scholarly journals Working memory implements distinct maintenance mechanisms depending on task goals

2017 ◽  
Author(s):  
Johannes J. Fahrenfort ◽  
Jonathan Van Leeuwen ◽  
Joshua J. Foster ◽  
Edward Awh ◽  
Christian N.L. Olivers
Keyword(s):  
Working Memory ◽  
Visual Search ◽  
Search Task ◽  
Visual Search Task ◽  
Recall Task ◽  
Neural Mechanisms ◽  
The Other ◽  
Informational Content ◽  
Current Task ◽  
Task Goals

AbstractWorking memory is the function by which we temporarily maintain information to achieve current task goals. Models of working memory typically debate where this information is stored, rather than how it is stored. Here we ask instead what neural mechanisms are involved in storage, and how these mechanisms change as a function of task goals. Participants either had to reproduce the orientation of a memorized bar (continuous recall task), or identify the memorized bar in a search array (visual search task). The sensory input and retention interval were identical in both tasks. Next, we used decoding and forward modeling on multivariate electroencephalogram (EEG) and time-frequency decomposed EEG to investigate which neural signals carry more informational content during the retention interval. In the continuous recall task, working memory content was preferentially carried by induced oscillatory alpha-band power, while in the visual search task it was more strongly carried by the distribution of evoked (consistently elevated and non-oscillatory) EEG activity. To show the independence of these two signals, we were able to remove informational content from one signal without affecting informational content in the other. Finally, we show that the tuning characteristics of both signals change in opposite directions depending on the current task goal. We propose that these signals reflect oscillatory and elevated firing-rate mechanisms that respectively support location-based and object-based maintenance. Together, these data challenge current models of working memory that place storage in particular regions, but rather emphasize the importance of different distributed maintenance signals depending on task goals.Significance statement (120 words)Without realizing, we are constantly moving things in and out of our mind’s eye, an ability also referred to as ‘working memory’. Where did I put my screwdriver? Do we still have milk in the fridge? A central question in working memory research is how the brain maintains this information temporarily. Here we show that different neural mechanisms are involved in working memory depending on what the memory is used for. For example, remembering what a bottle of milk looks like invokes a different neural mechanism from remembering how much milk it contains: the first one primarily involved in being able to find the object, and the other one involving spatial position, such as the milk level in the bottle.

Bottom-up perceptual salience and top-down retro-cues concurrently determine state in visual working memory

2020 ◽  
pp. 174702182096626
Author(s):  
Lingxia Fan ◽  
Lin Zhang ◽  
Liuting Diao ◽  
Mengsi Xu ◽  
Ruiyang Chen ◽  
...  
Keyword(s):  
Working Memory ◽  
Visual Search ◽  
Visual Working Memory ◽  
Search Task ◽  
Visual Search Task ◽  
Salient Feature ◽  
Active State ◽  
Top Down ◽  
Bottom Up ◽  
Perceptual Salience

Recent studies have demonstrated that in visual working memory (VWM), only items in an active state can guide attention. Further evidence has revealed that items with higher perceptual salience or items prioritised by a valid retro-cue in VWM tend to be in an active state. However, it is unclear which factor (perceptual salience or retro-cues) is more important for influencing the item state in VWM or whether the factors can act concurrently. Experiment 1 examined the role of perceptual salience by asking participants to hold two features with relatively different perceptual salience (colour vs. shape) in VWM while completing a visual search task. Guidance effects were found when either colour or both colour and shape in VWM matched one of the search distractors but not when shape matched. This demonstrated that the more salient feature in VWM can actively guide attention, while the less salient feature cannot. However, when shape in VWM was cued to be more relevant (prioritised) in Experiment 2, we found guidance effects in both colour-match and shape-match conditions. That is, both more salient but non-cued colour and less salient but cued shape could be active in VWM, such that attentional selection was affected by the matching colour or shape in the visual search task. This suggests that bottom-up perceptual salience and top-down retro-cues can jointly determine the active state in VWM.

