scholarly journals Working memory is not fixed capacity: More active storage capacity for real-world objects than simple stimuli

2020 ◽  
Author(s):  
Timothy F. Brady ◽  
Viola S. Störmer ◽  
George Alvarez
Keyword(s):  
Working Memory ◽  
Real World ◽  
Visual Information ◽  
Memory Task ◽  
Memory Systems ◽  
Long Term Memory ◽  
Term Memory ◽  
Active Storage ◽  
Working Memory Models

Visual working memory is the cognitive system that holds visual information active to make it resistant to interference from new perceptual input. Information about simple stimuli – colors, orientations – is encoded into working memory rapidly: in under 100ms, working memory ‘fills up’, revealing a stark capacity limit. However, for real-world objects, the same behavioral limits do not hold: with increasing encoding time, people store more real-world objects and do so with more detail. This boost in performance for real-world objects is generally assumed to reflect the use of a separate episodic long-term memory system, rather than working memory. Here we show that this behavioral increase in capacity with real-world objects is not solely due to the use of separate episodic long-term memory systems. In particular, we show that this increase is a result of active storage in working memory, as shown by directly measuring neural activity during the delay period of a working memory task using EEG. These data challenge fixed capacity working memory models, and demonstrate that working memory and its capacity limitations are dependent upon our existing knowledge.

scholarly journals Working memory is not fixed-capacity: More active storage capacity for real-world objects than for simple stimuli

2016 ◽  
Vol 113 (27) ◽  
pp. 7459-7464 ◽  
Author(s):  
Timothy F. Brady ◽  
Viola S. Störmer ◽  
George A. Alvarez
Keyword(s):  
Working Memory ◽  
Real World ◽  
Visual Information ◽  
Memory Task ◽  
Memory Systems ◽  
Long Term Memory ◽  
Term Memory ◽  
Active Storage ◽  
Working Memory Models

Visual working memory is the cognitive system that holds visual information active to make it resistant to interference from new perceptual input. Information about simple stimuli—colors and orientations—is encoded into working memory rapidly: In under 100 ms, working memory ‟fills up,” revealing a stark capacity limit. However, for real-world objects, the same behavioral limits do not hold: With increasing encoding time, people store more real-world objects and do so with more detail. This boost in performance for real-world objects is generally assumed to reflect the use of a separate episodic long-term memory system, rather than working memory. Here we show that this behavioral increase in capacity with real-world objects is not solely due to the use of separate episodic long-term memory systems. In particular, we show that this increase is a result of active storage in working memory, as shown by directly measuring neural activity during the delay period of a working memory task using EEG. These data challenge fixed-capacity working memory models and demonstrate that working memory and its capacity limitations are dependent upon our existing knowledge.

scholarly journals Interacting Memory Systems—Does EEG Alpha Activity Respond to Semantic Long-Term Memory Access in a Working Memory Task?

Biology ◽  
2014 ◽  
Vol 4 (1) ◽  
pp. 1-16 ◽  
Author(s):  
Barbara Berger ◽  
Serif Omer ◽  
Tamas Minarik ◽  
Annette Sterr ◽  
Paul Sauseng
Keyword(s):  
Working Memory ◽  
Memory Task ◽  
Memory Systems ◽  
Alpha Activity ◽  
Memory Access ◽  
Long Term Memory ◽  
Term Memory ◽  
Eeg Alpha ◽  
Eeg Alpha Activity

scholarly journals Neonatal Desflurane Exposure Induces More Robust Neuroapoptosis than Do Isoflurane and Sevoflurane and Impairs Working Memory

2011 ◽  
Vol 115 (5) ◽  
pp. 979-991 ◽  
Author(s):  
Mitsuyoshi Kodama ◽  
Yasushi Satoh ◽  
Yukiko Otsubo ◽  
Yoshiyuki Araki ◽  
Ryuji Yonamine ◽  
...  
Keyword(s):  
Working Memory ◽  
Open Field ◽  
Elevated Plus Maze ◽  
Memory Task ◽  
Adenosine Diphosphate ◽  
Long Term Memory ◽  
Neonatal Exposure ◽  
Term Memory ◽  
Plus Maze

