The role of temporal cue-target overlap in backward inhibition under task switching

One of the proposed mechanisms for sequential control in task-shift conditions is backward inhibition (BI), which is usually measured in terms of lag-2 task repetition costs in A-B-A task sequences relative to C-B-A task sequences. By considering the so far existing experiments it seems that these lag-2 repetition costs occur only with temporally overlapping cues and targets. In the present study this issue was further examined in two experiments, in which temporal cue-target overlap was varied blockwise (Experiment 1) and from trial-to-trial (Experiment 2). Experiment 1 shows that lag-2 repetition effects can only be observed with temporally overlapping cues and targets, indicating that there was no BI with temporally separated cues and targets. However, the results of Experiment 2 suggest that both irrelevant task sets are inhibited in this case, and that with temporally overlapping cues and targets only the previously relevant task set is inhibited.     

Predictability of the cue-target relation and the time-course of auditory inhibition of return

The possibility that the time-course of auditory inhibition of return (IOR) might depend on the temporal or spatial predictability of the cue-target relation was investigated. In all the experiments, a location cue was followed by a target that was to be localized. An inhibitory effect became apparent at a longer stimulus onset asynchrony (SOA) when either the temporal or the spatial relation was predictable, rather than when either was unpredictable. A facilitative effect was apparent at a 100-msec SOA, irrespective of the predictability of the cue-target relation. These results establish that the time-course of the inhibitory component of location-based auditory IOR depends on the predictability of the temporal and spatial relations of cue and target. The theoretical implications of these results are considered, and a dual-process model of auditory selective attention is offered.     

Temporal expectancy modulates inhibition of return in a discrimination task

This research examined the influence of cue temporal predictability on inhibition of return (IOR) in a discrimination task. In exogenous attention experiments, the cue that summons attention is noninformative as to where the target will appear. However, it is predictive as to when it will appear. In previous work, it was demonstrated that temporal predictability does not influence IOR in detection tasks. In this work, it is shown that IOR is influenced by temporal predictability in discrimination tasks. Predictability was manipulated by using three stimulus onset asynchrony distributions: nonaging, aging, and accelerated aging. IOR was found when the cue predicted target appearance and was modulated by temporal information. In the nonaging distribution (in which the cue did not predict target appearance), there was no IOR.     

The effect of task location and task type on backward inhibition

Alternating tasks in a sequence of task switches results in impaired performance, relative to switches across three different tasks, an effect known as backward inhibition. Despite the robustness of this effect across task and response variations, backward inhibition is not observed when tasks are uniquely located at different points in space (Arbuthnott, 2005). Three hypotheses about the source of this anomaly were tested. Experiment 1 indicated that perceptually distinct task features other than location did not eliminate backward inhibition. Experiment 2 indicated that when switches across task and location were manipulated independently (i.e., all tasks appeared at all locations), backward inhibition was observed for task switches even when consecutive trials appeared at different spatial locations, ruling out eye movement as the source of the difference. The third experiment indicated that when component tasks involved judgments of spatial location, backward inhibition was observed across unique task-location switches. These results indicate that sequential inhibition is a very flexible mechanism that is sensitive to the amount of interference from previous tasks.     

The effect of previous trial type on inhibition of return

Inhibition of return (IOR) refers to the finding that targets appearing at previously cued locations are more slowly responded to than targets appearing at previously uncued locations when a relatively long temporal interval occurs between the cue and target. This experiment was conducted to determine whether the magnitude of IOR is influenced by the type of preceding trial (cued or uncued) and/or the location of the cue/target on the previous trial. Although no effect of cue/target location is observed, there was a marked effect of previous trial type, as IOR was greater following an uncued trial relative to a cued trial. This effect was attributable to differences in the response time as a function of previous trial type: specifically, participants were faster to respond to cued and uncued trials when the previous trial type was identical.     

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.     

Inhibition of return in a discrimination task

Inhibition of return (IOR) refers to a bias against returning visual attention to a location that has been recently attended. Although IOR has been demonstrated in a wide range of detection tasks, it has not been reliably shown in discrimination tasks. The results of the present experiment, in which eye movement responses and a cue-target procedure were used, indicate that IOR can exist in a discrimination task. Moreover, the results indicate that the amount of IOR in the discrimination task was approximately equal to that found in the detection task. The results suggest that IOR will be obtained in a discrimination task if the prior allocation of attention does not yield any useful information concerning the forthcoming discrimination judgment.     

