The effects of expectancy on inhibition of return

Attention to space and time: Independent or interactive systems? A narrative review

While there is ample evidence for the ability to selectively attend to where in space and when in time a relevant event might occur, it remains poorly understood whether spatial and temporal attention operate independently or interactively to optimize behavior. To elucidate this important issue, we provide a narrative review of the literature investigating the relationship between the two. The studies were organized based on the attentional manipulation employed (endogenous vs. exogenous) and the type of task (detection vs. discrimination). Although the reviewed findings depict a complex scenario, three aspects appear particularly important in promoting independent or interactive effects of spatial and temporal attention: task demands, attentional manipulation, and their combination. Overall, the present review provides key insights into the relationship between spatial and temporal attention and identifies some critical gaps that need to be addressed by future research.

Contextual Similarity Between Successive Targets Modulates Inhibition of Return in the Target-Target Paradigm

Inhibition of return (IOR) refers to slower responses to a target presented at a previously cued vs. uncued location. The present study investigated the role of memory retrieval in IOR by manipulating the contextual similarity between two successive targets in the target-target IOR paradigm. Successive targets were presented in either the same color (same-context condition) or different colors (different-context condition). Results of two experiments showed that IOR was greater in the same-context than the different-context condition. In addition, Experiment 2 showed that this context effect occurs with long response times (RTs), suggesting that memory retrieval, which requires time to manifest, plays an important role in IOR.

Inhibitory and Facilitatory Cueing Effects: Competition between Exogenous and Endogenous Mechanisms

Inhibition of return is characterized by delayed responses to previously attended locations when the cue-target onset asynchrony (CTOA) is long enough. However, when cues are predictive of a target’s location, faster reaction times to cued as compared to uncued targets are normally observed. In this series of experiments investigating saccadic reaction times, we manipulated the cue predictability to 25% (counterpredictive), 50% (nonpredictive), and 75% (predictive) to investigate the interaction between predictive endogenous facilitatory (FCEs) and inhibitory cueing effects (ICEs). Overall, larger ICEs were seen in the counterpredictive condition than in the nonpredictive condition, and no ICE was found in the predictive condition. Based on the hypothesized additivity of FCEs and ICEs, we reasoned that the null ICEs observed in the predictive condition are the result of two opposing mechanisms balancing each other out, and the large ICEs observed with counterpredictive cueing can be attributed to the combination of endogenous facilitation at uncued locations with inhibition at cued locations. Our findings suggest that the endogenous activity contributed by cue predictability can reduce the overall inhibition observed when the mechanisms occur at the same location, or enhance behavioral inhibition when the mechanisms occur at opposite locations.

Monocular channels have a functional role in phasic alertness and temporal expectancy

The literature has long emphasized the neocortex's role in the tangled phasic-alertness and temporal-expectancy processes. In this work, we examined whether subcortical, monocular mechanisms have a functional role in these processes. This was done by assessing phasic alertness and temporal expectancy independently using a cue-target eye-of-origin manipulation. Participants performed target detection tasks in which a central cue and its ensuing peripheral target were each presented either to the same eye or to a different eye. In Experiment 1, phasic alertness, independent of temporal expectancy, was manipulated by presenting an alerting cue prior to the target presentation. The alerting effect elicited by the cue lasted for a longer duration when the cue and target were presented to the same eye than when they were presented to different eyes, indicating the involvement of subcortical regions in phasic alertness. In Experiment 2, the cue's temporal predictability regarding the target's onset time was manipulated by changing the cue-target interval's foreperiod distribution. A modulation in temporal expectancy was found when both the cue and the target were presented to the same eye, demonstrating the importance of subcortical mechanisms in temporal expectancy. Together, the results demonstrate that monocular channels are functionally involved in both phasic alertness and temporal expectancy. This study suggests that both phasic alertness and temporal expectancy are functionally dependent on monocular channels of the visual stream, and highlights the importance of direct examination of primitive, subcortical regions in higher cognitive functioning (e.g., temporal expectancy).

Using Rescorla's truly random control condition to measure truly exogenous covert orienting

Studies of exogenous covert orienting use peripheral cues (stimuli) that are spatially uninformative about the locations of subsequent targets. When the time course of the cue's influence on performance is explored (by varying the cue target onset asynchrony; CTOA), a biphasic pattern is usually seen with better performance at the cued location when the CTOA is short (typically attributed to attentional capture) and worse performance at the cued location when the CTOA is long (attributed to inhibition of return). However, while spatially uninformative, these cues (even when a nonaging foreperiod is used) entail a temporal contingency with the subsequent target. Consequently, this so-called capture may reflect an unintended consequence of endogenous allocation of temporal attention. Following Lawrence and Klein (Journal of Experimental Psychology: General, 142(2), 560-572, 2013) we used Rescorla's (Psychological Review, 74, 71-80, 1967) truly random control condition to ensure that the spatially uninformative peripheral stimuli were temporally completely uninformative. Even such completely uninformative peripheral stimuli generated the prototypical biphasic pattern.

