Investigating attention toward pain-related cues in an Arabic-speaking population with and without chronic pain

There is some evidence for attentional biases in individuals with chronic pain (CP). Cultural and linguistic differences might affect the manifestation of these processes across populations. However, such attentional biases have not been explored in the Arabic-speaking population. The current study investigated these attentional biases and possible associations with resilience. Two matched groups of Arabic-speaking participants with (58) and without (58) CP were recruited from Jordan and the United Kingdom. They completed emotionally modified versions of the Posner cueing and Stroop tasks, alongside questionnaires. Significant group differences were found for the Posner task, with the CP group exhibiting disengagement revealed by the inhibition of return (IOR) effect for sensory pain-related cues compared to delayed disengagement for the other cue types. The control group showed IOR across cue types. No group differences were found on the Stroop task. The CP group had lower resilience scores than healthy controls, and resilience moderated performance on the Posner task. The study provides preliminary evidence about the attentional processes in the Arabic population; the speed of disengagement is affected in the CP group with early disengagement for sensory pain-related information compared to affect pain and neutral stimuli. Furthermore, resilience levels in the CP and control group moderated the performance on the Posner task, suggesting that it influences attentional allocation. This study can help in understanding how the phenomenon of attention bias intertwines with the cultural and linguistic factors. Future research should further explore attentional dynamics across different time points in this population and the modulatory effect of resilience.

Adults at low reading level are sluggish in disengaging spatial attention

An increasing number of studies show that attentional shifting is a primary contributor during the process of learning to read. However, it remains unclear what is the relationship between attentional shifting and word-reading ability in adult readers whose reading skills have matured. More fundamentally, how attentional shifting affects individuals' reading ability remains poorly understood. To address these issues, we grouped adult readers by the level of Chinese character reading and examined the time course of attentional shifting by setting up multiple stimulus-onset asynchronies (SOAs) in the Posner cue-target paradigm. Based on the phonological mediation hypothesis, we also measured multiple abilities involving phonological processing (i.e., rapid automatic naming and phonological awareness). Results showed that compared with adults at the high reading level, adults at the low reading level showed a selective impairment of attentional disengagement. Rapid automatic naming of Chinese characters played a partially mediating role in the association between attentional shifting and word reading. These results provided evidence for the phonological mediation hypothesis, and suggest that attentional shifting affects word reading by influencing phonological processing in adult Chinese readers.

Bound to a spider without its web: Task-type modulates the retrieval of affective information in subsequent responses

Action control theories assume that upon responding to a stimulus response and stimulus features are integrated into a short episodic memory trace; repeating any component spurs on retrieval, affecting subsequent performance. The resulting so-called "binding effects" are reliably observed in discrimination tasks. In contrast, in localization performance, these effects are absent and only inhibition of return (IOR) emerges - a location change benefit. Affective information has been found to modulate binding effects; yet a modulation of IOR has led to mixed results, with many finding no influence at all. In the current study, participants discriminated letters (Experiment 1) or localized dots (Experiment 2) on a touchpad in prime-probe sequences. During the prime display two images - one with fruits and one with a spider - appeared, one of which spatially congruent with the to-be-touched area. In the discrimination task, previously touching a spider compared to a fruit slowed down response repetitions. In contrast, the localization task only showed IOR. This suggests that task-irrelevant valence is integrated with the response and affects subsequent responses due to retrieval. However, this is not ubiquitous but depends on task type. The results shed further light on the impact of affective information on actions.

Electrophysiological evidence of crossmodal correspondence between auditory pitch and visual elevation affecting inhibition of return

Inhibition of return (IOR) has proved to be weakened by audiovisual integration because of the increased perceptual salience of targets. Although other audiovisual interactions, such as crossmodal correspondence, have also been shown to facilitate attentional processes, to the best of our knowledge, no study has investigated the interaction between crossmodal correspondence and IOR. The present study employed Posner's spatial cueing paradigm and manipulated the cue validity, crossmodal correspondence congruency and time interval of auditory and visual stimuli (AV interval) to explore the effect of crossmodal correspondence on the IOR effect. The behavioral results showed a reduced IOR effect under the correspondence congruency condition in contrast to the correspondence incongruency condition at the AV interval of 200 ms, whereas at an AV interval of 80 ms, the decreased IOR effect under crossmodal correspondence congruency was eliminated. The electrophysiological results showed a reduced amplitude difference in P2 between valid and invalid cue conditions when the crossmodal correspondence effect decreased the IOR effect. The present study provided the first evidence of the weakened effect of the crossmodal correspondence effect on the IOR effect, which could be eliminated by audiovisual integration.

No evidence for rhythmic sampling in inhibition of return

When exogenously cued, attention reflexively reorients towards the cued position. After a brief dwelling time, attention is released and then persistently inhibited from returning to this position for up to three seconds, a phenomenon coined 'inhibition of return' (IOR). This inhibitory interpretation has shaped our understanding of the spatio-temporal dynamics of the attentional spotlight after an exogenous visual cue for more than three decades. However, a recent theory refines this traditional view and predicts that attention rhythmically alternates between possible target locations at a theta frequency, implying occasional returns of attention to the cued position. Unfortunately, previous IOR studies have only probed performance at a few, temporally wide-spread cue-target onset asynchronies (CTOAs) rendering a comparison of these contradictory predictions impossible. We therefore used a temporally fine-grained adaptation of the Posner paradigm with 25 equally and densely spaced CTOAs, which yielded a robust IOR effect in the reaction time difference between valid and invalidly cued trials. We modelled the time course of this effect across CTOAs as a linear or exponential decay (traditional IOR model), sinusoidal rhythm (rhythmic model) and a combination of both (hybrid model). Model comparison by means of goodness-of-fit indices provided strong evidence in favor of traditional IOR models, and against theta-rhythmic attentional sampling contributing to IOR. This finding was supported by an FFT analysis, which also revealed no significant theta rhythm. We therefore conclude that the spatio-temporal dynamics of attention following an exogenous cue cannot be explained by rhythmic attentional sampling.

Timing a fake punch: Inhibitory effects in a boxing-specific spatial attention task

The ability to respond quickly and accurately to spatial cues is of great importance to performance on any task where quick decision-making is required. The two main effects of spatial attention are priming, when a response to a target is facilitated after being cued at the same location, and inhibition of return (IOR), when the response to the target is slower to the cued area. Whether priming or IOR occurs is largely dependent on the length of the interval between the cue and the target. To determine whether these effects are relevant to dueling sports with deceptive actions we created a boxing-specific task that mimicked combinations of feints and punches. Altogether, we recruited 20 boxers and 20 non-boxers and found significantly longer reaction times to a punch thrown on the same side as a fake punch after a 600 ms interval, consistent with the IOR effect. We also found a moderate positive correlation between years of training and the magnitude of the IOR effect. This latter finding indicates that even athletes trained to avoid deception can be as susceptible as novices if the timing of the feint is right. Finally, our approach highlights the benefits of studying IOR using more sport specific settings, broadening the scope of the field.

