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Mental Imagery and Visual Working Memory

DOI: 10.1371/journal.pone.0029221
Keogh, R., & Pearson, J. (2011). Mental imagery and visual working memory. PLoS ONE, 6(12), e29221. doi:10.1371/journal.pone.0029221

Abstract

Visual working memory provides an essential link between past and future events. Despite recent efforts, capacity limits, their genesis and the underlying neural structures of visual working memory remain unclear. Here we show that performance in visual working memory--but not iconic visual memory--can be predicted by the strength of mental imagery as assessed with binocular rivalry in a given individual. In addition, for individuals with strong imagery, modulating the background luminance diminished performance on visual working memory and imagery tasks, but not working memory for number strings. This suggests that luminance signals were disrupting sensory-based imagery mechanisms and not a general working memory system. Individuals with poor imagery still performed above chance in the visual working memory task, but their performance was not affected by the background luminance, suggesting a dichotomy in strategies for visual working memory: individuals with strong mental imagery rely on sensory-based imagery to support mnemonic performance, while those with poor imagery rely on different strategies. These findings could help reconcile current controversy regarding the mechanism and location of visual mnemonic storage.

Authors

  • Rebecca Keogh15
  • Joel Pearson30

Understanding Visual Working Memory and Mental Imagery

Overview/Introduction

Visual working memory is crucial for connecting past experiences with future actions. It helps us remember and process visual information, but its capacity and the brain mechanisms behind it are still debated. This research explores how mental imagery—our ability to visualize things in our mind—relates to visual working memory. The study finds that people with strong mental imagery perform better in visual working memory tasks, and this performance can be influenced by changes in background light.

Methodology

The study involved 35 undergraduate students who participated in various memory and imagery tasks. Researchers used a technique called binocular rivalry to measure mental imagery strength. Participants were shown different visual patterns and asked to remember them. The study also tested how changes in background luminance (light) affected their performance. Tasks included visual working memory, iconic memory, and number-string memory, each designed to test different aspects of memory and imagery.

Key Findings

  • Mental Imagery and Visual Working Memory: Individuals with strong mental imagery performed better in visual working memory tasks. Their ability to visualize helped them remember visual information more accurately.
  • Impact of Luminance: For those with strong imagery, increasing background luminance reduced their performance in visual working memory and imagery tasks. This suggests that bright backgrounds disrupt sensory-based imagery processes.
  • Different Strategies: People with weaker mental imagery still performed well in visual working memory tasks, indicating they might use different strategies, such as verbal or semantic methods, to remember visual information.

Implications

  • Cognitive Strategies: The study suggests that people use different cognitive strategies for visual working memory tasks. Those with strong imagery rely on visualizing, while others might use more abstract or language-based strategies.
  • Educational and Clinical Applications: Understanding these differences can help tailor educational approaches and cognitive therapies, especially for individuals with varying memory and imagery abilities.
  • Theoretical Models: The findings challenge existing models of visual working memory by highlighting the role of individual differences in mental imagery.

Limitations

  • Sample Size and Diversity: The study involved a relatively small and homogenous group of participants, which may limit the generalizability of the findings.
  • Task Specificity: The tasks used in the study may not capture all aspects of visual working memory and imagery, suggesting the need for further research with diverse tasks and larger participant groups.
In summary, this research sheds light on the complex relationship between mental imagery and visual working memory, emphasizing the importance of individual difference...