Free summer school materials and videos

Last month, we hosted the first online version of our summer school on network analysis. All materials except solutions are now available on the OSF and – for a limited time (until October 31) – you can now get access via Eventbrite to 50+ video lectures for free.

Special thanks to everyone who helped make this possible: Sacha Epskamp, Adela Isvoranu, Ria Hoekstra, Denny Borsboom, Riet van Bork, Julian Burger, Jonas Haslbeck, Lourens Waldorp, Eiko Fried, Alessandra Mansueto, Karoline Huth, Jill de Ron, Adam Finnemann, Gaby Lunansky, Jolanda Van der Ree-Kossakowski, Pia Tio, and Lourens Waldorp.

The polarization within and across individuals: the hierarchical Ising opinion model

On May 7 2020 we published the paper The polarization within and across individuals: the hierarchical Ising opinion model’ in the Journal of Complex networks.

Polarization of opinions involves psychological processes as well as group dynamics. However, the interaction between the within individual dynamics of attitude formation and across person polarization is rarely studied. By modelling individual attitudes as Ising networks of attitude elements, and approximating this behaviour by the cusp singularity, we developed a fundamentally new model of social dynamics.

In this hierarchical model, agents behave either discretely or continuously depending on their attention to the issue. At the individual level the model reproduces the mere thought effect and resistance to persuasion. At the social level the model implies polarization and the persuasion paradox. We propose a new intervention for escaping polarization in bounded confidence models of opinion dynamics.

Han van der Maas, Jonas Dalege, and Lourens Waldorp

Psychological Methods, UvA

Job opportunities in Amsterdam!

This post was written by Sacha Epskamp, and cross-posted to the psychonetrics blog.

The old city center of Amsterdam – a location right next to the Institute for Advanced Studies which will partly host the PhD positions.

There are several exciting job vacancies in Amsterdam on topics very closely related to our research: one assistant professor position at the Psychological Methods Group, and several PhD positions hosted through the newly founded Center for Urban Mental Health. Note that PhD positions in the Netherlands are full-time 4-year paid jobs including the same benefits as any other job (e.g., pension buildup). Starting a PhD position in the Netherlands requires a Master’s degree. In this blog post, I will highlight some of the most relevant positions. Please consider applying if you are eligible, or forwarding these vacancies to eligible candidates you may know!

Assistant Professor of Psychological Methods

The first position I would like to point out is an assistant professor position at the Psychological Methods Group. The Psychological Methods group of the University of Amsterdam is one of the largest and most successful research and education centers in the field of psychological methods. In the past decade, several strong lines of research originated from this group, such as network modeling of psychological phenomena in the Psychosystems and the Psychonetrics lab groups, Bayesian statistical tools implemented in the open-source statistics program JASP, and adaptive testing implemented in the spin-off company Oefenweb. We have recently launched the increasingly popular Behavioral Data Science master program, which will be the focus of this assistant professorship as well.

Please note that this position does not come with a tenure-track (these do not exist at the Psychological Methods Group), but does come with an outlook on a permanent position!

PhD positions at the Center for Urban Mental Health

The University of Amsterdam has recently approved the foundation of the first-ever Center for Urban Mental Health, which will form an interdisciplinary approach to tackling common mental health problems from a complexity point of view. This center will at first be housed at the renowned Institute for Advanced Studies, right in the city center of Amsterdam. The Center for Urban Mental Health will be launched with several interdisciplinary PhD projects, all aiming to start early 2020. Below, I will list the most relevant positions that are currently open for applications!

Computational modeling of psychological and social dynamics in urban mental health conditions: the case of addictive substance use.

The first PhD vacancy is a PhD project between the Psychological Methods Group in the Department of Psychology, the Department of Computational Science in the Informatics Institute, and the Institute for Advanced Studies. This project will be supervised by me (Sacha Epskamp) and Michael Lees, and will be hosted at the Psychological Methods group and the Institute for Advanced Studies. The aim of this project is to form computational models (e.g., differential equations, agent based models, Ising models), that combine psychological dynamics with social dynamics. This means that we wish to form models that can simulate intraindividual dynamics of multiple people that also interact with each other in complex ways. We are specifically looking for a candidate with a background in using such models as well as a strong affinity with psychological research.

