In just under 10 minutes, Hank Green of YouTube’s famous SciShow gives the most scientific (while easily understandable) explanation of why people opt out of vaccines. His video follows the thinking of Nobel Prize winner Daniel Kahneman who claims that “[p]eople are much more afraid of their children dying from a vaccine than they are from a child dying of an illness that spreads naturally. If something would happen to their child after being vaccinated, their decision becomes a focus of enormous regret.” In Kahneman’s 2011 best seller, “Thinking, Fast and Slow,” he argues 2 systems of thinking. “System 1 is the automatic, reflexive process that fires when an event causes an emotional response.” “System 2, is the thought process involving slow, deliberate, conscious effort.” According to Kahneman, it’s System 2 thinking that is in use when an individual considers the benefits and risks of vaccines, but by then, fear of harm to the child has engaged System 1 thinking. No matter how many peer-reviewed studies disprove the infamous (and debunked) article linking autism to vaccines, there are enough parents out there today without proper answers to the inexplicable rise in autism diagnoses, who are going to find answers on their own, usually on the Internet. “And so a community is born, and the safety of vaccines is called into question,” Green says. Ironically, Green also adds that much of this ability to question vaccines is due to the success of vaccines themselves. We’ve also just forgotten how awful diseases like measles really are. The looming threat of autism is a lot more real to today’s parents than the risk of getting a disease that they know very little about. Unfortunately, that is a very dangerous way to think about a child’s health. Our inability to properly asses future risks is causing us to relearn (the hard way) why we should prevent previously eradicated diseases. We all suffer from logic traps and cognitive biases. And that’s OK. As Green so gently emphasizes, being bad at risk perception is not an anti-vaxxer problem, it’s a human problem.