Localized attentional interference affects object individuation, not feature detection

Modern theorists conceptualize visual selective attention as a competition between object representations for the control of extrastriate receptive fields, an account supported by the finding that attentional selection of one stimulus can degrade processing of nearby stimuli. In the present study the conditions that produce reciprocal interference between attended stimuli are examined. Each display contained either no, one, or two feature-defined target items among an array of homogeneous distractors. Observers performed two tasks, feature detection and object individuation. The feature-detection task required observers to determine if any targets were present within the display. The object-individuation task required observers to determine if the number of targets was exactly two. Spatially mediated interference between target pairs occurred in the object-individuation task, but had no effect on feature detection. Results suggest that localized interference between attended stimuli occurs only when observers are required to resolve the features of individual objects, consistent with the competitive interaction models of attention.     

The role of similarity in inattentional blindness: Selective enhancement,selective suppression,or both?†

When people selectively pay attention to one set of objects and ignore another, unexpected stimuli often go unnoticed. Noticing rates are higher when the unexpected object matches the features of the attended items and lower when it matches those of the ignored items. No prior studies have fully disentangled these aspects of similarity; in previous work, the unexpected object fell on a continuum between the attended and ignored objects, so increasing the similarity to one set of objects necessarily decreased it to the other. We designed an inattentional blindness task in which we held similarity to the attended set constant and varied it with respect only to the ignored set, or vice versa. In Experiment 1, objects that were more similar to the attended set were noticed more often and objects that were more similar to the ignored set were noticed less often. Experiment 2, using a different set of unexpected objects, replicated the result that similarity to the ignored set affected noticing, but showed no effect of similarity to the attended set. In both experiments, the pattern of noticing rates differed for similarity with respect to the attended and ignored items, suggesting that suppression of ignored objects functions independently of enhancement of attended objects.     

Spatial interference between attended items engenders serial visual processing

A pair of experiments investigated the architecture of visual processing, parallel versus serial, across high and low levels of spatial interference in a divided attention task. Subjects made speeded judgments that required them to attend to a pair of color-cued objects among gray filler items, with the spatial proximity between the attended items varied to manipulate the strength of interference between attended items. Systems factorial analysis (Townsend & Nozawa, Journal of Mathematical Psychology 39:321-359, 1995) was used to identify processing architecture. Experiment 1, using moderately dense displays, found evidence of parallel processing whether attended objects were in low or high proximity to one another. Experiment 2, using higher-density displays, found evidence of parallel selection when attended stimuli were widely separated but serial processing when they were in high proximity. Divided visual attention can operate in parallel under conditions of low or moderate spatial interference between selected items, but strong interference engenders serial processing.     

Intralist interference and imagery in deaf and hearing children

Children from populations lacking verbal proficiency were given an interference list of paired associates (high within-list stimulus similarity) or 1 of 2 noninterference lists (low stimulus similarity), under a standard control condition (pictorial items side by side) or an imagery condition (items depicted as interacting). In Experiment I, with deaf children 6–10 years old, the imagery condition facilitated performance on the interference list, mainly by reducing generalization errors. There was significant interference only in the control condition. Unexpectedly, imagery failed to improve performance on the noninterference lists. In Experiment II, with hearing children 4–5 years old, there was significant interference in both the imagery and the control condition. Imagery significantly facilitated performance in all lists, but did not reduce interference, apparently because it did not reduce generalization errors. Thus, imagery (a) facilitates performance by increasing the memorability of stimulus-response associations, and (b) reduces interference by reducing confusion among similar stimuli.     

How not to be seen: the contribution of similarity and selective ignoring to sustained inattentional blindness

When people attend to objects or events in a visual display, they often fail to notice an additional, unexpected, but fully visible object or event in the same display. This phenomenon is now known as inattentional blindness . We present a new approach to the study of sustained inattentional blindness for dynamic events in order to explore the roles of similarity, distinctiveness, and attentional set in the detection of unexpected objects. In Experiment 1, we found that the similarity of an unexpected object to other objects in the display influences attentional capture: The more similar an unexpected object is to the attended items, and the greater its difference from the ignored items, the more likely it is that people will notice it. Experiment 2 explored whether this effect of similarity is driven by selective ignoring of irrelevant items or by selective focusing on attended items. The results of Experiment 3 suggest that the distinctiveness of the unexpected object alone cannot entirely account for the similarity effects found in the first two experiments; when attending to black items or white items in a dynamic display, nearly 30% of observers failed to notice a bright red cross move across the display, even though it had a unique color, luminance, shape, and motion trajectory and was visible for 5 s. Together, the results suggest that inattentional blindness for ongoing dynamic events depends both on the similarity of the unexpected object to the other objects in the display and on the observer's attentional set.     

