Inhibition Of Return Mechanism Research Articles

A computational framework for attentional object discovery in RGB-D videos.

We present a computational framework for attention-guided visual scene exploration in sequences of RGB-D data. For this, we propose a visual object candidate generation method to produce object hypotheses about the objects in the scene. An attention system is used to prioritise the processing of visual information by (1) localising candidate objects, and (2) integrating an inhibition of return (IOR) mechanism grounded in spatial coordinates. This spatial IOR mechanism naturally copes with camera motions and inhibits objects that have already been the target of attention. Our approach provides object candidates which can be processed by higher cognitive modules such as object recognition. Since objects are basic elements for many higher level tasks, our architecture can be used as a first layer in any cognitive system that aims at interpreting a stream of images. We show in the evaluation how our framework finds most of the objects in challenging real-world scenes.

Exploring the effect of stimulus characteristics on location-based inhibition of return using abrupt and ramped stimulus presentation

A recent study illustrating the importance of sensory influences on inhibition of return (IOR) found stimuli biased towards the parvocellular (P) pathway produced greater IOR while stimuli biased towards the magnocellular (M) pathway produced less IOR (Brown, 2009; Guenther & Brown, 2007). The present study used a different sensory manipulation (temporal onset/offset) to further explore this relationship. Greater M activity was expected when stimuli were presented abruptly (M-biased) compared to when stimuli were ramped on and off (P-biased). Consistent with our recent findings, greater location-based IOR was found under ramped vs. abrupt conditions. The results showed location-based IOR is influenced by the nature of stimulus presentation (ramped vs. abrupt) providing convergent evidence of an IOR mechanism sensitive to M- and P-biased stimuli.

DEFICIENT INHIBITION OF RETURN IN SUBCLINICAL OCD ONLY WHEN ATTENTION IS DIRECTED TO THE THREATENING ASPECTS OF A STIMULUS

Inhibition of return (IOR) is thought to reflect inhibition of previously attended but irrelevant stimuli. Deficient IOR would increase the likelihood of revisiting previously searched locations or objects, thus leading to unproductive perseverations. Therefore, using a novel IOR task, we investigated whether high scoring checkers attentional biases to threat would result in dysfunctional inhibitory functioning compared to low checkers. In two tasks, we compared 53 subclinical high and 49 low checkers regarding IOR effects for stimuli that were concordant with the concerns of high but not of low checkers (electrical kitchen appliances: e.g., toaster, kettle). The difference between the two tasks was the cueing procedure. In one task, an appliance was switched "ON" and "OFF" as an unpredictive cue, drawing attention to the functionality of the stimulus. In this task, IOR was specifically attenuated in high checkers. In the other task, however, the cue was more abstract in form of a yellow outline that appeared around one of two appliances. Although the appliance was either "ON" or "OFF," this did not seem to matter and high checkers revealed a typical IOR pattern similar to low checkers. We conclude that IOR mechanisms might not be generally deficient in high checkers; rather only when attention is drawn to the threatening aspects of ecologically valid stimuli, then disengagement of attention is deficient in high checkers. We make suggestions on how our task-specific findings may inform cognitive interventions that target attentional control in the treatment of checking/obsessive-compulsive disorder.

Biasing the organism for novelty: A pervasive property of the attention system

Although the functional and anatomical independences between the orienting and the executive attention networks have been well established, surprisingly little is known about the potential neural interaction between them. Recent studies point out that spatial inhibition of return (IOR), a mechanism associated with the orienting network, and nonspatial inhibition of return, a mechanism associated with the executive network, might bias the organism for novel locations and objects, respectively. By orthogonally combining the spatial and the nonspatial IOR paradigms in this fMRI study, we demonstrate that the orienting and the executive networks interact and compensate each other in biasing the attention system for novelty. Behaviorally, participants responded slower to the target at the old location only when the color of the target was novel, and participants responded slower to the old color representation only when the target appeared at a novel spatial location. Neurally, the orienting network was involved in slowing down responses to the old location only when the nonspatial IOR mechanism in the executive network was not operative (i.e., when the color of the target was novel); the prefrontal executive network was involved in slowing down responses to the old color representation only when the spatial IOR mechanism in the orienting network was not functioning (i.e., when the target appeared at a novel location).

Effects of Supra- and Sub-liminal Emotional Cues on Inhibition of Return

In the classical exogenous cue-target paradigm, when a target is presented in the same location as a cue within a stimulus onset asynchrony (SOA) of 250 ms or less, target detection is facilitated. However, when the SOA is extended to more than 250 ms, target detection is slowed at the cued location. This phenomenon is called inhibition of return (IOR). IOR is generally assumed to be an adaptive mechanism which enhances the chance of success or survival by maximizing the chance of detecting important information in visual search during human evolution. If so, the time course and/or magnitude of IOR may be affected by biological information of the cue. If a cue provides information relevant to individual’s survival, then attention may not be inhibited from reorienting to the cue. However, previous evidence concerning this issue is controversial. This study is to further examine whether IOR is modulated by emotional valences of face, which convey important biological and social information. We hypothesized that emotional information conveyed through supraliminally presented face cues may not differentially affect the IOR effect, because this information could be suppressed by the top-down control settings demanding no interference from emotion, whereas emotional information conveyed through subliminally presented face cues may affect pattern of the IOR effect, because this information is processed automatically and it escapes from top-down suppression. A total of 32 undergraduate students participated in Experiments 1 and 2, which manipulated the number of simultaneously cued locations. Faces with different emotional valences (happy, angry and neutral) were as uninformative peripheral cues, supraliminally in Experiment 1 and subliminally in Experiment 2, while the participants were instructed to make detection responses to the target, which was presented at one of the cued locations or at an uncued location, as quickly and accurately as possible. Experiment 1 obtained an overall IOR effect but the magnitude of this effect was not affected by the emotional valences of face cues. Experiment 2 obtained a significant IOR effect, but only for the neutral face cues. These findings are consistent with our hypothesis, suggesting that IOR can be modulated by the property of biologically important cues. The evolutionary significance of the IOR mechanism was discussed.

