The effects of expectancy on inhibition of return

This research examined the influence of cue temporal predictability on inhibition of return (IOR). In exogenous attention experiments, the cue that summons attention is non-informative as to where the target will appear. However, it is predictive as to when it will appear. Because in most experiments there are equal numbers of trials for each cue-target interval (SOA--stimulus onset asynchrony), as time passes from the appearance of the cue, the probability of target presentation increases. Predictability was manipulated by using three SOA distributions: non-aging, aging and accelerated-aging. A robust IOR was found that was not modulated by temporal information within a trial. These results show that reflexive effects are relatively protected against modulation by higher volitional processes.     

Does low perceptual load enable capture by colour singletons?

There is considerable debate as to whether colour singletons can capture attention in a stimulus-driven manner. In this study, we explore one potential capture enabling condition—low perceptual load. To test this hypothesis, we manipulated perceptual load in a flanker task in which flanking letters sometimes were colour singletons. If low load enhances capture by colour singletons, then colour singletons should produce an especially large increase in overall reaction times and in flanker–target compatibility effects. Neither of these predictions was confirmed in any of the four experiments reported here, although we did replicate the classic load effects from previous studies. These experiments indicate that although perceptual load does strongly modulate overall performance, it does not facilitate capture by colour singletons. This finding contrasts sharply with findings from other types of salient stimuli (abrupt onsets and moving objects). Implications for theories of attentional capture will be discussed.     

Attentional sets influence perceptual load effects,but not dilution effects

Perceptual load theory [Lavie, N. (1995). Perceptual load as a necessary condition for selective attention. Journal of Experimental Psychology: Human Perception and Performance, 21, 451–468.; Lavie, N., & Tsal, Y. (1994) Perceptual load as a major determinant of the locus of selection in visual attention. Perception & Psychophysics, 56, 183–197.] proposes that interference from distractors can only be avoided in situations of high perceptual load. This theory has been supported by blocked design manipulations separating low load (when the target appears alone) and high load (when the target is embedded among neutral letters). Tsal and Benoni [(2010a). Diluting the burden of load: Perceptual load effects are simply dilution effects. Journal of Experimental Psychology: Human Perception and Performance, 36, 1645–1656.; Benoni, H., & Tsal, Y. (2010). Where have we gone wrong? Perceptual load does not affect selective attention. Vision Research, 50, 1292–1298.] have recently shown that these manipulations confound perceptual load with “dilution” (the mere presence of additional heterogeneous items in high-load situations). Theeuwes, Kramer, and Belopolsky [(2004). Attentional set interacts with perceptual load in visual search. Psychonomic Bulletin & Review, 11, 697–702.] independently questioned load theory by suggesting that attentional sets might also affect distractor interference. When high load and low load were intermixed, and participants could not prepare for the presentation that followed, both the low-load and high-load trials showed distractor interference. This result may also challenge the dilution account, which proposes a stimulus-driven mechanism. In the current study, we presented subjects with both fixed and mixed blocks, including a mix of dilution trials with low-load trials and with high-load trials. We thus separated the effect of dilution from load and tested the influence of attentional sets on each component. The results revealed that whereas perceptual load effects are influenced by attentional sets, the dilution component is not. This strengthens the notion that dilution is a stimulus-driven mechanism, which enables effective selectivity.     

Grounding spatial language in the motor system: Reciprocal interactions between spatial semantics and orienting

Shifts of attention that are directed by spatial words are thought to be mediated by a spatial frame of reference. Previous studies have documented a selection cost when visual attention is directed along the left/right axis relative to the above/below axis due to the greater ambiguity of the horizontal endpoints. The present study investigated whether the horizontal endpoints may be more fully disambiguated when “left/right” cues are first enacted by nondivisible, more discrete, modes of orienting such as directional motor responses. This issue was investigated using a repetition priming paradigm in which the effects of prior enactments were measured on the subsequent conceptual control of visual attention. The results of four experiments showed that grounding spatial language in the motor system can enhance the focus of visual attention by disambiguating the endpoints of the horizontal axis. In so doing, the present study extends previous research demonstrating that spatial concepts can influence the spatial distribution of attention by demonstrating that different modes of orienting can also influence the semantics of space. Implications for the premotor theory of attention and grounded theories of cognition are also discussed.     