The role of primary motor cortex in manual inhibition of return: A transcranial magnetic stimulation study

Inhibition of return (IOR) is a behavioural phenomenon characterised by longer response times (RTs) to stimuli presented at previously cued versus uncued locations. The neural mechanisms underlying IOR effects are not fully understood. Previous neurophysiological studies have identified a role of frontoparietal areas including posterior parietal cortex (PPC) in the generation of IOR, but the contribution of primary motor cortex (M1) has not been directly tested. The present study investigated the effects of single-pulse transcranial magnetic stimulation (TMS) over M1 on manual IOR in a key-press task where peripheral (left or right) targets followed a cue at the same or opposite location at different SOAs (100/300/600/1000 ms). In Experiment 1, TMS was applied over right M1 on a randomized 50% of trials. In Experiment 2, active or sham stimulation was provided in separate blocks. In the absence of TMS (non-TMS trials in Experiment 1 and sham trials in Experiment 2), evidence of IOR was observed in RTs at longer SOAs. In both experiments, IOR effects differed between TMS and non-TMS/sham conditions, but the effects of TMS were greater and statistically significant in Experiment 1 where TMS and non-TMS trials were randomly interspersed. The magnitude of motor-evoked potentials was not altered by the cue-target relationship in either experiment. These findings do not support a key role of M1 in the mechanisms of IOR but suggest the need for further research to elucidate the role of the motor system in manual IOR effects.

Inhibition of return as a foraging facilitator in visual search: Evidence from long-term training

Inhibition of return (IOR) discourages visual attention from returning to previously attended locations, and has been theorized as a mechanism to facilitate foraging in visual search by inhibitory tagging of inspected items. Previous studies using visual search and probe-detection tasks (i.e., the probe-following-search paradigm) found longer reaction times (RTs) for probes appearing at the searched locations than probes appearing at novel locations. This IOR effect was stronger in serial than parallel search, favoring the foraging facilitator hypothesis. However, evidence for this hypothesis was still lacking because no attempt was made to study how IOR would change when search efficiency gradually improves. The current study employed the probe-following-search paradigm and long-term training to examine how IOR varied following search efficiency improvements across training days. According to the foraging facilitator hypothesis, inhibitory tagging is an after-effect of attentional engagement. Therefore, when attentional engagement in a visual search task is reduced via long-term training, the strength of inhibitory tagging decreases, thus predicting a reduced IOR effect. Consistent with this prediction, two experiments consistently showed that IOR decreased while search efficiency improved through training, although IOR reached the floor more quickly than search efficiency. These findings support the notion that IOR facilitates search performance via stronger inhibitory tagging in more difficult visual search.

Levels of neuroticism can predict attentional performance during cross-modal nonspatial repetition inhibition

Inhibition of return (IOR) refers to the slower response to targets presented at previously attended locations, and such repetition-induced inhibition has been found to be differentially associated with personality traits. Although it has been well documented how personality traits affect spatial IOR, a mechanism associated with the attentional orienting network, there is not yet a consensus as to the relationship between personality traits and nonspatial repetition inhibition, a mechanism associated with the attentional executive network. The present study herein examined how the Big Five personality traits relate to cross-modal nonspatial repetition inhibition. Participants completed the NEO-PI-R and performed a cross-modal nonspatial repetition inhibition task built on the prime-neutral cue-target paradigm, in which the relationships of the identities and modalities between the prime and the target were manipulated. The results showed a significant nonspatial inhibitory effect and the effect was larger under the visual-auditory condition than under the auditory-visual condition. More importantly, neuroticism was associated with decreased cross-modal nonspatial inhibitory effect, presumably due to impaired attentional control. However, such a result was only found in the visual-auditory condition. We propose that retrieving previous prime representations under the visual-auditory condition requires a large consumption of cognitive resources, making inhibitory control more difficult for individuals with high neuroticism. These findings provide new insight into the influence of personality traits on attentional performance requiring nonspatial inhibitory control and enrich the relationship between neuroticism and repetition-induced inhibition.

The role of the parietal cortex in inhibitory processing in the vertical meridian: Evidence from elderly brain damaged patients

We explored the effects of parietal damage on inhibitory effects of visuospatial attention, inhibition of return (IOR) and inhibitory tagging (IT), in the vertical meridian. We combined a vertical spatial cue paradigm with a Stroop task employing three different temporal intervals between the spatial cue and the target (700, 1200 and 2000 ms) in two groups of patients, one with damage to the parietal cortex and underlying white matter (the parietal patients group) and the other with damage in other brain areas not including the parietal lobe (the control patient group), and a healthy control group. Healthy controls showed the expected inhibitory effects, IOR at the 700 and 1200 intervals and IT at the 1200 interval (as evidenced in a reduction in the magnitude of Stroop interference at the cued location). On the other hand, only the group of parietal patients showed delayed onset of inhibitory effects, IOR and IT appeared at the 1200 ms and 2000 ms intervals, respectively. These findings provide evidence for a role of the parietal cortex, and the underlying fibre tracts, in inhibitory processing in the vertical meridian, with damage to the parietal cortex altering the time course of attention-dependent inhibition.

Saccadic and manual response time data on inhibition of return during and after a visual search

In the present paper we present a dataset that provides data of two experiments in which we investigated the presence of Inhibition of Return (IOR) during and after a visual search. Participants either had to saccade (Experiment 1 and 2) or make a manual response (Experiment 2) to a probe during a visual search task (searching for a target letter among a set of distractors) or immediately after its completion. The data consist of the unprocessed raw data and one csv-file of the processed eye tracking data on eight (Experiment 1) and 18 (Experiment 2) participants, respectively. In total, we obtained 5,116 trials in Experiment 1 and 18,424 in Experiment 2. The data set is stored at the repository DOOR hosted by the University of Krems (https://door.donau-uni.ac.at/view/o:1014). Detailed information about the experiments and the interpretation of the data can be found in the paper “Post-search IOR: Searching for inhibition of return after search” (Höfler et al., 2019) [1].

Does temperament have a differential effect on Inhibition of Return (IOR)?