The dual effect of context on memory of related and unrelated themes: Discrimination at encoding and cue at retrieval

The influence of contextual factors on encoding and retrieval in recognition memory was investigated using a retroactive interference paradigm. Participants were randomly assigned to four context conditions constructed by manipulating types of presentation modality (pictures vs words) for study, interference, and test stages, respectively (ABA, ABB, AAA, & AAB). In Experiment 1 we presented unrelated items in the study and interference stages, while in Experiment 2 each stage contained items from the same semantic category. The results demonstrate a dual role for context in memory processes-at encoding as well as at retrieval. In Experiment 1 there is a hierarchical order between the four context conditions, depending on both target-test and target-interference contextual similarity. Adding a categorical context in Experiment 2 helped to specify each list and therefore better distinguish between target and interferer information, and in some conditions compensated for their perceptual similarity.     

Long-term proactive interference and novelty enhancement effect in monkey list memory

Serial-probe-recognition (SPR) performance by 2 monkeys deteriorated over several months of training. Three hundred and twenty different items were presented without repetition within a session (trial unique) but were repeated between sessions. The cause of the deterioration was identified as proactive interference (PI) due to repetitive use of items from day to day. Introduction of novel stimuli across days improved performance from 63% to 82% correct (Experiment 1). Tests with only probe items and no list items (Experiment 2) revealed that the monkeys were using a familiar/novel response strategy in combination with a relational strategy (relating the probe item to the list items) to further improve their SPR performance. Intermixing familiar baseline trials and novel transfer trials within a session (Experiment 3) encouraged the subjects to use a relational strategy, and it improved performance on baseline trials as well as on transfer trials. Possible qualitative similarity between the relational strategy and the familiar/novel response strategy is discussed along with theoretical implications of these findings for experiments which have used small number of repeating stimuli within a session.     

Recognition memory for realistic synthetic faces

A series of experiments examined short-term recognition memory for trios of briefly presented, synthetic human faces derived from three real human faces. The stimuli were a graded series of faces, which differed by varying known amounts from the face of the average female. Faces based on each of the three real faces were transformed so as to lie along orthogonal axes in a 3-D face space. Experiment 1 showed that the synthetic faces' perceptual similarity structure strongly influenced recognition memory. Results were fit by a noisy exemplar model (NEMO) of perceptual recognition memory. The fits revealed thatrecognition memory was influenced both by the similarity of the probe to the series items and by the similarities among the series items themselves. Nonmetric multidimensional scaling (MDS) showed that the faces' perceptual representations largely preserved the 3-D space in which the face stimuli were arrayed. NEMO gave a better account of the results when similarity was defined as perceptual MDS similarity, rather than as the physical proximity of one face to another. Experiment 2 confirmed the importance of within-list homogeneity directly, without mediation of a model. We discuss the affinities and differences between visual memory for synthetic faces and memory for simpler stimuli.     

All parts of an item are not equal: Effects of phonological redundancy on immediate recall

The process of redintegration is thought to use top-down knowledge to repair partly damaged memory traces. We explored redintegration in the immediate recall of lists from a limited pool of partly phonologically redundant pseudowords. In Experiment 1, four kinds of stimuli were created by adding the syllable /ne/ to two-syllable pseudowords, either to the middle (/tepa/ vs. /tenepa/) or to the end (/tepane/), or adding a different syllable to each item (/tepalo/, /vuropi/). The repeated syllable was thought to be available for redintegration. Lists of two-syllable pseudowords were recalled best, items with a redundant end were intermediate, and items with a redundant middle-syllable were as hard as nonredundant three-syllable items. In Experiment 2, the last syllable was predictable from context but not shared between all stimuli, reducing phonological similarity between items. Performance did not differ from the situation with identicallast syllables. In Experiment 3, a shared first syllable had a detrimental effecton memory. An error analysis showed that beneficial redundancy effects were accompanied by harmful similarity effects, impairing memory for nonredundant syllables. The balance between the two effects depended on syllable position.     

