In Civilization 5, do technologies still get cheaper as they get older/discovered by others? Or is there no difference which order you research them in? In previous Civs, I believe they got cheaper as they got discovered by others.
If you have met other civilizations that have discovered some technology you do not have, your cost to research that technology is discounted.
The formulas are
Here are the discounts for some civRatio values:
Given this information... one potential use is to push hard for civil service (food good for science), then catch up on other research.