Redundancy gains and costs in cognitive processing: effects of short stimulus onset asynchronies

In 7 experiments, the influence of varying stimulus onset asynchronies (SOAs) on the processing of redundant information about words and pseudowords was investigated. All stimuli were visually presented once or twice with 2 copies of the same item flashed either simultaneously or with short SOAs between presentations. The experiments revealed a redundancy gain for words that was absent for pseudowords. Furthermore, the redundancy gain disappeared at an SOA of 50 ms, and there was a gradual performance decline at longer SOAs. However, probing SOAs of 150 and 300 ms revealed that, compared with presentation of 1 target stimulus alone, words were processed significantly faster when target and redundantcopy appeared with a 150-ms lag. The results are tentatively explained in a neurocognitive framework.     

Attention effects of abrupt-onset precues with central, single-element, and multiple-element precues

Endogenous and exogenous processes of attention have been inferred with different types of precues used in allocation of attention to a target location. In the present research, a comparison was made between the typical peripheral single-element precue (SEP), a central precue, and a multiple-element precue (MEP) in order to further understanding of the processes involved in allocation of attention. Two precues were used on each trial in these experiments. An abrupt-onset precue appeared with an SEP, an MEP, or a central precue and was followed 50 or 300 ms later by a screen containing a target and two distractor characters. The abrupt-onset precue and the other precue each could be valid or invalid in indicating the location of the target, as in the study by Juola, Koshino, and Warner (1995). Response times to the targets showed that validity effects of the abrupt-onset precue and the MEP or central precue were additive, whereas those of the abrupt-onset precue and the SEP were interactive. These data suggest that, like a central precue, an MEP is an endogenous precue that guides conscious control of attention and has its attentional effects at a different processing level from an SEP, which is an exogenous precue and may compete for attentional resources with an abrupt-onset precue.     

Large and rapid improvement in form discrimination accuracy following a location precue

Processing of a visual stimulus can be improved by precuing its location. Most previous precue studies have used reaction time as the dependent measure and have found large effects; but when form discrimination accuracy has been used, precue effects have been relatively small. The present experiments yielded large, short-latency precue effects on form discrimination accuracy. A small square precue was briefly presented near one of four possible target locations. Then one of four possible targets (T-like figures) was presented in each location, followed by a mask. Observers attempted to identify the target that had been presented in the cued location. In experiment 1, target duration, cue-to-target distance, and cue-target onset asynchrony (SOA) were varied. Target discriminability (d') increased markedly with increasing precue-target SOA, even at very short SOAs. Thus, there was no evidence for a delay in the onset of precue effects (caused, for example, by the need to shift attention across the visual field). Performance was best for precues that were closest to the target, thus ruling out a forward masking explanation of the effect. Finally SOA and target duration interacted strongly - longer precue SOAs resulted in larger effects of target duration. In experiment 2, this interaction was replicated using an additional target duration and longer SOAs. One interpretation of this result is that focal attention increases the rate at which information can be extracted from a visual location.     

The Role of Precues in the Preparation of Motor Responses in Humans

The authors investigated how precues about the location of an upcoming target are used by the sensorimotor system to reduce manual reaction time. In 4 experiments, participants (N = 12 in each experiment) pressed a response key as fast as possible when a precued or a nonprecued visual target appeared. Precues remained effective when a visual mask was interposed between the display of the precue and the target (Experiment 1), which suggests that precues act downstream from visual sensory memory. The precue effect was abolished when precues were presented along with a task requiring attention and a verbal response (Experiment 2) but not when presented with a task that required verbal output but had no attention demands (Experiment 3). Those findings indicate that precues must be processed attentively to become effective. When the attention-demanding task was interposed between precue and target display, the precue effect was still abolished (Experiment 4), which suggests that individuals' attention must remain in the precued area until target appearance.     

Effects of spatial and symbolic precues on localization performance

One of the fundamental properties of spatial vision is the ability to localize objects in space. According to a recent proposal, accurate localization performance involves the operation of two systems: the attention system and the eye movement system. Upon stimulus presentation, attention is shifted to the target area: this provides coarse location information. Subsequently, a saccadic eye movement is executed: this provides fine location information. In this study we tested predictions derived from this model concerning the effects of precue information on localization performance. In a series of five experiments we manipulated duration of precue (71, 400, and 1,000 ms) and type of precue (spatial versus symbolic). Results showed that very short duration (i.e., 71 ms) spatial precues improved localization performance whereas very short duration symbolic precues did not. In contrast, the 1,000 ms duration precue condition showed similar amounts of precuing benefit for the spatial and symbolic precues. This pattern of differential precuing effects corroborated the two-process model of localization performance. Received: 24 June 1999 / Accepted: 28 January 2000     