The global precedence effect is not affected in inhibition of return

This study assessed whether inhibitory processes occurring in IOR affect perceptual processing of hierarchically organised stimuli. Experiment 1 used a global/local task that presented stimuli to the left or the right side. Results showed a global task advantage and a larger interference in the local than in the global task—the global precedence effect (GPE). These effects were larger than in previous studies using centrally presented stimuli, which suggests a greater involvement of low spatial frequency analysis with peripheral than with central stimuli. Experiment 2 combined the global/local task with IOR. Results replicated those of Experiment 1 but there was no interaction with stimulus location. That is, the GPE was not affected in IOR. Thus, we conclude that the GPE and inhibitory processing occurring in IOR are subserved by different mechanisms.     

Influence of endogenous and exogenous orientations of attention on inhibition of return in a cross-modal target-target aiming task

The authors conducted 2 experiments in which participants (N = 16 in each) executed successive unimanual aiming movements to target locations that were indicated by the onset of either an auditory or a visual stimulus. In Experiment 1 (exogenous orientation), inhibition of return (IOR) effects were observed, with reliable reaction time (RT) costs associated with movements returning to the same target and a trend toward larger IOR effects in left than in right space. There was no influence of stimulus modality on the magnitude of IOR. IOR was also observed in Experiment 2 (endogenous orientation), except the influence of stimulus modality reliably mediated those effect. In that case, IOR was evident only when the previous modality was visual and the current modality was auditory. Together, the results of those 2 experiments suggest that in situations in which 2 paired movements constitute the response criteria, IOR is both supramodal and lateralized to contralateral space.     

The processes of facilitation and inhibition in a cue-target paradigm: insight from movement trajectory deviations

Several researchers have examined the trajectories of aiming movements in cue-target paradigms to investigate the motoric and attentional underpinnings of the inhibition of return (IOR) effect. The results of separate studies have revealed inconsistent patterns of trajectory deviations. These discrepancies may have arisen because the studies used narrow ranges of cue-target onset asynchronies (CTOAs) which may have prevented the time courses of facilitation and inhibition effects to be fully assessed. The present study was designed to conduct an examination of temporal and spatial characteristics of aiming movements over a broader range of CTOAs to provide a more comprehensive assessment of the potential expression of attentional and motoric contributions to cuing effects. Participants aimed to targets which were preceded by a non-predictive cue at CTOAs of 100, 350, 850, and 1100 ms. Analysis of spatial and temporal characteristics of the movements revealed facilitatory and inhibitory cuing effects in the trajectories, but only inhibitory cuing effects in RT. Further, the inhibitory effects in RT appeared at a shorter CTOA than the inhibitory effects in trajectories. This pattern of results suggests that the inhibitory mechanisms underlying IOR affect both attention and motor systems, but that these effects are displaced in time.     

双通道分配性注意对视听觉返回抑制的影响

本研究基于线索-靶子范式, 操纵目标刺激类型(视觉、听觉、视听觉)与线索有效性(有效线索、中性条件、无效线索)两个自变量, 通过3个实验来考察双通道分配性注意对视听觉返回抑制(inhibition of return, IOR)的影响。实验1 (听觉刺激呈现在左/右侧)结果发现, 在双通道分配性注意条件下, 视觉目标产生显著IOR效应, 而视听觉目标没有产生IOR效应; 实验2 (听觉刺激呈现在左/右侧)与实验3 (听觉刺激呈现在中央)结果发现, 在视觉通道选择性注意条件下, 视觉与视听觉目标均产生显著IOR效应但二者无显著差异。结果表明：双通道分配性注意减弱视听觉IOR效应。     

Examining the effect of practice on inhibition of return in static displays

In a recent article, Weaver, Lupiáñez, and Watson (1998) reported that both object-based and location-based inhibition of return effects were reduced with practice. The present study was conducted to (1) replicate the reduction of inhibition of return with practice in single-session experiments with a variety of displays and responses and (2) to examine the notion that the reduction was, at least partly, due to habituation. However, no evidence for practice-related changes in the size of the inhibitory effect were found over a series of different inhibition of return experiments using static displays (using various numbers of target locations, types of keypress responses, and number of trials). Overall, the results suggest that inhibition of return is a robust phenomenon and may not, with static displays, be especially sensitive to practice effects.     

