Spatial attention: different mechanisms for central and peripheral temporal precues?

The external noise paradigm (Z.-L. Lu & B. A. Dosher, 1998) was applied to investigate mechanisms of spatial attention in location precuing. Observers were precued or simultaneously cued to identify 1 of 4 pseudocharacters embedded in various amounts of external noise. The cues were either central or peripheral. Both central and peripheral precuing significantly reduced threshold in the presence of high external noise (16% and 17.5%). Only peripheral precuing significantly reduced threshold in the presence of low, or no, external noise (11%). A perceptual template model identified different mechanisms of attention for central and peripheral precuing, external noise exclusion for central precuing, and a combination of external noise exclusion and stimulus enhancement (or equivalently, internal additive noise reduction) for peripheral cuing.     

Mask-dependent attentional cuing effects in visual signal detection: the psychometric function for contrast

A spatial-cuing paradigm was used to test the hypothesis of Carrasco, Penpeci-Talgar, and Eckstein (2000) that the mask-dependent cuing effects found in visual signal detection by Smith (2000a) were caused by submaximal activation of the transient-orienting system. Mask-dependent cuing was found with a range of stimulus contrasts with pure peripheral cues and with the mixed central-peripheral cues of Smith (2000a), contrary to the predictions of the submaximal activation hypothesis. The use of a pedestal detection task to control spatial uncertainty showed that the cuing effect was due to signal enhancement. A model of mask-dependent cuing is described, which assumes that attention affects the rate of information accumulation from the display and that masks limit the visual persistence of the stimulus. The model correctly predicts differential mask dependencies in sensitivity for detection and discrimination and the associated patterns of response times.     

Central and peripheral precuing of forced-choice discrimination

There are suggestions in the literature that spatial precuing of attention with peripheral and central cues may be mediated by different mechanisms. To investigate this issue, data from two previous papers were reanalysed to investigate the complete time course of precuing target location with either: (1) a peripheral cue that may draw attention reflexively, or (2) a central, symbolic cue that may require attention to be directed voluntarily. This analysis led to predictions that were tested in another experiment. The main result of this experiment was that a peripheral cue produced its largest effects on discrimination performance within 100 msec, whereas a central cue required approximately 300 msec to achieve maximum effects. In conjunction with previous findings, the present evidence for time differences between the two cuing conditions suggests that more than one process is involved in the spatial precuing of attention.     

Attentional capture by irrelevant color singletons

Four experiments investigated attentional capture by a color singleton in visual search for a nonsingleton target. B. S. Gibson and E. M. Kelsey (1998) found that a color singleton in a precuing array facilitated target discrimination at that location if the same color also signaled the target array onset. The authors found similar cuing effects regardless of whether the singleton color matched the target array and regardless of whether subjects could anticipate the singleton or target-array color. In Experiment 4, a color singleton captured attention when it appeared in the precuing array but not when it appeared in the target array. The results indicate that attentional control settings for displaywide attributes are imprecise: Although subjects may anticipate a specific color, they cannot avoid attentional capture by other irrelevant colors. In addition, the effect of irrelevant singletons depends on whether a target is simultaneously present in the array.     

Influence of display type and cue format on task-cuing effects: Dissociating switch cost and right-left prevalence effects

In previous studies of task switching and of the right-left prevalence effect, researchers have used a procedure in which the stimulus on each trial occurs in one of four quadrants, and responses are made by pressing one of two diagonally arranged response keys. Across these studies, discrepant effects of cuing interval have been reported. These discrepancies need clarification because cue-based preparation effects are frequently interpreted as reflecting cognitive control processes. In Experiment 1, we compared performance with display formats used by Meiran (1996; Meiran, Chorev, & Sapir, 2000; small display, cues located at sides of quadrants and displayed until response) to study task switching and by Proctor and colleagues (Proctor, Koch, & Vu, 2006; large display, cues located at center of display and shown until target onset) to study right-left prevalence. We found a decrease in task-switch cost with increasing cuing interval with the Meiran display, but not with the Proctor display, but the right-left prevalence effect was of similar size for the two display formats and was relatively unaffected by cuing interval. To determine the basis of the discrepant task-switch results, we used small and large displays in Experiments 2 and 3, respectively, with cue type and cue offset varied. With the side cues, the task-switch cost decreased in all cases at the longer cuing interval, but with the centered cues, it decreased only when the display size was small. Thus, the effects of cuing interval on switch costs are sensitive to variations of display characteristics, whereas cuing interval and display characteristics have little influence on the right-left prevalence effect, suggesting that prevalence effect is due to processes that are independent from those producing the switch cost.     

