The effects of implicit attentional learning and habituation on inhibition of return

In two experiments, the effects of implicit attentional learning and habituation on inhibition of return (IOR) were assessed. Experiment 1 consisted of an informative variant of the spatial cuing paradigm (Posner, 1980), with the target appearing most often at the location next to the cue. Short-term as well as long-term learning of the regularities could be observed. This learning took place even though the participants were not able to verbalize the learned information, suggesting that the learning was implicit. By spatially separating the effects of implicit learning and IOR, we demonstrated that the magnitude of IOR slightly decreased because of long-term implicit orienting. In Experiment 2, a noninformative variant of the spatial cuing paradigm, IOR was still found to decrease over the course of the experiment. This suggests that habituation due to the mere repeated initiation of IOR also affects the magnitude of the IOR. This theory is supported by the finding that IOR recovered after short breaks in Experiment 2. However, habituation presumably only played a secondary role in Experiment 1. In sum, IOR was abolished by neither implicit attentional learning nor habituation. Here, the finding that IOR is not easily replaced by implicitly learned orienting clearly indicates that IOR is a powerful, low-level mechanism. We discuss implications of these results for the debate on the function of IOR.     

Effects of relevant and irrelevant color singletons on inhibition of return and attentional capture

We tested whether color singletons lead to saccadic and manual inhibition of return (IOR; i.e., slower responses at cued locations) and whether IOR depended on the relevance of the color singletons. The target display was preceded by a nonpredictive cue display. In three experiments, half of the cues were response-relevant, because participants had to perform a discrimination task at the cued location. With the exception of Experiment 2, none of the cue colors matched the target color. We observed saccadic IOR after color singletons, which was greater for slow than for fast responses. Furthermore, when the relevant cue color matched the target color, we observed attentional capture (i.e., faster responses at cued locations) with rapid responses, but IOR with slower responses, which provides evidence for attentional deallocation. When the cue display was completely response-irrelevant in two additional experiments, we did not find evidence for IOR. Instead, we found attentional capture when the cue color matched the target color. Also, attentional capture was greater for rapid responses and with short cue–target intervals. Thus, IOR emerges when cues are relevant and do not match the target color, whereas attentional capture emerges with relevant and irrelevant cues that match the target color.     

The development of an attentional bias for angry faces following Pavlovian fear conditioning

Although it is well documented that fear responses develop following aversive Pavlovian conditioning, it is unclear whether fear learning also manifests in the form of attentional biases for fear-related stimuli. Boschen, Parker, and Neumann (Boschen, M. J., Parker, I., & Neumann, D. L. (2007). Changes in implicit associations do not occur simultaneously to Pavlovian conditioning of physiological anxiety responses. Journal of Anxiety Disorders, 21, 788-803.) showed that despite the acquisition of differential skin conductance conditioned responses to angry faces paired (CS+) and unpaired (CS−) with an aversive shock, development of implicit associations was not subsequently observed on the Implicit Association Test. In the present study, participants (N = 76) were assigned either to a Shock or NoShock group and completed a similar aversive Pavlovian conditioning procedure with angry face CS+ and CS− stimuli. Participants next completed a visual probe task in which the angry face CS+ and CS− stimuli were paired with angry face control stimuli and neutral faces. Results confirmed that differential fear conditioning was observed in the Shock group but not in the NoShock group, and that the Shock group subsequently showed a selective attentional bias for the angry face CS+ compared with the CS− and control stimuli during the visual probe task. The findings confirm the interplay between learning-based mechanisms and cognitive processes, such as attentional biases, in models of fear acquisition and have implications for treatment of the anxiety disorders.     

