People may be certain about why they made their decision, but, as we continue to learn about our species, our decisions are affected by many unknowns. I came up in the 60's so challenged most of what was status quo. Father an Episcopalian, so no pressures & no references to a faith other than to have me attend a church study class because I was foundering as a teenager. Hated it, & actually felt betrayed. Mother non-religious but not vocal about it. So ostensibly total freedom to choose. Interestingly, as I learned more in high school & college & it became clear there was no way back to any kind of faith, both my sisters became believers. Place in family: I was the youngest. Who knows how any of us arrived at our choices, but their both professing belief was a shock to me & an ongoing sadness. I wouldn't deprive them of their comfort, but the resulting loneliness mirrors one's general place in a Christian society- or any society unwilling to question or challenge accepted mores.

I'm quite certain why I became an unbeliever. It was, simply put, proximally caused by religious faith failing to accurately explain or predict experienced life outcomes. Once I recognized religious faith as an utterly failed epistemology, everything unraveled from there.

But this transition happened in my late 30s and early 40s and in many ways wasn't fully integrated into my thinking until my early 50s. So I would still qualify as someone who made it out of childhood and into early adulthood still believing. My family of origin had what this study would term "high CRED levels" and I was a compliant and dutiful son to my parents. I also had three older brothers who were very devout ... one ended up an elder, the other had a theological undergraduate degree and was on track to become a youth minister, the other was an engineer but very active in church and parachurch activities. And I attended a Bible institute for a year after high school myself.

So my apostasy was a function of belatedly growing up and getting a clue about how life actually works rather than how we wanted it to work. Interestingly, the brother with the undergrad degree hasn't darkened the door of a church in a quarter century and is an unbeliever in all respects except in not admitting it to himself or others. The church elder died of a freak cancer, emotionally crushed and confused as to what he'd done to deserve that. Only the relatively less overtly devout brother remains actually a practicing Christian. I guess the belief system didn't work out well for 75% of us siblings.

I quietly stopped believing in religious institutions decades ago, but continued sort of believing in god because I could feel connected to love, peace, and everything in the universe.

However, whatever I imagined, happened, whether or not it was "godly" or even good for me. I finally had to admit it was all me. Even my secular friends could make things happen by deciding them, so it wasn't because of "god."