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More than meets the eye: implicit perception in legally blind individuals
Alan S Brown1, Michael R Best, David B Mitchell
1Department of Psychology, Dedman College, Southern Methodist University, Dallas TX 75275, United States.
Consciousness and Cognition
|August 6, 2013
Summary
Legally blind individuals can identify visual cues like clock hands without conscious awareness. This suggests an unconscious visual pathway may process degraded visual input, aiding implicit perception.
Area of Science:
- Neuroscience
- Cognitive Psychology
- Ophthalmology
Background:
- The capacity for visual perception in individuals with severe visual impairment is an area of ongoing research.
- Implicit perception, or processing information without conscious awareness, has been demonstrated in various contexts.
Purpose of the Study:
- To investigate whether legally blind individuals can identify visual stimulus attributes unconsciously.
- To explore the role of unconscious visual processing in degraded visual input.
Main Methods:
- Legally blind participants (vision 20/200+) performed a visual identification task with corrective lenses removed.
- Participants guessed the hour-hand position on clock faces presented on a computer screen, in single-display and multiple-display conditions.
Main Results:
- Participants correctly identified the hour-hand position above chance levels in both single (28%) and multiple (21%) clockface displays.
- Accuracy in identifying the hand's presence in a multi-clockface display was similar whether the correct clockface was consciously identified or not (21% vs. 20%).
Conclusions:
- Legally blind individuals demonstrate the ability to perceive visual attributes unconsciously.
- Findings support the existence of an unconscious visual processing pathway, potentially via the superior colliculi, that can utilize degraded visual input.
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