Reaction times to targets presented at previously stimulated locations are longer after some time (approx. 300 ms) than to targets presented in new locations. This effect is widely known as Inhibition of Return (IOR). It is typically explained in terms of an inhibitory bias against returning attention to places previously attended to and thus promoting attentional activity elsewhere. Regardless of its attentional character, IOR seems to encapsulate the interaction between two fundamental dimensions of temperament: engaging in versus inhibition and withdrawal from activity. Approaching IOR in this perspective, the question has arisen as to whether individual differences in reactivity as a temperamental trait express themselves in the time course and magnitude of this effect. 90 subjects (30 low, 30 medium and 30 highly reactive individuals) participated in the study. To the best of our knowledge, there are no other studies of individual differences in these parameters of IOR that use saccadic responses to measure its effect on behavior. The results show that in individuals who are higher in terms of their reactivity, IOR starts earlier and continues at the following SOAs but its magnitude is smaller than in less reactive individuals. The results are explained and discussed in light of the Regulative Theory of Temperament. This is the final version of the Abstract which has been accepted in the revised manuscript.

Spatio-temporal properties of oculomotor activation by multiple, simultaneous peripheral stimuli

Oculomotor research shows that eye movements are primed toward the midpoint of an array of visual stimuli, such that an eye movement to a visual target is executed most rapidly when it appears near the midpoint of an earlier array. At longer intervals between the prime and target, this facilitatory effect can reverse to become inhibitory - such that eye movements are slower when made toward the midpoint - but the source of this inhibition is unclear. One of our prior studies suggests a global source: target proximity to the midpoint determines inhibition, consistent with the notion that oculomotor activation is responsible for the effect and the original definition of inhibition of return. A later study suggests a local source: target proximity to the nearest array element determines inhibition, consistent with the notion that repeat stimulation of an input pathway is responsible. To resolve the ambiguity we systematically test whether timing differences between studies altered the source of the inhibition. We find that both previously observed patterns are reproducible depending on the prime offset - target onset asynchrony. We also resolve the discrepancy by showing that when this asynchrony is less than 200 ms, target proximity to the array's midpoint and its proximity to any given array element can jointly determine inhibition, whereas when the asynchrony is approximately 200 ms, inhibition is robust at the midpoint of the array. At longer asynchronies, all inhibitory effects rapidly dissipate.

Location-response binding and inhibition of return in a detection task

In the present study, we investigated the binding of location and response in a detection task of the target-target paradigm of inhibition of return (IOR). Results showed a cost of responding to a target at the repeated location (IOR) when the response was not repeated and an effect of facilitation of return (FOR) when the response was repeated. These findings suggest that when responding to a target, its location and the response to it are integrated together. In addition, an analysis of the Vincentized cumulative response time (RT) distribution further showed that memory retrieval of event representations requires time to operate. These findings were discussed according to the theoretical framework of event files.

Cerebellar lesions disrupt spatial and temporal visual attention

The current study represents the first comprehensive examination of spatial, temporal and sustained attention following cerebellar damage. Results indicated that, compared to controls, cerebellar damage resulted in a larger cueing effect at the longest SOA - possibly reflecting a slowed the onset of inhibition of return (IOR) during a reflexive covert attention task, and reduced the ability to detect successive targets during an attentional blink task. However, there was little evidence to support the notion that cerebellar damage disrupted voluntary covert attention or the sustained attention to response task (SART). Lesion overlay data and supplementary voxel-based lesion symptom mapping (VLSM) analyses indicated that impaired performance on the reflexive covert attention and attentional blink tasks were related to damage to Crus II of the left posterior cerebellum. In addition, subsequent analyses indicated our results are not due to either general motor impairments or to damage to the deep cerebellar nuclei. Collectively these data demonstrate, for the first time, that the same cerebellar regions may be involved in both spatial and temporal visual attention.

Predictive remapping leaves a behaviorally measurable attentional trace on eye-centered brain maps

How does the brain maintain spatial attention despite the retinal displacement of objects by saccades? A possible solution is to use the vector of an upcoming saccade to compensate for the shift of objects on eye-centered (retinotopic) brain maps. In support of this hypothesis, previous studies have revealed attentional effects at the future retinal locus of an attended object, just before the onset of saccades. A critical yet unresolved theoretical issue is whether predictively remapped attentional effects would persist long enough on eye-centered brain maps, so no external input (goal, expectation, reward, memory, etc.) is needed to maintain spatial attention immediately following saccades. The present study examined this issue with inhibition of return (IOR), an attentional effect that reveals itself in both world-centered and eye-centered coordinates, and predictively remaps before saccades. In the first task, a saccade was introduced to a cueing task ("nonreturn-saccade task") to show that IOR is coded in world-centered coordinates following saccades. In a second cueing task, two consecutive saccades were executed to trigger remapping and to dissociate the retinal locus relevant to remapping from the cued retinal locus ("return-saccade" task). IOR was observed at the remapped retinal locus 430-ms following the (first) saccade that triggered remapping. A third cueing task ("no-remapping" task) further revealed that the lingering IOR effect left by remapping was not confounded by the attention spillover. These results together show that predictive remapping leaves a robust attentional trace on eye-centered brain maps. This retinotopic trace is sufficient to sustain spatial attention for a few hundred milliseconds following saccades.

Inhibition of return: An information processing theory of its natures and significance

Inhibition of return (IOR) is an inhibitory aftereffect of visuospatial orienting, typically resulting in slower responses to targets presented in an area that has been recently attended. Since its discovery, myriad research has sought to explain the causes and effects underlying this phenomenon. Here, we briefly summarize the history of the phenomenon, and describe the early work supporting the functional significance of IOR as a foraging facilitator. We then shine a light on the discordance in the literature with respect to mechanism-in particular the lack of theoretical constructs that can consistently explain innumerable dissociations. We then describe three diagnostics (central arrow targets, locus of slack logic and the psychological refractory period, and performance in speed-accuracy space) used to support our theory that there are two forms of inhibition of return-the form which is manifest being contingent upon the activation state of the reflexive oculomotor system. The input form, which operates to decrease the salience of inputs, is generated when the reflexive oculomotor system is suppressed; the output form, which operates to bias responding, is generated when the reflexive oculomotor system is not suppressed. Then, we subject a published data set, wherein inhibitory effects had been generated while the reflexive oculomotor system was either active or suppressed, to diffusion modelling. As we hypothesized, based on the aforementioned theory, the effects of the two forms of IOR were best accounted for by different drift diffusion parameters. The paper ends with a variety of suggestions for further research.

Exploring the temporal dynamics of inhibition of return using steady-state visual evoked potentials

Inhibition of return is characterized by delayed responses to previously attended locations when the interval between stimuli is long enough. The present study employed steady-state visual evoked potentials (SSVEPs) as a measure of attentional modulation to explore the nature and time course of input- and output-based inhibitory cueing mechanisms that each slow response times at previously stimulated locations under different experimental conditions. The neural effects of behavioral inhibition were examined by comparing post-cue SSVEPs between cued and uncued locations measured across two tasks that differed only in the response modality (saccadic or manual response to targets). Grand averages of SSVEP amplitudes for each condition showed a reduction in amplitude at cued locations in the window of 100-500 ms post-cue, revealing an early, short-term decrease in the responses of neurons that can be attributed to sensory adaptation, regardless of response modality. Because primary visual cortex has been found to be one of the major sources of SSVEP signals, the results suggest that the SSVEP modulations observed were caused by input-based inhibition that occurred in V1, or visual areas earlier than V1, as a consequence of reduced visual input activity at previously cued locations. No SSVEP modulations were observed in either response condition late in the cue-target interval, suggesting that neither late input- nor output-based IOR modulates SSVEPs. These findings provide further electrophysiological support for the theory of multiple mechanisms contributing to behavioral cueing effects.

