Atheists act like they are more rational than theists does atheism make a person more rational?
When it comes right down to it, atheism itself doesnt inherently mean all that much. Fundamentally, atheism itself isnt anything more than not believing in any gods. Why or how one might be without belief in gods is no more relevant to the definition of atheism than why or how one might believe in gods is relevant to the definition of theism.
What this indicates, then, is that the why and how of atheism will vary from individual to individual thus, not every atheist is going to be rational or even be an atheist because of rational reasons. Although gullibility is often attributed primarily to theists, the fact of the matter is atheists can just as easily fall victim to it.
Atheism and skepticism should go together, but in reality they often dont and many atheists are very unskeptical when it comes to all sorts of political, social, religious, and paranormal beliefs. There are many atheists who believe in ghosts, psychic powers, astrology, and many other irrational ideas being an atheist doesnt make them totally rational in every sphere.
Despite this, some atheists continue to assume that the superiority of skepticism over gullibility means that atheism is somehow inherently superior to theism and religion. Thus we will find some arguing that atheists are necessarily more rational or just plain better than theists. That, however, is not only naked bigotry, but is in fact an example of how atheists can fail to be rational and adopt just the sort of ridiculous beliefs which they find contemptible in others.
Skeptical atheists should make a habit of questioning the validity of religious and theist claims by requiring evidence which would allow for proof or disproof something which must be consciously practiced because it does not come naturally just because a person is an atheist. This does not mean simply dismissing theistic claims without a second glance (except, perhaps, when you really have heard it a million times).
Instead, it means giving the claimant a chance to support their assertions and then evaluating whether those assertions are credible or not. Reasonable skepticism is thus also an essential component of freethought (the idea that decisions about religion should be made independently and without relying on the demands of either authority or tradition). It is not the ultimate conclusions which are important to freethought; rather it is the method of arriving at those conclusions which constitutes its defining principle.
Naturally, such skeptical methodology is not infallible or immune to problems. Just because a claim cannot survive close skeptical questioning doesnt meant that it is false what it does mean, however, is that we dont have good reason to believe it, even if it is true. A rational skeptic is someone who insists that we have good reasons to believe something and who rejects a belief simply because it is emotionally or psychologically appealing. A person who believes something without having good reasons for it is not rational and that includes both atheists and theists.
On the other hand, a false claim might make it through our questioning. Because we lack the relevant facts or because of errors in thinking, we might come to believe an incorrect idea even though we have applied our critical tools to the best of our ability. Many people have believed the wrong things for the right reasons.
Thus, it should be clear that an important aspect of skepticism and a habit of reasonableness is that both the acceptance and the rejection of claims be provisional. If our beliefs are rational, then we always acknowledge them as fallible and we are always willing to amend in the light of new evidence or arguments.