Does cue processing modulate inhibition of return in a detection task?

While the abrupt onset of a peripheral visual cue usually leads to speeded responses to following targets at the cued relative to other positions, responses are slowed if targets lag behind the cue by more than ~200 ms. This response delay is termed inhibition of return (IOR) and has been considered as a mechanism to orient behavior toward novel areas. IOR has been found in both detection and discrimination tasks with later onset in discrimination tasks, probably due to a higher processing demand. Here we examined whether the processing demand of cues can modulate IOR in the detection task. The task to the peripheral cues, either color or gap cues, was passive viewing in one session (single task) and discrimination in another session (dual task). The results showed that the time course of IOR was resistant to the cue processing, while the magnitude of IOR was increased when the processing load became larger in the dual task relative to the single task. These results indicate that IOR in target detection is both reflexive in that its temporal dynamics remain invariant, and flexible in that its magnitude is modulated by task requirement.

Temporal expectancies and rhythmic cueing in touch: The influence of spatial attention

Attention resources can be allocated in both space and time. Exogenous temporal attention can be driven by rhythmic events in our environment which automatically entrain periods of attention. Temporal expectancies can also be generated by the elapse of time, leading to foreperiod effects (the longer between a cue and imperative target, the faster the response). This study investigates temporal attention in touch and the influence of spatial orienting. In experiment 1, participants used bilateral tactile cues to orient endogenous spatial attention to the left or right hand where a unilateral tactile target was presented. This facilitated response times for attended over unattended targets. In experiment 2, the cue was unilateral and non-predictive of the target location resulting in inhibition of return. Importantly, the cue was rhythmic and targets were presented early, in synchrony or late in relation to the rhythmic cue. A foreperiod effect was observed in experiment 1 that was independent from any spatial attention effects. In experiment 2, in synchrony were slower compared to out of synchrony targets but only for cued and not uncued targets, suggesting the rhythm generates periods of exogenous inhibition. Taken together, temporal and spatial attention interact in touch, but only when both types of attention are exogenous. If the task requires endogenous spatial orienting, space and time are independent.

Temporal ambiguity of onsets in a cueing task prevents facilitation but not inhibition of return

Cueing effects, i.e., early facilitation of reaction time and inhibition of return (IOR), are well-established and robust phenomena characterizing exogenous orienting and are widely observed in experiments with a traditional Posner cueing paradigm. Krüger, MacInnes, and Hunt (2014) proposed that facilitatory effects of peripheral cues are the result of a cue-target perceptual merging due to re-entrant visual processing. To test the role and timing of these feedback mechanisms in peripheral cueing effects, we modified the traditional cueing task in Experiments 1-3 by interleaving pre- and post-cue trials at the valid and invalid location and random cue-target onset asynchrony (CTOA) ranging from -300 to +1,000 ms. Analysis of the manual reaction time distribution over CTOA showed well-pronounced IOR in the valid pre-cue condition and a small cost of perceptual merging in the post-cue condition, but no early facilitation of reaction time was observed in the pre-cue condition. In Experiment 4, we tested directly whether temporal ambiguity eliminated facilitation by restricting CTOAs to only the pre-cue time range and including a between-subject manipulation of a) random, b) mixed discrete, and c) blocked discrete CTOAs. Results obtained in the continuous and binned conditions showed no facilitation but robust IOR. We found both early facilitation and IOR in the blocked condition. Overall, the present findings show a small perceptual merging result without accompanying facilitation, suggesting different underlying mechanisms. Second, they demonstrate that early facilitation is likely to be affected by the presence or absence of temporal expectations and that the early onset of IOR might be masked by stronger facilitation in traditional cueing experiments.

Changes in Tonic Alertness but Not Voluntary Temporal Preparation Modulate the Attention Elicited by Task-Relevant Gaze and Arrow Cues

Attention is engaged differently depending on the type and utility of an attentional cue. Some cues like visual transients or social gaze engage attention effortlessly. Others like symbols or geometric shapes require task-relevant deliberate processing. In the laboratory, these effects are often measured using a cuing procedure, which typically manipulates cue type and its utility for the task. Recent research however has uncovered that in addition to spatial orienting, this popular paradigm also engages two additional processes-tonic alertness and voluntary temporal preparation-both of which have been found to modulate spatial orienting elicited by task-irrelevant cues but not task-relevant symbols. Here we assessed whether changes in tonic alertness and voluntary temporal preparation also modulated attentional orienting elicited by task-relevant social gaze and nonsocial arrow cues. Our results indicated that while the effects of spatial attention were reliable in all conditions and did not vary with cue type, the magnitude of orienting was larger under high tonic alertness. Thus, while the cue's task utility appears to have the power to robustly drive attentional orienting, changes in tonic alertness may modulate the magnitude of such deliberate shifts of attention elicited by task-relevant central social and nonsocial cues.