Social information rapidly prioritizes overt but not covert attention in a joint spatial cueing task

Coordinating actions with others is crucial for our survival. Our ability to see what others are seeing and to align our visual attention with them facilitates these joint actions. In the present research, we set out to increase our understanding of such joint attention by investigating the extent to which social information would be able to prioritize overt (when moving the eyes to attend) and covert (when shifting attention without eye movements) attention in a joint spatial cueing task. Participants saw a cue and detected a target at the same or a different location alongside an unseen partner of either higher or lower social rank. In a novel twist, participants were led to believe that the cue was connected to the gaze location of their partner. In Experiment 1, where participants were told to not move their eyes (covert attention), the partner's social rank did not change how quickly participants detected targets. But in Experiment 2, where participants were free to move their eyes naturally (overt attention), inhibition of return effects (slower responses to cued than uncued targets) were modulated by their partner's social rank. These social top-down effects occurred already at a short SOA of 150 ms. Our findings suggest that overt attention might provide a key tool for joint action, as it is penetrable for social information at the early stages of information processing.

Human electrophysiology reveals delayed but enhanced selection in inhibition of return

Visual environment tends to be stable over the short run. An immediately visited location often doesn't provide new information and can be safely inhibited, as exemplified by inhibition of return (IOR)-attention takes longer to return to a previously cued location. Attention selection at this inhibited location has been widely characterized as inferior, in which the target at the cued location has diminished salience, with lower rate of accumulation in the priority map for attention selection. We demonstrate here that an electrophysiology index of visual selection-the N2pc component-is delayed but enhanced at the cued than uncued location, and this enhancement in the N2pc amplitude predicts reduction in the behavioral IOR effect. By isolating a pure target N2pc, these results reveal an active attention enhancement mechanism that facilitates adaptive allocation of attention when a target appears at a previously cued location, potentially acting as a compensation mechanism for inhibition.

When do response-related episodic retrieval effects co-occur with inhibition of return?

At some point, spatial priming effects more faithfully reflect response selection processes than they do attentional orienting or sensory processes. Findings from the spatial cueing literature suggest that two factors may be critical: (1) the amount of identity processing that is required in order to respond correctly (feature-based response hypothesis), and (2) the amount of spatial processing that is required in order to respond correctly (space-based response hypothesis). To test the first hypothesis, we manipulated whether observers made single keypress detection or two-choice localization responses to serially presented stimuli in peripheral vision and whether stimulus identity information processing was necessary before responding. Responses were always slowest when the target location repeated, consistent with an attentional orienting bias independent of keypress responding (i.e., inhibition of return; IOR). The localization procedure revealed a subtle additional cost for changing the target location and repeating a response, consistent with a response-related episodic retrieval effect predicted by the Theory of Event Coding (TEC). Neither effect was modulated by the need to discriminate features. To test the second hypothesis, we made spatial processing indispensable to response selection by requiring a decision between a detection and localization response, depending on where the target appeared. IOR was eliminated for detection, but not localization, responses, consistent with the TEC. Collectively, the findings suggest that the amount of space-based, but not feature-based, processing that is required to determine a response is responsible for the response retrieval effects that can co-occur with IOR.

No evidence for an independent retinotopic reference frame for inhibition of return

Inhibition of return (IOR) represents a delay in responding to a previously inspected location and is viewed as a crucial mechanism that sways attention toward novelty in visual search. Although most visual processing occurs in retinotopic, eye-centered, coordinates, IOR must be coded in spatiotopic, environmental, coordinates to successfully serve its role as a foraging facilitator. Early studies supported this suggestion but recent results have shown that both spatiotopic and retinotopic reference frames of IOR may co-exist. The present study tested possible sources for IOR at the retinotopic location including being part of the spatiotopic IOR gradient, part of hemifield inhibition and being an independent source of IOR. We conducted four experiments that alternated the cue-target spatial distance (discrete and contiguous) and the response modality (manual and saccadic). In all experiments, we tested spatiotopic, retinotopic and neutral (neither spatiotopic nor retinotopic) locations. We did find IOR at both the retinotopic and spatiotopic locations but no evidence for an independent source of retinotopic IOR for either of the response modalities. In fact, we observed the spread of IOR across entire validly cued hemifield including at neutral locations. We conclude that these results indicate a strategy to inhibit the whole cued hemifield or suggest a large horizontal gradient around the spatiotopically cued location. PUBLIC SIGNIFICANCE STATEMENT: We perceive the visual world around us as stable despite constant shifts of the retinal image due to saccadic eye movements. In this study, we explore whether Inhibition of return (IOR), a mechanism preventing us from returning to previously attended locations, operates in spatiotopic, world-centered or in retinal, eye-centered coordinates. We tested both saccadic and manual IOR at spatiotopic, retinotopic, and control locations. We did not find an independent retinotopic source of IOR for either of the response modalities. The results suggest that IOR spreads over the whole previously attended visual hemifield or there is a large horizontal spatiotopic gradient. The current results are in line with the idea of IOR being a foraging facilitator in visual search and contribute to our understanding of spatiotopically organized aspects of visual and attentional systems.

The role of transients in action observation

A large number of studies have now described the various ways in which the observation of another person's dynamic movement can influence the speed with which the observer is able to prepare a motor action themselves. The typical results are most often explained with reference to theories that link perception and action. Such theories argue that the cognitive structures associated with each share common representations. Consequently, action preparation and action observation are often said to be functionally equivalent. However, the dominance of these theories in explaining action observation effects has masked the potential contribution from processes associated with the detection of low-level "transients" resulting from observing a body movement, such as motion and sound. In the present review, we describe work undertaken in one particular action observation phenomenon ("social inhibition of return") and show that the transient account provides the best explanation of the effect. We argue that future work should consider attention capture and orienting as a potential contributing factor to action observation effects more broadly.

