Blind People Understand Color Through Language

Article: Blind People Can’t See Color but Understand It the Same Way as Sighted People
Source: Johns Hopkins University, via ScienceDaily, Technology Networks  and NEI
Published: August 16, 2021

How we learn what we know—whether through direct sensory experience, talking with others, or reasoning through our own thoughts—is a puzzle for empirical philosophy, whose subject matter centers on the idea that to truly know something, one must experience it directly. Recent research sheds light on this question through comparing the understanding of visual phenomena, in this case color, between congenitally blind and sighted people, only the latter of whom have personally experienced color. Contrary to what was predicted by empiricist philosophers such as John Locke, who argued that although individuals who are born blind might grasp arbitrary color facts without an understanding of color, cognitive neuroscientists found that both congenitally blind and sighted individuals possess in-depth understanding of object color, often making similar generative inferences for novel objects and giving similar causal explanations, although they do not necessarily agree about arbitrary color facts. For example, both blind and sighted people can infer that two natural kinds, e.g., two bananas, are more likely to have the same color. Similarly, both blind and sighted people can infer that two objects with functional colors, e.g., two stops signs, are more likely to have the same color than two objects with nonfunctional colors, e.g., two cars. However, relative to sighted people, blind people are less likely to infer that bananas are yellow or that stop signs are red. Even more surprising, blind people can sometimes generate independent, coherent causal explanations for object color. For example, when asked to predict the color of a polar bear, while sighted individuals said that polar bears are white to camouflage with the snow, some blind individuals said that polar bears are black in order to absorb heat and stay warm. The intuitions applied to novel scenarios, independent of memory, such as when asked to predict the color of objects on an imaginary island. These examples revealed that people develop intuitive and inferentially rich “theories” of color regardless of visual experience, and in turn illustrates the effectiveness of linguistic exposure and communication with people who talk about color as sufficient for forming intuitive theories and understanding of color. The researchers next plan to study how and when color understanding develops in the brain among blind and sighted children.

My rating of this study: ⭐⭐

Kim JS, Aheimer B, Manrara VM, et al. "Shared understanding of color among sighted and blind adults." PNAS.  118(33):e2020192118. 17 August 2021. https://doi.org/10.1073/pnas.2020192118