Found on
games console joypads. One of the pair of buttons on the top edge of the pad (facing the screen). Introduced by
Nintendo on the
Super Famicom pad, and in that instance, otherwise known as the
L &
R buttons. Pushed using the
index fingers, they add another combination of button pushes for things that you have to do at the same time as the functions performed by the face buttons. For example, hopping in
Mario Kart, or throwing knives in
Castlevania IV. (After all, you've only got two thumbs.) Something that baffled many people at first: "Bloody hell, who needs a joypad with
that many buttons?" But went on to be one of those innovations that become indespensible, and are taken for granted. Almost
every console joypad made sinse has featured this extra set of buttons. The
PlayStation even added an extra set (L2 and R2). Now with the acceptance of
analogue controls for games consoles, shoulder buttons have been phased out in favour of analogue
triggers. Analogue triggers were first featured on the
Sega Saturn 3-D Control Pad (aka
Sega Multi Controller), and are most commonly used as accelerators and brakes in
racing games.
Cheers to drinkypoo for the feedback