内源性和外源性视觉空间选择注意

以内源性和外源性注意选择为主题,空间选择性注意的控制性加工和自动加工过程成为近年来研究的一个活跃领域,特别是自动化加工过程,取得了一些新的实验证据：对其形成的机制提出了一些理论;提出了选择注意自动化和控制之间关系的理论框架。本文介绍了有关的实验研究和理论模型。     

Modeling automatic threat detection: development of a face-in-the-crowd task

An angry face is expected to be detected faster than a happy face because of an early, stimulus-driven analysis of threat-related properties. However, it is unclear to what extent results from the visual search approach-the face-in-the-crowd task-mirror this automatic analysis. The paper outlines a model of automatic threat detection that combines the assumption of a neuronal system for threat detection with contemporary theories of visual search. The model served as a guideline for the development of a new face-in-the-crowd task. The development involved three preliminary studies that provided a basis for the selection of angry and happy facial stimuli resembling each other in respect to perceptibility, homogeneity, and intensity. With these stimuli a signal detection version of the search task was designed and tested. For crowds composed of neutral faces, the sensitivity measure d' proved the expected detection advantage of angry faces compared to happy faces. However, the emotional expression made no difference if a neutral face had to be detected in crowd composed of either angry or happy faces. Results are in line with the assumption of a stimulus-driven shift of attention giving rise to the superior detection of angry target faces.     

Emotion and information search in tactical decision-making: Moderator effects of feedback

Information search during decision-making may be influenced both by selective attention and by the criterion used for ceasing to search. When the items searched are themselves emotive, the affective state of the decision-maker may bias these search processes. If an automatic selective attention bias operates, it may produce mood-congruent effects irrespective of context; e.g., negative affect may focus attention on negative items of information. An alternative possibility, suggested by the mood-as-input model, is that the influence of affect on search may depend on how decision-makers understand their emotions within a given context. The present study tested predictions derived from relevant theories of affective bias, using feedback as a means to generate a context of success or failure. Hundred and sixty participants were required to access positive and negative items of information in choosing between different routes for a search-and-rescue mission. Outcomes of choices were manipulated experimentally, so that in one condition participants received mostly positive feedback, and in a second condition participants received mostly negative feedback. Results showed that the feedback manipulation influenced affect, but there was considerable variation in affective state within each condition. Associations between affect and information search were moderated by feedback condition. For example, positive affect was associated with more frequent sampling of positive information in the negative feedback condition, but the association reversed when feedback was positive. Findings were consistent with the mood-as-input hypothesis, but not with an automatic selective attention bias. Context may influence how the decision-maker interprets their affective state.     

Conceptualizing control in social cognition: how executive functioning modulates the expression of automatic stereotyping

Two studies investigated the role of executive control in moderating the relationship between automatic stereotype activation and behavioral responses. Race bias in weapon identification was used to measure stereotyping, and a process dissociation procedure was used to measure automatic and controlled components of performance. In Experiment 1, the controlled component was shown to correlate with general attention control and race-specific motivations to control prejudice. Across multiple measures, automatic race bias was more likely to be expressed as behavioral discrimination among individuals with poor executive control. Experiment 2 found the same relationship between automatic and controlled components of behavior when predicting impressions of a Black individual. Executive control is discussed in the context of other control strategies in influential dual-process models of stereotyping.     

Effects of secondary tasks on search performance

Summary Two experiments studied the effect of secondary task load on continuous visual search. Two effects were observed when a secondary task was applied. Search speed (which is assumed to reflect the efficiency of nontarget rejection) was impaired, whereas target detection distance (which presumably reflects the efficiency of target detection) increased. These findings are explained in the framework of a two-process model of visual search which assumes that two operations are performed simultaneously during each fixation, that is, automatic detection and controlled search. The secondary task interferes with the operation of controlled search which reacts to this impairment by way of a compensatory slow-down of search speed. This gain in time also benefits the operation of automatic detection which converts the temporal gain into a spatial extension of the area under its control.     

Color-based grouping and inhibition in visual search: evidence from a probe detection analysis of preview search

In four experiments, we examined selection processes in visual search using a probe detection task to measure the allocation of attention. Under preview search conditions, probes were harder to detect on old relative to new distractors (Experiment 1). This cannot be attributed solely to low-level sensory factors (Experiment 2). In addition, probe detection was sensitive to color-based grouping of old distractors and to color similarity between old distractors (Experiments 3 and 4). These effects were dissociated when the color of the old distractors changed but probe detection effects remained. Collectively, the data indicate both group-based suppression of distractors and the separate inhibition of distractor features in search.     

