Kobe Desender
@kobedesender.bsky.social
1.8K followers 320 following 55 posts
Assistant professor at @KU_Leuven, working on #confidence, #decisionmaking and #cognitivecontrol => DesenderLab.com
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kobedesender.bsky.social
MANY figures in the paper showing that hMFC works, but highlighting this one: with as few as 500 trials per participant hMFC allows excellent recovery of single-trial criterion, look at panel C for a representative example participant - I'm (obviously biased) impressed by this!
kobedesender.bsky.social
We developed hMFC, a Bayesian hierarchical framework which allows estimating single-trial criterion states, by fitting data from different participants while taking into account of the nesting of data within participants.
kobedesender.bsky.social
Ignoring fluctuations in criterion is problematic: simulations show that criterion fluctuations induce apparent history biases (panel C), lead to underestimated psychometric slopes (panel D) and underestimated measures of sensitivity, such as d' (panel D)
kobedesender.bsky.social
Classic models of decision-making, like signal detection theory, assume that choices are made by comparing a decision variable (DV) to a criterion. Often this criterion is (implicitly) assumed to be constant; here we implement a fluctuating criterion following an autoregressive model.
kobedesender.bsky.social
Introducing hMFC: A Bayesian hierarchical model of trial-to-trial fluctuations in decision criterion! Now out in @plos.org Comp Bio.
led by Robin Vloeberghs with @anne-urai.bsky.social Scott Linderman

Paper: desenderlab.com/wp-content/u... Thread ↓↓↓

#PsychSciSky #Neuroscience #Neuroskyence
kobedesender.bsky.social
Full details, alternative valence-only models, and post-experiment questionnaires targeting awareness, etc. all in the paper!
kobedesender.bsky.social
At the group level, our learning model won over a non-learning alternative, but more participants were actually best fitted by the latter. Closer inspection revealed why: there was a dynamic group (showing a clear confidence learning effect) and a static group (showing, well, nothing)
kobedesender.bsky.social
At the group level, participants adapted their reporting of confidence to subtle changes in feedback (with no effects on accuracy or RTs). Panel E nicely shows how people adapt their confidence to feedback over time, panel D shows that our learning model closely captures this finding!
kobedesender.bsky.social
To experimentally test this, we provided participants with model-generated feedback, reflecting the probability that their choice was correct. Unbeknownst to them, we alternated between between blocks with subtly higher/lower feedback
kobedesender.bsky.social
We know (more or less) how humans compute confidence, but how do we learn to compute confidence? We propose that agents compute prediction errors (confidence-feedback) to update the weights underlying the computation of confidence
kobedesender.bsky.social
"Learning to be confident: How agents learn confidence based on prediction errors"! Now out in @cognitionjournal.bsky.social led by @pierreledenmat.bsky.social

Paper: desenderlab.com/wp-content/u... Thread ↓↓↓

#AcademicSky #PsychSciSky #Neuroscience #Neuroskyence
Reposted by Kobe Desender
kobedesender.bsky.social
Read the full paper for fancy time-frequency plots (replicating pre-stimulus occipital alpha & confidence), and multivariate decoding (showing cross-decoding between priors and confidence)!
kobedesender.bsky.social
We instead identified a frontal signal, which tracked confidence and was sensitive to prior beliefs. Although speculative, this might be the signal that integrates priors and evidence into a confidence judgment!
kobedesender.bsky.social
Critically, EEG measurements confirmed the key prediction: although the stimulus-locked CPP and response-locked Pe were sensitive to high vs low confidence (which happens because confidence is correlated with evidence), they were _not_ modulated by prior beliefs condition (panels B and C)!
kobedesender.bsky.social
Replicating previous work, our manipulations had clear and consistent effect on confidence: confidence integrates prior beliefs about performance with accumulated evidence.
kobedesender.bsky.social
This work makes a key prediction: evidence accumulation signals (such as CPP and Pe) reflect accumulated evidence which feeds into confidence, but do not directly reflect confidence. To test this, we trained people on easy/hard tasks and provided pos/neg feedback (i.e. to manipulate priors)
kobedesender.bsky.social
In 2024, @helenevanmarcke.bsky.social @pierreledenmat.bsky.social showed that confidence is computed _conditional_ on prior beliefs about task performance (journals.sagepub.com/doi/abs/10.1...), represented by the heat map in the figure.
kobedesender.bsky.social
Can we use confidence-driven information-seeking as a tool to combat fake news!? Really cool study by really cool @helenevanmarcke.bsky.social ↓↓↓
helenevanmarcke.bsky.social
Warning: this is *not* fake news! New preprint out w/ S. Kunkle & @kobedesender.bsky.social on how confidence-driven information seeking is suboptimal in the context of fake news 📰🔍🧵 (1/6):
osf.io/preprints/ps...
OSF
osf.io
kobedesender.bsky.social
Full-Force at #ccn2025 in Amsterdam. Come along for a chat if you're interested in metacognition, confidence, computational modelling, reasoning, etc. @yfvisser.bsky.social @jeremiebeucler.bsky.social @helenevanmarcke.bsky.social @alexandre-lietard.bsky.social @zoepurcell.bsky.social
kobedesender.bsky.social
Or if you want to make your life easier, simplify to SDT and see whether biased criterion alone suffices, or whether you also need biased confidence criteria (mapping onto v and v_s)
kobedesender.bsky.social
The model used here: pubmed.ncbi.nlm.nih.gov/38427319/ where you can test whether the prior affects confidence directly (via z or drift bias) or indirectly (via v_s), or both. These parameters are then updated based on the prediction error cue-stim weighted by a learning rate. Good luck :)
Manipulating Prior Beliefs Causally Induces Under- and Overconfidence - PubMed
Humans differ vastly in the confidence they assign to decisions. Although such under- and overconfidence relate to fundamental life outcomes, a computational account specifying the underlying mechanis...
pubmed.ncbi.nlm.nih.gov