奖赏预期调节局部注意干扰效应

局部注意干扰效应(Localized attentional interference, LAI)是指在视觉搜索任务中同时搜索在空间上分离的两个目标时, 或者目标周围存在一个无关奇异项时, 这两个关键刺激相距较近时产生的干扰现象。本实验采用视觉搜索范式, 探讨了奖赏预期对局部注意干扰效应的影响。实验1采用双目标搜索任务, 要求被试判断搜索画面中两个奇异项刺激的形状是否相同。结果显示奖赏条件和无奖赏条件都表现出显著的距离主效应, 随着目标间距离增大, 被试的正确率提高, 反应时下降。同时, 在远距离时, 奖赏条件下的正确率高于无奖赏条件, 而在近距离时, 奖赏条件下的正确率反而低于无奖赏条件, 即, 奖赏条件下局部注意干扰效应反而增大。高动机状态增强了两个目标的表征, 反而不利于解决局部注意干扰效应。实验2采用单目标搜索任务, 要求被试判断特定目标的方位并忽略另一无关奇异项刺激。与实验1不同的是, 实验2仅在无奖赏条件下观察到显著的距离主效应, 即被试行为表现在远距离时更好; 而在奖赏条件下, 被试在近距离和远距离的表现一样好, 即没有局部注意干扰效应。这说明在奖赏预期条件, 个体可以有效抑制分心物刺激的干扰, 将注意集中于目标刺激的加工, 从而对局部注意干扰效应产生调节。整个研究表明, 奖赏整体上能够提高对任务相关刺激的表征, 并抑制任务无关刺激, 虽然这并不总是能够提高任务表现。     

Viewers prefer predictive cues

Devaluation-by-inhibition hypothesis demonstrated that previously ignored items are judged more negatively than previously attended and novel items. Based on this view, the present study investigated the evaluation of preceding stimuli that presumably elicit attentional processes to task-relevant stimuli. Accordingly, we employed a Posner-type cueing task followed by evaluation of the preceding cues indicating left and right directions. The important manipulation is predictability of two different preceding cues which predict the target location with high or with low probability. In Experiment 1 with two different arrows, a low predictive arrow was judged more negatively than a high predictive cue. Experiment 2 using gaze cues of two persons instead of two different arrows supported the findings of Experiment 1. These findings are consistent with devaluation-by-inhibition, suggesting that cue items triggering attention to the target are devaluated when they have less predictability.     

Type-specific proactive interference in patients with semantic and phonological STM deficits

Prior neuropsychological evidence suggests that semantic and phonological components of short-term memory (STM) are functionally and neurologically distinct. The current paper examines proactive interference (PI) from semantic and phonological information in two STM-impaired patients, DS (semantic STM deficit) and AK (phonological STM deficit). In Experiment 1 probe recognition tasks with open and closed sets of stimuli were used. Phonological PI was assessed using nonword items, and semantic and phonological PI was assessed using words. In Experiment 2 phonological and semantic PI was elicited by an item recognition probe test with stimuli that bore phonological and semantic relations to the probes. The data suggested heightened phonological PI for the semantic STM patient, and exaggerated effects of semantic PI in the phonological STM case. The findings are consistent with an account of extremely rapid decay of activated type-specific representations in cases of severely impaired phonological and semantic STM.     

On the Irrelevance of Phonological Similarity to the Irrelevant Speech Effect

Irrelevant background speech disrupts immediate recall of visually presented items. Salame and Baddeley (1982) found that increasing the phonological similarity between the irrelevant speech and the visual items greatly increased this disruption. In contrast, Jones and Macken (1995) found little evidence for such an increase. The present experiments directly manipulated the phonological similarity of the irrelevant speech background and the to-be-remembered visual items. Experiments 1-4 compared background speech that shared virtually no phonemes with the visual stimuli with background speech that shared all of the phonemes of the visual stimuli. No effectof phonological similarity was found.Experiment5 replicatedthe method of Salame and Baddeley's critical experimentbut nottheir results. With regard to the two primary explanations ofthe irrelevant speech effect, these data present a strong challenge to the phonological store hypothesis while offering some support to the changing state hypothesis.     

The focus of attention in working memory: Evidence from a word updating task

Three experiments examined the cognitive costs of item switching within working memory with a novel word updating task, thereby extending previous research to the field of linguistic stimuli and linguistic-graphemic updating operations. In Experiments 1 and 2 costs for switching between working memory items were evident on the word level, and they increased with an increasing word set size (Experiment 2). In contrast, a surprisingly similar switch effect on the level of letters was not affected by word set size (Experiment 2). Experiment 3 showed that this effect is not simply based on the need for re-orienting visual spatial attention. To account for the overall picture of results, a recursive model of attentional foci is proposed. Moreover, individual working memory span appears to be associated with the accuracy of item switching, but not with its speed.     

