Thinking, Behaving, and Monkeys with Joysticks

I hope that the "thought" experiment I suggested last week stands on its own. The point was, at the least, to make people wonder how strong the causal relationship is between 'thinking about moving' and 'moving', and wonder if they might be very different phenomenon. Here I hope to demonstrate how the standard assumptions about the relationship between thinking and behaving can lead to some pretty awkward descriptions of phenomenon, and how a more embodied approach might do better. (Full disclosure, I'm still struggling with this, and will do a good, but definitely not great job.) Our case study come from the work of Dr. Miguel Nicolelis, who does ridiculously cool 'neuro-engineering' work down at Duke University. Our awkward descriptions of that work come from an interview on the Diane Rehm Show, aired on National Public Radio. There, Dr. Nicolelis describes research that culminates in a monkey moving a cursor on a computer screen via implants that detect neuronal activity in its brain. Here, roughly, is how the study works:

1.  A monkey is taught to play a joystick-controlled game. The monkey is reinforced for using the joystick to get an on-screen cursor onto a randomly placed dot. 
2. While the monkey is playing, we record neural activity in the motor cortex through direct implants.
3. The neural signals are sent to a computer in the next room, which is itself attached to a robotic arm in another room that is holding a joystick. 
4. Because the lab has some savvy programmers, the computer starts to replicate the monkey's movements pretty quickly, based on a pretty small number of inputs. To double check the computer, you have it run live with the monkey, and see that the monkey-held joystick and the robot-held joystick are moving the same, in real time, on novel trials.
5. You remove the joystick from the monkey's cage, but leave the implants, and let the monkey see the cursor movements generated by the robot arm... which the monkey does not know is in the other room.
6. Pretty quickly the monkey starts doing the task just as well as before.
7. Write a Science article.  

These experiments have been cranked up quite a bit (e.g., making a robot walk on another continent, etc.), but the basic outline of these fancier studies is identical.

The Easy Way to Sell This Work

Nicolelis explains this work well in the interview. He is engaging, communicates the medical and social importance of the work convincingly, and gets a surprising amount of the science into a general-audience-friendly form. Where he comes up short, I think, is in providing a more sophisticated way for listeners to understand the relationship between the monkey and the apparatus at the end of the study. In fairness to Nicolelis, that might not have been one of his goals in this context. I understand that things must be simplified for general audiences, and I really do not mind when that happens. However, I have seen talks in academic contexts where people use the same language, and have read a few of Nicolelis's articles just to confirm that they are not much better. Nicolelis presents his research in the context of modern brain-body dualism, with strong overtones of mind-body dualism. The succinct version of this is his statement that:

The monkey could enact its voluntary motor will just by thinking. 

Other questionable phrasings included:

she didn't need to move her body at all, she just had to imagine the movements that she had to make.

and

we can record the electrical brainstorms that are generated in the brain, in the cortex, the motor cortex, you know, where the plans for us to move are generated half a second before we even start moving.... [The brain] plans the future of our motion and during that window, half a second or so

 The Problem with the Easy Way

"Voluntary motor will"? "Imagine the movements"? "Plans for us to move"?

Is this really the best way to talk about what is happening here?

Of course, most people are dualists, so when they hear this type of talk, they nod their heads as if they understand the implications of this experimental work. But they don't. This can be seen plain as day when you leave the relative safety and sanity of NPR. For example, in this news report on similar work, the newscaster actually leads in by saying that, thanks to new research, telekinesis is possible! Nobody without a hell of background could have heard the NPR interview and thought:

And by 'decide' Nicolelis means something neurons do, and by 'motor will' he means something neurons do, and by 'imagine' he means something neurons do, and by 'plans' he means something neurons do.

