Ergative Psychology

I was thinking about making one of those "other projects" I mentioned in
my previous post an ergative language. I understand the basic mechanics
of ergative languages (one case for the subject of transitive verbs,
another case for the object of transitive verbs and the subject of
intransitive verbs, right ?) But I am wondering about the "psychology"
of ergative languages. In other words, what concepts are emphasized
differently ? How does that affect the world-view of the speakers ?

Could someone with more experience with such things please help me out ?
I'm not yet completely committed to the ergative idea; I'd like to
figure out if it would make sense with the culture the language is for.

Thanks

David Stokes