But Silas is not real. He is made from computer-generated shapes and looks a little as though he escaped from a Disney cartoon. Silas is one of a small but growing number of computer programs that can mimic the behavior of friends, pets, and other objects of human affection. Among them are Julia, with whom you can have long, if strange, conversations; Phink, an unpredictable dolphinlike creature; and Neuro-Baby, a digital infant who can analyze and react appropriately to your moods.
Building 'relationships' with these digital creatures is, of course, rather an unusual process. With Silas, for example, you have to stand in front of a video camera looking at a projection screen on which you see a picture of yourself, your room, and Silas, added in by the computer program. Of course, these are all virtual friends; robot friends with 'real' bodies are still a long way off. For the more immediate future, the scientists and artists who are creating digital companions want to explore what is needed to make these computer-generated objects more friendly and engaging to humans. Research is proving that we are often surprisingly willing to read intelligence and intention into the creations of computer programs.
'The research goal behind Silas is to understand how you can build an autonomous creature, like a dog, that seems to do the right thing over time,' says Bruce Blumberg, Silas' creator and a Ph.D. student at the Massachusetts Institute of Technology's Media Lab. People readily respond to Silas as though he were real, creating explanations for his behavior the way they would with a real dog. 'From the user's perspective,' says Blumberg, 'there's a sentient, intentional being there.'
The willingness of humans to see complex emotions in animals is well known to ethologists. 'People often ascribe feelings to a real dog that are over and above what they really would admit, if pushed, they believe the dog really feels,' says June McNicholas, a research fellow at the University of Warwick in England who has worked extensively on the bond between humans and animals. 'If you've had a bad day at work,' she says, 'your dog may seem to respond to this. And you'll say to yourself, 'He knows I had a bad day at work.' But you know that the dog doesn't know you had a bad day at work. All he knows is that you are moving and acting differently than you usually do. And you know this.'
Reacting to Silas involves similar rationalizations. For instance, Silas is interested in moving objects that are close to him. If you reach out to pat him, your hand will be both moving and close, and Silas will watch it. Silas doesn't have any way of knowing whether you're touching him or not, but because he's watching your hand so intentlyit 'appears' that he is responding to being patted. Users tend to explain his response in those terms ('I'm patting him, and he likes it') and the explanation has predictive value (whenever the user tries to pat the dog, the response is the same) and so, in the user's mind, Silas likes to be patted.
People find Silas fascinating partly because they enjoy trying to explain what he is doing. 'If a creature behaves exactly the same every time,' says Blumberg, 'that's not very interesting. It turns into a robot. On the other hand, if it's totally unpredictable, then it seems random, and it's hard for the user to develop an explanation with predictive value. The optimal place is where there's just enough surprise that you're constantly coming up with new explanations that make sense. I think that this is why we like having 'real' pets.'
But there is a very long way to go before Silas can become 'real.'
Bringing artificial pets into the outside world is far more complex than creating images on a screen. This is why robotic pets are many steps behind virtual ones. Skimer the robot illustrates these constraints. Kino Coursey of Daxtron Laboratories in Fort Worth, the developer of Skimer's software, says that the robot can identify objects visually and be trained to follow them around. To do this, one trainer drags a chair, say, while the other uses a joystick to instruct Skimer to move in pursuit of the chair.
Skimer builds a network of associations between the images it is seeing and the commands it is receiving. For example, when the chair moves out of the robot's field of view, moving from right to left, the trainer commands Skimer to turn to the left. Skimer remembers the sequence of images and the commands associated with them. Once Skimer has been trained, it will follow the left-turn command whenever it sees a chair moving across its vision to the left. The result, says Coursey, is that 'you can drag a chair around in front of it and he'll follow it anywhere.' But while Skimer does this very well, it can't do anything else. And it's a pretty hefty contraption, cobbled together from a child's six-wheeled riding toy, a camcorder, a computer, and 18 kilos of batteries. Skimer, as Coursey puts it, 'definitely belongs in the back yard. You wouldn't want him in the house.'
If Skimer could be made small and agile enough, could it replace the family dog or cat? Erika Friedmann, a specialist in pets and health in Brooklyn College's health and nutritional science department, acknowledges that the autonomy of artificial pets might attract people the way real pets do. 'People like pets because they don't have to make an effort to get positive feedback from another being,' she says. 'Your pet makes some kind of acknowledgment that you're there and entices you to interact with it.'
But pets provide people with far more than unstructured entertainment. They give us something to care for, something to touch and fondle. They provide a reason for exercise, a feeling of safety. McNicholas thinks that this is the fundamental weakness of the artificial dog. 'What kind of care could someone give a virtual pet?' she asks. 'A lot of the closeness in a relationship with a pet is based on how dependent the pet is on you. If an artificial pet doesn't depend on you, you don't feel needed.
Excerpted with permission from New Scientist (Sept. 16, 1995). Subscriptions: $140/yr.(52 issues) from Virgin Mailing and Distribution, 10 Camptown Rd., Irvington, NJ 07111.