I think about these beaver building a dam in a house out of toys, way too often.

Raised by humans as a newborn and still exhibiting this instinctive 'blood memory' behavior.

This certainly affects humans, we are just more creative in how it is expressed.

https://www.youtube.com/watch?v=-ImdlZtOU80

This video of the toy beaver dam and a deep understanding of the prisoner’s dilemma square will get you 95% of the way to understanding what the hell is going on with people 

The rest is mostly SSRI pharmacology