Rather, this dualistic language is appealing exactly because it misleads the listener. It allows the listener stay safely dualistic, while also allowing the researcher to pretend they are not promoting dualism. This last part would be evident if someone cornered the researcher within hearing distance of his academic colleagues. The researcher would quickly claim that he intended to use those terms in a totally non-dualistic way, placing the blame for any 'misunderstanding' on the part of the listener... while also claiming that their goal was to educate the listener. Alas, few will tell our researcher that if he doesn't want to encourage his listeners to think dualistically, he should stop using dualistic locutions. 

Even if we take the researcher at their word that they didn't intend anything dualistic... you are still left with the problem that there is absolutely no evidence that the monkey is 'thinking about moving', 'imagining moving', 'planning to move', or anything else along those lines. This criticism still stands, if we put aside any reductionist or eliminativist arguments. --- Granting a standard cognitive-neuroscience, 'brain = mind' model: Did the monkey use areas of the brain that are involved in thinking, imagining, and planning, or did they only use areas involved in moving? Certainly, in these experiments, we only have evidence that they are using the areas involved in moving. 

A Better Way of Presenting These Results

To better explain what is happening in these studies, we need to stick closely to the language of embodiment. What we have at the end of the study is 'a monkey moving a joystick'.

"But wait!", comes the knee jerk reaction, "you just skipped everything interesting. The whole point is that the monkey is not really moving the joystick, the computer and the robot arm are moving the joystick!"

Nope. The monkey is moving the joystick. The monkey, the computer, and the mechanical arm have become a single system that interacts with the environment, and that system moves the joystick. The monkey-brain, or at least the part of interest, is doing exactly what it did when its arm was moving, and that is the point - if that part of the brain was not doing the same thing, the whole set up would not work. Thus, the new relationship between monkey-brain and the mechanical-arm is the same type of relationship that there was originally between the monkey-brain and the monkey-arm. If we were willing to say that 'the monkey' was moving the joystick in the first case, we have been given no reason to change that. Returning to the interview quotes above:

The monkey could enact its voluntary motor will just by thinking. 

and

she didn't need to move her body at all, she just had to imagine the movements that she had to make had to move the joystick.

This creates a problem. The problem is that most people want to talk about the relationship between the monkey and the robot-arm in a different way than we talked about the relationship between the monkey and the monkey-arm. Given that the old cognitive language does nothing but continue to invoke dualistic notions and mislead people about what is happening, it needs to go away. This leaves us with two possible option: 1) Get over our discomfort and agree that the two relationships are the same and that all the same terms should be used to describe them. Given this option, we would still have the difficult task of creating conventions for deciding when a formerly-separate part of the world has become part of the organism. It should be noted that this is a problem biologists have been worrying about for a while. 2) Come up with a better way of talking about systems-level phenomenon like these that distinguishes the two situations. We need a better way to talk about systems level effects that involve the brain either way, and I'm not sure how that language would distinguish the robot-arm movements vs. the monkey-arm movements.

Concluding Thoughts

Just to re-emphasize the point, this is amazing research; my only complaint is with the way it is being discussed, because the way it is being discussed leads people to think inaccurately about broad aspects of psychology. I should mention that Dr. Nicolelis, in the same interview, does a great job of talking about how still-popular ideas about brain-area-specialization are increasingly suspect, both because of evidence for distributed influences throughout the brain and because of evidence for much neural-plasticity. Also, he does good educational things with kids in Brazil, which he talks about briefly towards the end (with other discussion here and here).

At any rate, to connect back to my demo from last time, I want to offer two concrete predictions. The first is phenomenological: When these types of 'mind-control' devices are attached to humans who can self-report, we will find out that controlling the robotic arm is experienced as very much like 'moving', and not at all like 'thinking about moving.' There are already similar-enough devices in humans that this could be checked easily.

The second prediction is neuroscientific: If you built a robot, and you want it to move the way a person is moving (or the way they would be moving if not paralyzed), you would connect the robot to different parts of the brain than if you wanted the robot to move the way the same person was imagining a robot moving.

What do you think? Am I full of it? Will those predictions pan out?