There are some challenges you might anticipate actors playing robots in HBO's new science fiction series Westworld encountered in developing their roles: Whether to squint in the sun, for example, or how a mechanical body might move. But the real difficulty lies in understanding how the motivations of an entity that runs on software compares to those of humans.

At the crux of the series about a Wild West theme park filled with humanoid robots are the implications of how humans interact with devices that come off convincingly as living people. Tourists visiting Westworld are permitted to treat the theme park's manufactured residents however they please. Some take this permission to commit rape or murder of the robots.

Things start to get complicated in the first episode, airing Sunday, when a new programming feature apparently allows some robots to develop memories, which leads to them seeming sentient.

During a round table discussion Thursday in Palo Alto, California, actors in the series explored the theme of being programmed--both as artificially intelligent entities and as humans.

The robots were programmed to have certain motivations and goals, said actress Thandie Newton, who plays the robot madam of a brothel in the theme park. Similarly, she said, people can seem unaware that they and others have, in ways, been programmed themselves.

By way of example, actress Evan Rachel Wood, who plays another Westworld robot, said you can see the "programming" of social media users in patterns of repetition on sites like Twitter and Facebook, through sharing of memes and quotes.

The idea of programming humans and robots alike matters in a setting like Westworld, where glitchy robots subject each other to homicidal binges and human tourists likewise commit violence with impunity toward the theme park's mechanical "hosts."

The similarity raises another question: In a virtual environment, how resistant can people be to the temptation to shed ethical behavior? It's a question that's long been mulled in the context of playing violent video games, which some believe dangerously desensitize people to violence in the physical world.

Playing a robot, said Newton, is little different than playing a human in certain ways. What might be most different is the pure focus of a robot's programming--something some but not all humans share.

"I felt more exquisitely human as a robot," she said.