HARVARD GAZETTE ARCHIVES

A panel of Harvard scientists and philosophers joined with colleagues from other institutions Sunday (Sept. 17) at Boylston Hall to ponder an enduring mystery, whether the human mind is merely a dizzyingly complicated organic machine or something more.

"Everything we do and feel - love, hate - all happens because of circuits in the brain," said Harvard Medical School (HMS) neurobiology professor Rick Born.

Whether that fact implies that someday networks of silicon circuits might think, feel, and eventually achieve consciousness spurred a lively discussion at the Mind, Brain, Behavior (MBB) Interfaculty Initiative's seventh annual Junior Symposium. The daylong session, a requirement for all juniors in the MBB track, probed the nature and workings of the human mind by bringing together investigators approaching the question from the differing perspectives of their various fields.

The diverse group of investigators is working to understand human behavior and mental life through study of the structure, function, evolution, development, and pathology of the human brain and nervous system.

A show of hands among several dozen MBB-track students in Boylston Hall's Fong Auditorium Sunday afternoon showed roughly two-thirds considered the human mind distinguished from today's computers only by its superior complexity.

"It's just matter," shrugged one student, who said he didn't see why the molecules that make up computers shouldn't, in time, be capable of anything the molecules that make a human brain are.

But some students expressed discomfort with the notion that the human mind amounts to a biological machine predictably crunching data and reacting to sensory input.

Robert Stickgold, associate professor of psychiatry at HMS, summarized the objections he heard from some students in breakout discussion sessions this way: "You can take all the resistors and transistors and integrated circuits you want and wire them together, you're never going to get something that feels sorrow."

But Born said we don't yet understand the workings of the brain well enough to rule out machine consciousness.

HMS Assistant Professor of Neurology Alice Flaherty, a neurologist at Massachusetts General Hospital, noted that throughout history people have had a poor record of recognizing the humanity and emotions of rival tribes and races.

"The fact that we can be so wrong about people makes me distrust my intuition about machines," she said.

In a small discussion group, Born described consciousness not as a single threshold of awareness, but as a spectrum with human beings at one end. In discussing whether machines might one day achieve a place on that continuum alongside people and animals, several students struggled with the meaning of terms like mind, consciousness, and understanding. Born said those concepts, while interesting, miss the fundamental problem in the field today.

"Really what we need to understand is the mechanism by which our brains work," Born said.

Sarah Heilbronner, a senior studying psychology in the MBB program, wondered whether the view of the human mind as a sophisticated biological computer implied that our perception of free will is an illusion.

"Is that still a useful idea or should we just leave it behind?" asked Heilbronner, who posited a scenario in which human behavior could be accurately predicted in the distant future by computer models capable of exactly copying the circuits of a particular brain.

Some in the session argued that knowing what a person will do doesn't mean that the person isn't choosing to do it. As a practical matter, Born said, modern scientists equipped with supercomputers aren't able to accurately predict the path of a billiard ball past a few collisions even though Newton's laws of motion have been well understood for more than 300 years.

During the closing panel in Fong Auditorium, students wondered whether scientists and doctors see any ethical lines that ought not to be crossed as new drugs, surgeries, and electrical stimulation technologies allow for greater external manipulation of the brain.

"I think it's an absolutely moving target, and it will evolve over time," Stickgold said.

"I don't know that there's ever been any innovation of any sort that people have held the line as immoral for long, with the exception of psychosurgery for violence … and that was more a question of effectiveness," he said.