Visual short-term memory always requires general attention

The role of attention in visual memory remains controversial; while some evidence has suggested that memory for binding between features demands no more attention than does memory for the same features, other evidence has indicated cognitive costs or mnemonic benefits for explicitly attending to bindings. We attempted to reconcile these findings by examining how memory for binding, for features, and for features during binding is affected by a concurrent attention-demanding task. We demonstrated that performing a concurrent task impairs memory for as few as two visual objects, regardless of whether each object includes one or more features. We argue that this pattern of results reflects an essential role for domain-general attention in visual memory, regardless of the simplicity of the to-be-remembered stimuli. We then discuss the implications of these findings for theories of visual working memory.     

Concurrent working memory load can facilitate selective attention: evidence for specialized load

Load theory predicts that concurrent working memory load impairs selective attention and increases distractor interference (N. Lavie, A. Hirst, J. W. de Fockert, & E. Viding). Here, the authors present new evidence that the type of concurrent working memory load determines whether load impairs selective attention or not. Working memory load was paired with a same/different matching task that required focusing on targets while ignoring distractors. When working memory items shared the same limited-capacity processing mechanisms with targets in the matching task, distractor interference increased. However, when working memory items shared processing with distractors in the matching task, distractor interference decreased, facilitating target selection. A specialized load account is proposed to describe the dissociable effects of working memory load on selective processing depending on whether the load overlaps with targets or with distractors.     

Impact of auditory selective attention on verbal short-term memory and vocabulary development

This study investigated the role of auditory selective attention capacities as a possible mediator of the well-established association between verbal short-term memory (STM) and vocabulary development. A total of 47 6- and 7-year-olds were administered verbal immediate serial recall and auditory attention tasks. Both task types probed processing of item and serial order information because recent studies have shown this distinction to be critical when exploring relations between STM and lexical development. Multiple regression and variance partitioning analyses highlighted two variables as determinants of vocabulary development: (a) a serial order processing variable shared by STM order recall and a selective attention task for sequence information and (b) an attentional variable shared by selective attention measures targeting item or sequence information. The current study highlights the need for integrative STM models, accounting for conjoined influences of attentional capacities and serial order processing capacities on STM performance and the establishment of the lexical language network.     

Visual short-term memory load suppresses temporo-parietal junction activity and induces inattentional blindness

The right temporo-parietal junction (TPJ) is critical for stimulus-driven attention and visual awareness. Here we show that as the visual short-term memory (VSTM) load of a task increases, activity in this region is increasingly suppressed. Correspondingly, increasing VSTM load impairs the ability of subjects to consciously detect the presence of a novel, unexpected object in the visual field. These results not only demonstrate that VSTM load suppresses TPJ activity and induces inattentional blindness, but also offer a plausible neural mechanism for this perceptual deficit: suppression of the stimulus-driven attentional network.     

Role of working memory load on selective attention to affectively valent information

Empirical evidence obtained with neutral stimuli has shown that selective attention relies on working memory functions as distractor processing occurs under conditions of high but not of low working memory load. We investigated whether these findings also hold for affectively valent distractors. In three experiments, participants completed the original Flanker task with famous people (Exps 1 and 2) and an affective Flanker task (Exp. 3) in which positive and negative words were presented superimposed onto happy, angry, and neutral faces under conditions of high or low working memory load. In line with past findings, results showed greater interference effects due to processing of distractors showing known people under high working memory load. In contrast interference effects due to processing of valent distractors occurred regardless of working memory load. The present findings are in contrast with those reported with neutral stimuli as they indicate that automatic evaluation of incoming affectively valent information occurs regardless of task priorities and of working memory load.     

Binding or prioritization: The role of selective attention in visual short-term memory

Whether selective attention binds features in visual short-term memory or prioritizes selection for memory consolidation and decision was investigated with a change detection paradigm. Two types of change were manipulated: Feature or conjunctions of features. Previous work suggests that the allocation of attentional resources affects binding; hence attentional shifts during retention should affect the detection of conjunction changes more than feature changes. The results of Experiments 1 and 2 showed that attention shifts had a similar impact on detecting feature and conjunction changes. Experiment 3 showed a performance benefit with a post-cue occurring 200 or 550 ms after stimulus offset, but no improvement was found when prioritization occurred with a delay of 800 ms. The results of Experiment 4 suggested that signals from both feature changes and conjunction changes contribute to detection. The theoretical implications are discussed.     