Social inhibition of return

Responses to a target stimulus can be slower when it appears in the same rather than a different location to a previous event, an effect known as inhibition of return (IOR). Recently, it has been shown that when two people alternate responses to a target, one person’s responses are slower when they are directed to the same locations as their partner’s previous response. The present study sought to investigate this highly novel effect, which we term social IOR (SIOR), in relation to what is known of IOR in individuals performing alone. We found that only a real conspecific can induce SIOR in another person, whereas an animated conspecific cannot. Additionally, SIOR emerges at locations to which a conspecific has been inferred to respond, even when direct observation of his/her responses is prevented. Finally, SIOR can be induced without the abrupt visual transients normally associated with the generation of IOR. These findings suggest that SIOR is the result of stronger activations of IOR mechanisms, or that it is subserved by entirely separate inhibitory processes.

Effects of endogenous and exogenous attention on visual processing: An Inhibition of Return study

We investigate early (P1) and late (P3) modulations of event-related potentials produced by endogenous (expected vs. unexpected location trials) and exogenous (cued vs. uncued location trials) orienting of spatial attention. A 75% informative peripheral cue was presented 1000 ms before the target in order to study Inhibition of Return (IOR), a mechanism that produces slower responses to peripherally cued versus uncued locations. Endogenous attention produced its effects more strongly at later stages of processing, while IOR (an index of exogenous orienting) was found to modulate both early and late stages of processing. The amplitude of P1 was reduced for cued versus uncued location trials, even when endogenous attention was maintained at the cued location. This result indicates that the perceptual effects of IOR are not eliminated by endogenous attention, suggesting that the IOR mechanism produces a perceptual decrement on the processing of stimuli at the cued location that cannot be counteracted by endogenous attention.

Inhibition versus attentional momentum in cortical and collicular mechanisms of IOR

Inhibition of return (IOR)—the automatic bias against returning attention or gaze to recently visited locations—is thought to have both collicular and cortical components and has been associated with the oculomotor system. Recently, distinct IOR mechanisms have been revealed that may have collicular and cortical origins: While standard luminance stimuli cause IOR in both manual and saccadic eye movement responses, “S cone” stimuli, which are invisible to the direct collicular pathway, caused manual IOR but not saccadic IOR. However, it has not been shown that the separate mechanisms are both inhibition of return, rather than facilitation due to attentional momentum or a visual motion transient. Here, we examined this question using four target and cue locations instead of two. Inhibition at the cued location predicts that responses for all noncued locations should be similar, whereas facilitation at the location opposite the cue predicts that the perpendicular locations would be more similar to the cued location than to the opposite location. Our results conform to the former prediction for both saccadic IOR and S cone generated IOR, demonstrating that both mechanisms of IOR are indeed inhibitory.

Inhibition of return in obsessive-compulsive disorder.

Obsessive-compulsive disorder (OCD) is characterized by repetitive obsessions and/or compulsions that interfere with daily functioning. Neuropsychological studies have suggested that such perseverative behaviors may be due to underlying attentional deficits. Inhibition of return (IOR) is an adaptive mechanism that is thought to assist visual search by biasing attention after a critical, short interval to novel, previously unattended areas. Therefore, this study aimed to examine whether deficient IOR mechanisms could underlie some of the attentional, and perhaps behavioral, problems, reported in OCD patients. Using a computerized IOR paradigm, participants were required to respond to a target that appeared at either the same or different location to a precue that was presented either 100 ms or 700 ms earlier. Results indicate that patients had a reduced IOR for targets presented in the left visual field, suggesting lateralized anomalies in shifting attention. Results are consistent with lateralization anomalies previously reported in OCD.

Inhibitory effects of repeating color and shape: inhibition of return or repetition blindness?

There is a current debate regarding whether attention is influenced by stimulus attributes other than location. The present article replicates and extends previous findings that repeating the nonspatial attribute of color leads to a delay in target detection (M. B. Law, J. Pratt, & R. A. Abrams, 1995). Repetition disadvantage effects were found for the stimulus attributes of both color and shape, as well as for location. However, the nonspatial repetition disadvantage disappeared if the stimuli were presented in peripheral locations (Experiments 3a, 3b, and 4) or the cue was presented for 50 ms (Experiment 6). Moreover, the magnitude of the repetition disadvantage tended to decline as the cue-target stimulus-onset asynchrony increased (Experiments 5a, 5b, and 6). These results suggest that a repetition blindness mechanism may underlie the repetition disadvantage effects of nonspatial features, rather than an inhibition of return mechanism.

Object-based and environment-based inhibition of return of visual attention.

Efficient search for an object often requires that attention be prevented from returning to recently examined environmental loci. M. I. Posner and Y. A. Cohen (1984) proposed that inhibition of return (IOR) of visual attention is a search mechanism that prevents such attentional perservation. The internal representations upon which IOR functions were examined and the following conclusions were drawn: First, IOR mechanisms have access to both object- and environment-based representations. Second, environment-based inhibition can be associated with a featureless environmental location, whereas the object-based mechanism requires that attention be oriented to a visible object. These findings are discussed in terms of physiological pathways that may mediate location- and object-based effects.