Being an expert can literally change the way you see

"You might assume we have basic vision machinery and that you could detect features of different letters even if you didn't know the language. But that's not the case," says Brenda Rapp. (Credit: Hernán Piñera/Flickr)

Do you see what I see when we look at the same thing? Perhaps not, if you know more about it than I do.

Objects can look significantly different to someone familiar with them than to someone who isn’t, a new study suggests.

“What we find [in the study] should hold true for any sort of object—cars, birds, faces. Expertise matters. It changes how you perceive things,” says Robert W. Wiley, a cognitive scientist at Johns Hopkins University. “Part of being an expert is learning what matters and what doesn’t matter—including visual features. You know what to look for.”

Wiley and colleagues studied the question using the Arabic alphabet as a frame of reference, looking at the perceptions of both experts in the language and subjects who didn’t know Arabic at all. They found clear evidence, they says, that visual processing is influenced by experience.

Arabic letter chart
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. The two groups saw the letters quite differently. (Credit: Robert W. Wiley/JHU)

Their findings are reported online by the Journal of Experimental Psychology: Human Perception and Performance.

“You might assume we have basic vision machinery and that you could detect features of different letters even if you didn’t know the language. But that’s not the case,” says senior author Brenda Rapp, a professor of cognitive sciences. “What you know affects how you see things.”

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Rapp and colleagues studied 25 experts in Arabic and 25 people who didn’t know the language. The team showed participants 2,000 pairs of letters, one pair at a time, and asked them to determine if the letters were the same or different. Answers were measured for speed and accuracy.

The team analyzed the results using a technique called hierarchical clustering to determine which letters looked similar to Arabic novices and which ones looked alike to experts in the language. Everyone tended to agree on the relationships between certain letters but there were also stark, surprising divergences.

The pairs that tripped up people who weren’t proficient in Arabic tended to look nothing like the ones that confused the Arabic speakers. Experts were biased by non-visual things they knew about the letters, like their names, how they are written, or the way they sound.

“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,'” says Wiley, the study’s lead author and a postdoctoral student. “If you’re an expert, things that look complex to a novice look simple to you.”

A grant from the National Institutes of Health funded the study.

Source: Johns Hopkins University