Task- and location-switching effects on visual attention

In two experiments, we examined the effects of task and location switching on the accuracy of reporting target characters in an attentional blink (AB) paradigm. Single-character streams were presented at a rate of 100 msec per character in Experiment 1, and successive pairs of characters on either side of fixation were presented in Experiment 2. On each trial, two targets appeared that were either white letters or black digits embedded in a stream of black letter distractors, and they were separated by between zero and five items in the stream (lags 1-6). Experiment 1 showed that report of the first target was least accurate if it immediately preceded the second target and if the two targets were either both letters or both digits (task repetition cost). Report of the second target was least accurate if one or two distractors intervened between the two targets (the U-shaped AB lag effect) and if one target was a letter and the other a digit (task switch cost). Experiment 2 added location uncertainty as a factor and showed similar effects as Experiment 1, with one exception. Lag 1 sparing (the preserved accuracy in reporting the second of two targets if the second immediately follows the first) was completely eliminated when the task required attention switching across locations. Two-way additive effects were found between task switching and location switching in the AB paradigm. These results suggests separate loci for their attentional effects. It is likely that the AB deficit is due mainly to central memory limitations, whereas location-switching costs occur at early visual levels. Task-switching costs occur at an intermediate visual level, since the present task switch involved encoding differences without changes in stimulus-response mapping rules (i.e., the task was character identification for both letters and digits).     

Modality-specific and amodal sources of interference in the attentional blink

When two masked targets (T1 and T2) are visually or auditorily presented in rapid succession, processing of T1 produces an attentional blink (AB)--that is, a transient impairment of T2 identification. The present study was conducted to compare the relative impact of masking T1 and T2 between vision and audition. Within a rapidly presented sequence, each of the two verbal targets, discriminated by their offset (Experiment 1) or their onset (Experiment 2), could be followed by either a single item, acting as a mask, or a blank gap. Masking of T2 appeared to be necessary for the occurrence of the AB for both the visual and the auditory modality. However, whereas masking of T1 affected the expression of the visual AB in both experiments, the same effect was observed in the auditory modality only when the targets varied at the onset. These results provide further evidence that processing auditory and visual information is restricted by similar attentional limitations but also suggest that these limits are constrained by properties specific to each sensory system.     

Spatial modulation of repetition blindness and repetition deafness

When two identical visual items are presented in rapid succession, people often fail to report the second instance when trying to recall both (e.g., Kanwisher, 1987). We investigated whether this temporal processing deficit is modulated by the spatial separation between the repeated stimuli within both audition and vision. In Experiment 1, lists of one to three digits were rapidly presented from loudspeaker cones arranged in a semicircle around the participant. Recall accuracy was lower when repeated digits were presented from different positions rather than from the same position, as compared to unrepeated control pairs, demonstrating that auditory repetition deafness (RD) is modulated by the spatial displacement between repeated items. A similar spatial modulation of visual repetition blindness (RB) was reported when pairs of masked letters were presented visually from either the same or different positions arranged on a semicircle around fixation (Experiment 2). These results cannot easily be accounted for by the token individuation hypothesis of RB (Kanwisher, 1987; Park & Kanwisher, 1994) and instead support a recognition failure account (Hochhaus & Johnston, 1996; Luo & Caramazza, 1995, 1996).     

A crossmodal attentional blink between vision and touch

There is currently a great deal of interest regarding the possible existence of a crossmodal attentional blink (AB) between audition and vision. The majority of evidence now suggests that no such crossmodal deficit exists unless a task switch is introduced. We report two experiments designed to investigate the existence of a crossmodal AB between vision and touch. Two masked targets were presented successively at variable interstimulus intervals. Participants had to respond either to both targets (experimental condition) or to just the second target (control condition). In Experiment 1, the order of target modality was blocked, and an AB was demonstrated when visual targets preceded tactile targets, but not when tactile targets preceded visual targets. In Experiment 2, target modality was mixed randomly, and a significant crossmodal AB was demonstrated in both directions between vision and touch. The contrast between our visuotactile results and those of previous audiovisual studies is discussed, as are the implications for current theories of the AB.     