Luminance-increment detection: capacity-limited or not?

Three experiments investigated whether spatial cuing influences luminance-increment detection accuracy. Ss saw multiple-target displays and responded yes or no to 4 locations, including cued position. To test whether cuing effects are due to the load on visual short-term memory from the number of locations, Experiments 1 and 2 presented displays with 4 or 8 relevant locations. Experiment 1 used peripheral cues; Experiment 2 used central cues. Significant cuing effects were less marked with 4- than 8-location displays. Cuing effects were largest with multiple targets, but a small reliable effect remained even with single targets. Experiment 3 replicated the single-target effect with predominantly multiple- and single-target displays. A capacity-limited selection account is developed for these findings and their implications are discussed for separate central and peripheral cuing mechanisms and the locus of spatial cuing effects.     

Forgetting and recovering the unforgettable

Two experiments demonstrated striking, reversible forgetting effects that occurred even for a list of expletives. The experiments used a procedure based on the classic memory mechanisms of interference and retrieval cuing. Interference reduced recall dramatically, although appropriate cues triggered complete recovery. Distinctive, emotionally charged materials were quite susceptible to the forgetting and recovery effects. Thus, powerful forgetting effects can be obtained when participants have no intentions to forget and the materials involved are distinctive, emotional materials with sexual and violent content. This forgetting is reversible with appropriate cues. The false-memory debate can and must be informed by experimental investigations not only of false memories, but also of blocked and recovered memories.     

Compatibility of precuing and of S-R mapping in choice reactions

This study investigates information processing elicited by precuing a subset of alternatives in a choice reaction task. The aim was to study the influence of some task variables on the effectiveness of precuing, in order to determine the locus of differential precuing effects, in either central decisional processing or in motor programming. Partial advance information (PAI) was given 300 msec in advance of the action signal and it indicated the subset from which the action signal would be chosen. Thus, precuing reduced the number of alternatives. The resulting decrease of reaction time (RT) was assessed under various levels of SR compatibility, response specificity and cue compatibility. Cue compatibility refers to the naturalness of the (spatial) relation between the cue signals and the stimulus-response pairs. This study shows that (a) precuing effectiveness is strongly affected by cue compatibility, and (b) cue compatibility should be viewed as a twofold concept: it refers to the naturalness of the relation of the cue signal, either with action signals or with responses.Experiment 1 compared a naming and a pointing task. Although in both tasks the cue signal was compatible with the cued action signals, the naming task had a lower level of SR compatibility and also a lower level of compatibility between the cue signal and responses. Precuing was highly effective when pointing towards the action signal, but hardly effective when naming ordinal positions. Experiments 2–4, using only a pointing task, showed a decrease of the precuing effect with a decrease of either type of cue compatibility, although cue compatibility with action signals was the strongest factor. Low SR compatibility further decreased the size of the precuing effect caused by low compatibility between cue and action signals. Differential precuing effects did not result from differences in response specificity (i.e., the lack of similarity among the cued responses). It is concluded that precuing and both types of cue compatibility affect the stage of response decision, while no evidence was found for effects on motor programming. Implications are discussed for movement precuing studies that rely on differential precuing effects to discover properties of motor programming.     

Top-down search strategies determine attentional capture in visual search: Behavioral and electrophysiological evidence

To investigate how attentional capture in visual search is affected by generalized top-down search strategies, ERPs and behavioral performance were measured in two experiments where spatially nonpredictive color singleton cues preceded visual search arrays that contained one of two equally likely color singletons. When both singletons served as targets, irrelevant-color singleton cues produced behavioral attentional capture effects and elicited an N2pc component, indicative of a singleton search mode. When responses were required to only one of the two color singletons, the same cues no longer elicited behavioral spatial cuing effects, and the N2pc to these cues was attenuated and delayed, in line with the hypothesis that search was now guided by a feature-specific search strategy. Results demonstrate that the ability of visual singleton stimuli to capture attention is not simply determined by their bottom-up salience, but strongly modulated by top-down task sets.     