The effects of multiphasic prepulses on automatic and attention-modulated prepulse inhibition

Prepulse inhibition (PPI) is widely viewed as an operational measure of sensorimotor gating. Previous research has shown that sensorimotor gating can occur automatically and also can be influenced by selective attention. The present research investigated the relationship of the transient detection response (TDR) with automatic and attention-modulated PPI using a novel “multiphasic” prepulse stimulus. Experiment 1 compared discrete versus multiphasic prepulse types in a no-task PPI protocol to validate multiphasic prepulses as effective elicitors of automatic sensorimotor gating. Results revealed that the two prepulse types elicited equivalent levels of PPI. Experiment 2 compared the effectiveness of continuous monophasic versus continuous multiphasic prepulses within a task-based PPI protocol using a lead interval of 120 ms. Results revealed a significant attention effect for monophasic prepulses only. However, robust PPI was produced by the multiphasic prepulses independent of attention as well as over time. These results suggest that multiple influences on PPI can be assessed concurrently depending on prepulse parameters designed to active the TDR when used in a PPI protocol capable of assessing the effects of selective attention on prepulse processing.     

Attention capture by contour onsets and offsets: No special role for onsets

In five experiments, we investigated the power of targets defined by the onset or offset of one of an object’s parts (contour onsets and offsets) either to guide or to capture visual attention. In Experiment 1, search for a single contour onset target was compared with search for a single contour offset target against a static background of distractors; no difference was found between the efficiency with which each could be detected. In Experiment 2, onsets and offsets were compared for automatic attention capture, when both occurred simultaneously. Unlike in previous studies, the effects of overall luminance change, new-object creation, and number of onset and offset items were controlled. It was found that contour onset and offset items captured attention equally well. However, display size effects on both target types were also apparent. Such effects may have been due to competition for selection between multiple onset and offset stimuli. In Experiments 3 and 4, single onset and offset stimuli were presented simultaneously and pitted directly against one another among a background of static distractors. In Experiment 3, we examined “guided search,” for a target that was formed either from an onset or from an offset among static items. In Experiment 4, the onsets and offsets were uncorrelated with the target location. Similar results occurred in both experiments: target onsets and offsets were detected more efficiently than static stimuli which needed serial search; there remained effects of display size on performance; but there was still no advantage for onsets. In Experiment 5, we examined automatic attention capture by single onset and offset stimuli presented individually among static distractors. Again, there was no advantage for onset over offset targets and a display size effect was also present. These results suggest that, both in isolation and in competition, onsets that do not form new objects neither guide nor gain automatic attention more efficiently than offsets. In addition, in contrast to previous studies in which onsets formed new objects, contour onsets and offsets did not reliably capture attention automatically.     

Aging and visual search: Generalized cognitive slowing or selective deficit in attention?

Abstract

Selective attention in normal aging was investigated using simple and conjoined feature visual search tasks. the effects of varying the location of the target (central vs. peripheral, left vs. right hemifield) and the complement of distractors, together with variability in task performance across subject groups, were also examined. the findings indicated that the feature extraction stage of visual search was preserved in older aged subjects. However, there was a differential age-related impairment in the feature integration stage of visual processing in the two older groups (66-75 years, 76-85 years). This was greater than the magnitude of decline predicted on the basis of generalized cognitive slowing. There was no evidence of a speed-accuracy trade-off in the performance of either search task. the findings of this study contribute towards the delineation of age-dependent and -independent processes subserving visual selective attention. the performance of older individuals may be relatively well preserved on more automatic, less demanding tasks such as simple feature search. By contrast, there may be differential age-related impairments on visual search tasks such as conjoined feature search, which may require more effortful or controlled attentional processing.     

The Relationship Between Measures of Cognitive Attention and Behavioral Ratings of Attention in Typically Developing Children

In the present study, we explored the relation between performance on cognitive measures of attention (selection, sustained, and control) and behavioral ratings of inattention and hyperactivity in a sample of typically developing children aged 3 to 7 years. We also examined the influence of chronological age and IQ on both task performance and behavior ratings. Four well-documented attention paradigms were employed, the Visearch (single-target search) task as a measure of selective attention, the Continuous Performance Test (CPT) as a measure of sustained attention, the Day-Night task as a measure of response inhibition, and the Visearch (dual-target search) task as a measure of inhibitory control. The Conners' Rating Scales (Cognitive/Inattention and Hyperactivity subscales) were used to allow for a finer tuned comparison of cognitive performance as related to inattentive behaviors versus hyperactive behaviors. Findings indicate that accuracy and speed in the Visearch dual search task were the most sensitive measures relating respectively to inattentive and hyperactive rated behaviors.     

