Time Course Of Inhibition Of Return Research Articles

When does “inhibition of return” occur in spatial cueing tasks? Temporally disentangling multiple cue-triggered effects using response history and conditional accuracy analyses

Abstract Research on spatial cueing has shown that uninformative cues often facilitate mean response time (RT) performance in valid- compared to invalid-cueing conditions at short cue-target stimulus-onset-asynchronies (SOAs), and robustly generate a reversed or inhibitory cueing effect at longer SOAs that is widely known as inhibition-of-return (IOR). To study the within-trial time course of the IOR and facilitation effects we employ discrete-time hazard and conditional accuracy analyses to analyze the shapes of the RT and accuracy distributions measured in two experimental tasks. Our distributional analyses show that (a) IOR is present only from ~160 ms to ~280 ms after target onset for cue-target SOAs above ~200 ms, (b) facilitation does not precede IOR, but co-occurs with it, (c) the cue-triggered motor response activation is selectively and actively inhibited before target onset, (d) the IOR effect consists of a facilitatory and an inhibitory component when compared to central cueing, (e) the addition of an extra central cue causes a temporary negative cueing effect in the conditional accuracy functions, and (f) the within-trial time course of IOR is not affected much by the task employed (detection or localization). We conclude that the traditional mean performance measures conceal crucial information on behavioral dynamics in spatial cueing paradigms.

A concurrent working memory load does not necessarily impair spatial attention: Evidence from inhibition of return

ABSTRACT Inhibition of return (IOR), an inhibitory aftereffect of attentional orienting, usually reveals itself in slower responses to targets appearing at previously attended locations in spatial cueing tasks. Many of the neural substrates underlying visual working memory are also closely linked to attention. The present study examined whether the contents held in working memory interfere with IOR by requiring participants to keep a set of spatial locations in working memory while they performed a spatial cueing task. Results revealed that the presence of a concurrent working memory load modulated IOR when the cueing task involved saccadic responses (Experiment 4), but not when more resource-demanding responses were required in the cueing task (Experiments 1–3). The present study also revealed that working memory load had little effect on the time course of IOR. We suggest that the attentional control setting (ACS) selected to accommodate the cognitive tasks at hand determines whether working memory will interfere with IOR and spatial attention in general.

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.

The Time Course of Inhibition of Return: Evidence from Steady-State Visual Evoked Potentials.

Inhibition of return (IOR) refers to slower responses to targets at a previously cued location than that at an uncued location. The time course of IOR has long been a topic of interest in the field. Investigations into the time course of IOR are typically performed by examining the magnitude of IOR under various cue-target onset asynchrony (CTOA) conditions. Therefore, the results are vulnerable to influence of factors that could affect the target processes (e.g., the frequency of the target type). In the present study, steady-state visual evoked potentials (SSVEPs) were implemented to directly take a continuous measurement of the degree to which cued location is processed, eliminating the influence mentioned above. The results indicate that, relative to the baseline interval (−400 to 0 ms), the presence of peripheral cues generated a typical two-stage effect on the SSVEP amplitude evoked by a 20 Hz flicker. Specifically, after the onset of the peripheral cues, the SSVEP amplitude first showed a significant increase, which subsequently turned into a significant inhibition effect after 200 ms. These results provide a continuous time course diagram of the cueing effect and suggest an effective way for future investigations of controlling the masking effects of target stimuli processing on IOR.

Inhibition of return and schizophrenia: A meta-analysis

Inhibition of return (IOR) is a phenomenon that involves inhibited or delayed orienting to previously cued locations in favor of attending to novel locations. To date, research on IOR in patients with schizophrenia has generated mixed, and seemingly conflicting, results. Some researchers report patients with schizophrenia exhibit blunted or delayed IOR, while other researchers report normal IOR, in terms of time course and magnitude. This meta-analysis summarizes the literature that has employed an IOR task in patients with schizophrenia and with controls while focusing upon a procedural feature, the use of a cue back to fixation, between the cue and target that is known to be important when executive control has been hampered in non-clinical populations. Fifteen experiments were located yielding a total sample of 362 patients with schizophrenia or schizoaffective disorder and 285 controls. Using a meta-analytic approach, results of the present analyses show that patients with schizophrenia demonstrate delayed IOR in the single cue procedure. In the cue back to fixation procedure, the time course of IOR among patients is more consistent with that of controls. Differences in measured IOR between patients with schizophrenia and controls are largely related to a deficit in endogenous disengagement of attention.

