There are two posters for the training room—"anatomy poster" and "brain anatomy poster"—both with the same attributes, most importantly "+1% training speed". The bonus stacks. Because unlocking costs 80 kudos do I even need the other one?
1 Answer
There is no reason for unlocking both, it's pure aesthetics.
By the way, if you are looking to optimize your training room, the encyclopedia bookshelf II offered by getting 2 stars in Mitton University gives you 4% per item, so you can get even more effective training using those instead of posters.