Please note that the closing date is already this Sunday (November 24). However, if you are interested in doing a PhD on the topic of computational modeling of psychological dynamics, feel free to contact me (Sacha Epskamp) as more positions related to this topic may become available.

Network Analysis and Urban Mental Health Interventions

The second PhD vacancy is a vacancy between the Department of Psychology and the Department of Communication Science. The project will be supervised by me (Sacha Epskamp), alongside Reinout Wiers, Julia van Weert, and Barbara Schouten. This project will start out as a methodological project, investigating ways of estimating network models from self-report time-series data (e.g., experience sampling method; ESM), after which the project will move towards a more applied clinical focus in which the candidate is expected to gather and analyze ESM data, followed by collaborating with clinicians to derive and evaluate intervention plans. We are specifically looking for a candidate that has both a strong focus on clinical research as well as good data analytic skills and an affinity or background in methodology.

Network theory of addiction and depression

The third PhD vacancy is a vacancy between the Psychological Methods Group in the Department of Psychology, the Department of Psychiatry at the Amsterdam UMC, location AMC, and the Institute for Advanced Studies. This project will be supervised by Maarten Marsman, Judy Luigjes, and Ruth van Holst. This project will build upon the view that depression and addictions form a complex system of mutually interacting problems and aims to formalize a network model of the two disorders in an urban context. The project will involve analyzing existing cross-sectional, longitudinal and clinical data, taken from an urban population. Where necessary, new techniques and models will be developed for the analysis of these data. The candidate should have a strong affinity to (clinical) psychological research and formal statistical modelling (e.g., Bayesian hierarchical modelling, or mathematical statistics), and proficiency in programming in at least R.

Even more positions!

If this was not enough, more positions will open up shortly! At the Center for Urban Mental Health! Currently there is a listing on the complexity of fear, depression and addiction among adolescents (in Dutch), and a listing on aging and mental health. And a few more positions are expected to open up. If you are interested in these, I encourage you to check the Urban Mental Health website and/or follow the Center for Urban Mental Health on Twitter. In addition, even more job opportunities may open up in the coming months, depending on various sources of funding. While I cannot go into detail on those, I highly recommend joining our very active Facebook group on Psychological Dynamics, in which both job opportunities on topics related to our research are routinely posted.

Network school & SEM materials + extended registration CCS session

This blog post was written by Sacha Epskamp

I would like to share the following three updates:

1. In January we hosted the annual Psychological Networks Amsterdam Winter School. On popular request, we have now made many of the materials publicly available on the Open Science Framework:

2. I teach two courses on Structural Equation Modeling at the University of Amsterdam, which are closely related and often touch on network modeling as well. Many materials (including video summaries) of the latest course are now available at

3. We have extended the deadline for our event in Singapore on complexities of adverse behavior and mental health ( to June 16! Please share this with anyone you think might be interested!

Complexities of Adverse Behavior – Registration open!

This blog post was written by Sacha Epskamp I am happy to announce the full day “Complexities of Adverse Behavior” event in Singapore on October 2! We now opened up registration for contributed talks, with a deadline of June 1. For more information and registration, please see our website. This will be part of the wider Conference on Complex Systems, which is the largest annual international conference on complexity science, bringing together many researchers from different fields of study. I attend this conference every year as I think the larger field of human behavior does not stop at the borders of psychological research (plus it is a really nice conference!) Screenshot 2019-05-07 at 11.41.25

Network Intervention Analysis

According to the network theory of mental disorders, mental disorders are developed and sustained through direct interactions between symptoms [1]. From this conceptualization it follows that treatment of mental disorders should involve changing the network of interrelated symptoms. While over the past years many studies have investigated the network structure of psychopathologies [2], the effect of psychological treatment on the network of interrelated symptoms has rarely been assessed. Moreover, network analysis techniques provide a unique opportunity to investigate treatment effects at a more detailed symptom level. In this new study we aspired to adopt and extent the network approach to investigate specific and sequential treatment effects—a technique we labelled Network Intervention Analysis (NIA) [3]. NIA involves estimating a network of interrelated symptoms and including an additional treatment indicator variable that encodes the treatment condition that a participants belongs to. Including such a variable into the network allows to see which symptoms are conditionally dependent on this treatment variable. Since the treatment can influence the symptoms but not vice versa, this dependency indicates the symptoms that are directly affected by treatment.

