“And then, little by little, he collected his thoughts and knew that he was hugging not Daneel but R. Daneel–Robot Daneel Olivaw. He was hugging a robot and the robot was holding him lightly, allowing himself to be hugged, judging that the action gave pleasure to a human being and enduring that action because positronic potentials of his brain made it impossible to repel the embrace and so cause disappointment and embarrassment to the human being.”
–Isaac Asimov. The Robots of Dawn. Kindle edition. Quote in chapter 7.