In fact, we distinguish androids from humanoids. Although both terms have a similar etymology ("man resembling," the former from Greek and the later from Latin) in robotics android refers to robots whose resemblance goes beyond gross morphology. It is not enough for an android to have a head, two arms, a torso, and perhaps two legs. It must be humanlike down to the look and feel of the skin, teeth, and hair. It must also have humanlike behavior.

The development of androids is key to exploring human activity because only very humanlike machines can elicit natural responses in people. Conversely, insights drawn from detailed investigations of human activity are required to build androids with humanlike behavior. We need to establish the new field of android science owing to the interdependent relationship between developing androids and investigating the mechanisms that support social activity. Androids will provide a unique means to embody and evaluate biobehavioral theories in relation to social interaction because scientists can evaluate both human and android responses in relative isolation from the effects of appearance. Owing to the impact of appearance, certain questions about human beings cannot be answered without employing androids experimentally. Androids provide the ultimate test bed for theories from the social and neurosciences and a platform for their eventual unification.

I know no-one will ever read this...

I see people responding "naturally" (whatever that means) to loads of things that aren't androids. People swear at their computers and hit their cars. If you're obsessed with "The Natural" then there are a load of other animals you know. I think er.. Sony might have thought as much.

The term "natural" is used as a kind of verbal shorthand for "the kind of responses that people direct toward other people." People may swear at their computers, and people have tended to anthropomorphize many phenomena. (Wilfrid Sellars talks about the manifest image; Daniel Dennett talks about how people take an intentional stance; and Reeves and Nass have discussed how we treat media socially in their book The Media Equation, the thesis being that media equals life.) However, that does not mean that our responses toward computers, robots, androids, and humans are identical.

These responses can be analyzed in many different ways, such as fMRI and other methods of imaging the brain, galvanic skin response, eye movement, vocal pitch, and gesture. Often in human-human interaction we see very closely coordinated interaction that is not comparable to human-robot interaction, much less human-computer interaction. For example, we have found differences in gaze fixation. Interlocutors tend to make eye contact by looking at the right eye, and this is true in North America and Japan. However, when interacting with the mechanical-looking robot Wakamaru, they tend to look more at other parts of the body when compared to their interactions with human subjects or androids. In fact, when interacting with androids, they can make more eye contact than when interacting with people, which may imply an absence of the modesty often felt among Japanese when they interact with other people. Ayse Saygin has found in fMRI studies differences in brain activity when a person sees an android with a human looking hand reach for an object as compared to when the same person sees a humanoid hand. (The movement and mechanism were the same except the human-looking silicone skin was replaced with a mechanical- looking covering.)