iRobot and Robby the Robot

In 1942, science fiction writer Issac Asimov spelled out his three rules of robots in which any robot must obey humans, must not harm humans, and must protect itself without breaking the first two rules.

This marked a shift in thinking about robots in that Asimov deliberately wrote stories, such as "I, Robot," where robots didn't turn on their creators and try to take over the world.

Characters, such as Robbie the Robot (pictured here), appeared in the mid-1950s and played roles in which they aided their human companions.