Petrolheads pour their energy into saving the manual transmission in cars like the Porsche 911 GT3, the kind of halo machine that gets magazine covers and forum crusades. The cheap commuter cars losing their third pedal get no such defense, and they’re disappearing far faster. A study out of Japan adds a wrinkle to the argument anyway, because the case for rowing your own gears may reach past the fun of it and into the health of your brain.