Return sweeps in reading: Processing implications of undersweep-fixations

Models of eye-movement control during reading focus on reading single lines of text. However, with multiline texts, return sweeps, which bring fixation from the end of one line to the beginning of the next, occur regularly and influence ~20% of all reading fixations. Our understanding of return sweeps is still limited. One common feature of return sweeps is the prevalence of oculomotor errors. Return sweeps, often initially undershoot the start of the line. Corrective saccades then bring fixation closer to the line start. The fixation occurring between the undershoot and the corrective saccade (undersweep-fixation) has important theoretical implications for the serial nature of lexical processing during reading, as they occur on words ahead of the intended attentional target. Furthermore, since the attentional target of a return sweep will lie far outside the parafovea during the prior fixation, it cannot be lexically preprocessed during this prior fixation. We explore the implications of undersweep-fixations for ongoing processing and models of eye movements during reading by analysing two existing eye-movement data sets of multiline reading.

Time course of the inhibitory tagging effect in ongoing emotional processing. A HD-tDCS study

When a cueing procedure that usually triggers inhibition of return (IOR) effects is combined with tasks that tap semantic processing, or involve response-based conflict, an inhibitory tagging (IT) emerges that disrupts responses to stimuli at inhibited locations. IT seems to involve the executive prefrontal cortex, mainly the left dorsolateral prefrontal cortex (DLPFC), in cognitive conflict tasks. Contrary to other inhibitory effects, IT has been observed with rather short intervals, concretely when the stimulus onset asynchrony (SOA) between the prime presented at the cued location, and the subsequent target is 250 ms. Here we asked whether IT is also applied to ongoing emotional processing, and whether the left DLPFC plays a causal role in IT using HD-tDCS. In two experiments with an emotional conflict task, we observed reduced conflict effects, the signature of IT, when the prime word was presented at the cued location, and once again when the prime-target SOA was just 250 ms. Also, the IT effect was eliminated when cathodal stimulation was applied to the left DLPFC. These findings suggest that the IT effect involves areas of the executive attention network and cooperates with IOR to favor attentional allocation to novel unexplored objects/locations, irrespective of their emotional content.

Post-search IOR: Searching for inhibition of return after search

Previous research has indicated that Inhibition of return (IOR) supports visual search by discouraging the re-inspection of recently inspected items during search. However, it is not clear whether IOR persists after a search is completed or whether this depends on the presence of a further search in the same display. To investigate this issue, we had participants search consecutively twice in the same display (Experiment 1). Immediately after the end of the first search and after the end of the second search we probed an item which had been recently inspected or not in the previous search. The results showed that IOR as measured by the saccadic latency to the probed items was absent after the end of each of the two successive searches. In Experiment 2, we measured both saccadic latencies and manual responses in a single-search paradigm. We found that IOR during and after the search was present for saccadic responses but absent for manual responses. This suggests that IOR during and after a visual search depends on the modality of the response and the number of required searches.

The gap effect reduces both manual and saccadic inhibition of return (IOR)

Inhibition of return (IOR) is the effect of slower responses to validly than invalidly cued targets. The discovery of IOR raised controversy as to whether it has two “flavors”, i.e., attentional/perceptual and motoric, or whether it is a homogeneous visual-motor phenomenon that should be understood in terms of the preparation of different effectors (mainly eye movement). Since manipulation of fixation offset (0 and 200 ms gap) is believed to affect the latency of saccades, we measured its influence on saccadic and manual IOR with a simple keypress response when eye movements were forbidden. In the two experiments which we carried out, the fixation offset decreased IOR in both the saccadic and the manual conditions. The results suggest the limitations of the attentional hypothesis, which assumes that manual IOR is independent of the motoric component; they are also in line with the tenets of the oculomotor hypothesis of IOR.

Bimodal-divided attention attenuates visually induced inhibition of return with audiovisual targets

Inhibition of return (IOR) refers to the slower response to a target appearing at a previously attended location in a cue-target paradigm. It has been greatly explored in the visual or auditory modality. This study investigates differences between the IOR of audiovisual targets and the IOR of visual targets under conditions of modality-specific selective attention (Experiment 1) and divided-modalities attention (Experiment 2). We employed an exogenous spatial cueing paradigm and manipulated the modalities of targets, including visual, auditory, or audiovisual modalities. The participants were asked to detect targets in visual modality or both visual and auditory modalities, which were presented on the same (cued) or opposite (uncued) side as the preceding visual peripheral cues. In Experiment 1, we found the comparable IOR with visual and audiovisual targets when participants were asked to selectively focus on visual modality. In Experiment 2, however, there was a smaller magnitude of IOR with audiovisual targets as compared with visual targets when paying attention to both visual and auditory modalities. We also observed a reduced multisensory response enhancement effect and race model inequality violation at cued locations relative to uncued locations. These results provide the first evidence of the IOR with audiovisual targets. Furthermore, IOR with audiovisual targets decreases when paying attention to both modalities. The interaction between exogenous spatial attention and audiovisual integration is discussed.

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.

The contribution of forward masking to saccadic inhibition of return

Inhibition of return is the name typically given to the prolonged latency of motor responses directed to a previously cued target location. There is intense debate about the origins of this effect and its function, but most take for granted (despite lack of evidence) that it depends little on forward masking. Therefore, we re-examined the role of forward masking in inhibition of return. Forward masking was indexed by slower saccadic reaction times (SRTs) when the target orientation repeated the cue orientation at the same location. We confirmed effects of orientation repetition in the absence of an attentional bias when cues were presented on both sides of fixation (bilateral presentation). The effect of orientation repetition was reduced with high target contrast, consistent with a low-level origin such as contrast gain control in early visual areas. When presenting cues on only one side of fixation (unilateral presentation), we obtained inhibition of return with longer cue-target intervals and facilitation with targets presented shortly after the cue. The effect of orientation repetition was reduced when facilitation was observed, but was as strong as with bilateral cues when inhibition of return was observed. Therefore, forward masking may contribute to the inhibition of return effect by delaying reaction times to repeated features at the same location, but is not a principal cause of inhibition of return; in agreement with previous views.

SIGNIFICANCE STATEMENT

The saccadic inhibition of return effect is a reaction-time cost when responding to a pre-cued location. Additional object updating costs are typically invoked to explain reaction-time costs observed when cue and target have the same shape. Yet, lower-level, forward masking of the target by the cue can not be ruled out. Importantly, we show an effect of orientation repetition that is consistent with low-level forward masking rather than object updating costs and that does not interact with inhibition of return.

Electrophysiological evidence of an attentional bias in crossmodal inhibition of return

Inhibition of return (IOR) refers to a delay in responding to targets when they appear at recently attended locations, relative to unattended locations. Within the visual modality, this attentional bias has been associated with a reduction in the N2pc event-related potential (ERP) component at previously attended locations. The present study examined whether a similar attentional bias was observed in crossmodal audio-visual IOR. Our results demonstrate that for visual targets, the attentional component of IOR behaves similarly for both unimodal and crossmodal target pairs, as indexed by a reduction in the N2pc component for targets appearing at previously attended locations. Further, similar IOR-related modulations on the auditory-evoked N2ac indicated that an attentional bias can be observed for auditory targets as well. Finally, we identified two additional ERP components - the ACOP and VCAN - that appear to reflect biasing of attention in the currently unattended sensory modality. These results suggest that the inhibitory attentional bias that underlies the IOR effect may be supramodal and bias attention away from previously attended locations regardless of sensory modality.

