Human-controlled avatars

Rascals is based on a core theorem proving engine that deduces results (proves theorems) about the world after pattern-matching its current situation against its knowledge base. Each proven theorem then initiates a response by virtue of having a synthetic character speak and/or move in the virtual world.

"Upon analysis, anything that our synthetic character says or does, is the result of a theorem being proven by the system," said Bringsjord. "So far, theorem provers have only been used in toy-problems. We are scaling that up to enough knowledge for a synthetic character, which requires a very fast supercomputer."

Bringsjord's research group recently passed a milestone by programming a synthetic character to understand a "false belief." For instance, to create a false belief you could hide a stuffed bear in a cabinet in front of a child and an adult, and then when the adult leaves the room, move the bear to a closet while the child is still watching. Here, the child should know that the adult now has a false belief--that the bear is still in the cabinet.

Unfortunately, children less than four years old don't typically conceptualize the beliefs of others, but only their own, and, thus, expect the adult to know that the bear has been moved. Somewhere around five years of age, however, children begin to have second-order beliefs--that is, beliefs about the beliefs of others, enabling them to understand that other people can have beliefs different from their own. Now, Bringsjord's research group claims to have achieved second- and third-order beliefs in their synthetic characters.

"Children below about four years old don't have second-order beliefs--they just have first-order beliefs. But we have a mathematical account that passes the test," said Bringsjord. "We have a formal theory of second- and third-order beliefs, and a way to make them computationally real."

The next milestone for the group will be passing the avatar version of the Turing test in October 2008, when EMPAC officially opens. The Rascals-powered synthetic character will carry on a conversation with human-controlled avatars, perhaps without the humans noticing the difference, and thus passing the Turing test.

Bringsjord's research is supported by IBM and is being performed with the assistance of Rensselaer doctoral candidates Andrew Shilliday, Joshua Taylor, and Micah Clark, as well as undergraduate researchers Ed Charpentier and Alexander Bringsjord.