视觉工作记忆负载类型对注意选择的影响

通过操纵Flanker任务相对于视觉工作记忆任务的呈现位置, 探讨在视觉工作记忆编码和保持阶段, 精度负载和容量负载对注意选择的影响。行为结果发现, Flanker任务呈现位置和视觉工作记忆负载类型影响注意选择; ERP结果发现, 在保持阶段, 当搜索目标和干扰项不一致时, 负载类型影响N2成分。研究表明, 在编码阶段, 视觉工作记忆负载主要通过占用更多知觉资源降低干扰效应, 支持知觉负载理论; 而在保持阶段, 当Flanker任务位于记忆项内部时, 两类负载在工作记忆表征过程中不同的神经活动导致投入到注意选择的认知控制资源不同, 可能是两类负载影响保持阶段注意选择的机制。     

Visual selective attention with virtual barriers

Previous studies have shown that interference effects in the flanker task are reduced when physical barriers (e.g., hands) are placed around rather than below a target flanked by distractors. One explanation of this finding is the referential coding hypothesis, whereby the barriers serve as reference objects for allocating attention. In five experiments, the generality of the referential coding hypothesis was tested by investigating whether interference effects are modulated by the placement of virtual barriers (e.g., parentheses). Modulation of flanker interference was found only when target and distractors differed in size and the virtual barriers were beveled wood-grain objects. Under these conditions and those of previous studies, the author conjectures that an impression of depth was produced when the barriers were around the target, such that the target was perceived to be on a different depth plane than the distractors. Perception of depth in the stimulus display might have led to referential coding of the stimuli in three-dimensional (3-D) space, influencing the allocation of attention beyond the horizontal and vertical dimensions. This 3-D referential coding hypothesis is consistent with research on selective attention in 3-D space that shows flanker interference is reduced when target and distractors are separated in depth.     

Visual short-term memory for sequential arrays

The capacity of visual short-term memory (VSTM) for a single visual display has been investigated in past research, but VSTM for multiple sequential arrays has been explored only recently. In this study, we investigate the capacity of VSTM across two sequential arrays separated by a variable stimulus onset asynchrony (SOA). VSTM for spatial locations (Experiment 1), colors (Experiments 2-4), orientations (Experiments 3 and 4), and conjunction of color and orientation (Experiment 4) were tested, with the SOA across the two sequential arrays varying from 100 to 1,500 msec. We find that VSTM for the trailing array is much better than VSTM for the leading array, but when averaged across the two arrays VSTM has a constant capacity independent of the SOA. We suggest that multiple displays compete for retention in VSTM and that separating information into two temporally discrete groups does not enhance the overall capacity of VSTM.     

Activation,attention, and short-term memory

The premise of this paper is that the popular term “short-term memory” (STM) is vague because it is used to refer to either (1) the set of representations from long-term memory currently in a state of heightened activation or (2) the focus of attention or content of awareness. A more coherent conception of STM is hierarchical, with the focus of attention depicted as a subset of the activated portion of long-term memory. Research issues are discussed to illustrate that this simple conception of STM leads to testable predictions and useful lines of inquiry.     

Perceptual load influences selective attention across development

Research suggests that visual selective attention develops across childhood. However, there is relatively little understanding of the neurological changes that accompany this development, particularly in the context of adult theories of selective attention, such as N. Lavie's (1995) perceptual load theory of attention. This study examined visual selective attention across development from 7 years of age to adulthood. Specifically, the author examined if changes in processing as a function of selective attention are similarly influenced by perceptual load across development. Participants were asked to complete a task at either low or high perceptual load while processing of an unattended probe stimulus was examined using event related potentials. Similar to adults, children and teens showed reduced processing of the unattended stimulus as perceptual load increased at the P1 visual component. However, although there were no qualitative differences in changes in processing, there were quantitative differences, with shorter P1 latencies in teens and adults compared with children, suggesting increases in the speed of processing across development. In addition, younger children did not need as high a perceptual load to achieve the same difference in performance between low and high perceptual load as adults. Thus, this study demonstrates that although there are developmental changes in visual selective attention, the mechanisms by which visual selective attention is achieved in children may share similarities with adults.     