Influences of part-list cuing on different forms of episodic forgetting

Across 3 experiments, we examined the interplay of part-list cuing and forgetting, employing 3 different methods to induce episodic forgetting-list--method directed forgetting, context-dependent forgetting, and proactive interference. For each form of forgetting, participants were asked at test to recall the target items of a previously studied list in the presence or the absence of the list's remaining items serving as retrieval cues. We found such part-list cuing to amplify the forgetting in proactive interference but to diminish the forgetting in list-method directed forgetting and context-dependent forgetting. These results show that the effects of part-list cuing on forgotten memories depend critically on the circumstances surrounding the forgetting. If the forgetting reflects impaired access to the original encoding context, as has been suggested in list-method directed forgetting and context-dependent forgetting (but not in proactive interference), part-list cues improve access to forgotten memories; if the forgetting does not reflect such a contextual effect, no such beneficial effects emerge, and access to forgotten memories may even be impaired.     

Differences in attentional set between athletes and nonathletes

The purpose of this study was to determine if the ability to set attention is different between athletes and nonathletes. University volleyball players were compared with nonathletes on a spatial cuing task similar to that of C. L. Folk, R. W. Remington, and J. C. Johnston (1992). As expected, both groups showed evidence of entering into a specific attentional set because attentional cuing effects were found only when cues and targets shared a task-relevant feature (onset or color). In addition, the cuing effects when the cues matched the targets were greater for the athletes than for the nonathletes. The results are discussed in terms of the orienting of attention and athletic performance.     

Target-related coupling in bimanual reaching movements

While bimanual interference effects can be observed when symbolic cues indicate the parameter values of simultaneous reaching movements, these effects disappear under conditions in which the target locations of two movements are cued directly. The present study investigates the generalizability of these target-location cuing benefits to conditions in which symbolic cues are used to indicate target locations (i.e., the end points of bimanual movements). Participants were asked to move to two of four possible target locations, being located either at the same and different distances (Experiment 1), or in the same and different directions (Experiment 2). Circles and crosses served as symbolic target-location cues and were arranged in a symmetric or non-symmetric fashion over the four target locations. Each trial was preceded by a variable precuing interval. Results revealed faster initiation times for equivalent as compared to non-equivalent target locations (same vs. different cues). Moreover, the time course of prepartion suggests that this effect is in fact due to target-equivalence and not to cue-similarity. Bimanual interference relative to movement parameter values was not observed. These findings suggest that cuing target locations can dominate potential intermanual interference effects during the concurrent programming of different movement parameter values.     

Part-list cuing can be transient and lasting: the role of encoding

The presentation of a subset of learned items as retrieval cues can have detrimental effects on recall of the remaining items. For 2 types of encoding conditions, the authors examined in 3 experiments whether such part-list cuing is a transient or a lasting phenomenon. Across the experiments, the detrimental effect of part-list cues was consistently found to be transient with a high degree of interim associations and lasting with a low degree. These results indicate that the persistence of part-list cuing depends on encoding, thus challenging both strategy disruption and retrieval inhibition as general accounts of part-list cuing. A 2-mechanism account is provided according to which the 2 mechanisms mediate the effect in different encoding conditions.     

The effect of the physical characteristics of cues and targets on facilitation and inhibition

The present experiment was conducted in order to examine the role of cue—target discriminability on early occurring attentional cuing effects and late occurring inhibition of return (IOR). The experiment used a single target stimulus in conjunction with three different cue stimuli. The cues were the same as the target, different in color, shape, and luminance to the target, or did not spatially overlap with the target. At shorter stimulus onset asynchronies (SOAs; 100 and 200 msec), attentional cuing effects were only found with the nonoverlapping cues. However, at longer SOAs (400 and 800 msec), approximately equal IOR effects were found with all three types of cues. The results indicated that the physical characteristics of the cues and targets affected the pattern of reaction times at the shorter SOAs but not at the longer SOAs. The conclusion is that the biphasic pattern of early facilitation and late inhibition following a peripheral cue should not be considered the definitive signature of the peripheral cuing paradigm.     

Why does the effect of short-SOA exogenous cuing on simple RT depend on the number of display locations?

When the stimulus onset asynchrony (SOA) between the cue and target is short (i.e., less than 200 msec) and the number of display locations is small (e.g., only two), exogenous spatial cues produce a benefit in simple response time (RT). However, several recent experiments have found significant costs in these tasks when a large number of display locations is employed (e.g., eight), even at the very short SOAs that usually produce a benefit. The present study explored the dependence of exogenous cuing on the number of display locations and found evidence that both the overall validity of the cues and the specific validity of the cue on the previous trial have strong, additive effects. When a large number of display locations is used, both of these factorswork against a benefit of exogenous cuing on simple RT, reversing the typical finding into a cost. These two effects are suggested to occur within motor and perceptual processes, respectively.     