The interaction between social saliency and perceptual saliency

The ability to select visual targets in hierarchical stimuli can be affected by both perceptual saliency and social saliency. However, the functional relations between the effects are not understood. Here we examined whether these two factors interact or combine in an additive way. Participants first learnt to associate geometric shapes with three people (e.g., triangle–self, square–stranger). After learning the associations, participants were presented with compound stimuli (e.g., a global triangle formed by a set of local squares) and had to select a target at the global or local level. In Experiment 1 the task was to identify the person associated with the local or global shape. In Experiment 2 the task was simply to identify the shape. We manipulated perceptual saliency by blurring local elements to form perceptually global salient stimuli or by contrasting the colours of neighbouring local elements (red vs. white) to form perceptually local salient stimuli. In Experiment 1 (person discrimination) there was a strong effect of saliency on local targets (there were faster and more accurate responses to high than to low saliency targets) when social and perceptual saliency occurred at same level. However, both perceptual and social saliency effects were eliminated when the effect of saliency at one level competed with that at the other level. In Experiment 2 (shape discrimination), there were only effects of perceptual saliency. The data indicate that social saliency interacts with perceptual saliency when explicit social categorizations are made, consistent with both factors modulating a common process of visual selection.     

The coupling between spatial attention and other components of task-set: A task-switching investigation

Is spatial attention reconfigured independently of, or in tandem with, other task-set components when the task changes? We tracked the eyes of participants cued to perform one of three digit-classification tasks, each consistently associated with a distinct location. Previously we observed, on task switch trials, a substantial delay in orientation to the task-relevant location and tendency to fixate the location of the previously relevant task—“attentional inertia”. In the present experiments the cues specified (and instructions emphasized) the relevant location rather than the current task. In Experiment 1, with explicit spatial cues (arrows or spatial adverbs), the previously documented attentional handicaps all but disappeared, whilst the performance “switch cost” increased. Hence, attention can become decoupled from other aspects of task-set, but at a cost to the efficacy of task-set preparation. Experiment 2 used arbitrary single-letter cues with instructions and a training regime that encouraged participants to interpret the cue as indicating the relevant location rather than task. As in our previous experiments, and unlike in Experiment 1, we now observed clear switch-induced attentional delay and inertia, suggesting that the natural tendency is for spatial attention and task-set to be coupled and that only quasi-exogenous location cues decouple their reconfiguration.     

Sensitivity to lateral information on a perceptual word identification task in French third and fifth graders

This study aimed at examining sensitivity to lateral linguistic and nonlinguistic information in third and fifth grade readers. A word identification task with a threshold was used, and targets were displayed foveally with or without distractors. Sensitivity to lateral information was inferred from the deterioration of the rate of correct word identification when displayed with distractors. Results show that the two reader groups were sensitive to both right and left lateral information. The area of sensitivity to this information was more extended for the identification of easy words than difficult words. Examination of the detrimental effect of distractors suggests that in both third and fifth graders, the impact of lateral information on foveal processing is the result of a general distraction effect, but also of linguistic processing whose nature remains to be clarified.     

Rapid allocation of temporal attention in the attentional blink paradigm

How fast can information of a first target (T1) in a rapid serial visual presentation be used for top-down allocation of attention in time? A valid cue about the temporal position of a second target (T2) was integrated into T1. The data show that 100 ms after T1 onset, T2 was identified better than without cue, raising the conditional T2 performance. T1 apparently triggers a facilitative effect of attention, known from other paradigms such as peripheral cueing.     

The attentional window configures to object and surface boundaries

Attention can select items based on location or features. Belopolsky and colleagues posited the attentional window hypothesis, which theorized that spatial and featural selection interact such that featural selection occurs within a “window” of spatial selection. Kerzel and colleagues recently found that the attentional window can take complex shapes, but cannot configure around non-contiguous locations. The current experiments investigated whether perceptual grouping cues, which produce perceptual objects or surfaces, enable the attentional window to configure around non-contiguous locations. Using the additional singleton paradigm, we reasoned that observers (1) would be slowed by a colour singleton distractor that appears within the observers’ attentional window and (2) would be unaffected by distractors that do not appear within the attentional window. In separate blocks of trials, a target appeared upon one of two objects. Observers were cued to the relevant surface, and we asked if responses were affected by distractors on the cued task-relevant surface, and on the uncued irrelevant surface. Colour singleton distractors slowed responses when they appeared on the cued surface, even when those locations were non-contiguous locations. Distractors on the irrelevant surface did not affect responses. The results support a highly adaptable attentional window that is configurable to the surfaces and boundaries established by intermediate-level vision.     

