Or Poul Anderson's Brainwave (1953), in which the Earth finally leaves a part of the galaxy which inadvertently made thinking hard. And everything with two neurons to rub together gets smarter, not just humans. Essentially, we evolved in what Vinge would later call "The Unthinking Depths" (if memory serves) to deal with the strain.
Came here to say the same thing - this is uncanny.
In some of his novels - most notably A Fire Upon the Deep (from 1992), he imagines the galaxy as divided into concentric zones, each with different physical laws and limits on intelligence and technology. These are referred to as "Zones of Thought," each affecting the potential for intelligence and technological development.
It's not a perfect match, as I think the new theory refers to relative time based on the density of matter at a given location.
Part of me wonders if this analogous to the "watched pot never boils" issue. Wander into the wilderness to do magic...
The "fire upon the deep" series describes zones where the speed of light differs, causing deserts from which escape is difficult, did to the slow speed at which ships must travel.
I think in those stories the speed of light is the same but the speed of thought differs. Close to the center of the galaxy you cannot be very smart and faster than light drives don't work, if you get too close to the edge you get victimized by those things that Yudkowsky is worried about. There's a certain range in which you get space opera.
The most obvious way to change the speed of thought is to change the speed of the electromagnetic signals (light) that produce them. Ignoring the current known laws of physics, of course.
It's both, the farther you get from the center of the galaxy technology can be more complex, the speed of light is higher, and computation can be faster.