The role of attentional set on attentional cueing and inhibition of return

When people know what critical feature will define a target for a block of trials, only cues that share a critical feature with targets will capture attention. This result is taken to mean that attentional control settings play a role in target identification. To examine the validity of the attentional control settings hypothesis while controlling for potential sensory artifacts, the first experiment compared conditions in which the critical target features were either blocked or randomized. The results indicated that all cues captured attention in the random conditions, but only cues that matched targets captured attention in the attentional set condition. The second experiment used the same two conditions to examine the effect of attentional set on inhibition of return (IOR). No differences were found between the blocked and random conditions, indicating that attentional set did not impact the IOR effects. Overall, the results indicate that (1) the previous findings of attentional set effects were not due to an artifact of the method, and (2) attentional set influences and early occurring attentional cueing effects but not later-occurring IOR effects.     

Temporal processing of emotional stimuli: the capture and release of attention by angry faces

Neuroimaging data suggest that emotional information, especially threatening faces, automatically captures attention and receives rapid processing. While this is consistent with the majority of behavioral data, behavioral studies of the attentional blink (AB) additionally reveal that aversive emotional first target (T1) stimuli are associated with prolonged attentional engagement or "dwell" time. One explanation for this difference is that few AB studies have utilized manipulations of facial emotion as the T1. To address this, schematic faces varying in expression (neutral, angry, happy) served as the T1 in the current research. Results revealed that the blink associated with an angry T1 face was, primarily, of greater magnitude than that associated with either a neutral or happy T1 face, and also that initial recovery from this processing bias was faster following angry, compared with happy, T1 faces. The current data therefore provide important information regarding the time-course of attentional capture by angry faces: Angry faces are associated with both the rapid capture and rapid release of attention.     

Irrelevant singletons capture attention: evidence from inhibition of return

Previous research has shown that a salient feature singleton may capture attention in a stimulus-driven, bottom-up fashion (e.g., Theeuwes, 1992,1994b). This conclusion has been challenged by others claiming that the observed attentional capture by irrelevant singletons may not be stimulus driven but due to top-down attentional control settings and/or nonspatial filtering costs. In the present study, we show that inhibition of return (IOR) occurs at the location of an irrelevant singleton. Participants were slower to detect a target presented at the location of the irrelevant singleton, relative to other locations. Since IOR can be observed only as a result of an exogenous, stimulus-driven shift of spatial attention, it isun-likely that top-down control settings and/or nonspatial filtering costs played a role. In line with earlier claims, the present findings provide strong evidence that salient singletons capture spatial attention in a purely bottom-up way.     

Irrelevant onsets cause inhibition of return regardless of attentional set

It is disputed whether onsets capture spatial attention either in a purely stimulus-driven fashion or only when they are contingent on one's attentional set. According to the latter assumption, interference from irrelevant onsets may result from nonspatial filtering costs. In the present study, we used inhibition of return (IOR) as a marker for spatial attention. IOR occurs mainly for locations that attention has visited before. Participants searched for a red object among white objects. An attentional set for redness was demonstrated by a spatial validity effect of red cues on response times. However, a stronger validity effect was found for irrelevant white onsets, which slowed responses when the onset contained a distractor, but speeded them when the onset contained a target. Most importantly, this onset benefit for targets turned into a deficit at longer SOAs, indicating IOR. We conclude that onset distractors capture spatial attention regardless of the observer's attentional set.     

Weaker inhibition after happy faces: evidence from an attentional blink task with emotional and neutral faces

Motivation and Emotion - In two experiments using a Rapid Serial Visual Presentation (RSVP) we investigated how emotional and neutral faces (T1) modulate temporal attention for a following neutral...     

Reconceptualizing inhibition of return as

Inhibition of return (IOR) is an effect on spatial attention whereby reaction times to a target presented at a location where a stimulus had recently been presented are increased, as opposed to when a target is presented at a new location. Despite early reports that habituation is not responsible for the IOR effect, the human cognitive literature provides indirect evidence in favor of the possibility. In addition, recent neurophysiological studies provide direct support for the idea that habituation is at least a contributing source for the IOR effect. The present article describes how habituation may account for the IOR effect and explores some of the predictions that this hypothesis suggests.     