The effects of acute stress and perceptual load on distractor interference

Selective attention can be improved under conditions in which a high perceptual load is assumed to exhaust cognitive resources, leaving scarce resources for distractor processing. The present study examined whether perceptual load and acute stress share common attentional resources by manipulating perceptual and stress loads. Participants identified a target within an array of nontargets that were flanked by compatible or incompatible distractors. Attentional selectivity was measured by longer reaction times in response to the incompatible than to the compatible distractors. Participants in the stress group participated in a speech test that increased anxiety and threatened self-esteem. The effect of perceptual load interacted with the stress manipulation in that participants in the control group demonstrated an interference effect under the low perceptual load condition, whereas such interference disappeared under the high perceptual load condition. Importantly, the stress group showed virtually no interference under the low perceptual load condition, whereas substantial interference occurred under the high perceptual load condition. These results suggest that perceptual and stress related demands consume the same attentional resources.     

Challenging perceptual tasks require more attention: The influence of task difficulty on the N1 effect of temporal orienting

Both filter and resource models of attention suggest an influence of task difficulty on the size of early attention effects. As for temporal orienting, the idea that early effects are modulated by task difficulty has not been tested directly, so far. To fill this empirical gap, the present study used an auditory temporal-orienting task, in which two differently pitched pure tones served as targets. To manipulate perceptual difficulty, the pitch difference between the targets was either small or large. Temporal orienting enhanced the N1 component of the auditory event-related potential. This early, sensory effect tended to be larger in the more difficult condition, particularly over the frontal scalp. Notably, increasing task difficulty affected predominantly the processing of attended stimuli. Hence, temporal orienting may operate by increasing processing resources or gain settings for the attended time point – rather than by withdrawing resources from the unattended time point.     

Detection of emotional expressions in rapidly changing facial displays in high- and low-socially anxious women

Facial information and attention to facial displays are distributed over spatial as well as temporal domains. Thus far, research on selective attention to (dis)approving faces in the context of social anxiety has concentrated primarily on the spatial domain. Using a rapid serial visual presentation (RSVP) paradigm, the present study examined the temporal characteristics of visual attention for happy and angry faces in high- (n=16) and low-socially anxious individuals (n=17), to test whether also in the temporal domain socially anxious individuals are characterized by threat-confirming attentional biases. Results indicated that presenting angry faces as the first target (T1) did not aggravate the detection of the emotional expression of the second target (T2). Yet, participants generally showed superior detection of the emotional expression of T2, if T2 was an angry face. Casting doubt on the role of such attenuated attentional blink for angry faces in social anxiety, no evidence emerged to indicate that this effect was relatively strong in high-socially anxious individuals. Finally, the presentation of an angry face as T2 resulted in a relatively hampered identification of a happy-T1. Again, this "backward blink" was not especially pronounced in high-socially anxious individuals. The present anger superiority effects are consistent with evolutionary models stressing the importance of being especially vigilant for signals of dominance. Since the effects were not especially pronounced in high-anxious individuals, the present study adds to previous findings indicating that socially anxious individuals are not characterized by a bias in the (explicit) detection of emotional expressions [Philippot, P., & Douilliez, C. (2005). Social phobics do not misinterpret facial expression of emotion. Behaviour Research and Therapy, 43, 639-652].     

Going the distance: Extra-symbolic contributions to the symbolic control of spatial attention

Over the past 30 years, researchers have used symbolic cues such as spatial words and arrows to direct observers' attention to the location of target objects that appear at a single, fixed distance in simple visual environments; however, they have done so by using symbolic cues that provide only partial—directional—information about the spatial location of target objects. Thus, it remains unclear whether observers can only shift their attention broadly in the cued direction in response to these cues or whether they can shift their attention to the specific location of the target by combining an expectation about direction (derived from apprehension of the directional cue) with an expectation about distance (derived from some extra-symbolic cue). The results of two experiments showed that observers do shift their attention to relatively coarse spatial locations by combining expectancies about direction and distance, and that the extent to which observers do so is modulated by the presence of visible markers and the expected distance of the target. These findings are important because they provide the first evidence that extra-symbolic information about distance contributes to the symbolic control of spatial attention.     

