Pro-tips for running linguistic and psychological experiments

As somebody who works on speech perception, a good portion of my research time is dedicated to finding willing participants, sitting them in a sound booth and watching them listen to words, ensuring that they come back to subsequent sessions, and that they stay awake and undistracted during the current one.

Although experimental design has been discussed ad nauseam in the science world, the more human, more practical aspects of this process is not covered in textbooks, in courses, and in experimental design books. So, in the interest of open research, here’s a selection of tips I’ve accumulated during my time running experiments. I hope some of them are helpful!

Lab Coats aren’t just for (medical) Doctors!

A collaborator in psychology once told me that you should always wear a lab coat during experiments, because studies [[CITATION NEEDED]] have shown that people return for subsequent sessions more often when the experimenter is wearing a lab coat.

This works for recruiting, too. As trite as it is, if you visit a classroom to recruit participants, wear your lab coat. In my experience (p = anecdotal), more people sign up when I’ve worn a lab coat on top of my street clothes.

So, considering you can get one for $15 on Amazon, there’s no reason not to!

Tear-off Tab Posters can be easy!

Tear-off-tab Posters (like this one (PDF)) are a royal pain to make in Word. But if you use LaTeX (and you should use LaTeX), it’s easy! Just download this template to create an easy-to-print PDF. Changing the tab text is now only a few keys away!

Also, always remember to include the email or sign-up information on the main poster, in case all the tabs are torn!

Check up on your posters

If you’ve put up posters all over the campus/area, it’s not a bad idea to take a stroll around and see which ones are getting the most traffic (torn tabs). This way, for the next round, you know what areas are getting the most eyes.

Also, if you’re recruiting a certain demographic (e.g. students, older speakers, etc), you can ask participants “where they heard about the study”, and favor postering locations which are bringing in lots of people in your target market.

Always “seed the pot”

In my brief career as a street musician (playing the Hammered Dulcimer), I quickly learned that you need to “seed the pot”, that is, put some change and a few crumpled up $1 and $5 bills into your open instrument case. This helps to show people that they can put money in your instrument case, and adds an element of social pressure to do so (“Well, somebody else donated!”). This works for experimenting, too!

When you hang tear-off posters, always tear off one specific tab (“fourth from the left” or the like). This way, there’s social justification (“Oh, somebody else was interested!”), but you still know whether a given poster is actually getting traffic.

Similarly, when you send around a sign-up sheet during a classroom visit, always have one or two previously-booked spots “claimed”, ideally in two different pen colors and hands. Blank pages have inertia, but if my friends Randy Waterhouse and Bobby Shaftoe have signed up, it can’t be all bad, right?

Miniature Water Bottles are worth their weight in Gold

If you see a participant getting sleepy during an experiment, which is pretty common during monotonous speech perception tasks, offer them a (sealed) bottle of water at the next break. For some reason, that seems to work better than any other trick to keep people from fading off. And it’s always handy to have a case or two of 8oz bottles around for speech production experiments.

Leave some forms out!

Whether they arrive early, you arrive late, or the last person runs long, sooner or later, a participant will have to wait around outside the lab. If your experiment design allows it, it’s a great idea to put up folders with some copies of the consent form and questionnaire, and a sign along the lines of “If the door is closed, fill out a consent form and questionnaire and then have a seat, we’ll be with you ASAP.”

It can save you a few minutes of watching a participant reading and let you jump straight to “Any questions about the consent forms or questionnaire?” and then into the experiment. It may only buy a few minutes, but some days, you need all the help you can get.

Check your bulbs

This was the best “weird little trick” I discovered for our lab. We have a large soundbooth with four floodlights, and always had trouble with excess heat in the booth, even with the booth fans running.

On a not-so-wild hunch, I replaced the four incandescent bulbs (which use 90% of their power to make heat) with LED floodlights, using university “green your lab” funding, and the excess heat problem all but disappeared. As a bonus, LEDs don’t emit much infrared light, which made dialing in our eye-tracker even easier. Win win!

Need a charge?

Asking that people leave their cell phones outside the sound booth during experiments is seldom effective and usually incites whining and objections. Not a great start to an experiment, and a recipe for distraction and GSM phone interference.

But if you provide charging cables and adapters for both iPhone and Android phones on the table with the consent forms, you can casually offer “you can charge your phone out here during the experiment”, most people will be thrilled to leave their phone outside the booth.