📣 Introducing ManyLabsDACH!
We are delighted to announce our new large-scale crowd-science study spanning Germany (D), Austria (A), and Switzerland (CH). Each participating lab will submit one design proposal, and all participating labs will then jointly select the design to be implemented.
My first PhD paper is out 🎉🐣
We examined transactions between Big Five traits and first sexual intercourse across up to 10 years and ~5,000 German adolescents.
Extraversion stood out 🔄🧠
Agreeableness + openness showed interesting patterns as well
Check them out here:
doi.org/10.1177/0890...
The effect of life events on personality and well-being is a hot topic. But our new paper on the effects of romantic partnering suggests you need to also consider the effect of NOT experiencing the life event. unromanticprof.substack.com/p/do-boosts-...
Comparing registrations to published papers is essential to research integrity - and almost no one does it routinely because it's slow, messy, and time-demanding.
RegCheck was built to help make this process easier.
Today, we launch RegCheck V2.
🧵
regcheck.app
Very excited to share our preprint (in press at Psychological Science) titled
"Associations between meat consumption and depression are small and unlikely to be causal". Have a read: lnkd.in/eM8Cd6Ss
@mdkraemer.bsky.social @peterhaehner.bsky.social @wiebkeb.bsky.social @chopwood.bsky.social
3 months later, this is still unsolved? When I search for preprints I know are on psyarxiv via DuckDuckGo/Google, I don't find them (only their traces on the web), maybe because you broke working links and indexers delisted? This is really bad.
Remaining single in your twenties is linked to lower life satisfaction
New paper – and my first ✨Registered Report✨: Do hormonal contraceptives affect women’s sexuality?
We studied both average effects and individual differences in effects using longitudinal data: doi.org/10.1177/2700...
Excited to see this paper now in print at JPSP! doi.org/10.1037/pspp...
You can find the postprint version here: osf.io/8c6sz_v2
Thanks again to @berndschaefer.bsky.social (shared 1st author 🙏), Cornelia Wrzus, Yannick Roos and @drichter77.bsky.social for the great collaboration!
The Department of Psychology @uzh-ch.bsky.social has an open position for a tenured Lecturer (Research) «Psychological Data Management and -Stewardship»
jobs.uzh.ch/job-vacancie...
#psychjobs
So...my undergrad thesis student is doing a quality analysis of studies found in meta-analyses. She identified a few and we contacted the authors to request their effect sizes and other variables for the studies in their papers.
Here's what happened:
scientiapsychiatrica.com/index.php/Sc...
‘A fragmented field: Construct and measure proliferation in psychology.’ (2025)
From ‘Language models accurately infer correlations between psychological items and scales from text alone.’ (2025)
From ‘Not within spitting distance: salivary immunoassays of estradiol have subpar validity for predicting cycle phase.’ (2023)
Work in progress with cycle tracking data from the app Clue
Want to make nice graphs with me, starting next year? I'm hiring for a position at the University of Witten/Herdecke.
uni-wh.softgarden.io/job/61280592...
Why do some people feel lonelier than others? Drawing on 441 effects, our meta-analysis shows a clear link between insecure attachment orientations (anxious or avoidant) and loneliness (r= .38).
Read the preprint: osf.io/preprints/ps...
Together with Natalie Kazianis & @bueckersusanne.bsky.social
New preprint!
Many claim that first sex is a huge risk for teens. We tested that claim in a large, nationally representative German sample. Core question: Do first sexual experiences harm adolescents, or do they reflect prior well-being?
osf.io/preprints/ps...
New preprint! 📚📱 osf.io/3kpf9_v1
Did you ever stand in a bookshop and wondered who tends to buy self-help books, and whether people who buy them actually change? Here, we looked at these questions for self-help products more generally (also apps, seminars, etc.), which are a rapidly (1/3)
change in personality and well-being between users and non-users, and among users depending on usage intensity. Thanks to @wiebkeb.bsky.social for making data collection possible in the PERCIVAL study, and to the rest of the team, Eva Asselmann, Claudia Harzer, and Jaap Denissen 🎉 (3/3)
growing market. In a representative Swiss sample, we found that users were more likely to be women, more educated and younger adults, those higher in openness, lower in emotional stability and self-esteem, and those desiring to change their personality. Notably, there were no differences in (2/3)
New preprint! 📚📱 osf.io/3kpf9_v1
Did you ever stand in a bookshop and wondered who tends to buy self-help books, and whether people who buy them actually change? Here, we looked at these questions for self-help products more generally (also apps, seminars, etc.), which are a rapidly (1/3)
Great opportunity for PhDs! The 2022 Madrid summer school was amazing
Buchcover: "Einsamkeit: Warum sie uns alle betrifft", Autorin: Maike Luhmann, Verlag: S. Fischer.
