Why do we build bipedal robots with similar body layout to humans? It’s our brains that are our best bit, not our bodies. Any idea @rockbot?— Tom Ashworth (@phuunet) August 2, 2013
That, good sir, is a fantastic question! And while I've done no specific research, I do have a few clues as to why we even bother with the two-legged robots:
Two legs are actually good for some things
When we think about mobility, we generally have two options: wheels and legs. Wheels (and I'm going to include treads here) are perfect for roads and generally flat surfaces. But legs - legs - are what will get us through forests, over rocky mountains, and up and around the Great Wall of China. 2-, 4-, 6-, and 8-legged animals have managed to roam the earth with ease for as long as animals have lived on this planet; wheels have only been around for a short period of time by comparison.
I'm pretty sure that the reason we humans have two legs is simply so that we can stand up and look around while carrying things with our other two legs (aka "arms"). In any event, having two legs is pretty useful.
We're more accepting of robots that look like us
Think about Star Wars. Which robot is easier to relate to? C-3PO or R2-D2? Luke hardly bothered interacting with R2, whereas he was in constant communication with C-3PO. (And it's not just because C-3PO could speak English; body language is critical to human communication.)
We like robots that look like humans. We want to interact with robots that look like humans. In fact, our world was created for humans, by humans.
It's an interesting challenge
Bipedal locomotion is a tough problem. Not only do you have to worry about balance, but you also have to worry about momentum. In particular, the center of gravity on a bipedal robot is actually off center for the robot, as opposed to in the center for a generic 4-wheeled robot. (This is so that when the robot is ready to move, it can actually move forward/backward, instead of simply lifting its legs up and down.)
Easy problems aren't nearly as interesting as tough ones, at least, in my opinion ;-)
We're a little narcissistic
We humans like to create things. Whether it's a house made of twigs or space rockets, we get this ridiculous satisfaction out of being able to say "I made that." Add to that notion the idea that we already know that we're the most interesting creatures on earth, and there's something undeniably cool about being able to create something in our own likeness. You can argue that you can create human life with a bit of biology, but as any parent will tell you - you don't have a chance in hell of making it do everything you want it to do, 100% of the time.
So now we have robots. Robots are totally under their creator's control. For better or for worse, your robot will do everything you ask it to do. Little boxes with wheels are certainly a good start, but for the truly power-hungry, maybe a robot that looks like a human is even more satisfying to control than your average, run-of-the-mill starter robot.
Yes, our brains are what make humans the coolest animals on planet Earth, but our bodies are pretty great, too. I hope this post sufficiently answers your question, Tom!