It's a topic that comes up in almost every debate between theists and atheists; why do surveys consistently indicate that the more education a person has the less likely they are to believe in gods? We've all seen polls like this that indicate the more educated one is the less likely they are to hold religious beliefs.
I would like to suggest that the reason better educated people tend to be non-believers in religion isn't what they know but rather how they came to know it. Education requires a desire to learn. Those who continue, often throughout their lives, to seek more education than they already have are conditioned by the process of learning to understand that their present knowledge is incomplete and that their awareness will change the more they learn. Wanting to learn requires a mind open to new possibilities or ideas not considered before; it requires healthy skepticism and the ability to discern well-establish information from guesswork and conjecture. Formal higher education generally imbues a student with an appreciation for references and additional sources, footnotes and citations. (I said "generally" remembering I'm not that far from Liberty University where those values are not appreciated.)
That said, there is truth in the claim that education can decrease a person's belief in unnatural or supernatural concepts like religion and superstitions. For example, once you learn the natural explanations for thunder and lightning there's no more need to wonder if Zeus is really behind those phenomena. Yet science does not provide us with absolute knowledge. All scientific conclusions about reality and the universe are conditional; subject to change as we continue to encounter more evidence and create better tools for examining it. Because science cannot and will not reach an absolute conclusion about things like the origin of life and the universe, knowledge alone is insufficient as a reason to disbelieve in gods. After all, it could easily be said that god exists in the parts of the universe we haven't explored or in a realm of reality inaccessible to science.For that reason alone I think contending that what we know is sufficient to explain why the better educated eschew religious belief misses the mark.
If the learned are less theistic I think it can be attributed to the process of learning and the values that process instills in students. They believe less because their goal is to know more.