New perceptual objects that capture attention produce inhibition of return

New perceptual objects are known to capture attention. We show that such attentional capture is similar to that produced by peripheral luminance changes, as opposed to symbolic central cues, in that it produces inhibition of return. Two experiments employed equiluminant texture changes that attracted attention, producing an initial attentional benefit (in detection and discrimination) followed by inhibition of return. However, when the display was altered so that the texture change did not define a new object, no facilitation or inhibition was observed. The results bolster recent claims of the importance of new perceptual objects and extend our understanding of the effect of such objects on attention.     

Attentional biases for angry faces: Relationships to trait anger and anxiety

In two experiments selective attention to angry faces was investigated in relation to trait anger and anxiety. A pictorial emotional Stroop task comparing colour-naming latencies for neutral and angry faces was employed. In Experiment 1 using an unmasked task, individuals scoring high on trait anger showed an attentional bias for angry faces. In Experiment 2, unmasked and masked versions of the task were used. Individuals were selected on low and high trait anxiety, but there was no indication of a relation between attentional bias scores and anxiety. When individuals were subsequently reallocated to groups on the basis of trait anger scores, the high anger group showed an attentional bias for angry faces in the unmasked and the masked task. Results are discussed in relation to recent neurobiological findings from our laboratory, as reflecting an evolutionary-evolved, content-specific response to the facial expression of anger.     

Pupillary attributions of college students to happy and angry faces.

As evidence for an hypothesis that pupil size plays an important role in nonverbal communication, Hess (1975) has reported that adults draw in appropriately sized pupils on his happy and angry faces task. However, he did not report a statistical test of his data. In this study, we replicated Hess' research and found congruent with his hypothesis that college students (n = 223) draw in significantly larger pupils on the happy face.     

Exogenous attention to angry faces in social anxiety: a perceptual accuracy approach

We investigated the interaction between endogenous and exogenous attention for the processing of emotional stimuli in individuals with high social anxiety using accuracy rates. Following the presentation of an endogenous cue at the centre, exogenous cues (i.e., angry and neutral faces) were presented at peripheral locations. Subsequently, non-emotional masked targets were presented, and the participants were instructed to discriminate between the targets. With respect to exogenous attention, high socially anxious people exhibited higher accuracy when the angry face and target appeared on the same side than when they appeared on different sides, whereas low socially anxious people did not exhibit such effects. On the other hand, different abilities of endogenous attention were not observed between high and low socially anxious people. These results suggest that exogenous attention is biased towards threat in high socially anxious people.     

Attentional capture and inhibition (of return): the effect on perceptual sensitivity

The present study was designed to determine the spatial distribution of attention in displays in which an irrelevant color singleton was present. The results show that at the location of an irrelevant singleton, there is, first, an increased sensitivity (d'), followed later by a reduced sensitivity. The increased sensitivity implies that, first, the irrelevant singleton captured spatial attention, producing an increased sensory gain for input at the irrelevant distractor location. The later-occurring, reduced sensitivity implies the operation of inhibitory processes, possibly related to inhibition of return.     

Remember to blink: Reduced attentional blink following instructions to forget

This study used rapid serial visual presentation (RSVP) to determine whether, in an item-method directed forgetting task, study word processing ends earlier for forget words than for remember words. The critical manipulation required participants to monitor an RSVP stream of black nonsense strings in which a single blue word was embedded. The next item to follow the word was a string of red fs that instructed the participant to forget the word or green rs that instructed the participant to remember the word. After the memory instruction, a probe string of black xs or os appeared at postinstruction positions 1–8. Accuracy in reporting the identity of the probe string revealed an attenuated attentional blink following instructions to forget. A yes–no recognition task that followed the study trials confirmed a directed forgetting effect, with better recognition of remember words than forget words. Considered in the context of control conditions that required participants to commit either all or none of the study words to memory, the pattern of probe identification accuracy following the directed forgetting task argues that an intention to forget releases limited-capacity attentional resources sooner than an instruction to remember—despite participants needing to maintain an ongoing rehearsal set in both cases.     

