There is an interesting study that has been floating around, referenced in articles such as The Conflict Between Science and Religion Lies in Our Brain, that religious / spiritual /emotional thinking shuts rational / scientific thinking. This has led some to jump to conclusions such as the idea that religious people are stupid (there is an association between lower intelligence and religious belief) or that atheists are sociopaths (there is an association between lack of empathy, a key component of sociopathy, and atheism).
It is easy to jump from associations to causation, which is an analytical fallacy. And the article points out that over the last hundred years or so, 90 percent of nobel prize winners have had religious belief, while only 10 percent were agnostic or atheistic.
This study actually does not really bother me, though it needs to be corroborated with other studies and does not equate to causation. Still, though I have a Biology degree and appreciate Science, I am more of a holistic thinker / theologican / practictioner, seeing the value in both "reason" and "emotion."
This is where this study has, I believe, practical application. Modern apologetics seeks to "prove the Bible" with "evidence that demands a verdict." Jesus was either a liar, a lunatic or Lord--now, tell us what you believe RIGHT NOW--and I have set a logical trap for you, forcing a person to come to the conclusion that a person is not prepared to come to EMOTIONALLY or SPIRITUALLY / heart wise. This is ultimately counter productive for most people as an entry level question, actually forcing them to just say, whatever, dude, or actively hardening their hearts.(And there are other options intellectually than these three.)
I think that modern apologetics can be confirming for Christians, but if used in the above manner, is not very helpful for most non-Christians. My personal experience--corroborated by research-- is that intellectual barriers to faith may be the stated reason for non-belief, but that the underlying causes are at the least, much more complex than that. What causes a break through to belief is a movement of the heart and emotion. And modern apologetical arguments can then provide enough justification for that person to not think that they have to be an idiot to become a person of faith. That in their own minds they can remain a "Reasonable" individual.
This study deals with associations, so it is improper to assign causation rather than theories. However, it may be that when we isolate the head from the heart, or vice verse, it leads us down a path that takes us away from God. From modernism, we are negatively geared against "working up the emotion" (particularly in the Restooration Movement, a movement that occurred at the height of the Modern movement). We don't want anyone to get "caught up in the moment" and just make an "emotional decision." (Of course, inherent in this criticism is the--correct--idea that in order to move most people towards a life changing decision, the heart/emotion must be engage.) But we ought to be equally skeptical of "purely rational" decisions that do not engage the heart/emotion. These are unlikely to be truly life changing or long lasting as well.
God made us to love God with our heart, mind, soul, and strength--our whole being--not in slices. To me, this type of study corroborates this belief. Both intellectual pride and emotional immaturity can lead us away from God. But the intellect and emotion properly guided--and most likely, balanced or at least both significantly engaged--can lead us to God. And from a conversion standpoint, if we want to reach people for Christ, we must give them compelling "reasons" that go beyond the head to engagement of the heart and emotion, such as the hope that we have in Christ, meaning and purpose in life, help and hope for relationships, etc. These are not superfluous, they are key in moving people towards God and reaching (and retaining) people for Christ.
And in order for people to come to God, they must have faith--which, by its nature, goes beyond evidences. We have reasons for our faith, but if we claim that we can absolutely prove our beliefs beyond a shadow of a doubt--well, that would cease to be faith, would it not? And the Bible says that without faith, it is impossible to please God.