Influence of Selection Difficulty on the Time Required for Icon Formation

Perception ◽  
1976 ◽  
Vol 5 (2) ◽  
pp. 225-231
Author(s):  
Robert T Solman
Keyword(s):  
Information Processing ◽  
Visual Search ◽  
Search Task ◽  
Visual Search Task ◽  
Probability Distributions ◽  
Target Selection ◽  
The Other ◽  
Cumulative Probability ◽  
Physical Similarity ◽  
Time Required

By increasing the number of display items and the physical similarity between the target and the irrelevant items it was possible to vary the difficulty of target selection in a visual-search task. The results showed that the accuracy with which the target was located declined as target selection became more difficult. On the other hand, estimates of the cumulative probability and the probability distributions of times necessary to form the icon indicated that these times were not influenced by changes in the difficulty of the task. The latter result supports Neisser's suggestion that the information processing carried out during the first stage of analysis can be attributed to the action of a distinct cognitive mechanism.

Visual Search Using Microfiche: Effects of Microfiche Reader Screen Scintillation on Visual Fatigue, General Fatigue, and Performance

1978 ◽  
Vol 22 (1) ◽  
pp. 299-302 ◽  
Author(s):  
William H. Cushman
Keyword(s):  
Visual Search ◽  
Search Task ◽  
Visual Search Task ◽  
The Other ◽  
Visual Fatigue ◽  
General Fatigue ◽  
Dependent Variables ◽  
And Performance

Nine subjects performed a visual search task for two 100-minute sessions using microfiche with positive appearing images and small, portable microfiche readers. During one session the subjects performed the task with a reader having a screen with highly visible scintillation. During the other they used a reader equipped with a screen that was nearly free from scintillation. Dependent variables were subjective visual fatigue, general fatigue, and number of targets located. Subjects reported significantly greater visual fatigue after viewing the “high” scintillation screen for 50–100 minutes than after viewing the “low” scintillation screen for the same length of time. When the high-scintillation screen was used, the subjects also reported an increase in general fatigue. Screen scintillation did not affect the subjects' performance on the search task, however.

scholarly journals Concurrent Guidance of Attention by Multiple Working Memory Items: Behavioral and Computational Evidence

2019 ◽  
Author(s):  
Cherie Zhou ◽  
Monicque M. Lorist ◽  
Sebastiaan Mathôt
Keyword(s):  
Working Memory ◽  
Visual Search ◽  
Visual Working Memory ◽  
Search Task ◽  
Visual Search Task ◽  
Response Times ◽  
Behavioral Data ◽  
Drift Diffusion ◽  
Single Item ◽  
Multiple Item

AbstractDuring visual search, task-relevant representations in visual working memory (VWM), known as attentional templates, are assumed to guide attention. A current debate concerns whether only one (Single-Item-Template hypothesis, or SIT) or multiple (Multiple-Item-Template hypothesis, or MIT) items can serve as attentional templates simultaneously. The current study was designed to test these two hypotheses. Participants memorized two colors, prior to a visual-search task in which the target and the distractor could match or not match the colors held in VWM. Robust attentional guidance was observed when one of the memory colors was presented as the target (reduced response times [RTs] on target-match trials) or the distractor (increased RTs on distractor-match trials). We constructed two drift-diffusion models that implemented the MIT and SIT hypotheses, which are similar in their predictions about overall RTs, but differ in their predictions about RTs on individual trials. Critically, simulated RT distributions and error rates revealed a better match of the MIT hypothesis to the observed data than the SIT hypothesis. Taken together, our findings provide behavioral and computational evidence for the concurrent guidance of attention by multiple items in VWM.Significance statementTheories differ in how many items within visual working memory can guide attention at the same time. This question is difficult to address, because multiple- and single-item-template theories make very similar predictions about average response times. Here we use drift-diffusion modeling in addition to behavioral data, to model response times at an individual level. Crucially, we find that our model of the multiple-item-template theory predicts human behavior much better than our model of the single-item-template theory; that is, modeling of behavioral data provides compelling evidence for multiple attentional templates that are simultaneously active.

scholarly journals Can you have multiple attentional templates? Large-scale replications of Van Moorselaar, Theeuwes and Olivers (2014) and Hollingworth and Beck (2016)

2018 ◽  
Author(s):  
Marcella Frătescu ◽  
Dirk Van Moorselaar ◽  
Sebastiaan Mathôt
Keyword(s):  
Working Memory ◽  
Visual Search ◽  
Boundary Conditions ◽  
Visual Working Memory ◽  
Large Scale ◽  
Search Task ◽  
Visual Search Task ◽  
Multiple State ◽  
Bias Attention ◽  
Larger Sample

