Inventing Iron Man (17 page)

It is worth also touching on another strange outcome of wearing a suit of armor. That is again the idea of aftereffects. What I mean here by “aftereffects” is the continuation of a sensation or a perception after whatever you are doing to cause the change in perception has finished. This is directly related to the issue of the aftereffects of wearing a suit of armor that we discussed in
chapter 5
. So I mean effects that … continue after. Probably the best example of an aftereffect that you have likely experienced is a playground merry-go-round. When you spin around and around, you activate neural circuits related to balance information from the inner ear that carry on having effects well after you stop spinning. Recall trying to run forward
after spinning on a merry-go-round. Although you sure do try to go forward in a straight line, you tend to deviate to one side despite your best efforts. Another example of similar vestibular aftereffects can be detected by being on an oceangoing boat all day with the sea rolling under you. If you do that and then sit down on a stable object like a chair at the end of the day, you often find that you can “feel” the roll of the boat even now that you are on land. This is where the idea of getting your “sea legs” comes from. Also, your nervous system is pretty specific about this. If you were sitting most of the time while at sea, the effects will be largest when you sit down later. What would it “feel like” to be Iron Man when the armor was off?

Let's go back to that concept of “embodiment” in relation to prosthetic limbs. The idea of embodiment is that the artificial bit—the prosthetic—becomes so fully integrated into the person and her perception of her body that there truly is no line dividing the two. In a clever experiment with an unusual outcome, a team of Swedish scientists headed up by Henrik Ehrsson recently provided an excellent example of this. They were able to create a stunning illusion in a group of upper limb amputees, which had been shown before in people without amputation and is called the “rubber hand illusion.” They created a sensation of embodiment that a rubber hand was actually a real hand attached to the stump where the amputated limb used to be. The experiment was very simple (as are most clever and truly illuminating scientific studies) and basically involved hiding the stump from view while placing a rubber hand in view of the participants (
figure 6.3
). Next, the experimenters used small paint-brushes to rub simultaneously the index finger of the rubber hand and the stump of the amputee for two minutes. Later, just the rubber hand was rubbed—but sensation was felt in the hand!

Despite the fact that a similar illusion works well in able-bodied persons, the researchers were skeptical that it could work after amputation. They were therefore greatly surprised when amputees identified generally the same illusions. In fact, strong illusions were found in one-third of the participants. Interestingly, the illusions were more powerful the sooner after amputation that the tests were done. The most important point, though, is that this clearly shows both the tremendous plasticity of somatosensory maps and how they can be changed after damage. And, how vision can trump our other senses—like we talked about above for phantom limbs and phantom limb pain. By the way, they also examined anxiety in participants using skin responses and
then plunged a syringe (panel C) into the rubber hand (which was not part of the body, remember). The participants had physiological responses of anxiety that would normally be present if the hand were part of their body. The strict relevance is that prosthetic limb designs that include sensors on the digits could be used to activate skin areas on the intact stump. Over time, this work suggests that the sensation from the artificial sensor on the prosthetic would become integrated into the perceptions of the person such that they are one with the body (enter, embodiment).

Figure 6.3. The “rubber hand” embodiment illusion. The stump of the amputee is stroked at the same time as a rubber hand that is in sight (
A
). Eventually the amputee perceives that the stroking of the rubber hand (with no activity on the stump) is actually coming from the stump (
B
). The illusion becomes so strong that in some people plunging a syringe into the rubber hand evokes physiological responses from the amputee (
C
). Photograph: Christina Ragnö, courtesy Ehrsson et al. (2008).

This raises the interesting idea that early versions (that is, before full nervous system integration) of an Iron Man suit of armor should have sensors on the fingers, hands, toes and whatever other body surface that activate skin areas on Tony Stark's body. In this way, Tony would really come to embody Iron Man in the way he declared in
Iron Man 2
, “the suit of Iron Man and I are one.”

Incredibly, a recent study showed that including sensation from a robotic limb improved the ability to learn brain-machine interface commands. In 2010, Aaron Suminski, Nicholas Hatsopoulos, and colleagues at the University of Chicago used a “sleeve” over an animal's arm to help train monkeys to move a cursor on a computer screen
based on recording activity in the motor cortex. This is just like the procedures for brain-machine interface we talked about back in
chapter 3
. The crucial difference was that the scientists at University of Chicago allowed the monkeys to use visual and somatosensory feedback together. Those monkeys learned how to control the cursor much faster and more accurately! I think this would likely have an effect on embodiment as well. This awaits future research.

Embodiment can arise from extensive use and practice with tools and devices. It is highly likely that this also occurs with extensive training with almost anything that is not part of the body naturally. This is also why learning to play a sport that uses tools—think golf or tennis, for example—is so challenging. This is probably because these tools or implements have not been extensively calibrated and mapped as parts of our physical bodies. Those somatosensory and motor maps have been continuously developed and recalibrated over all the years of your life to reflect your body size and habitual activities. But you use your body every day, and it has always been there for you. In contrast, the particular implements or tools that we use haven't been with us all the time and we don't use them continuously. Those maps we have for our bodies have to be able to integrate and incorporate the tools into our physical perception of ourselves. This is what is meant by embodiment. It does seem that, while these changes certainly do occur, the changes in our body maps are weaker than those for our actual body parts.

