Friday, February 09, 2007

another blow for substance dualism

Scientists have developed a new mind-mapping technology that purports to allow researchers to see intentions forming before a person acts on them.

The team used high-resolution brain scans to identify patterns of activity before translating them into meaningful thoughts, revealing what a person planned to do in the near future. It is the first time scientists have succeeded in reading intentions in this way.

"Using the scanner, we could look around the brain for this information and read out something that from the outside there's no way you could possibly tell is in there. It's like shining a torch around, looking for writing on a wall," said John-Dylan Haynes at the Max Planck Institute for Human Cognitive and Brain Sciences in Germany, who led the study with colleagues at University College London and Oxford University.
The research builds on a series of recent studies in which brain imaging has been used to identify tell-tale activity linked to lying, violent behaviour and racial prejudice.

The latest work reveals the dramatic pace at which neuroscience is progressing, prompting the researchers to call for an urgent debate into the ethical issues surrounding future uses for the technology. If brain-reading can be refined, it could quickly be adopted to assist interrogations of criminals and terrorists, and even usher in a "Minority Report" era (as portrayed in the Steven Spielberg science fiction film of that name), where judgments are handed down before the law is broken on the strength of an incriminating brain scan.

"These techniques are emerging and we need an ethical debate about the implications, so that one day we're not surprised and overwhelmed and caught on the wrong foot by what they can do. These things are going to come to us in the next few years and we should really be prepared," Professor Haynes told the Guardian.

The use of brain scanners to judge whether people are likely to commit crimes is a contentious issue that society should tackle now, according to Prof Haynes. "We see the danger that this might become compulsory one day, but we have to be aware that if we prohibit it, we are also denying people who aren't going to commit any crime the possibility of proving their innocence."

During the study, the researchers asked volunteers to decide whether to add or subtract two numbers they were later shown on a screen.

Before the numbers flashed up, they were given a brain scan using a technique called functional magnetic imaging resonance. The researchers then used a software that had been designed to spot subtle differences in brain activity to predict the person's intentions with 70% accuracy.

The study revealed signatures of activity in a marble-sized part of the brain called the medial prefrontal cortex that changed when a person intended to add the numbers or subtract them.

Because brains differ so much, the scientists need a good idea of what a person's brain activity looks like when they are thinking something to be able to spot it in a scan, but researchers are already devising ways of deducing what patterns are associated with different thoughts.

A substance dualist maintains that the mind is substantially different from the body. Different dualists have somewhat different views on what, exactly, this means. Some, for example, see the mind/body difference in terms of a "ghost in the machine," wherein mind is truly independent from the material body. This belief gives rise to the "interaction problem," because if mind has no physical location, it becomes hard to explain how a given mind is in any way linked to a given body. Other dualists have taken a more subtle, refined stance that is not as susceptible to critique, and many dualists respond to physicalist critiques by saying that scientsts presume that causality must only be physical.

Science, in the meantime, makes progress by proceeding according to physicalist assumptions about mind. I have yet to hear a good explanation from a substance dualist as to how or why this continued success is possible. Now here we are, about to breach the fortress walls of intentionality, and substance dualists are still singing the same tune.

_

4 comments:

Malcolm Pollack said...

Hi Kevin,

I was also going to comment on this story when I saw it yesterda.

This won't bother the dualists in the least; they already acknowledge a correlation of some sort between mind and brain, and evince no claustrophobia as they are painted into an ever-tighter corner.

Even the estimable Bill Vallicella, that Rambo of rationality, clings to a stubbornly dualistic view, and as recently as last week wrote that his brain no more thinks than his eyeglasses see.

Kevin said...

Malcolm,

You're probably right.

However... I thought Dr. Vallicella had, long ago, explicitly denied he was committed to a dualistic viewpoint.


Kevin

Addofio said...

Until someone can explain the subjective realities of consciousness--the qualia--I figure at least some people will still figure there's more to the mind than just the brain. And I don't think dismissing them as epiphenomenal quite counts as an explanation.

Kevin said...

Addofio,

Indeed. But a physicalist account of qualia probably won't be a dismissal so much as a full and comprehensive explanation. Once the explanation is given (whenever that will be), it will be up to people as to whether they buy the explanation. Science has explained many things that people continue vehemently to deny, including the idea that the earth isn't flat.

I doubt scientists will ever deny the reality of subjectivity, but I'm confident they will eventually demonstrate that there is no unbridgeable gap between first- and third-person ontology.

As I wrote in one long-ago essay, the fact that we can manipulate qualia through physical means is a big hint that qualia are themselves rooted in the physical. A surgeon who touches a wire to exposed areas of the human brain is able to produce sensations and emotions in a manner she can predict. How is this possible if mind is substantively different from matter?

Granted, an account of subjectivity will be a long time in coming. I doubt I'll be alive to hear it. But I'm pretty sure that science will offer an explanation in the end.


Kevin