A context-specific latent inhibition effect in a human conditioned suppression task

Three studies used a computer video game preparation to demonstrate latent inhibition in adult humans. In all studies participants fired torpedoes at a target spaceship by clicking the mouse. Conditioned stimuli (CSs) were presented in the form of coloured “sensors” at the bottom of the screen. Conditioning was conducted by pairing a sensor with an attack from the target spaceship. Participants learned to suppress their rate of mouse clicking in preparation for an attack. In Experiment 1 a total of 10 preexposures to the sensor CS, prior to conditioning, retarded acquisition of suppression. In Experiment 2 the effect of preexposure was shown to be context specific. Experiment 3 showed little generalization of the preexposure effect from one sensor CS to another. Experiment 3 also showed that preexposure did not make the sensor CS inhibitory. Comparisons with conditioned suppression procedures with animals and negative-priming procedures are briefly discussed.     

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.     

A context-specific latent inhibition effect in a human conditioned suppression task

Three studies used a computer video game preparation to demonstrate latent inhibition in adult humans. In all studies participants fired torpedoes at a target spaceship by clicking the mouse. Conditioned stimuli (CSs) were presented in the form of coloured “sensors” at the bottom of the screen. Conditioning was conducted by pairing a sensor with an attack from the target spaceship. Participants learned to suppress their rate of mouse clicking in preparation for an attack. In Experiment 1 a total of 10 preexposures to the sensor CS, prior to conditioning, retarded acquisition of suppression. In Experiment 2 the effect of preexposure was shown to be context specific. Experiment 3 showed little generalization of the preexposure effect from one sensor CS to another. Experiment 3 also showed that preexposure did not make the sensor CS inhibitory. Comparisons with conditioned suppression procedures with animals and negative-priming procedures are briefly discussed.     

Minimal use of working memory in a scene comparison task

Eye movement behaviour in hand-eye tasks suggests a preference for a “just in time” processing strategy that minimizes the use of working memory. In the present study, a scene comparison task was introduced to determine whether the preference holds when the task is primarily visual and when more complex naturalistic scenes are used as stimuli. In two experiments, participants made same or different judgements in response to simultaneously presented pairs of scenes that were identical or differed by one object. The number of fixations per scene glance and the number of fixations intervening between glances to corresponding objects suggest that frequently one object at a time is encoded and maintained in visual working memory. The same pattern of results was observed in a third experiment using word and object arrays. Overall, the results suggest a strong general bias toward minimal use of visual working memory in complex visual tasks.     

Searching for inhibition of return in the rat using the covert orienting of attention task

Inhibition of return (IOR) is an important psychological construct describing inhibited responses to previously attended locations. In humans, it is investigated using Posner’s cueing paradigm. This paradigm requires central visual fixation and detection of cued stimuli to the left or right of the fixation point. Stimuli can be validly or invalidly cued, appearing in the same or opposite location to the cue. Although a rat version of the spatial cueing paradigm (the covert orienting of attention task) does exist, IOR has so far not been demonstrated. We therefore investigated whether IOR could be robustly demonstrated in adult male rats using the covert orienting of attention task. This task is conducted in holed wall operant chambers with the central three holes mimicking the set-up for Posner cueing. Across four samples of rats (overall n = 84), we manipulated the following task parameters: stimulus onset asynchronies (Experiments 1–3), cue brightness (Experiment 1b) and the presence of a central reorienting event (Experiment 4). In Experiment 1, we also investigated strain differences by comparing Lister Hooded rats to Sprague–Dawley rats. Although Lister Hooded rats briefly showed evidence of IOR (Experiment 1a, and see Online Resource 1 data), we were unable to replicate this finding in our other experiments using different samples of this strain. Taken together, our findings suggest that IOR cannot be robustly demonstrated in the rat using the covert orienting of attention task conducted in holed wall operant chambers.     

Examining the effect of practice on inhibition of return in static displays.

In a recent article, Weaver, Lupiá?ez, and Watson (1998) reported that both object-based and location-based inhibition of return effects were reduced with practice. The present study was conducted to (1) replicate the reduction of inhibition of return with practice in single-session experiments with a variety of displays and responses and (2) to examine the notion that the reduction was, at least partly, due to habituation. However, no evidence for practice-related changes in the size of the inhibitory effect were found over a series of different inhibition of return experiments using static displays (using various numbers of target locations, types of keypress responses, and number of trials). Overall, the results suggest that inhibition of return is a robust phenomenon and may not, with static displays, be especially sensitive to practice effects.