Because of that more practice—or maintenance activity—is needed to keep those maps strong and intact. In my own physical activity experiences in martial arts, I can certainly attest that complex techniques and movement patterns with empty hand are easier to initially learn and subsequently remember than are techniques and patterns based around weapons. As a result, it is much, much easier to lose track of, forget, or lose skill with weapons technique than it is with the empty-hand technique. Empty hand training uses all the “weapons” of the body that have been part of your body since birth. Weapons use involves tools. And what is a more complex tool than an Iron Man suit of armor?

By the way, this kind of embodiment and plasticity can occur even in actual tool use in humans with no neurological damage. Lucilla Cardinali, along with other French and Italian scientists, performed a fascinating study to look at this. They developed a long (about 40 centimeter, 15.5 inch) handled extension that had a “grabber” at the end. By squeezing the close end, it was possible to pick up
objects and move them around. This was kind of like the grabber that can be seen everyday in parks and streets that cleaning staff move about picking up refuse and discarded items without having to bend down. In the study Cardinali and colleagues had people practice reaching with the grabber. Their research showed that using the grabber changed the movements of the arm even without using the grabber! Even more interestingly, the “aftereffects” due to using the grabber tool affected later simple pointing movements and also the perceived length of the arm. Participants had the impression that their arms were actually longer. The idea seems to be that the somatosensory schema of the body was changed by using the tool and the change had a general effect for many behaviors. Maybe even for Iron Man? In the 2007
Extremis
graphic novel, after using the new suit Tony talks about how the suit is “wired directly into my brain. I control the Iron Man with thought. Like it was another limb.” This would mean some process like that shown in
figure 6.2
would actually have to be occurring in Tony's brain.

Embodiment could apply to armored exoskeletons as well. Or spacesuits. I asked David Wolf from NASA about his experiences in space using a spacesuit. David is one of those astronauts who is an extravehicular specialist. That means he has spent a lot of hours literally in space, as in outside the spacecraft. His total time (including NASA and Russian MIR missions) is over 40 hours. In addition to that he has had more than 800 hours of water-based training wearing a spacesuit on earth. He has logged a total of 168 days, 8 hours, and 57 minutes in space. Approximately—but who's counting! Wolf explained to me that over time, wearing the suit is to “become one with the suit” (who does that sound like?). Eventually, wearing the suit “is like putting on your own armor and your old familiar tools…. It gets easier.” This resonates very well with the idea of neural plasticity associated with learning how to use a new tool we talked about earlier. In this case a tool you wear over your entire body. By the way, this being a book anchored on Iron Man, I did ask Wolf about comic books and his favorite character. He likes Superman, for the record.

I also spoke with David Williams of the Canadian Space Agency. (All right, I admit it. Yes, I only spoke with astronauts named Dave in honor of the book
2001: A Space Odyssey
by Arthur C. Clarke.)
Williams, now a professor at McMaster University in Hamilton, Ontario (coincidentally, I am a MAC alumnus, just saying), told me that “you're as good as your training.” It all comes down to the operator, in effect. He also emphasizes the role for mental imagery and rehearsal to memorize and perform sequences as rehearsed. This is to help “train like you fly, fly like you train.”

Let's close this chapter with a few comments about how fun—or not—it would really be to wear a suit of armor for prolonged periods. Going back to David Wolf, he said that it “sure feels better” to get the suit off and you are “very happy to get out of the suit” and that “wearing it for long time is like being in a tight balloon.” Additionally you have the concern about depending on the life support from the suit the entire time it is on. It is “probably like a race car driver when he gets out of the car after a race”; you are “hot, tired, hungry, and have been working at a very high level of peak concentration for a long time.” In the comics this was also noted by Tony Stark's trusted assistant Pepper Potts. In the story “World's Most Wanted, Part 7: The Shape of the World These Days” (Invincible Iron Man #14, 2009), Pepper has made use of a custom-designed armor suit for herself (Tony is on the lam). She goes on to say “it's been nine hours in this suit, and, no offense, but if I don't get to get out and take a shower soon, I'm going to start screaming.” With that, let's move on.

“I Can Envision the Future”

The next phase of Iron Man project development would require getting around the biological delays and control issues related to relying on physical movement to drive Iron Man's activities. The steps in this phase each would involve a slightly more invasive integration with the nervous system. The first is to get stable motor control by using Tony's own nerve signals as triggers for activating the motion of the suit. To apply the existing technology of basic neuroprosthetics to Iron Man would require improved processing to more effectively use the nerve signals for controlling complex movements. This would take about three or four years. The next step would be to get around the delays and control problems that go along with using measurement of muscle activity. Tony would instead try to use direct brain commands for moving the suit and would need to develop a suitable brain-machine interface. The basic technology to do this exists, but it typically involves surface electrodes on the scalp of the human head which has limited control options.

These kinds of brain recordings provide only limited two-dimensional (e.g., up/down, side to side) movement control; they could only be used for controlling a paper-thin Iron Man moving across the pages of a comic book. To be more usefully applied in three dimensions, Tony would need to spend another five years improving the understanding of brain output as a signal for controlling the armor. He would then likely try to use the signal recording with the highest content: direct single-cell neuronal recordings. The technology to get basic information for controlling simple arm movements is available but has been mostly restricted to studies of the monkey. Some limited information has also come from studies of patients undergoing neurosurgery. Moving
forward with this technology would take another five years. During this time, an improved knowledge of brain output from neuronal recordings would be needed, as would increased safety for recording from the human brain for prolonged periods. We are now almost 30 years into Iron Man development, and he would still be able to execute only rudimentary walking, lifting, and striking movements—and only by Tony paying strict attention and concentrating fully on the task at hand. More work remains. Tony continues to toil late into the night. Just about every night.