Steven
@stevengeysen.bsky.social
(he/him)
PhD student @peterslab.bsky.social,
University of Cologne, Germany
Cognitive psychology - (risky) decision-making
PhD student @peterslab.bsky.social,
University of Cologne, Germany
Cognitive psychology - (risky) decision-making
Pinned
Steven
@stevengeysen.bsky.social
· Oct 22
Ghrelin and risky decision-making: No credible evidence for homeostatic state modulation of neural or behavioural effects https://www.biorxiv.org/content/10.1101/2025.10.20.683454v1
‼️New preprint‼️
There does not seem to be an effect of ghrelin on risky decision-making in probability discounting. Not in behaviour, underlying computational processes, or neural activity.
More details ⬇️
There does not seem to be an effect of ghrelin on risky decision-making in probability discounting. Not in behaviour, underlying computational processes, or neural activity.
More details ⬇️
Reposted by Steven
Very happy that this is out www.nature.com/articles/s44.... Together with @stefankiebel.bsky.social we show that decision biases in context-dependent decision making, previously attributed to different forms of value normalization, are very well explained by habit-like action repetition.
Action repetition biases choice in context-dependent decision-making - Communications Psychology
This study shows that decision biases previously attributed to value normalization (e.g. relative value learning or range normalization) are better explained by action repetition. Repeating an action ...
www.nature.com
November 27, 2025 at 6:43 PM
Very happy that this is out www.nature.com/articles/s44.... Together with @stefankiebel.bsky.social we show that decision biases in context-dependent decision making, previously attributed to different forms of value normalization, are very well explained by habit-like action repetition.
Reposted by Steven
My paper is out!
Computational modeling of error patterns during reward-based learning show evidence that habit learning (value free!) supplements working memory in 7 human data sets.
rdcu.be/eQjLN
Computational modeling of error patterns during reward-based learning show evidence that habit learning (value free!) supplements working memory in 7 human data sets.
rdcu.be/eQjLN
A habit and working memory model as an alternative account of human reward-based learning
Nature Human Behaviour - In this study, Collins proposes an alternative dual-process (working memory and habit) model of reinforcement learning in humans.
rdcu.be
November 17, 2025 at 5:18 PM
My paper is out!
Computational modeling of error patterns during reward-based learning show evidence that habit learning (value free!) supplements working memory in 7 human data sets.
rdcu.be/eQjLN
Computational modeling of error patterns during reward-based learning show evidence that habit learning (value free!) supplements working memory in 7 human data sets.
rdcu.be/eQjLN
‼️New preprint‼️
There does not seem to be an effect of ghrelin on risky decision-making in probability discounting. Not in behaviour, underlying computational processes, or neural activity.
More details ⬇️
There does not seem to be an effect of ghrelin on risky decision-making in probability discounting. Not in behaviour, underlying computational processes, or neural activity.
More details ⬇️
Ghrelin and risky decision-making: No credible evidence for homeostatic state modulation of neural or behavioural effects https://www.biorxiv.org/content/10.1101/2025.10.20.683454v1
October 22, 2025 at 8:11 AM
‼️New preprint‼️
There does not seem to be an effect of ghrelin on risky decision-making in probability discounting. Not in behaviour, underlying computational processes, or neural activity.
More details ⬇️
There does not seem to be an effect of ghrelin on risky decision-making in probability discounting. Not in behaviour, underlying computational processes, or neural activity.
More details ⬇️
Today I will present some of our lab's work at #CCN2025
In two separate studies, we investigated the effect ghrelin, the hunger hormone, on probability discounting. We manipulated ghrelin levels by fasting (study 1) and 1 night if sleep deprivation (study 2)
More information and figures on poster 80
In two separate studies, we investigated the effect ghrelin, the hunger hormone, on probability discounting. We manipulated ghrelin levels by fasting (study 1) and 1 night if sleep deprivation (study 2)
More information and figures on poster 80
August 13, 2025 at 7:19 AM
Today I will present some of our lab's work at #CCN2025
In two separate studies, we investigated the effect ghrelin, the hunger hormone, on probability discounting. We manipulated ghrelin levels by fasting (study 1) and 1 night if sleep deprivation (study 2)
More information and figures on poster 80
In two separate studies, we investigated the effect ghrelin, the hunger hormone, on probability discounting. We manipulated ghrelin levels by fasting (study 1) and 1 night if sleep deprivation (study 2)
More information and figures on poster 80
2 years ago I built a fMRI preprocessing pipeline for ADNI data. Now I can share the work that was done with it.
Riccardo Leone, in the lab of Xenia Kobeleva, used it to model the effects of white matter hyperintensities using whole-brain modelling 🧠💻🧠📈
onlinelibrary.wiley.com/doi/10.1002/...
Riccardo Leone, in the lab of Xenia Kobeleva, used it to model the effects of white matter hyperintensities using whole-brain modelling 🧠💻🧠📈
onlinelibrary.wiley.com/doi/10.1002/...
Beyond Focal Lesions: Dynamical Network Effects of White Matter Hyperintensities
By combining whole-brain neural mass modeling with a virtual-lesioning approach informed by empirical WMH lesion masks, we provide evidence that WMH induce changes in brain dynamics by reducing the g...
onlinelibrary.wiley.com
December 5, 2024 at 8:42 AM
2 years ago I built a fMRI preprocessing pipeline for ADNI data. Now I can share the work that was done with it.
Riccardo Leone, in the lab of Xenia Kobeleva, used it to model the effects of white matter hyperintensities using whole-brain modelling 🧠💻🧠📈
onlinelibrary.wiley.com/doi/10.1002/...
Riccardo Leone, in the lab of Xenia Kobeleva, used it to model the effects of white matter hyperintensities using whole-brain modelling 🧠💻🧠📈
onlinelibrary.wiley.com/doi/10.1002/...
From our lab!
A meta reinforcement learning account of behavioral adaptation to volatility in recurrent neural networks https://www.biorxiv.org/content/10.1101/2024.05.09.593363v1
A meta reinforcement learning account of behavioral adaptation to volatility in recurrent neural networks https://www.biorxiv.org/content/10.1101/2024.05.09.593363v1
Natural environments often exhibit various degrees of volatility, ranging from slowly changing to ra
www.biorxiv.org
May 10, 2024 at 6:50 AM
From our lab!