of generalization (Experiment I) and that the response latency independent of the stimulus duration would be related to the amount of generalization (Experiment II). A particular generalization test stimulus (a tone of 40, 45, 50, 60, 65, or 70 dB) was presented only once always following two bar-pressing responses to training stimulus (tone of 55 dB) under each of two conditions of stimulus duration in Experiment I and under each of two conditions of response latency in Experiment II. It was found that under the condition of short response latency generalization was broader.     

Generalization and response latency

The present experiments investigated generalization in a reactio? time situation where the generalization stimulus, a tone, preceded the reaction time signal, a light. The hypotheses under investigation were that the duration of the cue stimulus would determine the degree of generalization (Experiment I) and that the response latency independent of the stimulus duration would be related to the amount of generalization (Experiment II). A particular generalization test stimulus (a tone of 40, 45, 50, 60, 65, or 70 dB) was presented only once always following two bar-pressing responses to training stimulus (tone of 55 dB) under each of two conditions of stimulus duration in Experiment I and under each of two conditions of response latency in Experiment II. It was found that under the condition of short response latency generalization was broader.     

Effects of gender marking in pronominal coindexation.

The naming latency of a pronoun was measured when a single previously presented name in a discourse either agreed or did not agree with the pronoun in gender and person. An effect of agreement was found both under conditions in which subjects were likely to have engaged in strategic processing of the pronoun (Experiment 1) and under conditions in which this was unlikely (Experiment 3). The effect of gender agreement was also investigated when two noun phrases were present in the discourse. The results continued to show an immediate effect of gender agreement (naming latencies increased when a pronoun did not agree with one of two previously presented nouns) under experimental conditions likely to engender strategic processing (Experiment 2). This last effect was not significant under experimental conditions that were not likely to engender strategic processing (Experiment 3). The results are discussed in terms of models of the process of identifying the referent of a pronoun in a discourse.     

Electrophysiological differences in the processing of affective information in words and pictures

It is generally assumed that affective picture viewing is related to higher levels of physiological arousal than is the reading of emotional words. However, this assertion is based mainly on studies in which the processing of either words or pictures has been investigated under heterogenic conditions. Positive, negative, relaxing, neutral, and background (stimulus fragments) words and pictures were presented to subjects in two experiments under equivalent experimental conditions. In Experiment 1, neutral words elicited an enhanced late positive component (LPC) that was associated with an increased difficulty in discriminating neutral from background stimuli. In Experiment 2, high-arousing pictures elicited an enhanced early negativity and LPC that were related to a facilitated processing for these stimuli. Thus, it seems that under some circumstances, the processing of affective information captures attention only with more biologically relevant stimuli. Also, these data might be better interpreted on the basis of those models that postulate a different access to affective information for words and pictures.     

Central slowing during the night

The present study determined whether central information processing is subject to a circadian rhythm and, therefore, contributes to the well-known time-of-day effect on reaction time (RT). To assess the duration of central processing chronometrically, we employed the psychological refractory period (PRP) paradigm. In this task, subjects make fast responses to two successive stimuli. RT to the second stimulus is usually prolonged as the interval between the two stimuli decreases. This PRP effect is commonly attributed to a central-processing bottleneck. Subjects performed the PRP task every 2 hr during 28 hr of constant wakefulness under controlled conditions. The PRP effect was most pronounced in the early morning. We conclude that central processing is subject to a circadian rhythm, exhibiting a slowing during the night and a nadir in the early morning.     

通道呈现方式与感知学习风格的匹配性对粤-普双言切换代价的影响

选取不同感知学习风格的熟练粤-普双言者被试, 比较在不同通道呈现方式下他们刺激命名任务的表现, 由此考察感知学习风格与通道呈现方式的匹配性对熟练双言者双言切换代价的影响。结果发现, 被试在视觉线索呈现条件下要比在听觉线索条件下的切换代价小; 当感知学习风格与通道呈现方式匹配时, 双言切换代价更低。表明感知学习风格与通道呈现方式的匹配性对于双言切换代价有调节作用。     

Coactivation in the perception of redundant targets

Reaction time (RT) to redundant stimuli was investigated while controlling for distraction effects and response competition. In Experiment 1, a redundancy gain was found for 2 target letters with identical features (redundant) compared to trials in which 2 different targets shared the same response assignment (compatible) indicating coactivation of stimulus inputs. No difference in RTs was found between compatible displays and displays containing 2 targets with different responses (incompatible), suggesting (with other evidence) that letters were serially processed. In Experiment 2, a redundancy gain was again found. Unlike in Experiment 1, incompatible displays produced response competition, indicating a redundancy gain with parallel processing. Three forms of redundancy gains operating under specific conditions are discussed.     

The gap effect in newborns

In four experiments we investigated the gap effect in infants within the first 3 days of life. Reaction times (RTs) to make a saccade to a peripheral target were measured on gap trials, in which the central fixation stimulus went off 500 ms before target presentation, and on overlap trials, in which the central fixation stimulus remained on. In every experiment the fixation stimulus was a flashing light. The target stimulus was a schematic face in Experiment 1, a flashing light shown at 20° eccentricity in Experiment 2, a flashing light shown at 30° eccentricity in Experiment 3, and an upside-down schematic face in Experiment 4. In Experiments 1–3 a gap effect was found. That is, RT was faster on gap than on overlap trials. In contrast, the gap effect was absent in Experiment 4. These findings are consistent with the view that the superior colliculus plays a major role in producing the gap effect at birth.     

Repetition benefit in mental rotation is independent of stimulus repetition

In this study, we investigated whether there is a repetition benefit in mental rotation that is independent of stimulus repetition (i.e., due to increased efficiency in postencoding processing). Three experiments were conducted, in which different conditions of stimulus repetition (different letters on consecutive trials in Experiment 1, letters of different orientations on consecutive trials in Experiment 2, and priming of rotation direction in Experiment 3) were used, and the extent of repetition of rotation direction between two consecutive trials was manipulated. The results of all three experiments showed clear evidence of a repetition benefit without repeating the stimulus, suggesting that this effect is independent of stimulus repetition and lending support to the notion of increased efficiency in mental rotation as a result of repeated rotation direction per se.     

The role of the head in configural body processing: Behavioural and electrophysiological evidence from the inversion and scrambling effect

The present study aimed to further explore the role of the head for configural body processing by comparing complete bodies with headless bodies and faceless heads (Experiment 1). A second aim was to further explore the role of the eye region in configural face processing (Experiment 2). Due to that, we conducted a second experiment with complete faces, eyeless faces, and eyes. In addition, we used two effects to manipulate configural processing: the effect of stimulus inversion and scrambling. The current data clearly show an inversion effect for intact bodies presented with head and faces including the eye region. Thus, the head and the eye region seem to be central for configural processes that are manipulated by the effect of stimulus inversion. Furthermore, the behavioural and electrophysiological body inversion effect depends on the intact configuration of bodies and is associated with the N170 as the face inversion effect depends on the intact face configuration. Hence, configural body processing depends not only on the presence of the head but rather on a complete representation of human bodies that includes the body and the head. Furthermore, configural face processing relies on intact and complete face representations that include faces and eyes.