AbstractStimuli that resemble the content of visual working memory (VWM) capture attention. However, theories disagree on how many VWM items can bias attention simultaneously. The multiple-state account posits a distinction between template and accessory VWM items, such that only a single template item biases attention. In contrast, homogenous-state accounts posit that all VWM items bias attention. Recently, Van Moorselaar et al. (2014) and Hollingworth and Beck (2016) tested these accounts, but obtained seemingly contradictory results. Van Moorselaar et al. (2014) found that a distractor in a visual-search task captured attention more when it matched the content of VWM (memory-driven capture). Crucially, memory-driven capture disappeared when more than one item was held in VWM, in line with the multiple-state account. In contrast, Hollingworth and Beck (2016) found memory-driven capture even when multiple items were kept in VWM, in line with a homogenous-state account. Considering these mixed results, we replicated both studies with a larger sample, and found that all key results are reliable. It is unclear to what extent these divergent results are due to paradigm differences between the studies. We conclude that is crucial to our understanding of VWM to determine the boundary conditions under which memory-driven capture occurs.

Colour Mechanisms Underlying Visual Search with Heterochromatic Distractors

Perception ◽  
1997 ◽  
Vol 26 (1_suppl) ◽  
pp. 50-50
Author(s):  
H Yamamoto ◽  
Y Ejima
Keyword(s):  
Visual Search ◽  
Test Stimulus ◽  
Search Task ◽  
Visual Search Task ◽  
The Other ◽  
Chance Level ◽  
Central Angle ◽  
Colour Space ◽  
Target Direction

We studied the colour mechanisms involved in a visual search task. The test stimulus consisted of a coloured target randomly positioned among heterogeneous distractors of two colours. Colours of the target and distractors were specified in the equiluminous plane; a pair of distractors was set to lie on a circle around the target and characterised by the radius, central angle, and chromatic direction of a right bisector of the chord between the pair. The stimulus was presented briefly, and observers were asked to report whether a target was present. Target detectability quantified by d' depended on the central angle and the chromatic direction of the bisector. The central angle affected the detectability of the coloured target but not that of the white one. The coloured-target detectability decreased and reached chance level with increasing central angle from 0° to 180°. For a fixed obtuse central angle, maxima of the coloured-target detectability occurred at two bisector directions, one orthogonal to the target direction and the other along the target direction. This suggests that only two orthogonal colour mechanisms were at play and they changed with the colour of the target. These results and previous findings that the target was detected preattentively when it was linearly separable from the distractors in colour space (D'Zmura, 1991 Vision Research31 951 – 966; Bauer et al, 1996 Vision Research36 1439 – 1465) may be explained by the same processes, colour selective filters that linearly combine cone signals followed by peak detectors.

Foggy windows: Pupillary responses during task preparation

2018 ◽  
Vol 71 (10) ◽  
pp. 2235-2248 ◽  
Author(s):  
Alexandra Trani ◽  
Paul Verhaeghen
Keyword(s):  
Working Memory ◽  
Visual Search ◽  
Search Task ◽  
Visual Search Task ◽  
Memory Task ◽  
Pupil Dilation ◽  
Attentional Resources ◽  
Task Preparation ◽  
Pupillary Responses ◽  
Post Trial

We investigated pupil dilation in 96 subjects during task preparation and during a post-trial interval in a visual search task and an auditory working memory task. Completely informative difficulty cues (easy, medium, or hard) were presented right before task preparation to examine whether pupil dilation indicated advance mobilisation of attentional resources; functional magnetic resonance imaging (fMRI) studies have argued for the existence of such task preparation, and the literature shows that pupil dilation tracks attentional effort during task performance. We found, however, little evidence for such task preparation. In the working memory task, pupil size was identical across cues, and although pupil dilation in the visual search task tracked the cue, pupil dilation predicted subsequent performance in neither task. Pupil dilation patterns in the post-trial interval were more consistent with an effect of emotional reactivity. Our findings suggest that the mobilisation of attentional resources in the service of the task does not occur during the preparatory interval, but is delayed until the task itself is initiated.

Role of aging and working memory in performance on a naturalistic visual search task

Cortex ◽  
2020 ◽  
Author(s):  
Jasmine R. Aziz ◽  
Samantha R. Good ◽  
Raymond M. Klein ◽  
Gail A. Eskes
Keyword(s):  
Working Memory ◽  
Visual Search ◽  
Search Task ◽  
Visual Search Task
Sign in / Sign up

Export Citation Format

Share Document