Cardiorespiratory Fitness Is Associated with Selective Attention in Healthy Male High-School Students

Background: Previous studies have shown associations of physical fitness and cognition in children and in younger and older adults. However, knowledge about associations in high-school adolescents and young adults is sparse. Thus, the aim of this study was to evaluate the association of physical fitness, measured as maximal oxygen uptake (V·O2max), muscle mass, weekly training, and cognitive function in the executive domains of selective attention and inhibitory control, in healthy male high-school students.

Methods: Fifty-four males (17.9 ± 0.9 years, 72 ± 11 kg and 182 ± 7 cm) completed a V·O2max test, a body composition test and a visual cognitive task based on the Posner cue paradigm with three types of stimuli with different attentional demands (i.e., stimuli presentation following no cue, valid cue or invalid cue presentations). The task consisted of 336 target stimuli, where 56 (17%) of the target stimuli appeared without a cue (no cue), 224 (67%) appeared in the same rectangle as the cue (valid cue) and 56 (17%) appeared in the rectangle opposite to the cue (invalid cue). Mean reaction time (RT) and corresponding errors was calculated for each stimuli type. Total task duration was 9 min and 20 s In addition, relevant background information was obtained in a questionnaire.

Results: Linear mixed model analyses showed that higher V·O2max was associated with faster RT for stimuli following invalid cue (Estimate = −2.69, SE = 1.03, p = 0.011), and for stimuli following valid cue (Estimate = −2.08, SE = 1.03, p = 0.048). There was no association of muscle mass and stimuli (F = 1.01, p = 0.397) or of weekly training and stimuli (F = 0.99, p = 0.405).

Conclusion: The results suggest that cardiorespiratory fitness is associated with cognitive performance in healthy male high-school students in the executive domains of selective attention.

If not When, then Where? Ignoring Temporal Information Eliminates Reflexive but not Volitional Spatial Orienting

A tremendous amount of research has been devoted to understanding how attention can be committed to space or time. Until recently, relatively little research has examined how attention to these two domains combine. The present study addressed this issue. We examined how implicitly manipulating whether participants used a cue to orient attention in time impacts reflexive or volitional shifts in spatial attention. Specifically, participants made speeded manual responses to the detection of a peripherally presented target that appeared either 100, 500, or 1000 ms after the onset of a central cue. Cues were either spatially non-predictive arrows (p = 0.50) or spatially-predictive (p = 0.80) letter cues. Whereas arrow cues can reflexively orient spatial attention even when non-predictive of a target’s spatial location, letters only orient spatial attention when they reliably predict a target location, i.e., the shift is volitional. Further, in one task, a target was presented on every trial, thereby encouraging participants to use the temporal information conveyed by the cue to prepare for the appearance of the target. In another task, 25% of trials contained no target, implicitly discouraging participants from using the cue to direct attention in time. Results indicate that when temporal information is reliable and therefore volitionally processed, then spatial cuing effects emerge regardless of whether attention is oriented reflexively or volitionally. However, when temporal information is unreliable, spatial cuing effects only emerge when spatial cue information is reliable, i.e., when spatial attention is volitionally shifted. Reflexive cues do not elicit spatial orienting when their temporal utility is reduced. These results converge on the notion that reflexive shifts of spatial attention are sensitive to implicit changes in a non-spatial domain, whereas explicit volitional shifts in spatial attention are not.

Automated symbolic orienting is not modulated by explicit temporal attention

Recent studies show that spatial attention is uniquely engaged by the selection history of a stimulus. One example of this process is Automated Symbolic Orienting, which is thought to reflect overlearned spatial links between a behaviorally relevant stimulus and a target event. However, since automated symbolic effects have been found to vary with temporal expectancies about when a target might occur, it is possible that this spatial effect may also depend on processing resources associated with voluntary temporal attention. To test this idea, here we elicited automated symbolic orienting and voluntary temporal attention in isolation and in combination. Across all conditions, both types of orienting remained typical without interacting. Thus, typical automated symbolic orienting is not modulated by participants' explicit utilization of temporal information; however, and as we have shown previously, typical ASO does appear to require the presence of an implicit temporal structure within a task.

