IPhone – Does iPhone 4 work with Bluetooth Headphones/Headsets that have Back/Next/Answer

It happens because a quick jog of the plug causes a short interruption in line level. It's the same with headphones -- Apple or otherwise -- that include a play/pause button (usually place on the cable itself, where it splits to go to each ear). That button functions in exactly the same way, by momentarily interrupting line-level on the phone's cables. iTunes starts playing because it assumes the interruption from plug movement (or a dirty plug) is a play/pause signal. As a simple demonstration, start iTunes playing something and wiggle the phones jack, same conditions as make iTunes launch and play, only if it's already playing this will make it pause.

You can try Track 8 - swipe to change tracks - but I'm not sure whether it is iOS 5 or later.