Background In animal models, neonatal exposure to volatile anesthetics induces neuroapoptosis, leading to memory deficits in adulthood. However, effects of neonatal exposure to desflurane are largely unknown. Methods Six-day-old C57BL/6 mice were exposed to equivalent doses of desflurane, sevoflurane, or isoflurane for 3 or 6 h. Minimum alveolar concentration was determined by the tail-clamp method as a function of anesthesia duration. Apoptosis was evaluated by immunohistochemical staining for activated caspase-3, and by TUNEL. Western blot analysis for cleaved poly-(adenosine diphosphate-ribose) polymerase was performed to examine apoptosis comparatively. The open-field, elevated plus-maze, Y-maze, and fear conditioning tests were performed to evaluate general activity, anxiety-related behavior, working memory, and long-term memory, respectively. Results Minimum alveolar concentrations at 1 h were determined to be 11.5% for desflurane, 3.8% for sevoflurane, and 2.7% for isoflurane in 6-day-old mice. Neonatal exposure to desflurane (8%) induced neuroapoptosis with an anatomic pattern similar to that of sevoflurane or isoflurane; however, desflurane induced significantly greater levels of neuroapoptosis than almost equivalent doses of sevoflurane (3%) or isoflurane (2%). In adulthood, mice treated with these anesthetics had impaired long-term memory, whereas no significant anomalies were detected in the open-field and the elevated plus-maze tests. Although performance in a working memory task was normal in mice exposed neonatally to sevoflurane or isoflurane, mice exposed to desflurane had significantly impaired working memory. Conclusions In an animal model, neonatal desflurane exposure induced more neuroapoptosis than did sevoflurane or isoflurane and impaired working memory, suggesting that desflurane is more neurotoxic than sevoflurane or isoflurane.

scholarly journals Is working memory inherently more ‘precise’ than long-term memory? Extremely high fidelity visual long-term memories for frequently encountered objects

2019 ◽  
Author(s):  
Annalise Miner ◽  
Mark Schurgin ◽  
Timothy F. Brady
Keyword(s):  
Working Memory ◽  
Visual Working Memory ◽  
Visual Memory ◽  
Memory Systems ◽  
Long Term Memory ◽  
Continuous Measure ◽  
High Fidelity ◽  
Term Memory ◽  
Naturalistic Setting

Long-term memory is often considered easily corruptible, imprecise and inaccurate, especially in comparison to working memory. However, most research used to support these findings relies on weak long-term memories: those where people have had only one brief exposure to an item. Here we investigated the fidelity of visual long-term memory in more naturalistic setting, with repeated exposures, and ask how it compares to visual working memory fidelity. Using psychophysical methods designed to precisely measure the fidelity of visual memory, we demonstrate that long-term memory for the color of frequently seen objects is as accurate as working memory for the color of a single item seen 1 second ago. In particular, we show that repetition greatly improves long-term memory, including the ability to discriminate an item from a very similar item ('fidelity'), in both a lab setting (Exps. 1-3) and a naturalistic setting (brand logos, Exp. 4). Overall our results demonstrate the impressive nature of visual long-term memory fidelity, which we find is even higher fidelity than previously indicated in situations involving repetitions. Furthermore, our results suggest that there is no distinction between the fidelity of visual working memory and visual long-term memory, but instead both memory systems are capable of storing similar incredibly high fidelity memories under the right circumstances. Our results also provide further evidence that there is no fundamental distinction between the ‘precision’ of memory and the ‘likelihood of retrieving a memory’, instead suggesting a single continuous measure of memory strength best accounts for working and long-term memory.

scholarly journals Is Long-Term Memory Used in a Visuo-Spatial Change-Detection Paradigm?

2021 ◽  
Author(s):  
Benjamin Goecke ◽  
Klaus Oberauer
Keyword(s):  
Working Memory ◽  
Change Detection ◽  
Memory Performance ◽  
Memory Task ◽  
Repetition Effect ◽  
Long Term Memory ◽  
Memory Representation ◽  
Term Memory ◽  
Hebb Repetition Effect

In tests of working memory with verbal or spatial materials repeating the same memory sets across trials leads to improved memory performance. This well-established “Hebb repetition effect” could not be shown for visual materials. This absence of the Hebb effect can be explained in two ways: Either persons fail to acquire a long-term memory representation of the repeated memory sets, or they acquire such long-term memory representations, but fail to use them during the working memory task. In two experiments, (N1 = 18 and N2 = 30), we aimed to decide between these two possibilities by manipulating the long-term memory knowledge of some of the memory sets used in a change-detection task. Before the change-detection test, participants learned three arrays of colors to criterion. The subsequent change-detection test contained both previously learned and new color arrays. Change detection performance was better on previously learned compared to new arrays, showing that long-term memory is used in change detection.

