Get just a taste of the "Eliza Effect," discussed in Rise of Roboethics, by watching these videos of relational artifacts.
Here, MIT's Kismet says "Do you really think so?" using different facial and vocal expressions:
The adorable Leo learns what it means to turn all the buttons on:
Jules, an especially realistic-looking robot, speaks with an emotional vocabulary:
A robot named Domo helps clean up:
Babybot experiments with objects, learning how to best interact with them:
Four models of Sony's QRIO dance:

