As far as I know it’s genetic which makes it structural and chemical. Our brains grow and evolve to facilitate survival and what we call instinct is the manifestation of that organ. So you can change that instinct by changing your brain structurally or chemically. You can get a lobotomy or you can get really drunk to change the way your brain operates. It’s just how the human race has evolved and there’s no “good” way to change yourself yet.

I was hoping for maybe a link to a book on something online that will go into this in a lot more depth

You might find the MBTI and Enneagram interesting. A lot of our personality styles and how we assimilate and process information and certain base preferences can also be related to intrinsic temperament and brain organizational preference.

There are oodles of books written upon how you can change and they are primarily written by those from the branch of analyses known as Behavioral Psychology.

Their techniques come under the broad term Behavioral Modification.

If you research both those terms, you’ll find plenty of books and articles.

However, just be forewarned that Behavior Mod does have it’s limitations (even tho some of it’s believers don’t like to think so).

It has proven very effective for problems with phobias. The person doesn’t even have to believe it will help. All they have to do is be willing to follow each step of the protocol.

It has proven of little effect for struggles related to sexual orientation or transgender issues.

Is there a particular issue that you are looking to change?

A lot more depth, eh? Enjoy!