Has been spent reading some excellent books...
Homo Sapiens was not always the most successful hominin on the planet. Homo Sapiens did not always have speech, art, or religion. Rebuffed by Homo Neanderthalensis in the Levant 100,000 years ago, Homo Sapiens returned to Africa where the entire species was nearly exterminated by the Mount Toba super-eruption. Homo Sapiens left Africa for the second time ~70,000 years ago and promptly colonized the entire planet. What changed? Why do all human societies have speech, dance, art, and religion? A compelling thesis is laid out in careful detail in Supernatural Selection: How Religion Evolved, by Matt Rossano.
Rossano expands on ideas expressed by James McClenon and others that receptivity to rhythmic vocalizations and simple dances rewarded participants with pleasantly altered states of consciousness and small group cohesion. In time the ability to sing and dance and a predisposition to hypnotic revery and the healing power of placebo was transmitted to future generations. Simple ritual grew into what we now think of as shamanism.
Rossano details the impact this sort of proto-religion had on egalitarian hunter gatherers. He explains why complex hunter gatherers began to exhibit social stratification and ancestor worship. In a world occupied and influenced by the all-seeing spirits of our ancestors - entities who took an interest in our daily activities and our thoughts - social order and group cohesion was enhanced by religion's tendency to reinforce and reward a moral faculty
The rest is pre-history.
This is a book I wish both William Lane Craig and Richard Dawkins would read. Religion need not be God-breathed or factual in order to have played an important role in human flourishing, evolution, and progress.
But then we'd both be wrong...
An area of deep interest to me is the nature of strongly held belief. Understanding how we come to know we're right and that others are wrong speaks to some very human impulses. It may also hold the key to moving beyond our current fixation with red state, blue state, conservative, progressive, abortion, gun control, religion, global warming, and other inflammatory topics playing out on the battle lines of the Culture War.
Robert A. Burton, MD came to my attention by way of Dr. Ginger Campbell's thoughtful Brain Science podcast. He's been on twice. In Dr. Burton's most recent appearance he discussed his latest book, A Skeptic's Guide to the Mind: What Neuroscience Can and Cannot Tell Us About Ourselves
After listening to the show I chose to check out Burton's first book, On Being Certain: Believing You Are Right Even When You're Not, which Dr. Campbell reviewed in BSP #42. It did not disappoint. Well-written and entertaining, philosophical and scientific, On Being Certain informs us (or reminds those who have been studying the topic recently) that most of our mental processes operate at an inaccessible subconscious level, that many of our decision are made before we are consciously aware of them, are then experienced as a "feeling of knowing," and then rationalized as needed. That is a daunting and somewhat frightening notion; an important idea that calls for careful consideration.
The answer is complicated and fascinating...

A
common argument offered by Christian apologists is, "Why would the
apostles and other early Christians have died for something they didn't
believe in?" In The Myth of Persecution: How Early Christians Invented a Story of Martyrdom, author Candida Moss, a skilled story teller and a thorough
academic, has answered that question with great thoughtfulness and in
deep detail. While intended for a popular audience, The Myth of Persecution is rigorously methodical and carefully referenced. Unlike like many other overly earnest volumes on such topics, it is also emotionally engaging in its presentation. After carefully laying a
historical foundation in the first five chapters, Moss builds an imposing
edifice in the last three, explaining how the largely inaccurate myth of
persecution has been put to poor use by the Church, Christians, and
Western political leaders since the 4th century. The Myth of
Persecution is as entertaining as it is erudite, as important as it is
troubling. The Myth of Persecution is an important book for anyone
interested in history of Christianity. If attempting to understand religion is
your thing this book is worth your time.