Dr. Marije aan het Rot: Unraveling the psychology and biology of social interactions
"One third of our life involves interaction with other people."
Have you ever wondered why on some days you feel blooming in the morning only to feel blue in the afternoon? Or have you encountered a person who cannot seem to hold a conversation without making sarcastic remarks all the time? Or a person you want to be with because of the positive energy he projects every time you talk to him? These and other related questions about mood and social interactions are what keeps Dr. Marije aan het Rot busy.Dr. aan het Rot is an Assistant Professor in the Department of Psychology. With a PhD degree in Neuroscience in 2007 from McGill University (Montreal, Canada) and a postdoctoral fellowship in the Mood and Anxiety Disorders Program at the Mount Sinai School of Medicine (New York, USA) until 2009, she has been working in the University of Groningen (RuG) since August 2009 where she studies serotonin and social interactions in the context of psychopathology. She received a VENI award from NWO to study the regulation of social functioning by serotonin in people at risk for depression. She is very curious about the interplay between social and biological factors in determining mood and influencing risk for mood disorders.
In the university website, under your research impression page, it says “for positive social interactions, you need both psychology and biology.” What’s the difference between the two fields?
“I don’t think there is necessarily a difference. You have a lot of people arguing that there is mind on one side and the brain on the other side, but that’s already a philosophical debate. Here in our department, I’m the only one who does experimental manipulations on the biological level, everybody else does cognitive manipulations, which is equally interesting and I learn a lot about that. For example, they let people read a very sad story; how does that influence people’s mood? Or they let people listen to a certain piece of music; how does that influence mood? So those are more psychological experiments, but at some level, I believe, they must get to the biology. Similarly, if I do a biological experiment, I am getting to the psychology because I am eliciting effects on mood.”
In February 2012, aan het Rot formally joined BCN, but she started supervising Kristina Miloserdov, a BCN Master student, before that, together with Marijke Gordijn (Chronobiology).
Who introduced you to BCN?
“I knew several people in BCN (Marijke Gordijn, Mark Nieuwenstein, Deniz Baskent) and I am currently co-advising a Master student on a joint project with Marijke. Also my PhD student Koen Hogenelst is a former BCN Master student.”
When you joined RuG you did not immediately become a member of BCN?
“No, I did not. I started working in Psychology, but the VENI project I am doing and also some other projects that I would like to do, but with unsuccessful grant applications so far, are very much interdisciplinary. One of them has something to do with light exposure and that is how I got to know Marijke. Then I knew Deniz Baskent through one of my colleagues here in psychology who is her husband. He is working in auditory psychology. Mark Nieuwenstein is involved in the teaching in BCN. He works here in the building and I talked to him about my projects that BCN Master students might be interested in joining. Through them I realized that I should really join BCN.”
You like the interdisciplinary nature of the BCN research school?
“Yes, because there’s people with all different kinds of backgrounds like engineering, psychology, genetics, physics, and hardcore neuroscience, of course, biochemistry, nutrition, who knows. It makes it more diverse.”
What would be your advice to students who are thinking of doing projects in BCN?
“To really find a project that somehow you connect with. One of the reasons I always ask students to write a motivation letter is that it forces them to put into words why they might be interested in working with me. Oftentimes, students, at least the ones here in psychology, get very nervous when I ask them to give a motivation letter and a CV. But it’s very helpful because it’s an effective way for me to get to know them. They get nervous but they have to make a choice; why choose to do this project and not another project. It’s important to look around I think but to also make a decision with something that somehow feels good because you’re going to spend a lot of time on it, and if you’re not enthusiastic about the research question, it’s going to be hard to pursue it.”
What can be improved in BCN, if anything?
“Perhaps I haven’t been a member long enough to give a good answer to this question, but on the website I could not find the list of members. I know that individual staff can add their discipline to their staff website. In my case, the default is psychology but I can add other disciplines myself like, for example, neuroscience, and then I suddenly show up in the BCN website. But I have to do it myself. I don’t think those in the database of BCN are automatically affiliated on the BCN website. Some people might do this and some don’t. I could not readily find in the BCN website who are the members. I personally think that increasing transparency at this level might be helpful to all members (faculty and students).”
Marijke told me about an incident at an international conference. A participant from Canada, Diane Boivin, approached her and asked her if she knew this really good Dutch scientist that Diane had worked with. Marijke said she did not know you at that time but she recalled that incident later when she met you.
