This post is a speculation on relativistic effects on the pace of evolution of Life and Civilizations in outer space.
A simple illustration is provided to show the effect of varying gravitational fields in different regions of space and their implications on the speed of the development of Galactic Civilizations (chart).
Since all physical process that occur in a region with lower gravity proceed faster relative to a region within a high-gravity zone (such as near a black hole), then Life that develops in a region with a weaker gravity will evolve faster and develop technology quicker relative to Life in a region with a more intense gravity - where time runs 'slower'.
The idea is simple: Processes and metabolisms run "faster" in a place where there is less gravity as compared to another place with greater gravity.
An example of a region which has low gravity (and where the clock ticks faster) is a galaxy with a moderately-massive blackhole at its center. Another example of low-gravity regions is in the outer edges of spiral galaxies.
We can also consider the relativistic effects of the velocity of stars that lie above or below the plane of the galaxy's spin. They would not be moving as fast as other stars who are within the plane and closer to the center of the galaxy. (Remember the whirlpool in your tub? Your toy boat accelerates as it gets closer to the drain hole).
In those regions described above where gravity and velocity is low, processes are faster, biochemical reactions will occur quicker, life will develop earlier, and evolve much faster. They will develop technology sooner and spread out into other solar systems.
Given the ratio of 1:10, for every 1,000 years on Region B, life in Region C would have advanced 10,000 years. This has massive implications specially when you think of the runaway exponential curve of technology once it takes hold. Remember the Singularity?
Since our sun lies somewhere in Region B of the Milky Way, it would make sense to point our SETI instruments and exoplanetology telescopes towards the outer fringes of The Milky Way's spiral arms.
As write this post, I am wondering why Relativity was not taken into account when the famous Drake Equation was formulated. Also, I am wondering why Fermi had not thought of this clue when he asked where the other civilizations are. Part of the answer, I believe, is that these advanced civilizations must be in a region where time flows faster relative to us.