Visual short-term memory: Central capacity limitations in short-term consolidation

We investigated whether there are central capacity limitations on consolidating information in visual short-term memory (VSTM). Subjects performed a visual memory task (deciding if two displays were the same or different) and a speeded tone pitch discrimination. When the tasks were performed concurrently, interference was observed in both tasks, suggesting that VSTM consolidation requires central resources. The cost of consolidating information in VSTM (as indexed by tone task performance) did not change as the number of to-be-consolidated items was increased, in contrast to previous work that used verbal materials (Jolic?ur & Dell'Acqua, 1998 Jolic?ur, P. and Dell'Acqua, R. 1998. The demonstration of short-term consolidation. Cognitive Psychology, 36: 138–202. [Crossref], [PubMed], [Web of Science ®] , [Google Scholar]). Results from Experiments 2 and 3 suggest that this apparent difference reflected a contribution from verbal coding in previous studies. Experiments 1 and 4 provided evidence that the capacity limitations had a central locus and were not merely due to preparing for a secondary task.     

Visual and auditory stores in short-term memory

If retrieval in short-term memory can be either from a pre-perceptual sensory store or from a post-perceptual memory then recall should vary as a function of input into sensory store. To test this possibility two experiments with paired associates compared visual and auditory presentation under conditions as comparable as possible. In both experiments modality interacted with retention interval: more recency with auditory but, in Experiment I, more primacy with visual. The interaction was taken as support for the hypothesis. An alternative hypothesis (that storage is post-perceptual but not a-historical) was discussed and weak negative evidence presented.     

Exogenous attention influences visual short-term memory in infants

Two experiments examined the hypothesis that developing visual attentional mechanisms influence infants' Visual Short-Term Memory (VSTM) in the context of multiple items. Five- and 10-month-old infants (N = 76) received a change detection task in which arrays of three differently colored squares appeared and disappeared. On each trial one square changed color and one square was cued; sometimes the cued item was the changing item, and sometimes the changing item was not the cued item. Ten-month-old infants exhibited enhanced memory for the cued item when the cue was a spatial pre-cue (Experiment 1) and 5-month-old infants exhibited enhanced memory for the cued item when the cue was relative motion (Experiment 2). These results demonstrate for the first time that infants younger than 6 months can encode information in VSTM about individual items in multiple-object arrays, and that attention-directing cues influence both perceptual and VSTM encoding of stimuli in infants as in adults.     

Distributing versus focusing attention in visual short-term memory

Visual short-term memory (VSTM) is traditionally considered a robust form of visual memory resistant to interference from subsequent visual input. This study shows that the robustness of VSTM depends on the way attention is allocated in VSTM. When attention is distributed across multiple memory items, VSTM for these items is vulnerable to interference from subsequent input, including passively viewed images and the postchange testing displays. Yet attention can readjust its focus in VSTM on the basis of an attentional orienting cue presented long after encoding. When attention is oriented to a particular memorized item, the memory is resistant to subsequent interference. This effect, however, is eliminated when the subset of items demanding focal attention exceeds one, suggesting that orienting attention in VSTM is less flexible than orienting attention in perception. We propose that the robustness of VSTM is influenced by whether attention is focused or distributed in VSTM.     

Release of inattentional blindness by high working memory load: elucidating the relationship between working memory and selective attention

An unexpected stimulus often remains unnoticed if attention is focused elsewhere. This inattentional blindness has been shown to be increased under conditions of high memory load. Here we show that increasing working memory load can also have the opposite effect of reducing inattentional blindness (i.e., improving stimulus detection) if stimulus detection is competing for attention with a concurrent visual task. Participants were required to judge which of two lines was the longer while holding in working memory either one digit (low load) or six digits (high load). An unexpected visual stimulus was presented once alongside the line judgment task. Detection of the unexpected stimulus was significantly improved under conditions of higher working memory load. This improvement in performance prompts the striking conclusion that an effect of cognitive load is to increase attentional spread, thereby enhancing our ability to detect perceptual stimuli to which we would normally be inattentionally blind under less taxing cognitive conditions. We discuss the implications of these findings for our understanding of the relationship between working memory and selective attention.     

Working memory load can both improve and impair selective attention: Evidence from the Navon paradigm

Selective attention to relevant targets has been shown to depend on the availability of working memory (WM). Under conditions of high WM load, processing of irrelevant distractors is enhanced. Here we showed that this detrimental effect of WM load on selective attention efficiency is reversed when the task requires global- rather than local-level processing. Participants were asked to attend to either the local or the global level of a hierarchical Navon stimulus while keeping either a low or a high load in WM. In line with previous findings, during attention to the local level, distractors at the global level produced more interference under high than under low WM load. By contrast, loading WM had the opposite effect of improving selective attention during attention to the global level. The findings demonstrate that the impact of WM load on selective attention is not invariant, but rather is dependent on the level of the to-be-attended information.