Time course of inhibition of return in a spatial cueing paradigm with distractors

Studies of endogenous and exogenous attentional orienting in spatial cueing paradigms have been used to investigate inhibition of return, a behavioral phenomenon characterized by delayed reaction time in response to recently attended locations. When eye movements are suppressed, attention is covertly oriented to central or peripheral stimuli. Overt orienting, on the other hand, requires explicit eye movements to the stimuli. The present study examined the time course of slowed reaction times to previously attended locations when distractors are introduced into overt and covert orienting tasks. In a series of experiments, manual responses were required to targets following central and peripheral cues at three different cue-target intervals, with and without activated oculomotor systems. The results demonstrate that, when eye movements are suppressed, behavioral inhibition is reduced or delayed in magnitude by the presence of a distractor relative to conditions without distractors. However, the time course of behavioral inhibition when eye movements are required remains similar with or without distractors.

Out with the new, in with the old: Exogenous orienting to locations with physically constant stimulation

Dominant methods of investigating exogenous orienting presume that attention is captured most effectively at locations containing new events. This is evidenced by the ubiquitous use of transient stimuli as cues in the literature on exogenous orienting. In the present study, we showed that attention can be oriented exogenously toward a location containing a completely unchanging stimulus by modifying Posner's landmark exogenous spatial-cueing paradigm. Observers searched a six-element array of placeholder stimuli for an onset target. The target was preceded by a decrement in luminance to five of the six placeholders, such that one location remained physically constant. This "nonset" stimulus (so named to distinguish it from a traditional onsetting transient) acted as an exogenous cue, eliciting patterns of facilitation and inhibition at the nonset location and demonstrating that exogenous orienting is not always evident at the location of a visual transient. This method eliminates the decades-long confounding of orienting to a location with the processing of new events at that location, permitting alternative considerations of the nature of attentional selection.

Inhibition of return for body images in individuals with shape/weight based self-worth

BACKGROUND

Attentional biases for body shape and weight information have been found in people with eating disorders, indicating disorder-specific changes in the way this information is processed. To date, the literature has focused on the initial capture of attention, with little research on the maintenance of attention to shape/weight-related information. The current study aims to investigate the occurrence of attentional maintenance through the use of an Inhibition of Return task to shape and weight stimuli in those with and without an eating disorder.

METHOD

Three groups of female participants between the ages of 16-30 years undertook an Inhibition of Return task with target images of female bodies and control images of animals. The groups were an eating disorder group (n = 20), a High shape/weight based self-worth group (n = 23), and a Low shape/weight based self-worth group (n = 26).

RESULTS

The results indicated differential patterns of Inhibition of Return between the High and Low shape/weight based self-worth groups. The High group displayed increased inhibition of return for the shape/weight stimuli relative to control stimuli, while the Low group displayed reduced inhibition of return for the shape/weight stimuli compared to control stimuli. The ED group displayed a similar pattern of results to the High group, but this did not reach significance.

CONCLUSION

The current findings indicate that young women without an eating disorder who base their self-worth on shape/weight display a pattern of avoidance of shape/weight stimuli that is in direct contrast to those at low risk of developing eating disorders. The possible implications of these specific patterns of inhibition of return across those at varying levels of risk for an eating disorder are discussed along with their implications for intervention approaches.

Placeholders dissociate two forms of inhibition of return

Decades of research using Posner's classic spatial cueing paradigm has uncovered at least two forms of inhibition of return (IOR) in the aftermath of an exogenous, peripheral orienting cue. One prominent dissociation concerns the role of covert and overt orienting in generating IOR effects that relate to perception- and action-oriented processes, respectively. Another prominent dissociation concerns the role of covert and overt orienting in generating IOR effects that depend on object- and space-based representation, respectively. Our objective was to evaluate whether these dichotomies are functionally equivalent by manipulating placeholder object presence in the cueing paradigm. By discouraging eye movements throughout, Experiments 1A and 1B validated a perception-oriented form of IOR that depended critically on placeholders. Experiment 2A demonstrated that IOR was robust without placeholders when eye movements went to the cue and back to fixation before the manual response target. In Experiment 2B, we replicated Experiment 2A's procedures except we discouraged eye movements. IOR was observed, albeit only weakly and significantly diminished relative to when eye movements were involved. We conclude that action-oriented IOR is robust against placeholders but that the magnitude of perception-oriented IOR is critically sensitive to placeholder presence when unwanted oculomotor activity can be ruled out.

Social Beliefs and Visual Attention: How the Social Relevance of a Cue Influences Spatial Orienting

We are highly tuned to each other's visual attention. Perceiving the eye or hand movements of another person can influence the timing of a saccade or the reach of our own. However, the explanation for such spatial orienting in interpersonal contexts remains disputed. Is it due to the social appearance of the cue—a hand or an eye—or due to its social relevance—a cue that is connected to another person with attentional and intentional states? We developed an interpersonal version of the Posner spatial cueing paradigm. Participants saw a cue and detected a target at the same or a different location, while interacting with an unseen partner. Participants were led to believe that the cue was either connected to the gaze location of their partner or was generated randomly by a computer (Experiment 1), and that their partner had higher or lower social rank while engaged in the same or a different task (Experiment 2). We found that spatial cue‐target compatibility effects were greater when the cue related to a partner's gaze. This effect was amplified by the partner's social rank, but only when participants believed their partner was engaged in the same task. Taken together, this is strong evidence in support of the idea that spatial orienting is interpersonally attuned to the social relevance of the cue—whether the cue is connected to another person, who this person is, and what this person is doing—and does not exclusively rely on the social appearance of the cue. Visual attention is not only guided by the physical salience of one's environment but also by the mental representation of its social relevance.

Peripheral stimuli generate different forms of inhibition of return when participants make prosaccades versus antisaccades to them

Inhibition of return (IOR) is usually viewed as an inhibitory aftermath of visual orienting typically seen in the form of slower responses to targets presented in a previously oriented to location. As shown by Taylor and Klein (2000. Journal of Experimental Psychology: Human Perception and Performance, 26, 1639-1656), the nature of the inhibitory effects resulting from an uninformative cue seem to be contingent on the activation state of the oculomotor system. Here we contrast target discrimination performance following either a prosaccade or antisaccade in the spatial cueing paradigm. Our findings suggest that the level of activation of the reflexive oculomotor system determines the dynamics of the inhibitory effect, wherein an effect nearer to the input end of processing is observed when the reflexive oculomotor system is actively suppressed, and an effect nearer to the output end of processing is observed when the reflexive oculomotor system is actively engaged. These effects interact differently with the Simon effect-providing converging evidence that they are dissociable inhibitory phenomena.

