Hiro-chan is a very simple, inexpensive, and, er, faceless robotic baby doll designed to comfort elderly people. (Video below.) Unlike the very similar looking Amish dolls that lack faces for religious reasons, Hiro-chan's developers Vstone say that leaving the features up to the individual's imagination is an effective way to increase the emotional bond. From Evan Ackerman's article at IEEE Spectrum:
Hiro-chan’s entire existence seems to be based around transitioning from sad to happy in response to hugs. If left alone, Hiro-chan’s mood will gradually worsen and it’ll start crying. If you pick it up and hug it, an accelerometer will sense the motion, and Hiro-chan’s mood will improve until it starts to laugh. This is the extent of the interaction, but you’ll be glad to know that the robot has access to over 100 utterance variations collected from an actual baby (or babies) to make sure that mood changes are fluid and seamless.
...Since the functionality of the robot depends on you getting it go from sad to happy, Vstone says that giving the robot a face (and a fixed expression) would make that much less convincing and emotionally fulfilling—the robot would have the “wrong” expression half the time. Instead, the user can listen to Hiro-chan’s audio cues and imagine a face. Or not. Either way, the Uncanny Valley effect is avoided (as long as you can get over the complete lack of face, which I personally couldn’t), and the cost of the robot is kept low since there’s no need for actuators or a display.
And from Vstone:
In tests at nursing homes that cooperated with the development of Hiro-chan, even those who did not respond to facility staff etc., spontaneously started crying when Hiro-chan started crying, When "Hiro-chan" started laughing, she was seen smiling. By introducing "Hiro-chan", you can expect not only the healing of the user himself, but also the effect of reducing the labor of the facility staff.