McLaren have recently been using steering wheels with 4 paddles, rather than the usual two. The 'telegraph' have reported that, while the upper paddles are used for conventional up and downshifting, the additional levers allow the driver to select a different engine mapping, independently from the gear shifting.
The currently used standard engine control unit enable to teams to program a number of predefined engine mappings, optimising traction or driveability in different conditions or at different speeds. The new system enables the driver to change gears and simultaneously change to a different engine mapping by pulling the paddles at the same time. Most importantly, it looks to be allowed by current regulations as these only stipulate that engine mappings can only be changed by the driver. Any automatic change acting upon a gear shift is forbidden.
Already considered a manual traction control system, the drivers have not the ability to effectively limit wheel spin when accelerating out of slow corners while not reducing power at higher speeds. When finally considered legal by the FIA, Ferrari is likely to be quick and copy the system to recover from their current performance deficit.