“I worked with Diane Boivin during my PhD studies. It is nice to hear this, because when you work with her, she teaches you very strict lab methods. She’s very precise and thorough; time is very important, of course, because she does chronobiology studies. I did not do a chronobiology study so for me sometimes it was a little bit like “Do I have to do this? I will lose research participants, and it’s not essential”. But she told me a lot of valuable things about the importance of time-keeping and being very precise and good about data recording. Things like that. So I had to learn that. And I think that once I learned that, we got along very well. I know she was happy when I left, especially because the paper got published in a nice journal.
It’s nice to hear that I made a good impression on her especially because I know it is difficult to get to that level with her. She sets her standards very high.”
You live in Zwolle. Why not closer to Groningen?
“The way it worked is that my husband got an offer to work at the University of Twente. He does work in medical robotics. So if one of us is in Enschede and the other one is in Groningen, then the only place you can be is in the middle, and that is in Zwolle.”
How did you meet your husband?
“I was a student in Maastricht. In my last year, I did an internship in McGill, in this group where eventually I did my PhD. My husband was doing his master’s at McGill at the time. He worked on space robotics, and then he switched to medical robotics for his PhD.”
Tell us about your education prior to your PhD.
“I did my undergraduate degree in Maastricht. It usually takes four years to finish this degree but I did five years because there was one more year of my scholarship. That is why I went to Canada in the fifth year. I did 9 months research in McGill then I had to come back to the Netherlands because I had decided to apply for the PhD program, and that took one year. So I got my degree from Maastricht in 2000 and I started my PhD in 2001. In between, I took courses in psychology in Amsterdam, because I did my research project in the psychology department. I did not study psychology before so I wanted to learn many things specifically about that. I studied Biological Health Sciences; it’s like human biology but more focused on nutrition. It was a study on food and the brain.”
You were supervising BCN Research Master students before you became a BCN member?
“Yes, Kristina Miloserdov. She’s a great student; veryproactive and excited about her study; and she’s very precise. She started her 6-month project officially in January. It’s very, very pleasant to work with her. It’s a collaboration project with Marijke. Also like I said Koen Hogenelst, my PhD student, is a former BCN Research Master student. I am very happy with him as well.”
Let’s talk about your research. I am not familiar with psychology so I should ask this question first before we proceed to your research findings so far: how do you define “mood”?
(After about 15 seconds of silence) “I think that is already a very hard question. For me, what I find interesting most about it is how much it may vary, not so much on how it is at the general level but on the variability around the mean that people have. Some people feel the same – whether you call that mood, affect, or emotion, I don’t really care – but some people feel the same pretty much all the time, while other people are very much influenced by their environment. I am really interested in what might cause that variability around the mean. Again, I don’t really care if you call that mood, or emotion, or feeling.”
Can we call it a subjective interpretation of the individual about himself?
“I think it also has something to do with wellbeing. I think I would mostly equate it with that in some way, at least over longer periods of time.”
From your 2006 paper, my impression is that tryptophan can make a person less quarrelsome and more agreeable to others. Is this an accurate interpretation of your results?
“Sure. What I like about this study, and, in fact, I still use the method is that when you ask about social interactions, you can ask people to come in to the lab and either do a computer task or interact with one random person. It does not really tell you much about how most people go about their daily lives. So what I like about the method used in this study is it asks people to keep a ‘diary’, to simply fill-out forms every time they had a social interaction, and on that form there’s a list of behaviors which you might have such as, for example, ‘making a sarcastic comment’ while you talk with someone else. That would be a good example of a ‘quarrelsome behavior’. You can also ‘compliment or praise’ the other person in the social interaction, and that would be an example of an ‘agreeable behavior’. What I like about this is that the very concrete behaviour that a lot of people have all the time depends on who they talk to, whether it’s Monday or Friday, and what time of the day, and so forth, they record it in the diary. They fill out forms every time. (Showing the form) So there is a defined number of items in each of the forms, and the forms change from day to day.”
This looks to me as a simple task. If I were a subject in your experiment and without any formal background in psychology, I could easily fill out that form.
