Whenever people experience specific medical symptoms, they might research it online and find out that there is a possibility of a certain cancer being the culprit, they then might see that the chances of getting that cancer is 1 in a million. So they would often shrug it off as "Well that will never happen to me!", whereas that same person might go to the local store to purchase a lottery ticket that has a chance of winning set at 1 in 30 million and they then feel like the chance is high enough to win.
I am looking to find out if there is a particular name for this type of behaviour / thought process. I'm interested in research papers regarding these behaviours.