Throwing up is always unpleasant. But throwing up in zero gravity, with your vomit just floating in front of your face, taunting you, is much, much, worse. Especially when your feet aren’t anchored to the ground and the force created by your heaving sends you spinning in circles.
When I first heard about NASA’s grant for aspiring scientists to conduct research in zero gravity, I was convinced it was made for me. An undergraduate at the time, and an avid science fiction reader, my creativity to common sense ratio was badly skewed. (It still is, but not quite as egregiously.) So I walked into the office of my advisor, cognitive psychology professor Mike Watkins, and declared my plan to conduct a study in zero-g. “Danny,” he replied, “unfortunately, there’s gravity on Earth.”
Undeterred by that trivial detail, I convinced Professor Watkins and a fellow psych major that we could come up with something. I knew I’d never be an astronaut—my eyesight was too poor—but this was my chance to make my nerdy, sci-fi dreams of astronaut training come true.
After a bit of brainstorming, the idea came to us: state-dependent memory. A few decades earlier, David Godden and Alan Baddeley had run a classic study on how scuba divers learn pressure tables. Divers who studied while underwater remembered the material better when tested underwater, whereas divers who studied while on land remembered better when tested on land. This suggested that the environment where you learn influences how well you remember later.
Nobody had ever explored whether the effect would generalize to gravitational states. If we learn in zero gravity, do we remember better when in zero gravity later? The answer could have implications for training astronauts.
In retrospect, the theoretical advance of the proposal could be generously described as modest, but I think NASA was so surprised by the novelty of an application from behavioral scientists that our proposal was approved anyway.
“Danny,” he replied, “unfortunately, there’s gravity on Earth.”
To prepare to go into zero-g on NASA’s KC-135 airplane, we had to go through several weeks of training. We trained in oxygen deprivation chambers and learned how to deal with rapid decompression. At all times during the training period and for a time after the experiment, we were required to wear a little card that said, “NASA Hazardous Duty” (yes, I still have it), because if I collapsed or needed to go to the hospital, the doctors would need to know.
The KC-135 creates weightlessness by first climbing to high altitudes and then entering free fall, allowing passengers to float (relative to the plane around them) for about 30 seconds before the plane levels out and begins the cycle again. During the climb, passengers experience close to twice the normal gravitational forces; during the fall, passengers experience zero-g.
In additional to weightlessness, passengers also commonly experience nausea, thus earning the KC-135 the moniker “Vomit Comet.” Fortunately, NASA has come up with a way to prevent passengers on the KC-135 from suffering the extreme nausea that such an experience normally induces: Scop-Dex, a mixture of scopolamine (a drug that prevents motion sickness) and Dexedrine (a stimulant that counters the side effects of scopolamine). So rest assured, if you have to go into zero gravity, you won’t have to deal with the debilitating nausea that the Vomit Comet is known for.
Unless, of course, you run into trouble with the research ethics review board (something that only we, as behavioral scientists, had to deal with), and they don’t approve Scop-Dex.
The ethics board thought that giving undergraduates the opportunity to go into zero gravity was coercive because no undergraduate could turn down an opportunity like that. And because it was coercive, we shouldn’t be allowed to do it at all. This was compounded by the fact that my college didn’t have a medical school, and so the reviewers were nervous about participants taking any drugs. In NASA’s eyes, what we were doing—having people remember things—was not an issue and paled in comparison to the tests they put would-be astronauts through. After much back and forth, we reached a compromise. The study could go ahead, but with no Scop-Dex.
On the KC-135, we set up our experiment alongside the other research teams. One I remember in particular was a group of engineering students who were testing power drills that displaced the torque; if you used a regular power drill in zero-g, you’d end up spinning in circles.
We equipped our participants with noise-cancelling headphones. They were going to hear a list of words and had to note whether each word was new or old, depending on whether they had heard it before. Early on, this is easy, because all the words are new. But eventually, the words are mixed more evenly. The question is: If you hear a word for the second time in the same gravitational conditions that you originally heard it, are you more likely to remember it? The plane took off and the lists started.
Ten to 15 minutes later, after only a few of the zero-g parabolas, I threw up for the first time.
On Earth, what goes up must come down. In zero-g, what comes up, floats. And in zero-g, the esophageal thrust, so to speak, sends you spinning. And your eyes are closed because you’re vomiting. And you’re trying to hold the NASA-approved bag around your mouth, hoping as little as possible escapes. Then a flashing light comes on indicating you have a handful of seconds to get to the floor of the plane, before the parabola finishes and gravity reasserts itself (remember, at near twice the force of regular gravity). But since you’ve been spinning with your eyes closed, you don’t know which way is down. So you’re trying to watch other people to figure out where they go, but they’re trying to finish their experiments, so you only have a few seconds to get to the floor before gravity hits. And you’re really, really trying not to let the bag slip off of your mouth.
After a few parabolas, it was hopeless. Some of the members from the other teams (the ones who could take Scop-Dex) strapped me down in the back of the plane. There, I counted down the remaining parabolas—50 more. 50 more left. Only 50 more left. 49. Only 49 left.
On Earth, what goes up must come down. In zero-g, what comes up, floats.
The two and a half hours of that flight were some of the worst of my life. I’ll never forget one research team blowing bubbles (their project investigated surface tension of bubbles in zero gravity) having the time of their lives. And when we finally got down to zero parabolas left, the captain came on and asked, “Before we go down, would anyone like to see what lunar gravity is like? We can emulate lunar gravity …”
The bubble-blowing scientists cheered. Why not? Wouldn’t it be fun to blow bubbles on the moon?
I moaned; unfortunately, I was so hoarse from heaving that no one heard. So I experienced lunar gravity cargo-strapped to a plane with a bag over my mouth. And Martian gravity too. By the time the KC-135 landed, I had lost 10 pounds.
Only one of our participants made it through the whole experiment without getting sick. In the end, we didn’t get much data, though my research conclusively demonstrated one thing: people don’t remember whether a word is new or old while vomiting. Unfortunately, this finding was not considered surprising or important enough for publication.
Many behavioral researchers do extraordinarily clever things to collect data given the constraints imposed by the environment. Maybe they’re doing research in a country where research is very difficult, because of issues with the government or language barriers or limited technology. Maybe they’re testing theories that require conditions rarely seen in naturalistic settings. So maybe behavioral science in zero gravity isn’t as strange as it sounded when I walked into Professor Watkins’s office all those years ago.
In spite of the misery of that experience . . . I was hooked on research and thinking creatively about the different ways we might investigate a problem.
And, in spite of the misery of that experience, there were some silver linings. First, my motion sickness was cured. I used to be the person who couldn’t get on a boat, and when in a car on twisty mountain roads would always have to sit in the front seat and have to stop. But not since this incident.
Second, I was hooked on research and thinking creatively about the different ways we might investigate a problem. Looking back, 20 years later, now as a full professor, it was a fun challenge to design stimuli given the unusual logistical constraints. And it obviously didn’t dampen my enthusiasm for research.
As scientists curious about human behavior, we want to see whether our findings generalize beyond the lab, and going beyond the lab is tricky. Outside of the lab, we lose control over many things, sometimes even the contents of our stomachs.
This article first appeared in Behavioral Scientist’s award-winning print edition, Brain Meets World.
