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The Functional Impact of Mental Imagery on Conscious Perception

DOI: 10.1016/j.cub.2008.05.048
Pearson, J., Clifford, C. W., & Tong, F. (2008). The functional impact of mental imagery on conscious perception. Current Biology, 18(13), 982–986. doi:10.1016/j.cub.2008.05.048

Abstract

Mental imagery has been proposed to contribute to a variety of high-level cognitive functions, including memory encoding and retrieval, navigation, spatial planning, and even social communication and language comprehension 1, 2, 3, 4, 5. However, it is debated whether mental imagery relies on the same sensory representations as perception 1, 6, 7, 8, 9, 10, and if so, what functional consequences such an overlap might have on perception itself. We report novel evidence that single instances of imagery can have a pronounced facilitatory influence on subsequent conscious perception. Either seeing or imagining a specific pattern could strongly bias which of two competing stimuli reach awareness during binocular rivalry. Effects of imagery and perception were location and orientation specific, accumulated in strength over time, and survived an intervening visual task lasting several seconds prior to presentation of the rivalry display. Interestingly, effects of imagery differed from those of feature-based attention. The results demonstrate that imagery, in the absence of any incoming visual signals, leads to the formation of a short-term sensory trace that can bias future perception, suggesting a means by which high-level processes that support imagination and memory retrieval may shape low-level sensory representations.

Authors

  • Joel Pearson28
  • Colin W.G. Clifford1
  • Frank Tong2

Understanding the Impact of Mental Imagery on Perception

Overview/Introduction

Mental imagery, the ability to visualize things in our mind without any external visual input, plays a crucial role in various cognitive functions like memory, navigation, and language. However, there has been debate about whether mental imagery uses the same sensory processes as actual perception. This study explores how imagining a visual pattern can influence what we consciously perceive later, especially when faced with competing visual stimuli.

Methodology

To investigate this, researchers used a phenomenon called binocular rivalry, where two different images are shown to each eye, causing the brain to alternate between them. Participants were asked to either imagine or passively view these patterns. The study measured how these mental images affected which pattern participants perceived as dominant during subsequent rivalry displays.
  • Participants viewed a green vertical grating with one eye and a red horizontal grating with the other.
  • They reported which pattern appeared dominant after each presentation.
  • The effects of imagining versus seeing these patterns were compared, along with the influence of weak visual stimuli and feature-based attention.

Key Findings

  • Imagery Biases Perception: Imagining a pattern increased the likelihood of perceiving that pattern as dominant in future rivalry displays.
  • Specific and Accumulative Effects: The effects were specific to the location and orientation of the imagined pattern and grew stronger with prolonged imagery.
  • Comparison with Weak Visual Stimulation: Imagining a pattern had similar effects to viewing a faint version of it, suggesting that both create a short-term sensory trace.
  • Distinct from Attention: The effects of mental imagery differed from those of feature-based attention, which influenced perception more quickly and consistently across different conditions.

Implications

These findings suggest that mental imagery can create a sensory memory trace that influences future perception. This has practical implications for understanding how our expectations and memories shape what we see. It could impact fields like visual learning, rehabilitation for visual impairments, and even virtual reality design, where mental imagery could be harnessed to enhance user experience.

Limitations

While the study provides valuable insights, it mainly focuses on visual patterns and may not fully represent how imagery affects other types of sensory perception. Additionally, the effects were tested under controlled conditions, which might differ from real-world scenarios.
In conclusion, this research highlights the powerful role of mental imagery in shaping our conscious perception, opening new avenues for exploring how the mind's eye influences the way we see the world.