A new component of visual orienting: Implicit effects of peripheral information and subthreshold cues on covert attention.

Four experiments examined effects of peripheral cue stimuli on covert spatial attention. In Experiment 1 target stimuli were preceded by a pair of bilaterally presented cue letters. The relative location of the cues predicted target location (left or right), but participants were not informed of this. After a brief practice period, visual orienting was influenced by the letter cues. This implicit peripheral cuing effect was unrelated to participants' awareness of the cue-target relationship. Experiments 2 and 3 showed that visual orienting may occur independently of both perceptual awareness of the peripheral cue event itself and contingency awareness concerning the cue–target relation. Experiment 4 demonstrated that implicit peripheral cuing is qualitatively distinct from voluntary orienting. These findings are discussed in relation to work on spatial attention, implicit learning, and perception without awareness. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effect of same- and different-modality spatial cues on auditory and visual target identification.

A target identification paradigm was used to study cross-modal spatial cuing effects on auditory and visual target identification. Each trial consisted of an auditory or visual spatial cue followed by an auditory or visual target. The cue and target could be either of the same modality (within-modality conditions) or of different modalities (between-modalities conditions). In 3 experiments, a larger cue validity effect was apparent on within-modality trials than on between-modalities trials. In addition, the likelihood of identifying a significant cross-modal cuing effect was observed to depend on the predictability of the cue-target relation. These effects are interpreted as evidence (a) of separate auditory and visual spatial attention mechanisms and (b) that target identification may be influenced by spatial cues of another modality but that this effect is primarily dependent on the engagement of endogenous attentional mechanisms. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Heterogeneity of dendritic cells in human superficial lymph node: in vitro maturation of immature dendritic cells into mature or activated interdigitating reticulum cells

A target identification paradigm was used to study cross-modal spatial cuing effects on auditory and visual target identification. Each trial consisted of an auditory or visual spatial cue followed by an auditory or visual target. The cue and target could be either of the same modality (within-modality conditions) or of different modalities (between-modalities conditions). In 3 experiments, a larger cue validity effect was apparent on within-modality trials than on between-modalities trials. In addition, the likelihood of identifying a significant cross-modal cuing effect was observed to depend on the predictability of the cue-target relation. These effects are interpreted as evidence (a) of separate auditory and visual spatial attention mechanisms and (b) that target identification may be influenced by spatial cues of another modality but that this effect is primarily dependent on the engagement of endogenous attentional mechanisms.     

Short cue presentations encourage advance task preparation: A recipe to diminish the residual switch cost.

In the task-switching literature, it has frequently been demonstrated that although advance task preparation reduces the switch cost, it never really eliminates the switch cost. This remaining residual switch cost received much attention, and it has been argued that advance preparation is restricted in nature. In the present study, the role of task-cue presentation in the establishment of the residual switch cost was investigated. In 4 experiments, the cue was removed during the preparation interval, and it was hypothesized that this would encourage participants to complete advance task preparation. The results of all 4 experiments provided support for this hypothesis: When the cue was presented for a short time and then removed, the residual switch cost completely disappeared. This was found for different cue types. Furthermore, Experiment 3 demonstrated that it was not the presence of the cue itself but merely differences in advance task preparation that caused the effects. This suggests that advance task preparation is not as restricted in nature as previously assumed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Dissociating cue-related and task-related processes in task inhibition: Evidence from using a 2:1 cue-to-task mapping.

Performance of task sequences is assumed to rely on activation and inhibition of tasks. An empirical marker of task inhibition is the so-called n - 2 repetition cost, which is assessed by comparing performance in trial n - 2 task repetitions (i.e., ABA) with that in n - 2 task switches (i.e., CBA). Current theoretical accounts assume that inhibition acts on the level of task representations (i.e., task sets). However, another potential target of task inhibition could be the representation of the task cue. To decide between these two alternatives, the authors used a 2:1 cue-to-task mapping design. They found significant n - 2 task repetition costs both with n - 2 cue repetitions and n - 2 cue switches. These costs were about equal (Experiment 1), and this data pattern was found for both short and long cuing intervals (Experiment 2). Together, the data suggest that task inhibition acts on task sets and not on cue representations. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Attentional priming and visual search in pigeons.

