“Acupuncture relieved my back pain, that’s why I know it works.”
“After my daughter got vaccinated when she was two, she became autistic. How can anyone think that vaccines don’t cause autism?”
“My uncle’s wife’s nephew’s cousin’s neighbour had his cancer go into remission after using only herbal remedies. They’re way better than chemotherapy.”
“Homeopathy is effective because I am living proof that it can cure herpes.”
You may know someone who has expressed something similar to the above. Perhaps you yourself have a personal story to tell about how you became a believer in carb-free dieting/UFO abductions/traditional Chinese medicine after being exposed to ‘evidence’ that confirmed your biases. The confirmation bias and cherry picking fallacies are largely responsible for why Aunt Maria insists that it’s the power of prayer that cured her of her haemorrhoids.
Steven Novella has written a brilliant article explaining how anecdotes and anomalies can lead people to draw inaccurate or plain wrong conclusions, and why a large volume of personal testimonies does not count as proof. The plural of ‘anecdote’ is ‘anecdotes’, not ‘data’. Dr Novella’s article educates us on the nature and proper role of both anecdotes and anomalies in science. As he writes, “Context is king.”
I highly recommend that you also read the comments in response to the post. They contain more instructive information and examples of faulty thinking that further illustrate Dr Novella’s points.
This kind of knowledge should really be taught in schools to develop students’ critical thinking skills. It would certainly reduce the number of adults who subscribe to all sorts of dubious beliefs, simply because they lack an understanding of logical fallacies like confirmation bias, cherry picking, argument from ignorance, equating correlation with causation, and creating false dichotomies. Many don't know how to think about thinking – what psychologists call ‘exercising metacognition’. Thankfully we have great science educators like Dr Novella to teach us the ropes.