I spent years on and off drugs and alcohol, but I've been sober for six years. I'm just not the same self-centered immature brat I was. Last week, I reached out to my best friend's brother to apologize for things I did about seven years ago. He still hasn't responded to my text (requesting time to talk to make amends). He told my friend he was having a hard time believing I'm any different. But I am, and I want to prove to him I have changed. How can I do that?

--Sincere

He's seen you swear off drugs and alcohol before -- typically for several hours on a Tuesday.

This view he has of you is likely to have some serious staying power. That's because our brain is big on automatic processes -- forming and storing what I call "thinkpacks" so we don't have to put cognitive energy into things we've already figured out. For example, say you do something for the first time, like opening a weird latch on a cupboard. Each time you do it again, the more automatic -- that is, the more unthinking -- opening it becomes.

Believing works similarly. Once we form a belief, we tend to just go with it -- automatically. Questioning a belief, on the other hand, takes mental effort: yanking out our reasoning ability and forcing it to do a bunch of cognitive chores.

Not surprisingly, research by social psychologist Lee Ross, among others, finds that we're prone to taking the mentally easy way out, succumbing to "confirmation bias": clinging to what we already believe and ignoring info that says, "Hey, there just might be a new and improved truth in town."

There's another problem: Our ego is bound up in our clinging to our beliefs -- that is, believing that we were right all along. And though it sounds like you've changed your value system -- which probably bodes well for your staying sober -- if he goes with the idea that you're on the wagon for good, he risks being proved wrong.

The error that you, like many people, make is in thinking, "I'll just change somebody's mind!" and it'll happen pronto. However, consider your goal: apologizing. You can do that by writing a letter. A letter of apology takes an investment of effort that a phoned or texted apology does not -- which makes it more likely to be seen as sincere.

And frankly, if you follow through with the steps for a meaningful apology -- detailing how you wronged him, expressing remorse, and explaining the new values you are now living by -- you lay the best foundation for him to...possibly...someday...believe that you truly have changed.

Sure, it's possible you'll black out again, but maybe just if somebody clocks you for going overboard with the sobervangelizing. It won't be like that time when you were drunk and handcuffed and yelling, "Occifers, I'll have you know that my nickname in middle school was Houdini!"

For pages and pages of "science-help" from me, buy my latest book, "Unf*ckology: A Field Guide to Living with Guts and Confidence." It lays out the PROCESS of transforming to live w/confidence.