Advance information about a target's identity improved visual search efficiency in pigeons. Experiments 1 and 2 compared information supplied by visual cues with information supplied by trial sequences. Reaction times (RTs) were lower when visual cues signaled a single target rather than two. RTs were lower (Experiment 1) or accuracy improved (Experiment 2) when a sequence of trials presented a single target rather than a mixture of 2. Experiments 3, 4, and 5 considered the selectivity of visual priming by introducing probe trials that reversed the usual cue–target relationship. RT was higher following such miscues than following the usual 1- or 2-target cuing relationships (Experiment 3); the miscuing effect persisted over variations in the target's concealment (Experiments 4 and 5), but did not occur when the target was presented alone (Experiment 4). Findings indicate that priming modifies an attentional mechanism and suggest that this effect accounts for search images. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Spatial attention and audiovisual interactions in apparent motion.

In this study, the authors combined the cross-modal dynamic capture task (involving the horizontal apparent movement of visual and auditory stimuli) with spatial cuing in the vertical dimension to investigate the role of spatial attention in cross-modal interactions during motion perception. Spatial attention was manipulated endogenously, either by means of a blocked design or by predictive peripheral cues, and exogenously by means of nonpredictive peripheral cues. The results of 3 experiments demonstrate a reduction in the magnitude of the cross-modal dynamic capture effect on cued trials compared with uncued trials. The introduction of neutral cues (Experiments 4 and 5) confirmed the existence of both attentional costs and benefits. This attention-related reduction in cross-modal dynamic capture was larger when a peripheral cue was used compared with when attention was oriented in a purely endogenous manner. In sum, the results suggest that spatial attention reduces illusory binding by facilitating the segregation of unimodal signals, thereby modulating audiovisual interactions in information processing. Thus, the effect of spatial attention occurs prior to or at the same time as cross-modal interactions involving motion information. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Interactive Activation in Visual Word Recognition: Constraints Imposed by the Joint Effects of Spatial Attention and Semantics.

Two lexical-decision experiments investigated the effects of semantic priming and stimulus intensity when target location varied and was cued by an abrupt onset. In Experiment 1, the spatial cue was a good predictor of target location, and in Experiment 2 it was not. The results indicate that word recognition processes were postponed until spatial attention was focused on the target and that whether attention further affected word recognition depended on cue validity. The joint effects of cue validity and priming interacted when cue validity was high but were additive when cue validity was low. The joint effects of stimulus intensity and semantic priming also varied according to cue validity (i.e., interactive when high and additive when low). The results are discussed in terms of their implications for visual word recognition, the distinction between exogenous and endogenous spatial attention, and how attention is affected by visual word recognition processes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Capture of attention in selective frequency listening.

Four signal-detection experiments demonstrated robust stimulus-driven, or exogenous, attentional processes in selective frequency listening. Detection of just-above-threshold signal tones was consistently better when the signal matched the frequency of an uninformative cue tone, even with relatively long cue-signal delays (Experiment 1) or when as few as 1 in 8 signals were at the cued frequency (Experiment 2). Experiments 3 and 4 compared performance with informative and uninformative cues. The involvement of intentional, or endogenous, processes was found to only slightly increase the size of the cuing effect beyond that evident with solely exogenous processes, although the attention band, a measure of how narrowly attention is focused, was found to be wider when cues were informative. The implications for models of auditory attention are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Age differences in the selection of mental sets: The role of inhibition, stimulus ambiguity, and response-set overlap.