Working Memory Has Better Fidelity Than Long-Term Memory: The Fidelity Constraint Is Not a General Property of Memory After All

2018 ◽  
Vol 30 (2) ◽  
pp. 223-237 ◽  
Author(s):  
Natalie Biderman ◽  
Roy Luria ◽  
Andrei R. Teodorescu ◽  
Ron Hajaj ◽  
Yonatan Goshen-Gottstein
Keyword(s):  
Working Memory ◽  
Hierarchical Modeling ◽  
Real Life ◽  
Memory Systems ◽  
Long Term Memory ◽  
Model Parameters ◽  
Total N ◽  
Term Memory ◽  
Memory Representations

How detailed are long-term-memory representations compared with working memory representations? Recent research has found an equal fidelity bound for both memory systems, suggesting a novel general constraint on memory. Here, we assessed the replicability of this discovery. Participants (total N = 72) were presented with colored real-life objects and were asked to recall the colors using a continuous color wheel. Deviations from study colors were modeled to generate two estimates of color memory: the variability of remembered colors—fidelity—and the probability of forgetting the color. Estimating model parameters using both maximum-likelihood estimation and Bayesian hierarchical modeling, we found that working memory had better fidelity than long-term memory (Experiments 1 and 2). Furthermore, within each system, fidelity worsened as a function of time-correlated mechanisms (Experiments 2 and 3). We conclude that fidelity is subject to decline across and within memory systems. Thus, the justification for a general fidelity constraint in memory does not seem to be valid.

scholarly journals Neural substrates of successful working memory and long-term memory formation in a relational spatial memory task

2016 ◽  
Vol 17 (4) ◽  
pp. 377-387 ◽  
Author(s):  
Heiko C. Bergmann ◽  
Sander M. Daselaar ◽  
Guillén Fernández ◽  
Roy P. C. Kessels
Keyword(s):  
Working Memory ◽  
Spatial Memory ◽  
Memory Task ◽  
Neural Substrates ◽  
Memory Formation ◽  
Long Term Memory ◽  
Term Memory ◽  
Spatial Memory Task

scholarly journals Expectations of Task Demands Dissociate Working Memory and Long-Term Memory Systems

2015 ◽  
Vol 26 (3) ◽  
pp. 1176-1186 ◽  
Author(s):  
T. P. Zanto ◽  
W. C. Clapp ◽  
M. T. Rubens ◽  
J. Karlsson ◽  
A. Gazzaley
Keyword(s):  
Working Memory ◽  
Memory Systems ◽  
Task Demands ◽  
Long Term Memory ◽  
Term Memory

scholarly journals Comparing Visual Memories to Novel Visual Input Risks Lasting Memory Distortion

2021 ◽  
Author(s):  
Joseph M. Saito ◽  
Katherine Duncan ◽  
Keisuke Fukuda
Keyword(s):  
Working Memory ◽  
Young Adults ◽  
Real World ◽  
Eyewitness Testimony ◽  
Long Term Memory ◽  
Memory Distortion ◽  
Term Memory ◽  
Memory Accuracy ◽  
Memory Distortions

Maintaining perceptual experiences in visual working memory (VWM) allows us to flexibly accomplish various tasks, but some tasks come at a price. For example, comparing VWM representations to novel perceptual inputs can induce inadvertent memory distortions. If these distortions persist, they may explain why everyday memories often become unreliable after people perform perceptual comparisons (e.g., eyewitness testimony). Here, we conducted two experiments to assess the consequences of perceptual comparisons using real-world objects that were temporarily maintained in VWM (n = 32) or recalled from long-term memory back into VWM (n = 30). In each experiment, young adults reported systematic memory distortions following perceptual comparisons. These distortions increased in magnitude with the delay between encoding and comparisons and were preserved when memories were retrieved again a day later. These findings suggest that perceptual comparisons play a mechanistic role in everyday memory distortions, including situations where memory accuracy is vital.

scholarly journals Is long-term memory used in a visuo-spatial change-detection paradigm?

2021 ◽  
Author(s):  
Benjamin Goecke ◽  
Klaus Oberauer
Keyword(s):  
Working Memory ◽  
Change Detection ◽  
Memory Performance ◽  
Memory Task ◽  
Repetition Effect ◽  
Long Term Memory ◽  
Memory Representation ◽  
Term Memory ◽  
Hebb Repetition Effect

AbstractIn tests of working memory with verbal or spatial materials, repeating the same memory sets across trials leads to improved memory performance. This well-established “Hebb repetition effect” could not be shown for visual materials in previous research. The absence of the Hebb effect can be explained in two ways: Either persons fail to acquire a long-term memory representation of the repeated memory sets, or they acquire such long-term memory representations, but fail to use them during the working memory task. In two experiments (N1 = 18 and N2 = 30), we aimed to decide between these two possibilities by manipulating the long-term memory knowledge of some of the memory sets used in a change-detection task. Before the change-detection test, participants learned three arrays of colors to criterion. The subsequent change-detection test contained both previously learned and new color arrays. Change detection performance was better on previously learned compared with new arrays, showing that long-term memory is used in change detection.

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