Absence of attentional capture in parallel search is possible: A failure to replicate attentional capture in a non-singleton target search task

The notion of a singleton versus a feature search mode (Bacon & Egeth, 1994) in visual search is generally widely accepted. Yet Theeuwes (2004) claimed a different, potentially more parsimonious position. He suggested that the size of an attentional window is under top-down control and that salient distractors within this window capture attention. We report on four experiments. The first two experiments represent our various initial attempts to replicate the crucial Experiment 1 in the Theeuwes (2004) study, all of which were not successful. In Experiment 3, we showed that our distractor was able to yield attentional capture in a situation promoting the use of the singleton search mode (Bacon & Egeth, 1994). Experiment 4 was similar to Experiment 1 but incorporated further details that may account for the discrepant findings. Still, no attentional capture was found. In sum, it was not possible to replicate a crucial piece of evidence for the attentional window hypothesis, and our results are more consistent with the assumption of two different search modes.     

Eye tracking unconscious face-to-face confrontations: dominance motives prolong gaze to masked angry faces

In primates, dominance/submission relationships are generally automatically and nonaggressively established in face-to-face confrontations. Researchers have argued that this process involves an explicit psychological stress-manipulation mechanism: Striding with a threatening expression, while keeping direct eye contact, outstresses rivals so that they submissively avert their gaze. In contrast, researchers have proposed a reflexive and implicit modulation of face-to-face confrontation in humans, on the basis of evidence that dominant and submissive individuals exhibit vigilant and avoidant responses, respectively, to facial anger in masked emotional Stroop tasks. However, these tasks do not provide an ecologically valid index of gaze behavior. Therefore, we directly measured gaze responses to masked angry, happy, and neutral facial expressions with a saccade-latency paradigm and found that increased dominance traits predict a more prolonged gaze to (or reluctance to avert gaze from) masked anger. Furthermore, greater non-dominance-related reward sensitivity predicts more persistent gaze to masked happiness. These results strongly suggest that implicit and reflexive mechanisms underlie dominant and submissive gaze behavior in face-to-face confrontations.     

The modulation of inhibition of return by objectinternal structure: Implications for theories of object-based attentional selection

Recently, Vecera, Behrmann, and McGoldrick (2000), using a divided-attention task, reported that targets are detected more accurately when they occur on the same structural part of an object, suggesting that attention can be directed toward object-internal features. We present converging evidence using the object-based inhibition of return (IOR) paradigm as an implicit measure of selection. The results show that IOR is attenuated when cues and targets appear on the same part of an object relative to when they are separated by a part boundary. These findings suggest that object-based mechanisms of selection can operate over shape representations that make explicit information about objectinternal structure.     

Affect of the unconscious: Visually suppressed angry faces modulate our decisions

Emotional and affective processing imposes itself over cognitive processes and modulates our perception of the surrounding environment. In two experiments, we addressed the issue of whether nonconscious processing of affect can take place even under deep states of unawareness, such as those induced by interocular suppression techniques, and can elicit an affective response that can influence our understanding of the surrounding environment. In Experiment 1, participants judged the likeability of an unfamiliar item—a Chinese character—that was preceded by a face expressing a particular emotion (either happy or angry). The face was rendered invisible through an interocular suppression technique (continuous flash suppression; CFS). In Experiment 2, backward masking (BM), a less robust masking technique, was used to render the facial expressions invisible. We found that despite equivalent phenomenological suppression of the visual primes under CFS and BM, different patterns of affective processing were obtained with the two masking techniques. Under BM, nonconscious affective priming was obtained for both happy and angry invisible facial expressions. However, under CFS, nonconscious affective priming was obtained only for angry facial expressions. We discuss an interpretation of this dissociation between affective processing and visual masking techniques in terms of distinct routes from the retina to the amygdala.