Endogenous temporal and spatial orienting: Evidence for two distinct attentional mechanisms

The requirement to orient attention in space and time usually occurs simultaneously. Previous reports were indecisive regarding possible interactions between temporal and spatial orienting. The present study examined whether temporal and spatial orienting can operate simultaneously and independently in the framework of a detection task. Participants completed three consecutive target detection tasks: in the first two tasks a central cue provided predictive information regarding either the temporal delay of the target or its spatial location. In a third task the temporal and spatial cues from the first two tasks were combined into a single cue. Temporal and spatial information provided by the combined cue could be valid or invalid for each type of information separately. Results from the combined temporal-spatial task revealed that at a short cue-to-target interval temporal validity effects were significant at the attended and unattended spatial locations and were not modulated by spatial validity conditions. Spatial validity effects were also significant and comparable between the valid and invalid temporal conditions. Moreover, temporal and spatial validity effects in the combined task were equivalent to those attained in the separate tasks. At a long cue-to-target delay, spatial validity effects were significant and were not modulated by temporal validity but there were no temporal validity effects. Overall, the results suggest that participants were able to extract temporal and spatial information provided by a single cue simultaneously and independently. We conclude that temporal and spatial endogenous orienting function orthogonally in a task that does not require demanding perceptual discrimination.

Temporal cues derived from statistical patterns can overcome resource limitations in the attentional blink

Previous studies have shown that humans are sensitive to statistical patterns indicating the likely locations, identities, and timings of visual targets. Here we tested whether participants can also use this kind of information to ameliorate the attentional blink (AB)—a reduction in accuracy for the second of two targets (T1, T2) presented at brief intertarget intervals (lags). In particular, we asked whether participants can use patterns arising from differential distributions of intertarget lags across trials to predict the arrival of T2. We tested this by comparing the ABs in an aging versus a nonaging distribution of trials, where aging refers to the increased likelihood of T2, given that it has not yet occurred, when lags occur with equal frequencies. Experiments 1 and 2 showed that the aging condition yielded greater T2 accuracy at longer lags than did the nonaging condition. In Experiment 3, we used a more sensitive response time measure to show faster T2 discrimination at shorter lags in the nonaging condition. These results demonstrate that participants can predict the likely onset of T2 by using statistical patterns present in the AB task, and that they can use this ability to more effectively direct limited processing resources.

Measuring attention using the Posner cuing paradigm: the role of across and within trial target probabilities

Numerous studies conducted within the recent decades have utilized the Posner cuing paradigm for eliciting, measuring, and theoretically characterizing attentional orienting. However, the data from recent studies suggest that the Posner cuing task might not provide an unambiguous measure of attention, as reflexive spatial orienting has been found to interact with extraneous processes engaged by the task's typical structure, i.e., the probability of target presence across trials, which affects tonic alertness, and the probability of target presence within trials, which affects voluntary temporal preparation. To understand the contribution of each of these two processes to the measurement of attentional orienting we assessed their individual and combined effects on reflexive attention elicited by a spatially nonpredictive peripheral cue. Our results revealed that the magnitude of spatial orienting was modulated by joint changes in the global probability of target presence across trials and the local probability of target presence within trials, while the time course of spatial orienting was susceptible to changes in the probability of target presence across trials. These data thus raise important questions about the choice of task parameters within the Posner cuing paradigm and their role in both the measurement and theoretical attributions of the observed attentional effects.

A short-lived face alert during inhibition of return

In the present study, we explored the role of faces in oculomotor inhibition of return (IOR) using a tightly controlled spatial cuing paradigm. We measured saccadic response latency to targets following peripheral cues that were either faces or objects of lesser sociobiological salience. A recurring influence from cue content was observed across numerous methodological variations. Faces versus other object cues briefly reduced saccade latencies toward subsequently presented targets, independently of attentional allocation and IOR. The results suggest a short-lived priming effect or social facilitation effect from the mere presence of a face. In the present study, we further showed that saccadic responses were unaffected by face versus nonface objects in double-cue presentations. Our findings indicate that peripheral face cues do not influence attentional orienting processes involved in IOR any differently from other objects in a tightly controlled oculomotor IOR paradigm.

Inhibitory interaction: the effects of multiple non-predictive visual cues

When the interval between a non-predictive cue and a target appearing at the same spatial location is longer than about 200 ms, target performance is typically poorer than when the cue and target appear at different locations. Recent studies have shown that this effect, known as inhibition of return (IOR), can occur at multiple cued locations, and is enhanced when multiple cues are presented at the same spatial location. However, little is known about how the magnitude of IOR at one spatial location is influenced by a subsequent or preceding cue presented at a different spatial location. We investigated this issue by presenting single or multiple cues at varying inter-cue intervals prior to target onset. Results suggest that the magnitude of IOR at a given location is influenced by the presentation of a preceding cue, but that once IOR occurs, it is unaffected by the presentation of a subsequent cue.