Representational momentum and the flash‐lag effect

Representational momentum (RM) is a distortion where the final orientation of a moving object is misremembered as further along its trajectory. Experiments reported here examine RM when an additional object was flashed just as the moving object disappeared. When the task was to judge the flashed object, participants reported that the flash appeared to lag behind (flash‐lag effect; FLE). When the task was to judge the moving object, larger forward distortions for the moving object were found when the flash was present, despite previous evidence that the FLE depends on the moving object's continued presence. The results suggest that some part of the FLE depends upon what precedes the flash. In addition, equivalent RM was observed for implied and smoothly animated events, a possible limit to the velocity effect for RM was found, and larger positive distortions were found for downward rotations.     

Fast priming during eye fixations in reading.

Near-threshold primes were "flashed" in a target location prior to the onset of a target word while Ss read. The type and duration of the prime were manipulated. In Exp. 1, identical, related, and unrelated primes were presented for 60, 45, or 30 ms from onset of an eye fixation. The prime was then replaced with the target word, which remained in place while Ss finished reading the sentence. Fixation time on the target word was measured. Exp. 2 replicated Exp. 1, with two exceptions: A random letter string replaced the identical prime condition, and prime durations of 39, 30, or 21 ms were used. In both experiments, significant priming effects (related vs. unrelated) were obtained when the prime was presented for 30 ms. Results are discussed with regard to subliminal priming effects. Applications to the study of word recognition processes are also discussed.     

Temporal ventriloquism: sound modulates the flash-lag effect

A sound presented in close temporal proximity to a visual stimulus can alter the perceived temporal dimensions of the visual stimulus (temporal ventriloquism). In this article, the authors demonstrate temporal ventriloquism in the flash-lag effect (FLE), a visual illusion in which a flash appears to lag relative to a moving object. In Experiment 1, the magnitude and the variability of the FLE were reduced, relative to a silent condition, when a noise burst was synchronized with the flash. In Experiment 2, the sound was presented before, at, or after the flash (+/- approximately 100 ms), and the size of the FLE varied linearly with the delay of the sound. These findings demonstrate that an isolated sound can sharpen the temporal boundaries of a flash and attract its temporal occurrence.     

图词间隔时间影响口语词汇产生中语义效应的机制：图词干扰范式研究

口语词汇产生过程中存在语义抑制和语义促进效应, 可能发生在概念准备和词汇选择或者后词汇水平阶段。本研究采用图画-词汇干扰实验任务, 变化图画与词汇出现点之间的时间间隔(stimulus onset asynchrony, SOA), 运用脑电技术考察口语词汇产生中语义效应发生的时间进程。结果显示, 当SOA为0 ms时表现出语义抑制效应, 语义效应发生在词汇选择阶段(344~418 ms); 当SOA为-400 ms时, 语义效应发生在概念准备阶段(0~76 ms)和词汇选择阶段(274~390 ms); 460~594 ms时间窗口内的语义效应可能表明讲话者对语义信息的自我监测。词汇产生中存在语义促进效应和抑制效应的权衡, 影响了行为结果中语义效应的方向, 上述发现支持了口语词汇产生的词汇竞争假说。     

Automatic Versus Directed Attention with Single-element and Multiple-element Precues

Four experiments were conducted to determine whether peripheral singleelement precues (SEPs) and multiple-element precues (MEPs) would elicit similar attention effects on target identification. For an MEP, characters were presented near each possible target location; however, one that differed from the others by either colour or luminance specified the target location. At short precue-target intervals (SOAs), target identification accuracy rose more quickly with SEPs than with MEPs; at long SOAs, performance declined with SEPs, but not with MEPs. Furthermore, when validity of the precue was manipulated, an SEP attracted attention automatically even if the precue was irrelevantas to target location, whereas an irrelevant precue did not benefit performance with MEPs. Accuracy atlong SOAs with MEPs was more similarto thatproduced by a precue at fixation than to that produced by an SEP. Thus, MEPs do not elicit attention in the same manner as SEPs.     

Preparation for Donders' type B and C reaction tasks

Several variants of a precued reaction time experiment were performed to assess preparation for Choice (Donders' type B) or Go/No-Go (type C) reaction tasks. On each trial, the imperative stimulus could necessitate either a keypress with the left forefinger, the right forefinger, or no response. A precue given at lead times of 50-750 ms either informed the subject whether the task was a type B task (left or right forefinger response), a type C task (e.g., left forefinger or No Go), or carried no information (all three possibilities remained open). The noninformative cue produced minor facilitation of reaction time at long lead times only. At lead times of 50-250 ms, the other two precues speeded reactions by about 50 ms. At precue intervals of 400-750 ms, Go/No-Go reactions averaged 25 ms faster than Choice reactions in an experiment which utilized appropriate controls for stimulus and task parameters. The mixed-trial design rules out gross motor (e.g., postural) adjustments as an explanation for the advantage of C over B reactions. An interpretation in terms of a two-stage theory of motor preparation is discussed.     

