Mechanics & Interface: The Third Hand
Friday, January 22, 2010 at 2:59PM
Richard Terrell (KirbyKid) in Controller Design, Mechanics

When I was in elementary school, I watched a program on the Discovery channel on the Alien Hand Syndrome (AHS). Wikepedia describes it well....

An alien hand sufferer can feel normal sensation in the hand and leg, but believes that the hand, while still being a part of their body, behaves in a manner that is totally distinct from the sufferer's normal behavior. They lose the 'sense of agency' associated with the purposeful movement of the limb while retaining a sense of 'ownership' of the limb. They feel that they have no control over the movements of the 'alien' hand, but that, instead, the hand has the capability of acting autonomously — i.e., independent of their voluntary control. The hand effectively has 'a will of its own.' 

Imagine what it's like to have a limb of your body acting on its own. Interestingly, if you're a seasoned gamer you've probably experienced something very similar to AHS. Remember when I talked about how gamers recall events in video games? To recap, if someone retells the events in a game and uses the word "I" they feel like they had some control over the events. If they refer the characters or objects by their name, then they are acknowledging a lack of control. In a similar way, when the characters we play in video games do things that we don't want, command, or think we command, the experience can seem like the characters are acting out on their own. It's almost like there's a third hand on the controller that you can't see or feel trying to play the same game in a very different way. 


We're exploring what makes controls work... and not work.

Think even farther back when I covered mechanics and abstractions on this blog. One of the four qualities to describe gameplay mechanics is how individual it is. When a button/input is only mapped to a single mechanic, that mechanic is completely individual. The simplest games have the best chances of featuring individual mechanics. Moving in Pong. SHOOT and BOMB in Geometry Wars. And Mario's JUMP mechanic are individual. However, in Super Mario Bros. the RUN button is also the SHOOT FIREBALL button making both of these mechanics non-individual. Why bother designing individual mechanics? What makes individual mechanics better than non individual or grouped mechanics? These are very good questions.

The answer is grouped mechanics inherently add potential kinks in the player-game interaction through the emergent criss crossing of function and input. In other words, the more mechanics use the same input, the more likely it is for a range of things to happen when the player intends to do one thing. Let's look at Super Mario Brothers for a simple example. You can RUN by holding the B button. And you can SHOOT a fireball by pressing the B button (one fireball per button press). Because of the input design of these grouped mechanics, you cannot continually RUN and SHOOT fireballs. This isn't too big of a problem for a dexterously skilled player. With a rapid release and press of the B button players can RUN and SHOOT fireballs without dropping in speed very much at all.

On the flip side, player's can't RUN without SHOOTing a fireball as Fire Mario. Normally this isn't a big deal. Mario has infinite ammo so players can waste as many fireballs as they want. There are times, however, when the fireball you SHOOT inadvertently kills an enemy when you only wanted to RUN. Though rare, I've died after SHOOTing a flying Para Koopa when I intended to RUN and JUMP on it. I've also accidentally killed a Koopa I intended on kicking into incoming enemies for a 1up combo. It's like Mario decides to throw a fireball every time I decide to run. Mario either has a mind of his own, or he's controlled by "the third hand." 

Grouped mechanics can complicate the interface between the player and the game by combining and limiting mechanics. Understanding a game's interface becomes much more difficult when dealing with anything other than individual mechanics. With that said, grouped mechanics aren't the only kind of design that can complicate the interface of a game. Take the following design features for example...



Adding complexities to a game's interface design usually makes playing and understanding the game harder. So the next time something happens to you that you don't expect, consider why you couldn't make it happen. Is it your fault? The game's fault? Or does the blame land somewhere in the middle, on some third party (interface)? 

Article originally appeared on Critical-Gaming Network (
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