Virtual insanity

Gregory Nemec

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Not long ago, with only minimal prodding from a Yale psychiatrist, a computer claimed responsibility for a Mafia-related bombing.

This, of course, was crazy. But the computer—more accurately, an “artificial neural network”—was experiencing symptoms of schizophrenia. DISCERN, as the neural network is named, was at the center of an experiment led by Yale psychiatry professor Ralph Hoffman and computer scientists at the University of Texas–Austin. The resulting paper, in Biological Psychiatry, seeks to help resolve a debate about what causes some symptoms of the illness.

Schizophrenics frequently display disordered speech, moving rapidly from one topic to the next in a process called “derailment.” They can also suffer delusions, situating themselves at the center of grand and fantastical plots. Researchers have offered multiple hypotheses about what causes these symptoms, and Hoffman and his coauthors decided to test the hypotheses on DISCERN.

DISCERN—when compos mentis—is able to learn, memorize, and recall stories. But the researchers undermined its integrity in various ways. They found that by tweaking one mechanism in particular—the rate at which DISCERN consolidated memories—they caused it to display speech derailment remarkably similar to that of schizophrenic patients. DISCERN also confused banal stories with grandiose ones and swapped subjects across multiple narratives—leading to that false confession about the bombing.

Hoffman suspects that a similar process may take place in the brain of the human schizophrenic: something goes biologically wrong, speeding up memory consolidation so much that “things get confused.” The patient’s language patterns might suffer, and the protagonist of a plain autobiographical narrative may be transferred into a sweeping cultural one, spawning delusional beliefs.

Some observers of the artificial intelligence community have questioned the wisdom of driving computers insane. But it’s just another case of confused narratives. “It’s not that we drove a computer crazy,” Hoffman explains. “More literally, we made a simulated artificial brain go crazy.”