Upshifted decision criteria in attentional blink and repetition blindness

A large number of “unawareness” phenomena have been explained and quantified in terms of sensitivity (d′) fluctuations, with very few attempts at addressing an alternative putative cause, i.e., fluctuations of subjects’ response criteria (c). Response criteria fluctuations are particularly likely under dual-task paradigms with unbalanced sensitivities (Gorea & Sagi, 2000) such as those used in evidencing attentional blink (AB) and repetition blindness (RB) phenomena. The present study inquires into whether AB and RB are indeed prone to a deviant decisional behaviour. AB and RB were studied with a yes/no task allowing the assessment of d′ and c for the detection (presence/absence) of a target letter T2 as a function of its temporal lag relative to the presentation of another (AB) or of the same (RB) letter, T1 (Experiment 1). A significant criterion increase was observed in both cases. Additional experiments demonstrate that this criterion effect is typical of these dual-task AB and RB paradigms as it is not observed in a standard contrast detection task with mixed contrasts (Experiment 2), in a “control” AB design stripped off its first task T1 (Experiment 3), or in a metacontrast experiment (Experiment 4). We propose that the observed criterion shifts are the consequence of the inherent dual-task AB and RB designs (where observers have to judge two events of unequal saliencies) and that they entail an enhancement of the AB and RB effects as long as these effects are assessed via subjective (yes/no or matching) procedures.     

Attentional control and competition between episodic representations

The relationship between attentional control and episodic representation was investigated in six experiments that employed a variant of the classic attentional blink paradigm. We introduced a task-irrelevant (unpredictive) color match between the first and second target stimulus in a three-stream rapid serial visual presentation task. When this match was present, the first target reliably elicited a priming benefit to the identification of the second, lateralized target. However, this was only the case when the identities of the targets did not belong to the same category (digits, letters, or symbols). When targets did belong to the same category, interference was observed instead of priming, particularly at Lag 1. Furthermore, when color was the target-defining feature, interference at Lag 1 gave way to priming at longer lags. The interference effect is attributed to partial overlap between competing episodic target representations, which affects the availability of their overlapping features for successive attentional selection in rapid serial visual presentation.     

The meaning of the mask matters: evidence of conceptual interference in the attentional blink

The rapid serial visual presentation (RSVP) experiment reported here investigated the role of conceptual interference in the attentional blink (AB). Subjects were presented with RSVP streams that contained five stimuli: Target 1, a distractor, Target 2, a second distractor, and a symbol mask. Target 1 was a green letter, Target 2 was a red letter, and the distractors were either white letters or white digits. The stimuli were presented in a font typically seen on the face of a digital watch. Thus, "S" and "O" were identical to "5" and "0," respectively. This allowed us to present streams that were conceptually different even though featurally identical: The two letter targets were followed by distractors that were recognized either as "5" and "0" or as "S" and "O." The AB was substantially attenuated when subjects were told the distractors were digits rather than letters. This result indicates that conceptual interference plays a role in the AB.     

The impact of order incongruence between a task-irrelevant auditory sequence and a task-relevant visual sequence

A novel effect is reported in which serial recall of visual digits was disrupted to a greater degree by the presence of the same set of digits presented as an irrelevant auditory sequence than by the presence of irrelevant auditory consonants, but only when the order of the irrelevant digits was incongruent with that of the to-be-remembered digits (Experiment 1). Experiment 2 replicated this order-incongruence effect and showed also that disruption was dictated by the number of order-incongruent transitions but not by the number of novel tokens contained within the irrelevant sequence. The results favor an interference-by- process approach to the disruption of serial memory by irrelevant sound over approaches based on notions of interference by content and/or interference by depletion of attentional resources.     

Cross-modal links in exogenous covert spatial orienting between touch, audition, and vision

Three experiments investigated cross-modal links between touch, audition, and vision in the control of covert exogenous orienting. In the first two experiments, participants made speeded discrimination responses (continuous vs. pulsed) for tactile targets presented randomly to the index finger of either hand. Targets were preceded at a variable stimulus onset asynchrony (150,200, or 300 msec) by a spatially uninformative cue that was either auditory (Experiment 1) or visual (Experiment 2) on the same or opposite side as the tactile target. Tactile discriminations were more rapid and accurate when cue and target occurred on the same side, revealing cross-modal covert orienting. In Experiment 3, spatially uninformative tactile cues were presented prior to randomly intermingled auditory and visual targets requiring an elevation discrimination response (up vs. down). Responses were significantly faster for targets in both modalities when presented ipsilateral to the tactile cue. These findings demonstrate that the peripheral presentation of spatially uninforrnative auditory and visual cues produces cross-modal orienting that affects touch, and that tactile cues can also produce cross-modal covert orienting that affects audition and vision.     

