Yeah, it boosts your players' ratings for the next half inning. From the help:
General Description - From this page, you may set the tendencies of you manager at each level. In simulated game play, these settings are used to make managerial decisions. For example, if you set your manager's argumentative rating to a five he is highly likely to contest a call at a pivotal point in the game. In this case, if he argues the call his players immediately receive a ratings boost for that half inning. However, if he is ejected, the bench coach must take over for the remainder of the game. Bench coaches use the default neutral managerial settings. Also, having an argumentative manager will increase the player's temper rating. There are positives and negatives associated with every tendency. Users are recommended to choose the brand of baseball they most believe in and stick to it. Changing managerial settings often is not recommended as consistency fosters player development