The blog i09 has a posting by an unknown author, The Science (Fiction) of Embodied Cognition. (here). He asks how the projection of a personality or mind into an alien body would work in reality as opposed to science fiction stories like Avatar?

That’s what the science of “embodied cognition” is all about. The basic idea in this new(ish) research area (which overlaps with cognitive psychology, neuroscience, artificial intelligence, robotics, and others) is this: Your mind is defined by your physical form. Not just in terms of “the mind is what the brain does”-we all are pretty down with that already. This takes it further to encompass the whole enchilada: your mind-your “I”-is a function of a cephalized, bipedal, plantigrade, bilaterally symmetrical body between 1.5 and 2 meters tall with two arms terminating in five-fingered hands with opposable thumbs, two lungs, a warm-blooded vascular system, mostly hairless skin, two front-focused eyes, etc. etc. Change any aspects of that physical configuration-in subtle or radical ways-and the mind will inevitably change too….Your perceptions, actions and thoughts all feel direct, integrated, and grounded. You don’t “drive” your body, you ARE it. So why do we still assume that we might take that “little man” out and plop him into a different body to “look out of”, without any consequences? …. it does point the way toward a much more interesting angle on Avatar‘s “going native” plotline. If you spent most of your waking hours embodied as a Na’Vi, how could you NOT be increasingly at risk of going native? Your essential psychological human-ness would inevitably drift and deform ….

At least most aliens we imagine are sort of humanoid – maybe we can’t imagine otherwise.