Attention effects of moving and stationary single-element and multiple-element precues: Limits of automaticity

A multiple-element precue (MEP), in which one unique element defines the actual precue, results in efficient precuing for identification of a target. The time course for identification in this case is similar to that for a central precue, even though it is presented peripherally (Chastain, 1996; Chastain & Cheal, in press). Five experiments were conducted to gain further information on the function of MEPs and to question what advantage prior knowledge of the precue may give. In Experiments 1 and 2, it was shown that for “pop-out” features, accuracy of identification of a target was higher if the precue type was known in advance. In contrast, as shown in Experiments 3, 4, and 5, when the precue was defined by apparent motion, there was no difference in accuracy due to advanced knowledge of the precue. Further, accuracy was considerably better for motion precues than for stationary precues.     

Active inhibition of a distractor word: the distractor precue benefit in the Stroop color-naming task

The current study investigated attentional control through active inhibition of the identity of the distractor. Adapting a Stroop paradigm, the distractor word was presented in advance and made to disappear, followed by the presentation of a Stroop stimulus. Participants were instructed to inhibit the distractor in order to reduce its interference. Experiments 1 and 2 demonstrated that the distractor precue facilitated Stroop color naming by reducing Stroop interference. Experiment 3 demonstrated beneficial effects of the distractor precue when congruent trials were introduced. Experiment 4 showed that the distractor precue benefit was observed when the cue and target were in different forms. Experiment 5 indicated that if the item used as the cue became the target, naming it took longer in order to overcome the inhibitory effect. Experiment 6 demonstrated that the benefit of the distractor precue was not observed when the cue was uninformative. Finally, Experiment 7 demonstrated that active inhibition required working-memory resources to operate. This study suggests that the best explanation for the distractor precue benefit is the active inhibition account.     

Allocation of visual attention depends on type of precue

To distinguish between theoretical concepts of how attention is allocated, participants were presented with different types of precues in 6 experiments. In 1 condition with 100% valid precues (Experiments 1 and 2), the time course of attention effects revealed that (a) higher accuracy was obtained with dynamic multiple-element precues (MEPs in which the unique element was defined by apparent motion) than with static MEPs, in which the elements did not move once they were presented (Cheal & Chastain, 1998); (b) a longer precue-target interval (stimulus-onset asynchrony; SOA) was needed to reach asymptote accuracy with dynamic MEPs than with dynamic single-element precues (SEPs); and (c) all dynamic precues (both MEPs and SEPs) resulted in a decline in accuracy at long SOAs. These results suggest that static and dynamic MEPs result in delayed engagement of attention relative to SEPs. Further, a decline in accuracy at long intervals is associated with static and dynamic SEPs and dynamic MEPs, but not with static MEPs. With irrelevant precues (Experiments 3 to 5), there was capture by precues in which the unique element moved briskly, smoothly, or abruptly, or simply flashed on and off, although there were differences in the amount of capture. The strongest capture occurred with smooth movement in static background elements and the weakest with smooth movement in abruptly moving background elements. It was shown in Experiment 6 that a static MEP will not capture attention if one element changes to a unique brightness near the time of precue onset, but if the element changes after 1,000 ms, it will capture attention. The authors suggest that different types of precues result in unequal influence of endogenous and exogenous components of attention, even when the same targets are used. In addition, they show that neither singleton detection mode nor contingent involuntary orienting is necessary for the capture of attention.     

Interaction of stimulus and contextual information during reading: Identifying words within sentences

In general, studies on the effects of a sentence context on word identification have focused on how context affects the efficiency of processing a single target word, presented separately from the context. Such studies probably would be incapable of measuring contextual facilitation resulting from cascaded or parallel processing of neighboring words within a sentence. To measure these and other types of facilitation, we presented entire phrases and sentences for subjects to read as fast as possible and to monitor for nonwords. Subjects read at rates representative of natural reading. Experiment 1 demonstrated a large contextual facilitation effect on decision time. Experiment 2 showed that facilitation is caused by specific semantic information and, perhaps to a greater degree, by nonpredictive syntactic information. Experiment 3 showed that the amount of facilitation is greater than could be accounted for by separate contributions from autonomous word level and sentence level processes. These results present difficulties for an autonomous model of reading, but are consistent with interactive models, in which the results of ongoing sentential analyses are combined with stimulus information to identify words.     