Switching between tasks leads to response-time (RT) costs at switch points (local switch costs) and often to RT costs at no-switch transitions that occur in the context of a task-switching block (global set-selection costs). With trial-to-trial cuing of tasks, moderate age effects were obtained for local switch costs, but large age effects were obtained for global selection costs. In Experiment 1, set-specific inhibition was found to be at least as large in old as in young adults, thus ruling out an inhibition deficit as a reason for age differences in global costs. In Experiment 2, large age differences in global costs were limited to conditions of ambiguous stimuli and full response-set overlap. This pattern of results suggests a greater reliance on set-updating processes in old than in young adults. The role of these processes is to ensure unambiguous internal control settings when ambiguity arises from stimuli and response specifications. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of stimulus modality and task condition on blink startle modification and on electrodermal responses

Participants in Experiments 1 and 2 performed a discrimination and counting task to assess the effect of lead stimulus modality on attentional modification of the acoustic startle reflex. Modality of the discrimination stimuli was changed across subjects. Electrodermal responses were larger during task-relevant stimuli than during task-irrelevant stimuli in all conditions. Larger blink magnitude facilitation was found during auditory and visual task-relevant stimuli, but not for tactile stimuli. Experiment 3 used acoustic, visual, and tactile conditioned stimuli (CSs) in differential conditioning with an aversive unconditioned stimulus (US). Startle magnitude facilitation and electrodermal responses were larger during a CS that preceded the US than during a CS that was presented alone regardless of lead stimulus modality. Although not unequivocal, the present data pose problems for attentional accounts of blink modification that emphasize the importance of lead stimulus modality.     

Voluntary Task Switching: Chasing the Elusive Homunculus.

In the voluntary task switching procedure, subjects choose the task to perform on a series of bivalent stimuli, requiring top-down control of task switching. Experiments 1-3 contrasted voluntary task switching and explicit task cuing. Choice behavior showed small, inconsistent effects of external stimulus characteristics, supporting the assumption of top-down control of task choice. Switch costs were smaller when subjects chose to switch tasks than when instructed by an external cue. Experiments 4-6 separated choice costs from switch costs. These findings support models of task switching that incorporate top-down processes in accounts of switch costs. The degree to which task switching procedures capture top-down versus bottom-up processes may depend on the extent of environmental support provided by the procedure. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Task switching versus cue switching: Using transition cuing to disentangle sequential effects in task-switching performance.

Recent methodological advances have allowed researchers to address confounds in the measurement of task-switch costs in task-switching performance by dissociating cue switching from task switching. For example, in the transition-cuing procedure, which involves presenting cues for task transitions rather than for tasks, cue transitions (cue switches and cue repetitions) and task transitions (task switches and task repetitions) can be examined in a complete factorial design. Transition cuing removes the confound between cue transitions and first-order task transitions, but it introduces a confound between cue transitions and longer task sequences. In the present study, transition cuing was studied with two cues per transition (REPEAT and AGAIN for task repetitions; SWITCH and CHANGE for task switches), enabling a partial deconfounding of cue transitions and task sequences. Two experiments revealed robust sequential effects, with higher order task transitions affecting performance when cue transitions were held constant and with cue transitions affecting performance when task sequences were held constant. Methodological and theoretical implications of these findings for research on task switching are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Is object-based attention mandatory? Strategic control over mode of attention.

Is object-based attention mandatory or under strategic control? In an adapted spatial cuing paradigm, participants focused initially on a central arrow cue that was part of a perceptual group (Experiment 1) or a uniformly connected object (Experiment 2), encompassing one of the potential target locations. The cue always pointed to an opposite, different-object location. By varying cue validity, the strategic incentive to prevent the spread of attention to the entire cue object, and consequently to the same-object location, was manipulated: With invalid cuing and (consequently) equal probability of targets at same-object and different-object locations, a same-object target identification advantage was observed. With highly valid cuing and targets much more probable at the different-object location than at the same-object location, the same-object advantage disappeared. Object-based attention appears to be a default mode that may be ecologically adaptive but can be overridden by strategic control when there is a strong immediate benefit in doing so. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Modeling Task Switching Without Switching Tasks: A Short-Term Priming Account of Explicitly Cued Performance.

Switch costs in task switching are commonly attributed to an executive control process of task-set reconfiguration, particularly in studies involving the explicit task-cuing procedure. The authors propose an alternative account of explicitly cued performance that is based on 2 mechanisms: priming of cue encoding from residual activation of cues in short-term memory and compound cue retrieval of responses from long-term memory. Their short-term priming account explains the repeated cue encoding benefit, switch cost, reduction in switch cost with preparation time, and other effects. The authors develop a mathematical model of their priming account and fit it to data from 3 experiments, demonstrating that a set of basic psychological processes can produce several effects--including putative switch costs--without switching tasks. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The effects of recent practice on task switching.