知觉负载、注意定势与选择性注意

本研究采用Eriksen Flanker（侧抑制）范式,将当前任务区分为高、低知觉负载两种条件．并系统操纵边缘视野干扰项与中央靶子的不同加工层次关系,从而考察注意选择的知觉负载理论。实验一发现,高知觉负载情况下没有任何flanker冲突效应,而低知觉负载情况下既有知觉层次和反应层次的冲突效应,也有一致条件下的促进效应。实验二增加了一致条件试次的比例,从而操纵自上而下的注意定势,发现高、低知觉负载情况下都存在知觉冲突效应和一致条件下的促进效应。这些发现表明,对任务无关信息的加工既受到任务相关信息的知觉负载和剩余加工资源的分配的影响,也受到自上而下注意定势的影响;自下而上和自上而下过程相互作用,共同决定加工资源的分配和注意选择的认知阶段。     

注意捕获对注意瞬脱的消弱作用

本研究在经典的注意瞬脱研究范式中变化干扰刺激T2-1或目标刺激T2的颜色特征,探究由新异刺激特征引发的注意捕获对注意瞬脱的影响。结果发现,当改变T2-1或T2的颜色时,这些与任务无关的新异信息可以自下而上地引发注意捕获并减小注意瞬脱。注意瞬脱起因于有限注意资源的分配,资源的分配方式受注意捕获的自动调节。这为解决注意瞬脱到底是有限资源限制还是资源分配提供了新的实证和理论解释。     

Focal spatial attention can eliminate inhibition of return

Inhibition of return (IOR) is an orienting phenomenon characterized by slower responses to spatially cued than to uncued targets. In Experiment 1, a physically small digit that required identification was presented immediately following a peripheral cue. The digit could appear in the cued peripheral box or in the central box, thus guaranteeing a saccadic response to the cue in one condition and maintenance of fixation in the other. An IOR effect was observed when a saccadic response to the cue was required, but IOR was not generated by the peripheral cue when fixation was maintained in order to process the central digit. In Experiment 2, IOR effects were observed when participants were instructed to ignore the digits, whether those digits were presented in the periphery or at fixation. These findings suggest that behaviorally manifested, cue-induced IOR effects can be eliminated by focal spatial attentional control settings.     

Mental effort and task interference in auditory attention

Dual-task performance was examined in three experiments. The primary task was to repeat or to add one to four digits presented auditorily at a rate of 1 digit/second. This primary task was combined with three different secondary tasks in which subjects listened to a list of words either for later recognition of some of the words (Experiment 1) or for detection and a later report of a target word (Experiments 2 and 3). Different patterns of task interference were obtained. Recognition performance was sensitive to between-task variations in capacity demands but did not reflect momentary attentional demands within the primary task. Detection performance reflected both between-task and within-task variation in capacity demands of the primary task. The interference between the primary and the secondary task was mutual, with more interference when the selection-cue in the detection task was a category name than when it was the target word itself. These findings are discussed in terms of effort theory of attention and the role of attentional strategies in dual-task performance.     

Alerting enhances target identification but does not affect the magnitude of the attentional blink

Identification of the second of two targets is impaired when presented less than about 500 ms after the first. The magnitude of this attentional blink (AB) is known to be modulated by tonic factors (e.g., observer's state of relaxation). The present work examined the effects of a phasic change in observer's state brought about by an alerting stimulus (an aggregate of faint rings) presented in temporal proximity to either letter-target inserted in a temporal stream (RSVP) of digit distractors. In four experiments, identification accuracy of each target was substantially improved by presenting the alerting stimulus either in the target's frame or in the preceding RSVP frame. However, alerting did not modulate the magnitude of the AB. The appearance of an alerting effect on the AB in Experiment 1 was ascribed to a ceiling effect in Experiment 2. Experiment 3 ruled out endogenous temporal cueing effects; Experiment 4 examined the temporal gradient of alerting. Independence of the alerting and AB effects suggests that the alerting stimuli and the letter targets may be processed along distinct visual pathways.     

Voice-specific information and the 20-second delayed-suffix effect

Two experiments were conducted to investigate the nature of the delayed-suffix effect reported by Watkins and Todres (1980). In both experiments, subjects were presented lists of digits for serial recall. At the end of each list either a tone or a voice reading aloud the word go was presented. The voice was either in the same voice that read the digits or in a different voice. Past research has indicated that the tone control produces the least interference, followed by the different-voice suffix, which in turn produces less interference than the same-voice suffix. The results of both experiments indicated that when subjects were tested on immediate recall for the lists, the typical ordering of tone control, different-voice suffix, and same-voice suffix on recall at the last serial position was found. However, when there was a 20-s filled interval between the last list item and the suffix, there was only a difference between the tone control and the same- and different-voice suffixes with no difference between the latter two conditions. In addition, Experiment 2 failed to support a simple attentional account of the differential influence of voice in the immediate and delayed-recall conditions. The results are viewed as supporting a perceptual tuning mechanism in which perceptual specificity decreases with the passage of time.     