Spatial negative priming: Location or response?

In tasks requiring a response to the location of a target stimulus (for example, reaching), responses often are slower to a location that was recently occupied by an irrelevant distractor stimulus. In most demonstrations of this "spatial negative priming" (SNP), there is a 1-to-1 correspondence between possible stimulus locations and possible responses. As such, it is ambiguous whether the effect is due to a location-specific processing delay or to inhibition of a response. In the present experiment, subjects were required to press a key corresponding to the ordinal position of a target O in one of four locations, ignoring a distractor X appearing in another location. Location markers were widely or narrowly spaced, such that the inner two locations of wide displays corresponded to the outer two locations of narrow displays (hence, requiring different responses). SNP occurred when a target appeared at the location of a recent distractor, regardless of whether the response was associated with the distractor. In contrast, no SNP occurred for a target sharing the same response as a distractor, but in a different location. The results strongly support a location-specific, rather than response-specific, locus of SNP.

A comprehensive look at phobic fear in inhibition of return: Phobia-related spiders as cues and targets

BACKGROUND AND OBJECTIVES

The so called inhibition of return (IOR) effect refers to a bias against returning attention to a location which was previously investigated. Because emotionally salient material has the capacity to capture and hold attention it has been suggested that this material may disrupt this otherwise impressively stable phenomenon.

METHODS

40 students participated in the experiment. Black and white schematic drawings of a spider, a butterfly or a cross were used as cues. A black dot, a spider, a butterfly or a cross were used as targets. Participants were required to press a key whenever the target picture appeared. Subsequently, they rated the pictures on valence and arousal.

RESULTS

Results showed that the IOR effect remained stable and did not diminish with either fear-related cues or fear-related targets. This data adds strong arguments for the stability of IOR.

LIMITATIONS

The spider fearful participants were not diagnosed patients. They still meet the criteria for spider fear but follow-up studies should pursue the same question with a specific focus on participants' levels of anxiety.

CONCLUSIONS

This study is a contribution to the debate on how emotions affect or do not affect attentional processes such as the IOR. IOR appears to be a robust phenomenon and the emotional valence of neither the cue nor the emotional valence of the target can override it.

Stimulus-response incompatibility eliminates inhibitory cueing effects with saccadic but not manual responses

There are thought to be two forms of inhibition of return (IOR) depending on whether the oculomotor system is activated or suppressed. When saccades are allowed, output-based IOR is generated, whereas input-based IOR arises when saccades are prohibited. In a series of 4 experiments, we mixed or blocked compatible and incompatible trials with saccadic or manual responses to investigate whether cueing effects would follow the same pattern as those observed with more traditional peripheral onsets and central arrows. In all experiments, an uninformative cue was displayed, followed by a cue-back stimulus that was either red or green, indicating whether a compatible or incompatible response was required. The results showed that IOR was indeed observed for compatible responses in all tasks, whereas IOR was eliminated for incompatible trials-but only with saccadic responses. These findings indicate that the dissociation between input- and output-based forms of IOR depends on more than just oculomotor activation, providing further support for the existence of an inhibitory cueing effect that is distinct to the manual response modality.

Object files across eye movements: Previous fixations affect the latencies of corrective saccades

One of the factors contributing to a seamless visual experience is object correspondence-that is, the integration of pre- and postsaccadic visual object information into one representation. Previous research had suggested that before the execution of a saccade, a target object is loaded into visual working memory and subsequently is used to locate the target object after the saccade. Until now, studies on object correspondence have not taken previous fixations into account. In the present study, we investigated the influence of previously fixated information on object correspondence. To this end, we adapted a gaze correction paradigm in which a saccade was executed toward either a previously fixated or a novel target. During the saccade, the stimuli were displaced such that the participant's gaze landed between the target stimulus and a distractor. Participants then executed a corrective saccade to the target. The results indicated that these corrective saccades had lower latencies toward previously fixated than toward nonfixated targets, indicating object-specific facilitation. In two follow-up experiments, we showed that presaccadic spatial and object (surface feature) information can contribute separately to the execution of a corrective saccade, as well as in conjunction. Whereas the execution of a corrective saccade to a previously fixated target object at a previously fixated location is slowed down (i.e., inhibition of return), corrective saccades toward either a previously fixated target object or a previously fixated location are facilitated. We concluded that corrective saccades are executed on the basis of object files rather than of unintegrated feature information.

Social-Emotional Inhibition of Return in Children with Autism Spectrum Disorder Versus Typical Development

In typical development there is a bias to orient visual attention to social information. Children with ASD do not reliably demonstrate this bias, and the role of attention orienting has not been well studied. We examined attention orienting via the inhibition of return (IOR) mechanism in a spatial cueing task using social-emotional cues; we studied 8- to 17-year-old children with ASD (n = 41) and typically developing controls (TDC) (n = 25). The ASD group exhibited a significantly stronger IOR effect than the TDC group, and the IOR effect correlated positively with social impairments but was unrelated to co-occurring ADHD or anxiety symptoms. The results provide evidence of an early altered attention mechanism that is associated with to core social deficits in ASD.

Adverse orienting effects on visual working memory encoding and maintenance

Visual working memory (VWM) representations can be strengthened by pre-cues presented before, and retro-cues presented after, the memory display, providing evidence that attentional orienting plays a role in memory encoding and maintenance. It is unknown whether attentional orienting to VWM stimuli can also have adverse effects (known as inhibition of return; IOR), as has been found for perceptual-cueing tasks. If so, this would provide further evidence for common attentional orienting mechanisms for mnemonic and perceptual representations. In Experiment 1, we used pre-cueing and demonstrated an increased encoding probability, but not precision, at short SOAs, but probability decreased at long SOAs, reminiscent of the classic IOR findings. In Experiment 2, we used retro-cueing and showed that it improved memory performance, unless attention was cued back to the center of the display by a second cue. In this case, the deleterious effects were on precision, indicating that the item was still retained, but its quality of representation suffered. Together, these results provide further evidence for universal spatial attentional mechanisms operating on perceptual as well as mnemonic representations.

