Examples of 'strong, general optimization pressures'? Maybe the sorts of things in that table from Superintelligence. ?Optimization pressure = something like a selective filter, where "strong" means that it was strongly selected for? And maybe the reason to say 'optimization' is to imply that there was a trait that was selected for, strongly, in the same direction (or towards the same narrow target, more like?) for many "generations". Mm, or that all the many different elements of the agent were built towards that trait, with nothing else being a strong competitor. And then "general" presumably is doing something like the work that it does in "general intelligence", ie, not narrow? Ah, a different meaning would be that the agent has been subject to strong pressures towards being a 'general optimizer'. Seems less strongly implied by the grammar, but doesn't create any obvious meaningful interpretive differences.
Oh, or "general" could mean "along many/all axes". So, optimization pressure that is strong, and along many axes. Which fails to specify a set of axes that are relevant, but that doesn't seem super problematic at this moment.
It's not obvious to me that filtering for agents powerful enough to be relevant will leave mainly agents who've been subjected to strong general optimization pressures. For example the Limited Genie described on the Advanced Agent page maybe wasn't?
For self optimization, I assume this is broadly because of the convergent instrumental values claim?