In our illustration of NIA we investigated the effect of cognitive behavioral therapy for insomnia (CBTI) on co-occurring insomnia and depression symptoms. More traditional analyses had showed that after completion, the treatment had relieved both insomnia and depression symptoms [4]. It remained unclear, however, whether the effect of treatment on the depression symptoms occurred via improving the sleep problems, or whether CBTI influenced the depression symptoms directly. Using NIA across 10 measurement weeks (2 prior to treatment, 5 during treatment, and 3 after treatment) we could identify that CBTI predominantly affected the sleep problems, indicating that the improvements in depression likely occur via CBTI-induced improvements in sleep.


Figure. Network structure before, during, and after treatment. The networks include the Insomnia Severity Index and Patient Health Questionnaire items (circles) and treatment (square). The size of the node is proportional to the difference in symptom severity between the treatment and control group, where smaller node sizes represent greater differences in favor of the treatment group. All ten networks corresponding to each of the measurement weeks are shown in the paper. An animated version can be found online.

This paper is a first illustration of how NIA can be used to investigate sequential and symptom-specific treatment induced changes over time. We hope to further develop NIA into a more sophisticated technique to investigate treatment effects over time—to ultimately better understand treatment mechanisms and reveal clues to their optimization.

[1] Borsboom, D. (2017). A network theory of mental disorders. World Psychiatry, 16, 5-13.

[2] Fried, E.I., Van Borkulo, C.D., Cramer, A.O.J., Boschloo, L., Schoevers, R.A., Borsboom, D. (2017). Mental disorders as networks of problems: A review of recent insights. Social Psychiatry and Psychiatric Epidemiology,

[3] Blanken, T.F.*, Van der Zweerde, T.*, Van Straten, A., Van Someren, E.J.W., Borsboom, D., Lancee, J. (2019). Introducing Network Intervention Analysis to investigate sequential, symptom-specific treatment effects: A demonstration in co-occurring insomnia and depression. Psychotherapy and Psychosomatics,

[4] Van der Zweerde T, Van Straten A, Effting M, Kyle SD, Lancee J. (2018). Does online insomnia treatment reduce depressive symptoms? A randomized controlled trial in individuals with both insomnia and depressive symptoms. Psychological Medicine, 49, 501-599.

*shared first authors

The Psychosystems group evolves

Busy times at the Psychosystems group! In 2018, Max Hinne joined us as a postdoc, working on a position shared between Psychosystems and Eric-Jan Wagenmakers’ Bayesian research group (the people behind the fantastic JASP program, which now incorporates a network analysis module designed by Don van den Berg). Max studies ways to integrate information on network structure and network dynamics by utilizing Bayesian approaches. Also in 2018, NWO-Veni laureate Maarten Marsman, who works on network models in the context of educational measurement, was awarded a research fellowship at the Institute for Advanced Studies in Amsterdam. In addition, Ria Hoekstra and Julian Burger successfully applied for a Research Talent grant of the Netherlands Organization for Scientific Research and are starting their Ph. D. projects this month. Ria will study methods to address heterogeneity in network structures, with Denny Borsboom acting as promotor. Julian, whose primary location is at Groningen University with Robert Schoevers acting as promotor, will develop ways to translate dynamical systems theory and network modeling into tools that are useful in clinical practice. Sacha Epskamp, who (directly after winning the 2018 Psychometric Society Dissertation Award for his thesis on network psychometrics) secured an NWO-Veni project on network modeling which also happens to start this month, will be involved in the supervision of the new Ph. D. projects, acting as co-promotor and daily supervisor, while Maarten Marsman will also be involved in Julian’s project. Incidentally, Sacha was not the only person receiving praise for his Ph. D. thesis this year, as Claudia van Borkulo finished second in the Van Swinderen Prize 2018 for her dissertation on symptom network models in depression research. Finally, Jonas Dalege is transitioning into a postdoc position this month; he will work on Denny Borsboom’s ERC consolidator grant in a joint position with the Social Psychology department at the University of Amsterdam.