Neural processes of attentional inhibition of return traced with magnetoencephalography

Inhibition of return (IOR) is a phenomenon that involves reaction times (RTs) to a spatially cued target that are longer than RTs to an uncued target when the interval between the cue and target is prolonged. Although numerous studies have examined IOR, no consensus has yet been reached regarding the neural mechanisms responsible for it. We used magnetoencephalography (MEG) and measured the human neural responses underlying the time course of IOR, applying a typical spatial cueing paradigm. The cue-target interval was 600±200 ms. Three experimental conditions were employed. Cued; the cue and target were presented at the same location. Uncued; the two stimuli were presented at opposite locations. Neutral; the cue stimulus was presented bilaterally. We found differences in the amplitudes of signals in the postero-temporal and bilateral temporal areas, and peak latencies in a central area between the cued and uncued conditions. These signals were localized to the extrastriate cortex, bilateral temporal-parietal junction (TPJ), and primary motor cortex, respectively. Bilateral TPJ activities are related to the identification of salient events in the sensory environment both within and independent of the current behavioral context and may play an important role in IOR in addition to extrastriate and the primary motor cortex.

Inhibition of return to social signals of fear.

The present study examined whether inhibition of return (IOR) is modulated by the fear relevance of the cue. Experiment 1 found similar magnitude of IOR was produced by neutral and fear faces and luminance matched cues. To allow a more sensitive measure of endogenously directed attention, Experiment 2 removed a central reorienting cue and more precisely measured the time course of IOR. At stimulus onset asynchronies (SOAs) of 500, 1,000 and 1,500 ms, fear face and luminance matched cues resulted in similar IOR. These findings suggest that IOR is triggered by event onsets and disregards event value. Views of IOR as an adaptive "foraging facilitator," whereby attention is guided to promote optimal sampling of important environmental events, are discussed.

Rapid onset and long-term inhibition of return in the multiple cuing paradigm

Inhibition of return (IOR) refers to the finding that targets at cued locations are responded to more slowly than targets at uncued locations when a relatively long temporal interval occurs between the two events. In studies which have examined the time course of IOR (e.g., Samuel & Kat in Psychonomic Bulletin & Review, 10, 897-906, 2003), the effect is generally shown to develop at around 200 ms and dissipate at around 3,000 ms following a cue. A number of recent studies, however, have demonstrated that IOR can develop much more quickly (up to 50 ms following a cue) and last much longer (up to 13 min following a cue) in certain tasks. The present study uses the multiple cuing paradigm to determine whether IOR can be observed outside the normally reported temporal boundaries (300-3,000 ms) when attention is shifted very quickly (every 15 ms) or very slowly (every 1,500 ms) throughout the visual field. IOR was observed as quickly as 30 ms following cue onset and as long as 6,000 ms following cue onset. Implications for the role of IOR in visual search are discussed.

The effects of memory load on the time course of inhibition of return

Inhibition of return (IOR) refers to a processing disadvantage at a recently attended location. It is generally agreed that when elicited in a cue-target task, IOR will not be apparent until attention is disengaged from the originally cued location and returned to a neutral state. Here we test the hypothesis that when such disengagement is dependent on endogenous control, a secondary task that taxes working memory capacity should delay the appearance of IOR. Participants were given a six-item verbal working memory load prior to the peripheral cue in a cue-target detection task. Consistent with the hypothesis, the appearance of IOR was delayed on trials for which participants had to hold information in working memory. Converging evidence was derived from a second experiment in which the time course of IOR's appearance, when we added a central cue to exogenously remove attention from the peripheral cue, was unaffected by the memory load.

Examining Task Difficulty and the Time Course of Inhibition of Return: Detecting Perceptually Degraded Targets.

The ability to efficiently direct visual attention to salient features in the environment is a critical function of the visual system. The finding that people are slower to detect a target that appears at a previously cued location is thought to reflect a mechanism known as inhibition of return (IOR). Past research has shown that difficult target discriminations result in a greater amount of time needed to inhibit previously attended locations (i.e., a delayed onset of inhibition), suggesting that task difficulty plays a critical role in the allocation of attention. In this study, IOR was measured at a wide range of SOAs while participants detected either a perceptually degraded target or a standard, high luminance target. When responses were made to a perceptually degraded target, the time course of IOR was delayed by approximately 250 ms (relative to the control group), suggesting that the difficulty in detecting targets also influences the allocation of attention. The results are consistent with the notion that IOR is not simply a reflexive subcortical mechanism but rather involves top-down attentional control settings.

Aging and the time course of inhibition of return in a static environment

Age-related differences on the time course of inhibition of return (IOR), a phenomenon that refers to a slowed response time for targets appearing at a previously attended location, were examined in 30 young and 30 elderly adults. Stimulus onset asynchronies (SOAs) between peripheral cues and targets were systematically manipulated on a detection task with a double-cue procedure to capture the onset and offset of IOR. Results show that IOR in elderly people developed 50 ms later as compared to young adults, at an approximately 200 ms cue-target interval. The magnitude of IOR for elderly people was also weaker than that for young adults during short SOAs. Similar magnitude and dissipation of IOR at an approximately 3.5 s cue-target interval during long SOAs were observed for both young and elderly people. Possible reasons underlying the age effects on the time course of IOR and the involvement of temporal processing mechanisms are discussed.