Identification of letters in words and of single letters with pre- and postknowledge vs. postknowledge of the alternatives

Two experiments were conducted to test how the “word letter phenomenon” (WLP)—a letter is better identified when embedded in a word than when presented alone—is affected by prior knowledge of the alternatives in a forced choice paradigm with tachistoscopic exposures. In Experiment 1, one group of subjects, who were given knowledge of the alternatives after the display, showed the usual WLP. The WLP was eliminated in a second group of subjects who were given knowledge of the alternatives both before and after the display. In Experiment 2, the same subjects were either precued or not precued on alternating trials of each block. It appeared that the WLP suppression with precuing resulted from a decrease in word performance whereas letter performance was unaffected by precuing. It is suggested that precuing exerts a detrimental effect, because, instead of attending to the word as a whole, subjects search for where in the word the forced choice would be plausible.     

Selectively ignoring locations does not modulate contingent involuntary orienting,but selectively attending does

Attending to a location in the visual field facilitates processing of objects in that location, and numerous studies have revealed processing benefits by precuing target locations. Recent studies have also demonstrated that precuing a location to ignore reduces distraction by items in that location; however, precuing a feature (colour) to ignore increases distractor interference, at least before a template for rejection is established. Thus, locations, not features, can be selectively ignored. The present study used a spatial cuing task to examine whether featurally-relevant items are selected when they appear in ignored locations. The results revealed contingent attentional capture by target-relevant cues (red cue when searching for red targets, but not for onset targets), even when the cue appeared in a location that was ignored. Importantly, this was equivalent to contingent capture elicited by cues in non-ignored locations. However, when observers were precued to the target location, contingent capture was largely eliminated. The results suggest salient items with target-relevant features are selected from selectively ignored locations, but focusing attention onto a location can preclude capture by salient and target-relevant items.     

自上而下的注意控制定势在注意捕获中的作用

采用经典前线索范式的变式, 通过100%有效的提示考察了自上而下的注意控制定势在注意捕获中的作用。实验1要求被试在整个实验中只搜索一个固定颜色的目标, 但是通过在每个试次前对目标进行提示加强注意控制定势的强度。实验2通过在每个试次中变化要搜索的目标颜色使被试必须建立两个更强的注意控制定势。实验结果一致表明和目标颜色相匹配的线索捕获了注意, 而和目标颜色无关的线索被抑制; 实验2的捕获效应和抑制效应都显著大于实验1; 对无关冲突线索和无关中性线索的注意抑制效应没有差异, 抑制效应显著小于捕获效应。研究表明自上而下的注意控制定势通过把注意从和目标不匹配的特征位置转移发挥作用, 支持注意转移假说; 对匹配线索的捕获和对无关线索的抑制运用了同一加工系统, 抑制作为捕获的附加产品出现, 两者都可以作为注意捕获的指标。     

Does facial expression affect attention orienting by gaze direction cues?

In 6 experiments, the authors investigated whether attention orienting by gaze direction is modulated by the emotional expression (neutral, happy, angry, or fearful) on the face. The results showed a clear spatial cuing effect by gaze direction but no effect by facial expression. In addition, it was shown that the cuing effect was stronger with schematic faces than with real faces, that gaze cuing could be achieved at very short stimulus onset asynchronies (14 ms), and that there was no evidence for a difference in the strength of cuing triggered by static gaze cues and by cues involving apparent motion of the pupils. In sum, the results suggest that in normal, healthy adults, eye direction processing for attention shifts is independent of facial expression analysis.     

The verbal label: Mediator or classifier?

Three experiments on the role of verbal labels and perceptual cues in concept attainment are reported. Ss were kindergarten and second-grade upper-middle-class children. The results indicated that when Ss learned to associate two labels (or two perceptual cues) with each stimulus no positive transfer resulted, despite the fact that one of the labels (or cues) was relevant to solution. When one label only (or one perceptual cue) was associated with each stimulus, substantial positive transfer was observed. The effects of verbal labeling and perceptual cuing were identical.On the basis of these finding the authors reject the hypothesis that labels give rise to representational responses which act as mediators, and instead propose a new hypothesis, that labels and perceptual cues facilitate performance because they facilitate the division of the stimulus set into subsets which are correlated with the response systems the subjects are expected to learn.