Precuing the Target Location in Visual Searching by a Chimpanzee (Pan troglodytes): Effects of Precue Validity

A chimpanzee ( Pan troglodytes ) performed a visual search task using a modified matching-to-sample procedure in which a sample stimulus was followed by the search display, which contained one stimulus identical to the sample (target) and several uniform stimuli different from the sample (distractors). On cued trials, while the subject was observing the sample, a white square (precue) appeared at the location where the target was to be presented (valid trials), or elsewhere (invalid trials). The validity of the precue (correspondence between the cued and the target locations) was changed from 0% to 100% across conditions. Cost-benefit analyses were performed on the difference between valid and noncued trials (benefit) and between invalid and noncued trials (cost). Under the high-validity conditions, the response times were shorter when the cued location corresponded to the target location than when the precue did not appear. When the cued location did not correspond to the target location, on the other hand, the subject took longer to select the target than on noncued trials. When the validity of the precue was relatively low, however, cost of the invalid trials disappeared, while benefit of the valid trials remained. These results confirmed the two-process (automatic and attentional) theory of priming in human information processing; the advance information had the same effects on a chimpanzee's visual search performance as on humans'.     

The effect of inducing panic search on the detection of fear-relevant and neutral images

Panic search occurs when the presentation of a fearful facial expression precue, prior to a search display, improves target detection relative to when neutral and positive expressions are used. In the present study, fearful and neutral expressions acted as precues and targets were images of either neutral or threatening animals. It was predicted that detection of a threatening image following a fearful precue would be particularly facilitated. In a first experiment, target detection was better when targets were threatening than neutral, but the predicted cue enhancement did not occur. In a second experiment, when cue type was blocked, participants were particularly facilitated in responding to threatening targets following fearful precues. It is concluded that consistent and repeated exposure to threatening facial expression results in a generalized increase in processing efficiency and that such a state induces a particular facilitation in responding in the presence of threatening targets.     

A paradoxical exposure-duration effect in the Stroop task: temporal segregation between stimulus attributes facilitates selection.

In comparison with the situation in which target and distractor are presented until response, Stroop interference substantially decreases when the target color is removed from the display 150-160 ms after stimulus onset (W. La Heij, N. A. Kaptein, A. C. Kalff, & L. de Lange, 1995; O. Neumann, 1986). Six experiments showed that this paradoxical exposure-duration effect is robust, that it is not due to the target's exposure duration per se, and that it is not due to an increased spatial selectivity of input selection. The present findings support and extend earlier observations that changes in the display during stimulus exposure affect attentional selection. The findings are tentatively interpreted in terms of (a) reduced duration of input selection or (b) facilitation of attribute selection.     

What do graded effects of semantic transparency reveal about morphological processing?

We examined the influence of semantic transparency on morphological facilitation in English in three lexical decision experiments. Decision latencies to visual targets (e.g., CASUALNESS) were faster after semantically transparent (e.g., CASUALLY) than semantically opaque (e.g., CASUALTY) primes whether primes were auditory and presented immediately before onset of the target (Experiment 1a) or visual with an stimulus onset asynchrony (SOA) of 250 ms (Experiment 1b). Latencies did not differ at an SOA of 48 ms (Experiment 2) or with a forward mask at an SOA of 83 ms (Experiment 3). Generally, effects of semantic transparency among morphological relatives were evident at long but not at short SOAs with visual targets, regardless of prime modality. Moreover, the difference in facilitation after opaque and transparent primes was graded and increased with family size of the base morpheme.     

Investigating the time course of tactile reflexive attention using a non-spatial discrimination task

Peripheral cues are thought to facilitate responses to stimuli presented at the same location because they lead to exogenous attention shifts. Facilitation has been observed in numerous studies of visual and auditory attention, but there have been only four demonstrations of tactile facilitation, all in studies with potential confounds. Three studies used a spatial (finger versus thumb) discrimination task, where the cue could have provided a spatial framework that might have assisted the discrimination of subsequent targets presented on the same side as the cue. The final study circumvented this problem by using a non-spatial discrimination; however, the cues were informative and interspersed with visual cues which may have affected the attentional effects observed. In the current study, therefore, we used a non-spatial tactile frequency discrimination task following a non-informative tactile white noise cue. When the target was presented 150 ms after the cue, we observed faster discrimination responses to targets presented on the same side compared to the opposite side as the cue; by 1000 ms, responses were significantly faster to targets presented on the opposite side to the cue. Thus, we demonstrated that tactile attentional facilitation can be observed in a non-spatial discrimination task, under unimodal conditions and with entirely non-predictive cues. Furthermore, we provide the first demonstration of significant tactile facilitation and tactile inhibition of return within a single experiment.