Continuous selection

Summary A model of target selection in continuous search tasks is outlined. The model was designed to account for two basic observations that are difficult to cover within the framework of the traditional target-control-type models of search, namely, pure detection (detection without identification) and pseudotarget detection (detection of new items not to be searched for). The model combines two basic assumptions: first, that targets are detected by default, that is, by virtue of the fact that they do not fit into an internal model of to-be-expected events (target detection by default) and second, that this internal model is generated, maintained, and updated on the basis of the nontarget information encountered during search (integration of non-target information). Furthermore, it is assumed that non-target integration and target detection can both be carried out at several processing levels simultaneously. The evidence available to support and develop the model is reviewed, and some of its general implications for a theory of selective attention are discussed.This paper is a selective summary of experimental work done in collaboration with Dieter Nattkemper and Cristina Meinecke and supported by the Deutsche Forschungsgemeinschaft (grant Pr 118/5)     

Automatization and training in visual search.

In several search tasks, the amount of practice on particular combinations of targets and distractors was equated in varied-mapping (VM) and consistent-mapping (CM) conditions. The results indicate the importance of distinguishing between memory and visual search tasks, and implicate a number of factors that play important roles in visual search and its learning. Visual search was studied in Experiment 1. VM and CM performance were almost equal, and slope reductions occurred during practice for both, suggesting the learning of efficient attentive search based on features, and no important role for automatic attention attraction. However, positive transfer effects occurred when previous CM targets were re-paired with previous CM distractors, even though these targets and distractors had not been trained together. Also, the introduction of a demanding simultaneous task produced advantages of CM over VM. These latter two results demonstrated the operation of automatic attention attraction. Visual search was further studied in Experiment 2, using novel characters for which feature overlap and similarity were controlled. The design and many of the findings paralleled Experiment 1. In addition, enormous search improvement was seen over 35 sessions of training, suggesting the operation of perceptual unitization for the novel characters. Experiment 3 showed a large, persistent advantage for CM over VM performance in memory search, even when practice on particular combinations of targets and distractors was equated in the two training conditions. A multifactor theory of automatization and attention is put forth to account for these findings and others in the literature.     

Is attention impaired in ADHD?

Explanations of Attention Deficit Hyperactivity Disorder (ADHD) in terms of a weakness in Executive Function (EF) or related concepts, such as inhibition, are briefly reviewed. Some alternative views are considered, in particular a proposal by Manly and others that ADHD is a weakness primarily of sustained attention (plus control of attention), but not of selective attention, as measured by the Test of Everyday Attention in Children (TEA-Ch; Manly et al., 2001). The underlying structure of the TEA-Ch is analysed and it is concluded that the distinction between selective attention, sustained attention, and control of attention in this battery is not well-founded. Furthermore, evidence from studies by Wilding and others, from visual search tasks similar to those employed by Manly et al. to measure selective attention, demonstrates that, while unimpaired- and impaired-attention groups do not differ in speed of performance on such tasks (the measure employed in the TEA-Ch), they do differ reliably in accuracy. Available evidence from other visual search tasks comparing such groups is reviewed and found to be inconsistent. An attempt is made to resolve the inconsistencies and it is suggested that search tasks including demands that engage EF processes are more likely to demonstrate differences between these groups. It is concluded therefore that the most plausible explanation at present of impaired attention is in terms of weaknesses in EF. Suggestions for improving the precision and detail of this type of explanation are offered.     

Does training under consistent mapping conditions lead to automatic attention attraction to targets in search tasks?

Schneider and Shiffrin (1977) proposed that training under consistent stimulus-response mapping (CM) leads to automatic target detection in search tasks. Other theories, such as Treisman and Gelade's (1980) feature integration theory, consider target-distractor discriminability as the main determinant of search performance. The first two experiments pit these two principles against each other. The results show that CM training is neither necessary nor sufficient to achieve optimal search performance. Two other experiments examine whether CM trained targets, presented as distractors in unattended display locations, attract attention away from current targets. The results are again found to vary with target-distractor similarity. Overall, the present study strongly suggests that CM training does not invariably lead to automatic attention attraction in search tasks.     

Automatic processing, code dissimilarity, and the efficiency of successive memory searches.

