The automatic gearbox is controlled electronically. The gears are shifted up or down automatically according to preset gearshift programmes.
When you drive at moderate speeds the gearbox will select the most economical shift programme. It will then change up early and delay the downshifts to give better fuel economy.
If you drive at higher speeds with heavy acceleration, if you open the throttle quickly, or if you use the kick-down or the car's maximum speed, the gearbox will automatically select the more "sporty" shift programmes.
Torque is transmitted via a torque converter.