According to a recent study in the Journal of Experimental Psychology, knowledge has a real impact on how we see the world. From everyday objects like cars, plants, and animals, to letters of the alphabet, expertise can change the details that seem salient to us, and the way we draw comparisons between visually similar things. 

Using the Arabic alphabet, researchers compared the way experts in the language interpreted letter groups compared to how novices viewed the same letters. Researchers showed 25 experts and 25 novices pairs of letters and asked them to determine whether the letters were the same or different. Recording volunteers’ accuracy and speed, they found that experts were more accurate, while novices were quicker with their answers. Additionally, the more curves and lines a letter had, the slower novices were, while the opposite was true for experts. 


This chart groups letters based on how similar they looked to test participants who didn’t know Arabic and to test participants who were experts in the language. Johns Hopkins researchers found the two groups saw the letters quite differently. (via Johns Hopkins)

The researchers say the study illustrates the way knowledge—or familiarity with a subject—affects visual perception. “When you become an expert in reading an alphabet, what does that change? Does your visual system see the same thing as a beginner? We say no,” researcher Robert Wiley said in a press release. “If you’re an expert, things that look complex to a novice look simple to you.”

What's more, the researchers believe their study extends past letters, and can be applied to anything with which humans have visual experience. For instance, bird watchers likely see birds quite differently from those without avian expertise; mechanics and professional drivers see cars differently than casual drivers. “What we find should hold true for any sort of object—cars, birds, faces. Expertise matters. It changes how you perceive things,” says Wiley. “Part of being an expert is learning what matters and what doesn’t matter—including visual features. You know what to look for.”