Two experiments examined the effects of automatic processing and code dissimilarity on the performance of successive memory searches through a single memory set having the same or different kinds of information (i.e., verbal and spatial). The results of both experiments showed that the total time to complete the successive searches was less when automatic processing was involved compared with when both searches required controlled processing. Performance of the successive searches improved substantially with practice. Both experiments also showed an asymmetrical temporal interference between the two searches. Aspects of the to-be-performed second search did not affect first-search reaction times (RTs), but performing the first search did affect the second-search RTs. The interfering effect of the first search was greatest when controlled processes that used the same code were required for both searches, whether the code was verbal or spatial. Several interpretations are offered for the interference generated by the first search. The joint effects of automatic processing and code dissimilarity are also discussed.     

Separating automatic and intentional inhibitory mechanisms of attention in adults with attention-deficit/hyperactivity disorder

Researchers in the cognitive sciences recognize a fundamental distinction between automatic and intentional mechanisms of inhibitory control. The use of eye-tracking tasks to assess selective attention has led to a better understanding of this distinction in specific populations, such as children with attention-deficit/hyperactivity disorder (ADHD). This study examined automatic and intentional inhibitory control mechanisms in adults with ADHD using a saccadic interference task and a delayed ocular response task. Thirty adults with ADHD were evaluated against 27 comparison adults on measures of inhibitory control. The delayed ocular response task showed that adults with ADHD were less able than comparison adults to inhibit a reflexive saccade toward the sudden appearance of a stimulus in the periphery. However, saccadic interference task performance showed that the ADHD group did not differ significantly from the comparison group on a measure of automatic inhibitory control. These findings suggest a dissociation between automatic and intentional inhibitory deficits in adults with ADHD.     

Suppression of involuntary spatial response activation requires selective attention

The role of selective attention in resolving within‐object response conflict was explored in a visual‐search variant of the Simon task. We asked whether selective attention is required for the suppression of involuntary spatial response activation. In two experiments we systematically introduced delays between target onset and target selection, and between target selection and response. Participants made speeded left or right key‐presses to the colour of a target letter O that appeared among varying numbers of nontarget Qs. This difficult search task separated the time of target onset from the time of target selection. Experiment 1 showed that the time course of spatial response suppression was not synched to target onset, but to the time of selective attention to the target. In Experiment 2, the response relevant colour was delayed for variable intervals after the onset of the search array. In this way target selection could occur before the response to the target could be determined. Compatibility effects now decreased with the delay between target selection and the relevant response information. These results show that selective attention is necessary for involuntary response suppression, and they constrain possible models for the control of action in complex environments.     

Automatic attraction of attention to former targets in visual displays of letters

Shiffrin and Schneider (1977, Experiment 4d) reported that after consistent training in search for particular alphanumeric characters, presentation of one of these characters (former targets) as a distractor impeded detection of simultaneously presented current targets. Even if presented in an irrelevant display location, the former target appeared to attract attention. Here, we analyze weaknesses in the design of Experiment 4d and report four follow-up experiments ranging from a fairly close replication of the original multiframe experiment to a rather conventional single-frame search study. In each experiment, presentation of former targets consistently impeded detection of simultaneously presented current targets. The results suggest that automatic attention attraction to individual alphanumeric characters develops not only in the special experimental paradigm used by Shiffrin and Schneider, but also in standard visual search tasks. The fact that attention appeared to be attracted by shapes as complex as individual letters supports the assumption that simultaneously presented visual stimuli can be compared in parallel against memory representations of alphanumeric characters.     

Modulation of selective attention by sequential effects in visual search tasks

In visual search detection of a target on one display facilitates its subsequent recognition on the next (Rabbitt, Cumming and Vyas, 1977). Experiment I shows that facilitation also occurs when a different display intervenes between two displays containing targets. Two further experiments show that detection of target letters among background letters is also facilitated if the same background letters recur on successive displays. Facilitation is greatest if background letters reappear in identical left-to-right spatial locations, but is also evident when the same background letters recur in different locations on successive displays. The results suggest modifications to models for the ways in which selective attention is continuously modulated by successive events during serial search.     

The role of attentional resources in automatic detection

The question of whether an automatic detection task requires the use of limited-capacity resources was investigated in a series of dual-task experiments. The automatic task required subjects to detect a consistently mapped target digit in a display of letters. This task was paired with a variety of concurrent visual discriminations that could either occur in close proximity to the automatic target or in a disparate display area. The main finding was that accuracy in each task was higher in conditions allowing attention to be shared than when it had to be divided between separate areas. These results indicate that detection of automatic targets depends on the allocation of spatial attention to the target's area.