Looking for test subjects

In the basement of the Linnaeusborg at the Zernike campus is the timeless room. There is no clock, no windows, and the ceiling consists of fluorescent tubes to regulate the light. This is where PhD student Renske Lok studies how light and darkness influence our alertness. To do this, she wakes up her test subjects at night and has them perform small tasks. She makes them fill out questionnaires, measures their body temperature, and registers each and every one of their eye movements, no matter how small.

But who would be crazy enough to subject themselves to this?

Usually, they’re students. That’s because Lok needs test subjects between eighteen and thirty years old. This group has an easier time taking a night off than working people. They’re also tempted by the financial compensation. ‘Students are used to skipping a night’s sleep’, Lok says. ‘But they’re also intrigued by the timeless room and want to see what it looks like. They often ask if I’ll keep them posted on the results. They’re really interested in what we study here.’

Depression study

Fellow PhD student Rozemarijn van Kleef has a much harder time finding test subjects. At the UMCG, she studies how to prevent depressed patients from relapsing. ‘After three depressions, the chance of relapse is at 90 percent. We want to know what makes people so vulnerable.’ To do this, Van Kleef studies participants’ brains with an MRI machine. She makes her test subject perform all kinds of tasks in the scanner. She wants to see if preventive behavioural therapy can teach people to regulate their emotions.

But it is not that easy. While Lok has her pick of healthy students, Van Kleef is specifically looking for former depressed people. Participants may not be taking antidepressants or have recently undergone cognitive behavioural therapy. Unfortunately, those are the two most common treatments for depression. People over sixty are not suitable either: their brains show signs of ageing, which can influence the results.

For each single study, Van Kleef needs 75 people with a history of multiple depressions, and 25 healthy subjects to act as a control group. She recruits people through websites, social media, and posters in supermarkets. She searches as far as the Randstad. The control group is full. For the second group, 920 people have signed up. Perfect, you might think, but nothing could be further from the truth. Out of the 920 eager beavers, only 41 match the strict standards.

They have to have fully recovered from their latest depression. ‘Otherwise we’d be measuring the effect of the behavioural therapy on the recovery, and not the relapse’, Van Kleef explains. ‘Sometimes, people turn out to still be depressed. It’s also striking that many people do not feel that they have been properly helped.’

Behavioural therapy

Some people sign up because of the behavioural therapy the study provides. ‘It hurts me to tell these people, who are the ones we want to help, that they can’t participate. We always refer them to other places that can help them.’

Even when participants do appear to match the criteria, there are still problems. When people have had surgery in the past, for example. ‘We have to be very careful. If we can’t find out whether or not someone has metal parts in their body, we can’t put them in the MRI.’ The machine works through strong magnetic radiation. ‘We have two people whose full-time job it is to figure this out. Sometimes we contact manufacturers from years ago.’

Those who can participate have twelve hours ahead of them during which Van Kleef screens them and makes the test subjects do various tasks in the MRI machine. It doesn’t pay much: participants are offered 75 euros and eight therapy sessions.

Van Kleef: ‘We also offer the behavioural therapy session to the control group, for free.’ Yet that doesn’t seem to be the main motivation for people to participate. ‘I’ve been pleasantly surprised by how motivated people are. I think they want to do something positive with their history of depression. They’re very altruistic, which is great to see. We’re so grateful and truly appreciate what they do for us. We know we’re asking a lot.’

Going out there

Linguist Martijn Wieling has a completely different way of recruiting test subjects. Rather than making people come to his lab, he takes his lab, which fits into a suitcase, to them. On site, he sticks electrodes to his victims’ face and tongue and measures the movements. This so-called articulograph led him to discover that Northern dialect speakers have their tongues further back in their mouths than Southern dialect speakers – even when they weren’t speaking at all.

Psychology is not a very well-funded research area, and anyone who wants to use non-students will have to pay

‘If you’re stuck in a lab in a single location, you’ll always have a select group of people, namely, those who live close by and are willing to travel’, he says. That is why he travelled out to high schools, filled with test subjects he wouldn’t normally see in his lab. Ten euros are usually enough for students to participate. ‘We even had to devise a pre-test to see if they truly spoke the dialect, because non-proficient students tried to participate.’ There are drawbacks to doing research on location, however. ‘At the lab, you’re in a controlled situation. Here, I never know where I end up. Often it’s an office with a lot of background noise, which is less than ideal.’

Mandatory participation

And then there are the psychologists, whose research and education is highly dependent on people takings tests and filling out questionnaires. So much so, that there was a shortage of test subjects a few years ago. The Paid Participant Pool for non-psychology students partially solved the crisis. The other part consisted of psychology students for whom it was mandatory to participate.

Smart, and an educational experience to boot, says lecturer Katherine Stroebe. Although this method has its drawbacks as well. Test subjects are not allowed to know what is being studied, as this could influence the results. ‘I studied subtle discrimination. If I were to discuss it during my class, I would be worried if I wanted to do my study a month later.’

Psychologists also face the problem of their test subjects’ demographics. They are overwhelmingly white, highly education, and grew up in economically affluent families. ‘Psychologists are slowly beginning to expand their research population. But psychology is not a very well-funded research area, and anyone who wants to use non-students will have to pay’, says associate professor Pontus Leander.

It’s a situation you have to handle carefully, says Leander. He always asks questions at the end of each task. What was the research about? Were there any questions they felt were pushing them towards a certain answer? Between 1 and 5 percent of test subjects indicate they feel they knew what the study was about. Leander: ‘You have to then ask yourself how you interpret the results. I always mention it in my publications. In the end, you always have to ask if what you find in one particular group reflects on psychology as a whole.’

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