Aliens

Is the human race too conceited or just naive?

Why is it that whenever we consider the possibility of alien life forms, we almost always imagine them as being at least vaguely humanoid? I can't think of too many representations that haven't followed our basic shape - 2 arms, 2 legs, 1 head etc. Of course, there are exceptions, but I'm struggling to think of any right now [message from the future - I've just remembered the Tralfamadorians from Slaughterhouse 5] - filmic representations and even allegory from those who claim to have been abducted (but never just invited) by aliens all seem to follow this same basic concept. One part may be tweaked (tentacles instead of arms, maybe; no legs, perchance) but it's generally the same old story.

Why on [insert your home planet of choice] would this be the case in real life? We've evolved into this body shape as it's what's required to be top of the food chain in our environment. Yet we still share this planet with cats, dogs, birds etc. and I'm sure the dolphins are only biding their time until they prove that they truly are the most evolved life form on the planet - secretly sponsoring the causes of global warming so the ice caps melt, the world is drowned and they take over.

Wouldn't life-forms that evolved to survive and thrive in different environments be more likely to have evolved in different ways? Fishy aliens (or dolphins!) from oceanic planets, amorphous blobs from... well planets where that's what it takes to be king?

It's almost as if we're claiming that we're nearing perfection. This claim is given added weight when we consider the most common depiction of aliens that may have travelled to our planet. Because they've mastered space-travel we consider these ones to be intellectually superior to us, and signify this by giving them diminished bodies, and larger heads to house their larger brains.

Doesn't this go against our concept of evolution though? We've created a world that focuses on reducing the size of things as we improve them (with perhaps the exception of televisions). The first computer was the size of a large room and could just about add 2 + 2. I'm typing this on a laptop that's... well, small enough to fit on top of the average lap, while it runs multiple applications in the background thanks to the tiny microscopic chips inside it, and the processor that only 10 years ago we were convinced would never be able to reach 1 gig without melting. Wouldn't highly-evolved beings be more likely to have increased the efficiency of their brains so much that they could be much smaller, do much more, and be stored somewhere way less obvious and more safe than an over-sized head atop an under-sized body?

So yeah, I've come to the conclusion that we're just too conceited. And, strangely, it's angered me somewhat. I hope the space-tadpoles consider this when they invade, and save me a gruesome death!