The focus of attention in working memory: evidence from a word updating task

Three experiments examined the cognitive costs of item switching within working memory with a novel word updating task, thereby extending previous research to the field of linguistic stimuli and linguistic-graphemic updating operations. In Experiments 1 and 2 costs for switching between working memory items were evident on the word level, and they increased with an increasing word set size (Experiment 2). In contrast, a surprisingly similar switch effect on the level of letters was not affected by word set size (Experiment 2). Experiment 3 showed that this effect is not simply based on the need for re-orienting visual spatial attention. To account for the overall picture of results, a recursive model of attentional foci is proposed. Moreover, individual working memory span appears to be associated with the accuracy of item switching, but not with its speed.     

Adult age differences in the perception and learning of artistic style categories

Adult age differences in conceptual behavior were studied using informationally complex stimuli from real-world categories: paintings by two impressionist artists. In Experiment 1 we examined perceptions of category structure by having subjects sort paintings according to style similarity. Young adults were observed to depend more on abstract information in making style judgments, whereas older adults relied more on similarity in content. This resulted in different category structures between age groups, but similarity judgments in both groups appeared to correspond to actual style differences between the two artists. In Experiment 2, learning efficiency was shown to increase with a painting's category centrality, but older adults had particular trouble learning noncentral items. At transfer, both age groups were able to use abstracted central tendency information to categorize new paintings, although young adults appeared to have better access to information about specific category exemplars from acquisition. The results are generally consistent with those from studies using simpler artificial stimuli.     

Why is 9+7 harder than 2+3? Strength and interference as explanations of the problem-size effect

In four experiments, the problem-size effect was investigated, using an alphabet-arithmetic task in which subjects verified such problems as A + 2 = C. Problem size was manipulated by varying the magnitude of the digit addend (e.g., A + 2, A + 3, and A + 4). The frequency and similarity of problems was also manipulated to determine the contribution of strength and interference, respectively. Experiment 1 manipulated frequency at low levels of practice and found that strength could account for the problem-size effect. Experiment 2 manipulated frequency at higher levels of practice, and found that strength alone could not account for the problem-size effect at asymptote. Experiment 3 manipulated frequency and similarity and found a substantial problem-size effect at asymptote, suggesting that both strength and interference contribute to the problem-size effect. Experiment 4 manipulated similarity, keeping frequency constant, and found no problem-size effect at asymptote, suggesting that interference alone is not responsible for the problem-size effect. The results are related to findings with number arithmetic.     

Effects of age on searching for and enumerating targets that cannot be detected efficiently

We investigated the effects of old age on search, subitizing, and counting of difficult-to-find targets. In Experiment 1, young and older adults enumerated targets (Os) with and without distractors (Qs). Without distractors, the usual subitization-counting function occurred in both groups, with the same subitization span of 3.3 items. Subitization disappeared with distractors; older adults were slowed more overall by their presence but enumeration rates were not slowed by ageing either with or without distractors. In contrast, search rates for a single target (O among Qs) were twice as slow for older as for young adults. Experiment 2 tested and ruled out one account of age-equivalent serial enumeration based on the need to subvocalize numbers as items are enumerated. Alternative explanations based on the specific task differences between detecting and enumerating stimuli are discussed.     

Perceptual processing of adjacent and nonadjacent tactile nontargets.

Previous research has shown that subjects appear unable to restrict processing to a single finger and ignore a stimulus presented to an adjacent finger. Furthermore, the evidence suggests that, at least for moving stimuli, an adjacent nontarget is fully processed to the level of incipient response activation. The present study replicated and expanded upon these original findings. The results of Experiment 1 showed that an equally large response-competition effect occurred when the nontarget was presented to adjacent and nonadjacent fingers (on the same hand). The results of Experiment 2 showed that the effects observed in Experiment 1 (and in previous studies) were also obtained with stationary stimuli. Although small, there was some indication in the results of Experiment 2 that interference may dissipate more rapidly with distance with stationary stimuli. An additional finding was that interference effects were observed in both experiments with temporal separations between the target and nontarget of up to 100 msec. In Experiment 3, target and nontarget stimuli were presented to opposite hands. Although reduced, interference was still evident with target and nontarget stimuli presented to opposite hands. Varying the physical distance between hands did not produce any change in the amount of interference. The results suggest that the focus of attention on the skin extends nearly undiminished across the fingers of one hand and is not dependent upon the physical distance between sites of stimulation.