The researchers at the National Institute for Physiological Sciences in Japan have made a fascinating discovery. They found that when digital numerals are partially obscured, our brains can interpret their meanings in multiple ways. Additionally, prolonged exposure to normal numerals can influence how we perceive the partially obscured ones.
Understanding numerical characters is crucial for functioning in modern society. By studying the mechanisms behind how we recognize and interpret these characters, we can gain valuable insights.
In this study, the researchers investigated a phenomenon called bistable perception, focusing on a specially designed character called an occluded digital numeral. This research sheds light on the complex processes involved in recognizing numbers and has implications for various electronic applications such as traffic countdown timers and digital calculators.
“Because of the simple design of digital numerals, a partial occlusion causes visual ambiguities. In other words, the visual input does not contain enough information for us to make a unique semantic interpretation of the occluded numerical character,” said Dr. Junxiang Luo of the National Institute for Physiological Sciences, a researcher who led this project.
Researchers conducted a compelling behavioral experiment on healthy human participants using visual adaptation tasks. This innovative task paradigm effectively examined how exposure to specific types of visual input biases perception. Following the prolonged presentation of normal digital numerals to the visual system, participants consistently reported seeing a unique number biased away from the adaptation numeral.
“Visual adaptation selectively reduces the neural sensitivity of a certain visual processing stage to a certain category of visual stimuli, so by evaluating how much the interpretation biases away from the bistable state after adaptation to different types of visual information, we have a chance to know at which visual processing level that the perceptual recognition of numerals may happen,” said Dr. Luo.
The researchers have identified a range of potential adaptation stimuli. They have found that the observed bistability is not influenced by basic visual information or high-level semantic content, indicating that midlevel visual processing, which encodes complex shapes and symbolic number forms, may play a crucial role.
This psychophysical discovery could pave the way for future physiological studies, allowing researchers to investigate brain activity during different perceptual interpretations of occluded numerals.
“We hope to extend this study using some physiological methods to get a deeper understanding and more precise localization of the brain areas that generate the perceptual bistability,” said Dr. Luo.
Journal reference:
- Junxiang Luo, Isao Yokoi, Serge O. Dumoulin, Hiromasa Takemura. Bistable perception of symbolic numbers. Journal of Vision, 2024; DOI: 10.1167/jov.24.9.12