Priming T2 in a visual and auditory attentional blink task

Participants performed an attentional blink (AB) task including digits as targets and letters as distractors within the visual and auditory domains. Prior to the rapid serial visual presentation, a visual or auditory prime was presented in the form of a digit that was identical to the second target (T2) on 50% of the trials. In addition to the "classic" AB effect, an overall drop in performance on T2 was observed for the trials on which the stream was preceded by an identical prime from the same modality. No cross-modal priming was evident, suggesting that the observed inhibitory priming effects are modality specific. We argue that the present findings represent a special type of negative priming operating at a low feature level.     

Differential impact of emotional task relevance on three indices of prioritised processing for fearful and angry facial expressions

It is commonly assumed that threatening expressions are perceptually prioritised, possessing the ability to automatically capture and hold attention. Recent evidence suggests that this prioritisation depends on the task relevance of emotion in the case of attention holding and for fearful expressions. Using a hybrid attentional blink (AB) and repetition blindness (RB) paradigm we investigated whether task relevance also impacts on prioritisation through attention capture and perceptual salience, and if these effects generalise to angry expressions. Participants judged either the emotion (relevant condition) or gender (irrelevant condition) of two target facial stimuli (fearful, angry or neutral) imbedded in a stream of distractors. Attention holding and capturing was operationalised as modulation of AB deficits by first target (T1) and second target (T2) expression. Perceptual salience was operationalised as RB modulation. When emotion was task-relevant (Experiment 1; N?=?29) fearful expressions captured and held attention, and were more perceptually salient than neutral expressions. Angry expressions captured attention, but were less perceptually salient and capable of holding attention than fearful and neutral expressions. When emotion was task-irrelevant (Experiment 2; N?=?30), only fearful attention capture and perceptual salience effects remained significant. Our findings highlight the importance for threat-prioritisation research to heed both the type of threat and prioritisation investigated.     

Audiovisual links in exogenous covert spatial orienting

Subjects judged the elevation (up vs. down, regardless of laterality) of peripheral auditory or visual targets, following uninformative cues on either side with an intermediate elevation. Judgments were better for targets in either modality when preceded by an uninformative auditory cue on the side of the target. Experiment 2 ruled out nonattentional accounts for these spatial cuing effects. Experiment 3 found that visual cues affected elevation judgments for visual but not auditory targets. Experiment 4 confirmed that the effect on visual targets was attentional. In Experiment 5, visual cues produced spatial cuing when targets were always auditory, but saccades toward the cue may have been responsible. No such visual-to-auditory cuing effects were found in Experiment 6 when saccades were prevented, though they were present when eye movements were not monitored. These results suggest a one-way cross-modal dependence in exogenous covert orienting whereby audition influences vision, but not vice versa. Possible reasons for this asymmetry are discussed in terms of the representation of space within the brain.     

Auditory attentional blink: masking the second target is necessary, delayed masking is sufficient.

When two target items (T1 and T2) are presented in rapid succession among fillers, processing T2 is often impaired. This phenomenon is known as the attentional blink (AB). Within the visual modality, this second-target deficit generally occurs only if T2 is masked by a trailing item. The current study was designed to examine whether masking of T2 also plays a critical role in the auditory AB. Results showed a reliable AB effect even when the item following T2 was replaced by silence. However, the AB deficit was abolished when T2 was the last presented stimulus. Our results suggest that, as in vision, T2 masking is necessary for the AB to take place in audition, but that masking is effective even when delayed, providing evidence that the phenomenon shares some functional mechanisms across sensory modalities.     

Testing the embodied account of object naming: A concurrent motor task affects naming artifacts and animals

Embodied theories of object representation propose that the same neural networks are involved in encoding and retrieving object knowledge. In the present study, we investigated whether motor programs play a causal role in the retrieval of object names. Participants performed an object-naming task while squeezing a sponge with either their right or left hand. The objects were artifacts (e.g. hammer) or animals (e.g. giraffe) and were presented in an orientation that favored a grasp or not. We hypothesized that, if activation of motor programs is necessary to retrieve object knowledge, then concurrent motor activity would interfere with naming manipulable artifacts but not non-manipulable animals. In Experiment 1, we observed naming interference for all objects oriented towards the occupied hand. In Experiment 2, we presented the objects in more ‘canonical orientations’. Participants named all objects more quickly when they were oriented towards the occupied hand. Together, these interference/facilitation effects suggest that concurrent motor activity affects naming for both categories. These results also suggest that picture-plane orientation interacts with an attentional bias that is elicited by the objects and their relationship to the occupied hand. These results may be more parsimoniously accounted for by a domain-general attentional effect, constraining the embodied theory of object representations. We suggest that researchers should scrutinize attentional accounts of other embodied cognitive effects.