For our eyes, reading is hardly a smooth ride. They stutter across the page, lingering over words that surprise or confuse, hopping over those that seem obvious in context (you can blame that for your typos), pupils widening when a word sparks a potent emotion. All this commotion is barely noticeable, occurring in milliseconds. But for psychologists who study how our minds process language, our unsteady eyes are a window into the black box of our brains.

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