Recent experiences influence the processing of new information even when those experiences are irrelevant to the current task. Does this reflect the indirect effects of a passively maintained representation of the previous experience, or is this representation reactivated when a new event occurs? To answer this question, we attempted to decode the orientation of the stimulus on the previous trial from the electroencephalogram on the current trial in a working memory task. Behavioral data confirmed that the previous-trial stimulus orientation influenced the reported...

Complex cognition relies on both on-line representations in working memory (WM), said to reside in the focus of attention, and passive off-line representations of related information. Here, we dissected the focus of attention by showing that distinct neural signals index the on-line storage of objects and sustained spatial attention. We recorded electroencephalogram (EEG) activity during two tasks that employed identical stimulus displays but varied the relative demands for object storage and spatial attention. We found distinct delay-period signatures for an attention...

Visual working memory is constrained by a limited resource that must be shared between multiple stimuli, such that remembering more items decreases the precision with which each item can be recalled. Here we investigated how the sensory quality of an item affects the working memory resource allocated to storing it. In two cued-recall continuous orientation reproduction experiments, we manipulated the signal strength of memoranda either by varying stimulus contrast (internal or sensory noise) or by varying within-stimulus orientation variability (external or stimulus...

Neural measures of working memory storage, such as the contralateral delay activity (CDA), are powerful tools in working memory research. CDA amplitude is sensitive to working memory load, reaches an asymptote at known behavioral limits, and predicts individual differences in capacity. An open question, however, is whether neural measures of load also track trial-by-trial fluctuations in performance. Here, we used a whole-report working memory task to test the relationship between CDA amplitude and working memory performance. If working memory failures are due to...

When an object we represent in visual working memory (VWM) changes, its representation is modified accordingly. VWM can either access and change the existing representation by an updating process, or it can reset, by encoding the object in its novel status as a new representation. Our goal was to show that the determining factor of updating versus resetting is the availability of a stable correspondence between the object and its VWM representation. Here, we demonstrate that updating relies on the object-to-representation mapping to access and modify the appropriate...

The visual working memory (VWM) resetting process is triggered when the mapping between an object in the environment and its corresponding VWM representation becomes irrelevant. Resetting involves discarding the no longer relevant representations, and encoding novel representations and mappings. We examined how resetting operates on VWM’s contents. Specifically, we tested whether losing only part of the encoded mappings led to resetting all of the VWM representations. Subjects monitored moving polygons for an abrupt shape-change. Occasionally, a polygon separated into...

There is a consensus that visual working memory (WM) resources are sharply limited, but debate persists regarding the simple question of whether there is a limit to the total number of items that can be stored concurrently. Zhang and Luck (2008) advanced this debate with an analytic procedure that provided strong evidence for random guessing responses, but their findings can also be described by models that deny guessing while asserting a high prevalence of low precision memories. Here, we used a whole report memory procedure in which subjects reported all items in...

Reinforcement learning theory distinguishes “model-free” learning, which fosters reflexive repetition of previously rewarded actions, from “model-based” learning, which recruits a mental model of the environment to flexibly select goal-directed actions. Whereas model-free learning is evident across development, recruitment of model-based learning appears to increase with age. However, the cognitive processes underlying the development of model-based learning remain poorly characterized. Here, we examined whether age-related differences in cognitive processes underlying...

The article introduces an interference model of working memory for information in a continuous similarity space, such as the features of visual objects. The model incorporates the following assumptions: (a) Probability of retrieval is determined by the relative activation of each retrieval candidate at the time of retrieval; (b) activation comes from 3 sources in memory: cue-based retrieval using context cues, context-independent memory for relevant contents, and noise; (c) 1 memory object and its context can be held in the focus of attention, where it is represented...

Growing evidence demonstrates that alpha-band (8–12 Hz) oscillations play an important role in spatial attention and working memory (WM). Here we combined electroencephalography (EEG) with an inverted spatial encoding model to examine whether the topography of alpha-band oscillations across the scalp tracks the specific spatial locations held in WM. Across three experiments, human participants performed spatial delayed-estimation tasks in which they remembered the precise angular location of a stimulus across a delay period and then reproduced that location on a...

Attentional control and working memory capacity are important cognitive abilities that substantially vary between individuals. Although much is known about how attentional control and working memory capacity relate to each other and to constructs like fluid intelligence, little is known about how trialby- trial fluctuations in attentional engagement impact trial-bytrial working memory performance. Here, we employ a novel whole-report memory task that allowed us to distinguish between varying levels of attentional engagement in humans performing a working memory task....

Three questions have been prominent in the study of visual working memory limitations: (a) What is the nature of mnemonic precision (e.g., quantized or continuous)? (b) How many items are remembered? (c) To what extent do spatial binding errors account for working memory failures? Modeling studies have typically focused on comparing possible answers to a single one of these questions, even though the result of such a comparison might depend on the assumed answers to both others. Here, we consider every possible combination of previously proposed answers to the...