“So what I like about it is (a) that we use that method and (b) when you read the serotonin literature on behavior you often see links with aggression. However, there’s much less information about agreeable behavior, so in my study when I gave people tryptophan not only did it inhibit some sort of undesirable behavior and people made fewer sarcastic comments, but also people effectively became more pleasant towards others, which I think was the most interesting part of the finding.”
Sa palabas na Mara Clara, dalawang personahe ang tampok, ang isa ay masungit.“Exactly. This was specifically done with a group of people who responded to my ads in the newspaper that said things like ‘Do you easily get upset with others?’ or something along those lines. So people came in and said ‘Yes I have so many troubles at work because I can’t keep my mouth shut, et cetera.”
Being a non-psychologist myself, I wonder if it is safe to say that eating tryptophan-rich food will make a person less quarrelsome and more agreeable to others.
“Can you give an example of a tryptophan-high food?”
Well, in Wikipedia, there’s a list of food items and their tryptophan content.
“This is in line with what people commonly think and in a way it may indeed be correct. However, foods that are high in tryptophan are usually also high in other amino acids. For tryptophan to increase the serotonin levels in the brain, tryptophan has to be high relative to other amino acid levels because they compete for transport into the brain. So if you give a tryptophan pill then of course you are changing the balance in favor of tryptophan so it becomes easier, but if you increase tryptophan by eating a protein-rich food that also has other amino acids then the balance doesn’t really change. If anything, when you eat a protein-rich food, because tryptophan is one of the least abundant amino acids in protein-rich food, you usually decrease it a little bit.”
So does eating protein makes us more quarrelsome?
“No, because most people eat it with at least a small amount of carbohydrate and it nullifies the effect. There are people who will say that you might be influenced to some degree, but I think this research is mostly based on animal studies, and animals ingest a much larger proportion of their body weight with each meal so of course you can imagine that the effects in the brain will be higher than in humans. At least that’s the theoretical idea about it. There is some debate about it but I would be the last person to convince people that that is true. And I would be the last person to say that everybody should start taking tryptophan, for example.”
In your 2010 paper about the effects of bright light in relation to tryptophan depletion, it seems that bright light can shield a person from the negative effects of tryptophan depletion. First of all, can you describe what tryptophan depletion is and how it occurs in an individual?
“Tryptophan depletion is very much the opposite of what I just told you. If you give people a protein shake, an amino acid mixture, and you specifically leave out tryptophan, then the competition at the level of the brain will not be in favor of tryptophan so there is less tryptophan going into the brain and, temporarily, the serotonin level is known to decrease.”
So that’s the way you do it in your experiment?
“Yes, we give people an amino acid mixture that lacks tryptophan, or not in the placebo.”
Sounds like an easy and straightforward experimental procedure.
“Well, that protein shake does not exactly taste like a McDonald’s milk shake and people tend to become full from them, but otherwise, yes it’s a relatively simple experiment. That’s what I like about the method. That’s how I ended up working in McGill because I used this method in Maastricht and I liked it and went to McGill to work with the person who invented the method, and I did my PhD with him.”
What comes to mind are protein supplements used by people who, for example, want to build muscles in their body. Do you know the tryptophan component of these supplements?
“Usually they are mixed on the spot. I asked actually at my gym about that and I even asked what’s in the tryptophan bottle, but it’s mixed with other things as well. So it’s not only tryptophan that people are getting, usually they get a mixture of things. It’s not as clean as what we use in our experiment. We get those protein mixtures from the pharmacy; they are specially made at the UMCG.”
In relation to the bright light aspect of your study, would you say that people closer to the equator, where light is more abundant, are more sensitive to the emotions of others?
“I don’t know if you can generalize it that way, but people who live close to the equator are known to be less sensitive to seasonal affective disorder (SAD). They’re less likely to develop winter depression, effectively. If I would continue along that line, their mood is less influenced by the environment, in this case their physical environment in terms of light exposure, but maybe it also means that they are less emotional towards other people. I don’t think I can make that claim but the question surprises me because based on the prevalence rate of SAD, it might be easier for me to explain the opposite.”
So they are less sensitive to the emotions of others? My understanding of your study is that bright light can suppress the negative effects of tryptophan depletion on recognizing emotions in faces.
“Yes, bright light helps to regulate mood. So if you get more light throughout the year, in some ways your mood is going to be more regular. But it’s very hard to make that claim because you have to keep in mind that, for example, temperature also affects mood. High temperatures in tropical areas can affect your mood in terms of increasing irritability and so forth. So temperature plays a role as well. And maybe people in more northern places have developed cognitive ways in dealing with their emotions.”
