Gravesend Inn-frasound: The Experiment

In Part I of this series, I laid out the background of the research study we recently completed at City Tech; this entry details the experiment itself.

To do human subject research in an academic setting, we must first get approval from our school’s “Institutional Review Board” (IRB). This board is charged with protecting the interests of the institution and the test subjects, and the process also ensures that any research done in the name of the institution is held to high standards. Thankfully, Dr. Toija Riggins took over this critical part of the process: creating the formal experimental design, and applying to the IRB for approval. The IRB application serves as the blueprint for the whole experiment (download a PDF of our entire original application here), and lays out the goals of the research:

Despite the fact that there are several thousand years of live entertainment tradition, there has been very little systematic research investigating the ways that audiences react to various forms of entertainment.  Audience members are bombarded with sensory input during a show, and we are interested in learning more about that sense perception.

The purpose of our proposed research is to examine the role of infrasound (sound waves below 20 cycles per second) on emotional states in audience members in our existing Gravesend Inn “Haunted Hotel” attraction.  Infrasound is already present in the designed soundscape of the Gravesend Inn; we are attempting to quantify the potential effect of infrasound as a possible arousal agent in this study.  The results of the study can be used in the short range to improve our haunted house, and may have broader applications in the field of live performance.

. . .

The investigation proposed by student [now alumna], Toija Riggins, Ph.D. and Professor John Huntington in the Entertainment Technology Department, would consist of a greatly simplified, in-laboratory extension of the Tandy & Lawrence and Angliss & Wiseman research [which I covered in part I of this series]. During the department’s annual Gravesend Inn theme park-style haunted hotel attraction in Voorhees Theater in October 2010, participants will be recruited to join the research study that will be held in a separate department classroom--the department’s scenic construction shop.

Once in this environment, participants will hear the pre-recorded description of an unusual event that allegedly took place in that location--the supposed murder of a college professor.  We will expose one-half of participants to infrasound during this presentation, while the other half will not be exposed.  Promptly after the pre-recorded voiceover ends, the lights will be turned off.

The proposed design is completely double-blind; neither the researcher nor the participants will know during which sessions infrasound is being generated.  After the presentation has concluded, participants will be asked to complete a brief questionnaire.

The questionnaire asks respondents to rate their emotions on Happy-Sad, Aroused-Sleepy, Exited-Bored, Angry-Calm, and Confident-Fearful, five-point Likert scales.  (The “Confident-Fearful” scale was added specifically for this study because of its subject matter and was not included in the Infrasonic research.) [You can download a PDF of the survey we used here, and note that this survey includes an additional question about superstition which was approved by the IRB in a filing ammendment]

The playback of the background story, execution of the eerie event, the infused infrasound, the length of the experiment, and the random assignment of participants to groups will all be strictly controlled by “show control” technology...

which will be covered in more depth in a subsequent entry.  To perform the voiceover, I recruited the great sideshow artist and actor Todd Robbins (whose excellent new show, Play Dead, directed by Teller, just opened). Here’s the voiceover script, a mixture of fact and fiction (and a slight modification from the script included in the IRB application to adjust for Todd's performance):

Hello, I'm Professor T.L Robbins, Chair of the History department here at City Tech. And I'd like to personally thank you for participating in our study.  The reason we are here today is because faculty and students have reported, well, strange experiences in this room, and we are trying to get to the bottom of it.  I'm going to tell you a little of the history of City Tech, and of this building and  afterwards, we're going to ask a few questions about your experiences here.  This should only take a few minutes, so let's get started.

In 1946, New York Governor Thomas E. Dewey proposed legislation to assist GI’s returning from World War II, and this legislation provided funding for several experimental institutes, including the predecessor to what we know today as City Tech. The story has been told that in 1948, the room in which you are standing was a woodworking shop, where students learned basic construction techniques, and the shop was overseen by Professor Wiseman, the school’s beloved carpentry instructor.  Professor Wiseman was alone working on some paperwork late on Halloween eve. Tragically, students reporting for class the next morning discovered Professor Wiseman's body--he had been murdered!

Rumors persist to this day that the last person seen entering the shop that fateful Halloween eve was a shell-shocked World War II veteran named Sergeant Angliss, who was very angry about a grade that he received.  He was never seen again, and it is believed that Sergeant Angliss escaped into the underground Con Ed tunnels that runs beneath this very floor. Students and faculty working in this space late at night often report unusual experiences.  And as you are here, today--have you noticed anything?”

At this moment, the lights go out for fifteen seconds. We had originally thought of creating some sort of apprarition, but thought this wouldn't make sense since the research subject had just exited the obviously fake Gravesend Inn attraction, and they might then be rating our handiwork and not the effect of the infrasound.  The lights come back up and and the voiceover finishes with: 

Thank you for your participation! My assistant will now show you back out to the other room where you can fill out a brief questionnaire.

Here's a video of the experiment setup with voiceover, from the research subjects' perspective:

Back to the IRB application:

Because information about this experiment that is passed on to other potential subjects would damage the validity of their responses, participants will be only partially debriefed during the experimental sessions.  They will be provided a full debriefing statement via email once all study activity has completely concluded.  Statistical analyses will include a multivariate analysis of variance to evaluate differences among means of the treatment group (infrasound present) versus control group (infrasound absent) on the set of questionnaire scales (dependent variables). 

And here's the core of our hypothesis:

If earlier findings are supported, we would expect these analyses to reveal that those exposed to infrasound should report greater feelings of emotional discomfort than those not exposed to it.  That is, we should expect higher scale scores in the treatment group than in the control group.

To ensure that our infrasound secret was kept, we were very, very careful about to whom we disclosed information, and in what ways.  And to help run the experiment we didn’t want to use current students, since we felt that the information about infrasound would eventually get out, poisoning a potential research pool.  So we recruited from NYC Skeptics group for volunteers, and required applicants to complete university-mandated human subject research training and sign a non-disclosure agreement before we discussed anything. That whittled down the initial 16 volunteers to a brave group of 5, who we especially thank, since their time and dedication made the experiment possible: Sarah Babkirk, Alex Consilvio, Clinton Freeman (who worked every single shift!), Tsee Lee, and Tom Myruski. In addition, we recruited recent Entertainment Technology graduate Andrew Puccio to be our expert operating technician for the experiment (he also had to complete the training, and volunteered for every shift), and current student Erin Grabe was key to helping us recruit as many people as possible from the audience exiting the Gravesend Inn.

In Part III of this series, I discuss the challenges we faced in generating and measuring the 19Hz subsonic sound.