Seabrook is correct. The -50% is the game pace setting 'slow or very slow' I noticed this as well. If you look at the above pic on my research planet I am playing on normal pacing. I do not have the -50% that Erischild is referring to, but I have seen it in games where I wanted a slower game.
I would ask, if we change game pacing such as slower tech or over all pacing slower does it also affect all the ai? Will they also be slower?