A few weeks ago, I was having dinner with a friend when a controversial subject came up. My friend had an extremely strong opinion about the harm caused by vaccination, and his argument went something like this: "I've seen the data. There was an infographic laying it all out." He couldn't remember specific numbers from the visualization he'd seen or the author of the article. He couldn't even remember the name of the publication, but the data visualization's overall argument was firmly lodged in his mind. His situation is not unique, and it provides telling insights on how we, as humans, perceive and respond to big data visualization.