Four experiments investigated the effect of recent selective practice on the cost of switching between 2 tasks afforded by letter-digit pairs: alphabet arithmetic and shape comparison. Experiments 1 and 2 found a greater cost associated with switching to the more recently practiced task: evidence that task-set inertia contributes to switching costs. Experiment 3 found this effect to be limited to trials on which a recently trained stimulus followed another such stimulus: a result problematic for all current theories of task-set priming. Experiment 4 showed that the effect of recent practice was eliminated by active preparation for a task switch: It appears that endogenous task-set preparation reduces the effects of task-set inertia. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The suppression of reflexive visual and auditory orienting when attention is otherwise engaged.

Two experiments were conducted to examine whether abrupt onsets are capable of reflexively capturing attention when they occur outside the current focus of spatial attention, as would be expected if exogenous orienting operates in a truly automatic fashion. The authors established a highly focused attentional state by means of the central presentation of a stream of visual or auditory characters, which participants sometimes had to monitor. No intramodal reflexive cuing effects were observed in either audition or vision when participants performed either an exogenous visual or auditory orthogonal cuing task together with the central focused attention task. These results suggest that reflexive unimodal orienting is not truly automatic. The fact that cuing effects were eliminated under both unimodal and cross-modal conditions is consistent with the view that auditory and visual reflexive spatial orienting are controlled by a common underlying neural substrate. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Differential effects of cue changes and task changes on task-set selection costs.

A task-switching paradigm with a 2:1 mapping between cues and tasks was used to separate cue-switching processes (indexed through pure cue-switch costs) from actual task-switching processes (indexed through additional costs in case of cue and task changes). A large portion of total switch costs was due to cue changes (Experiments 1 and 2), and cue-switch costs but not task-switch costs were sensitive to effects of practice (Experiment 1) and preparation (Experiment 2). In contrast, task-switch costs were particularly sensitive to response-priming effects (Experiments 1 and 2) and task-set inhibition (Experiment 3). Results suggest two processing stages relevant during task-set selection: cue-driven retrieval of task rules from long-term memory and the automatic application of rules to a particular stimulus situation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Reflexive and voluntary orienting of visual attention: Time course of activation and resistance to interruption.

To study the mechanisms underlying covert orienting of attention in visual space, subjects were given advance cues indicating the probable locations of targets that they had to discriminate and localize. Direct peripheral cues (brightening of one of four boxes in peripheral vision) and symbolic central cues (an arrow at the fixation point indicating a probable peripheral box) were compared. Peripheral and central cues are believed to activate different reflexive and voluntary modes of orienting (J. Jonides, 1981; M. I. Posner; see record 1981-09397-001). Experiment 1 showed that the time courses of facilitation and inhibition from peripheral and central cues were characteristic and different. Experiment 2 showed that voluntary orienting in response to symbolic central cues is interrupted by reflexive orienting to random peripheral flashes. Experiment 3 showed that irrelevant peripheral flashes also compete with relevant peripheral cues. The amount of interference varied systematically with the interval between the onset of the relevant cue and of the distracting flash (cue-flash onset asynchrony) and with the cuing condition. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of signaling retention interval length on delayed matching-to-sample in pigeons.

Pigeons were trained initially on a delayed matching task in which colors served as sample and comparison stimuli. During subsequent training, additional stimuli compounded with the sample signaled whether that trial involved a short (1 s) or a long (5 s) delay. In Experiment 1, miscuing reduced accuracy at the short delay markedly and tended to increase accuracy at the long delay slightly. Experiments 2 and 3 revealed a robust effect of cuing when the cues followed sample termination, thereby refuting the view that such cues evoke differential attention to the sample stimulus. Experiment 4 revealed that the cues did not influence rate of forgetting, and Experiment 5 revealed no effect of point of cue placement within the retention interval. It was concluded that cues correlated with retention interval length modulated matching accuracy independently of memory, perhaps by signaling different rates of reinforcement. (PsycINFO Database Record (c) 2010 APA, all rights reserved)