The role of spatial attention and other processes on the magnitude and time course of cueing effects

We are quite often exposed to multiple objects present in the visual scene, thus attentional selection is necessary in order to selectively respond to the relevant information. Objects can be selected on the basis of the location they occupy by orienting attention in space. In this paper, we review the evidence showing that attention can be oriented in space either endogenously, on the basis of central cues, predictive of the relevant location, or exogenously, automatically triggered by the salient properties of visual stimuli (peripheral cues). Several dissociations observed between orienting on the basis of the two types of cues have led to the conclusion that they do not represent just two modes of triggering the orienting of the very same attentional mechanism, but rather they modulate processing differently. We present a theoretical framework according to which endogenous predictive cues facilitate target processing by orienting attention, thus amplifying processing at the attended location. In contrast, apart from attentional orienting, peripherally presented discrepant cues might trigger additional cue-target event-integration and event-segregation processes, which modulate processing in a different way, thus leading to cueing effects that are exclusively triggered by peripheral cues.     

Visual and motor effects in inhibition of return

Inhibition of return (IOR) refers to slowed reaction times (RTs) when a target appears in the same rather than a different location as a preceding stimulus. The present study tested the hypothesis that IOR reflects a motor bias rather than a perceptual deficit. Two signals (S1 and S2) were presented on each trial. These signals were peripheral onsets or central arrows. The responses required to S1 and S2 were, respectively, no response-manual, manual-manual, saccadic-manual, no response-saccadic, manual-saccadic, and saccadic-saccadic. Uniting perceptual and motor bias views of IOR, the results demonstrated inhibition for responding to (a) peripheral signals when the eyes remained fixed (slowed visual processing) and (b) both peripheral and central signals when the eyes moved (slowed motor production). However, the results also emphasized that the nature of IOR depends fundamentally on the response modality used to reveal its influence.     

Emotional facial expressions and the attentional blink: Attenuated blink for angry and happy faces irrespective of social anxiety

Although facial information is distributed over spatial as well as temporal domains, thus far research on selective attention to disapproving faces has concentrated predominantly on the spatial domain. This study examined the temporal characteristics of visual attention towards facial expressions by presenting a Rapid Serial Visual Presentation (RSVP) paradigm to high (n=33) and low (n=34) socially anxious women. Neutral letter stimuli (p, q, d, b) were presented as the first target (T1), and emotional faces (neutral, happy, angry) as the second target (T2). Irrespective of social anxiety, the attentional blink was attenuated for emotional faces. Emotional faces as T2 did not influence identification accuracy of a preceding (neutral) target. The relatively low threshold for the (explicit) identification of emotional expressions is consistent with the view that emotional facial expressions are processed relatively efficiently.     

Hold the future,let the past go: Attention prefers the features of future targets

Previous studies have shown that attention can be captured by task-irrelevant distractors under the guidance of attentional control settings. However, it is unknown whether people can establish an attentional control setting (ACS) for a sequence of distinct events. The present study tested that question by asking observers to expect a sequence of two colored targets in a specific order. The results show that irrelevant distractors that matched either the color of the first expected target or that of the second target captured attention. Thus observers are unable to temporarily suppress the color of the future target in their ACS. However, the temporal order of targets is still useful for guiding attention: Observers were able to abandon the color of the first target and maintain an ACS for the second one as long as there was a sufficient time interval between the two targets.     

Right hemispatial neglect: frequency and characterization following acute left hemisphere stroke

The frequency of various types of unilateral spatial neglect and associated areas of neural dysfunction after left hemisphere stroke are not well characterized. Unilateral spatial neglect (USN) in distinct spatial reference frames have been identified after acute right, but not left hemisphere stroke. We studied 47 consecutive right handed patients within 48h of left hemisphere stroke to determine the frequency and distribution of types of right USN using cognitive testing and MRI imaging. The distribution of USN types was different from the previously reported distribution following acute right hemisphere stroke. In this left hemisphere stroke population, allocentric neglect was more frequent than egocentric neglect.     

The integration of temporally shifted visual feedback in a synchronization task: The role of perceptual stability in a visuo-proprioceptive conflict situation

The present study examined whether the beneficial role of coherently grouped visual motion structures for performing complex (interlimb) coordination patterns can be generalized to synchronization behavior in a visuo-proprioceptive conflict situation. To achieve this goal, 17 participants had to synchronize a self-moved circle, representing the arm movement, with a visual target signal corresponding to five temporally shifted visual feedback conditions (0%, 25%, 50%, 75%, and 100% of the target cycle duration) in three synchronization modes (in-phase, anti-phase, and intermediate). The results showed that the perception of a newly generated perceptual Gestalt between the visual feedback of the arm and the target signal facilitated the synchronization performance in the preferred in-phase synchronization mode in contrast to the less stable anti-phase and intermediate mode. Our findings suggest that the complexity of the synchronization mode defines to what extent the visual and/or proprioceptive information source affects the synchronization performance in the present unimanual synchronization task.