Auf Englisch sagt man, "I have a book inside me." Das hatte ich bis vor kurzem auch, aber jetzt nicht mehr - denn ich habe es tatsächlich (fast) geschrieben, und am 24.3.2026 wird es so erscheinen:
#Einsamkeit
New paper out 🎓:
Personality Traits and Provision of Grandparental Childcare: Evidence from Europe (w/ @valeriabordone.bsky.social, Giorgio Di Gessa & @mdkraemer.bsky.social
Using data from @share-eric.bsky.social, we find personality matters for grandhild care provision
doi.org/10.1080/1535...
In a new paper, my colleagues and I set out to demonstrate how method biases can create spurious findings in relationship science, by using a seemingly meaningless scale (e.g., "My relationship has very good Saturn") to predict relationship outcomes. journals.sagepub.com/doi/10.1177/...
Models as Prediction Machines: How to Convert Confusing Coefficients into Clear Quantities Abstract Psychological researchers usually make sense of regression models by interpreting coefficient estimates directly. This works well enough for simple linear models, but is more challenging for more complex models with, for example, categorical variables, interactions, non-linearities, and hierarchical structures. Here, we introduce an alternative approach to making sense of statistical models. The central idea is to abstract away from the mechanics of estimation, and to treat models as “counterfactual prediction machines,” which are subsequently queried to estimate quantities and conduct tests that matter substantively. This workflow is model-agnostic; it can be applied in a consistent fashion to draw causal or descriptive inference from a wide range of models. We illustrate how to implement this workflow with the marginaleffects package, which supports over 100 different classes of models in R and Python, and present two worked examples. These examples show how the workflow can be applied across designs (e.g., observational study, randomized experiment) to answer different research questions (e.g., associations, causal effects, effect heterogeneity) while facing various challenges (e.g., controlling for confounders in a flexible manner, modelling ordinal outcomes, and interpreting non-linear models).
Figure illustrating model predictions. On the X-axis the predictor, annual gross income in Euro. On the Y-axis the outcome, predicted life satisfaction. A solid line marks the curve of predictions on which individual data points are marked as model-implied outcomes at incomes of interest. Comparing two such predictions gives us a comparison. We can also fit a tangent to the line of predictions, which illustrates the slope at any given point of the curve.
A figure illustrating various ways to include age as a predictor in a model. On the x-axis age (predictor), on the y-axis the outcome (model-implied importance of friends, including confidence intervals). Illustrated are 1. age as a categorical predictor, resultings in the predictions bouncing around a lot with wide confidence intervals 2. age as a linear predictor, which forces a straight line through the data points that has a very tight confidence band and 3. age splines, which lies somewhere in between as it smoothly follows the data but has more uncertainty than the straight line.
Ever stared at a table of regression coefficients & wondered what you're doing with your life?
Very excited to share this gentle introduction to another way of making sense of statistical models (w @vincentab.bsky.social)
Preprint: doi.org/10.31234/osf...
Website: j-rohrer.github.io/marginal-psy...
Wie verändert sich unsere Persönlichkeit über ein Jahr? Dazu starten wir heute eine neue Studie und suchen nach Teilnehmenden zwischen 18-40 Jahren, die Interesse haben, Einblicke in ihre Persönlichkeit, Wohlbefinden und Verhalten über ein Jahr zu erhalten und bis zu 173 CHF (~185€) zu verdienen.
Check out our preprint - the result of a really fun collaboration!
Self-improvement, self-acceptance, and/or methods effects? Travis Miller, @chopwood.bsky.social , and @wiebkeb.bsky.social, and I examined factors that might explain personality change intervention effects - now in print at JPSP 🥳: doi.org/10.1037/pspp...
Starting to look like I might not be able to work at Harvard anymore due to recent funding cuts. If you know of any open statistical consulting positions that support remote work or are NYC-based, please reach out! 😅
...with @wiebkeb.bsky.social, @chopwood.bsky.social, @peterhaehner.bsky.social, @rosalieandrae.bsky.social and Philippe Sloksnath & Lina Hungerbühler who are not on here yet 🦋
