"Interest rate futures" can mean a lot of things. Fed Funds, Eurodollars, Notes, Bills, Bonds, not to mention Bunds, Euroyen, etc.
Eurodollars will reflect the fed target rate. As a result, the more fed meetings between now and the expiration of the contract, the more chances the target rate will change. In addition, there's a certain amount of "long tail" behavior that goes on--if you expect the fed to raise rates 25bp in the next 3 months, isn't it somewhat likely they'll raise 75bp in the next 12? Now imagine if the fed gave signals that they were going to lower rates--the short expiration might move 50bp down while the long expiration might move 150bp down.