Influence of initial fixation position in scene viewing

During scene perception our eyes generate complex sequences of fixations. Predictors of fixation locations are bottom-up factors such as luminance contrast, top-down factors like viewing instruction, and systematic biases, e.g., the tendency to place fixations near the center of an image. However, comparatively little is known about the dynamics of scanpaths after experimental manipulation of specific fixation locations. Here we investigate the influence of initial fixation position on subsequent eye-movement behavior on an image. We presented 64 colored photographs to participants who started their scanpaths from one of two experimentally controlled positions in the right or left part of an image. Additionally, we used computational models to predict the images' fixation locations and classified them as balanced images or images with high conspicuity on either the left or right side of a picture. The manipulation of the starting position influenced viewing behavior for several seconds and produced a tendency to overshoot to the image side opposite to the starting position. Possible mechanisms for the generation of this overshoot were investigated using numerical simulations of statistical and dynamical models. Our model comparisons show that inhibitory tagging is a viable mechanism for dynamical planning of scanpaths.

Revisiting the global effect and inhibition of return

Saccades toward previously cued locations have longer latencies than saccades toward other locations, a phenomenon known as inhibition of return (IOR). Watanabe (Exp Brain Res 138:330–342. doi:10.1007/s002210100709, 2001) combined IOR with the global effect (where saccade landing points fall in between neighboring objects) to investigate whether IOR can also have a spatial component. When one of two neighboring targets was cued, there was a clear bias away from the cued location. In a condition where both targets were cued, it appeared that the global effect magnitude was similar to the condition without any cues. However, as the latencies in the double cue condition were shorter compared to the no cue condition, it is still an open question whether these results are representative for IOR. Considering the double cue condition can provide valuable insight into the interaction of the mechanisms underlying the two phenomena, here, we revisit this condition in an adapted paradigm. Our paradigm does result in longer latencies for the cued locations, and we find that the magnitude of the global effect is reduced significantly. Unexpectedly, this holds even when only including saccades with the same latencies for both conditions. Thus, the increased latencies associated with IOR cannot directly explain the reduction in global effect. The global effect reduction can likely best be seen as either a result of short-term depression of exogenous visual signals or a result of IOR established at the center of gravity of cues.

Spatial inhibition of return as a function of fixation history, task, and spatial references

In oculomotor selection, each saccade is thought to be automatically biased toward uninspected locations, inhibiting the inefficient behavior of repeatedly refixating the same objects. This automatic bias is related to inhibition of return (IOR). Although IOR seems an appealing property that increases efficiency in visual search, such a mechanism would not be efficient in other tasks. Indeed, evidence for additional, more flexible control over refixations has been provided. Here, we investigated whether task demands implicitly affect the rate of refixations. We measured the probability of refixations after series of six binary saccadic decisions under two conditions: visual search and free viewing. The rate of refixations seems influenced by two effects. One effect is related to the rate of intervening fixations, specifically, more refixations were observed with more intervening fixations. In addition, we observed an effect of task set, with fewer refixations in visual search than in free viewing. Importantly, the history-related effect was more pronounced when sufficient spatial references were provided, suggesting that this effect is dependent on spatiotopic encoding of previously fixated locations. This known history-related bias in gaze direction is not the primary influence on the refixation rate. Instead, multiple factors, such as task set and spatial references, assert strong influences as well.

Inhibitory cueing effects following manual and saccadic responses to arrow cues

With two cueing tasks, in the present study we examined output-based inhibitory cueing effects (ICEs) with manual responses to arrow targets following manual or saccadic responses to arrow cues. In all experiments, ICEs were observed when manual localization responses were required to both the cues and targets, but only when the cue-target onset asynchrony (CTOA) was 2,000 ms or longer. In contrast, when saccadic responses were made in response to the cues, ICEs were only observed with CTOAs of 2,000 ms or less-and only when an auditory cue-back signal was used. The present study also showed that the magnitude of ICEs following saccadic responses to arrow cues decreased with time, much like traditional inhibition-of-return effects. The magnitude of ICEs following manual responses to arrow cues, however, appeared later in time and had no sign of decreasing even 3 s after cue onset. These findings suggest that ICEs linked to skeletomotor activation do exist and that the ICEs evoked by oculomotor activation can carry over to the skeletomotor system.

Visual perception is dependent on visuospatial working memory and thus on the posterior parietal cortex

Visual perception involves complex and active processes. We will start by explaining why visual perception is dependent on visuospatial working memory, especially the spatiotemporal integration of the perceived elements through the ocular exploration of visual scenes. Then we will present neuropsychology, transcranial magnetic stimulation and neuroimaging data yielding information on the specific role of the posterior parietal cortex of the right hemisphere in visuospatial working memory. Within the posterior parietal cortex, neuropsychology data also suggest that there might be dissociated neural substrates for deployment of attention (superior parietal lobules) and spatiotemporal integration (right inferior parietal lobule).

When do fearful faces override inhibition of return?

Inhibition of return (IOR) occurs when more than about 300 ms elapses between the cue and the target in atypical peripheral cueing task: reaction times (RTs) become longer when the cue and target locations are the same versus different. IOR could serve the adaptive role of optimizing visual search by discouraging the re-inspection of previously attended locations. As such, IOR should not reduce our chances of noticing relevant event information and emotional stimuli, in particular. However, previous studies have led to inconsistent results. The present study offers a systematic investigation of the conditions under which target fearful faces can modulate either the magnitude or the time course of the IOR effect. Notably, we manipulated the depth of facial processing required to perform the task and/or the task relevance of the facial expressions. When participants localized target faces (Experiment 1) or discriminated them from non-face stimuli (Experiment 2), their emotional expression had no impact on IOR whatsoever. However, IOR occurred later for fearful versus neutral faces when the participants performed emotion (Experiment 3) or gender (Experiment 4) discrimination tasks. These findings are discussed with regard to the mechanisms responsible for IOR and to the processing of emotional facial expressions.

Inhibition of return and attentional facilitation: Numbers can be counted in, letters tell a different story

Prior research has provided strong evidence for spatial-numerical associations. Single digits can for instance act as attentional cues, orienting visuo-spatial attention to the left or right hemifield depending on the digit's magnitude, thus facilitating target detection in the cued hemifield (left/right hemifield after small/large digits, respectively). Studies using other types of behaviourally or biologically relevant central cues known to elicit automated symbolic attention orienting effects such as arrows or gaze have shown that the initial facilitation of cued target detection can turn into inhibition at longer stimulus onset asynchronies (SOAs). However, no studies so far investigated whether inhibition of return (IOR) is also observed using digits as uninformative central cues. To address this issue we designed an attentional cueing paradigm using SOAs ranging from 500 ms to 1650 ms. As expected, the results showed a facilitation effect at the relatively short 650 ms SOA, replicating previous findings. At the long 1650 ms SOA, however, participants were faster to detect targets in the uncued hemifield compared to the cued hemifield, showing an IOR effect. A control experiment with letters showed no such congruency effects at any SOA. These findings provide the first evidence that digits not only produce facilitation effects at shorter intervals, but also induce inhibitory effects at longer intervals, confirming that Arabic digits engage automated symbolic orienting of attention.