So it is clear that bright light affects mood. Could you explain the biological basis of this effect?
“Marijke Gordijn can better tell you about this. There is a recently discovered photoreceptor (melanopsin) that has nothing to do with vision, but it goes to more emotional pathways, that’s my understanding of it. It’s also present in other species. The idea is that it helps regulate mood either through serotonin pathways, or by dopamine pathways, or melatonin pathways.”
Which is more effective: antidepressants or sunlight?
“When I said that I would not be the first person to recommend tryptophan to everybody, it is because it is related to the fact that tryptophan increases serotonin and you can argue that antidepressants often do it as well. I am the last person to say that all depressed people should start taking antidepressants. However, there certainly is evidence,such as the tryptophan depletion study that I did, that suggests that bright light can help regulate the serotonin system as well. You know that most people these days sit in an office. Well I have a nice window where much light can come in, but I live in Groningen where there’s not that much
sunlight. You can argue that I may be getting a lot less sunlight than a lot of people in places with better weather. It is also possible that before the industrial
revolution people would get a lot more light exposure. You might even argue that maybe depression is now more prevalent because people don’t get enough light exposure. In the US, especially in the northern part, and in Canada, there are so many people who go to Florida during winter, that’s not without reason. I don’t think I can argue that one is better than the other, but I certainly think that getting light exposure for the sake of stimulating your brain is not a bad thing.”
“One third of our life involves interaction with other people.” What is the basis for this estimate?
“Of course, it’s just an estimate. I think I read it somewhere. But I think I can argue that as well. There’s 24 hours in a day and I work in 8 of them. I spend a lot of my time at work talking to people. Even if I’m sitting in my office and I don’t talk to people, I’m at home or I go to places and I talk to people, so 8 hours is easy to achieve.”
Can using Facebook be considered a kind of social interaction? If so, what would be the difference in effect on mood between using Facebook and face-to-face interactions?
“I cannot answer that question right now. Actually, in the diary study that I am doing now, I ask people to distinguish in-person or on-the-phone social interactions, and I want one of the Psychology Master students currently working with me to see if people’s behavior and mood during those social interactions are different. I don’t think people have really looked at it in that much detail. For people who are participating in this study, they ask the students: what about text messaging, can we use it? For this study, we decided no, because it creates a variable that we cannot control right now. We would have to change the forms and add it. For future study, I would be interested to look at this question. If you can call it an interaction, I would probably argue that the interactions might be very short, and you might be distracted by other things happening as well. Whereas if you are sitting at someone’s house and you’re having dinner together, for starters the interaction is longer and you’re probably much more focused on the person, unless of course you’re checking your phone all the time.”
Many students use Facebook nowadays, do you think professors should also start using it?
“I have a Facebook account, but I set it such that people, unless they are my direct friends, cannot look at it. I use LinkedIn and people can look at that because I think that’s a professional alternative. For example, in my LinkedIn page I refer to my staff website, and also to BluesClues.nl, which is the Dutch website that is talking about the research that my PhD student is
doing.”
Would you like to invite students to work with you?
“I honestly think that the projects that I am currently running and one that I am thinking of as well can actually be very interesting especially to BCN students. I think their background will be fairly similar to mine. There are suitable projects to be helping out on and for half a year. In one of the projects that I’m thinking of, I don’t think I can actually do it otherwise.”
Other things you would like to add?
“One thing that has not come up which I like is that, we’ve talked about this diary method and I supplement it with laboratory methods of looking at social behaviour because you need the two in order to be able to really say something. In the lab you have a much more controlled environment, so having people do computer tasks and just trying to find ecologically valid ones with respect to social interaction is going to be helpful in terms of finding out what I want to know.”
References
[1] M. aan het Rot, D.S. Moskowitz, G. Pinard, & S.N. Young (2006), Social behaviour and mood in everyday life: the effects of tryptophan in quarrelsome individuals, J Psychiatry Neurosci 31(4), 253-62
[2] M. aan het Rot, N. Coupland, D.B. Boivin, C. Benkelfat, & S.N. Young (2010), Recognizing emotions in faces: effects of acute tryptophan depletion and bright light, J Psychopharmacol 24(10), 1447-54
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