Harrison Ritz
@hritz.bsky.social
cybernetic cognitive control 🤖
computational cognitive neuroscience 🧠
postdoc princeton neuro 🍕
he/him 🇨🇦 harrisonritz.github.io
computational cognitive neuroscience 🧠
postdoc princeton neuro 🍕
he/him 🇨🇦 harrisonritz.github.io
Pinned
Harrison Ritz
@hritz.bsky.social
· Jul 27
We put out this preprint a couple months ago, but I really wanted to replicate our findings before we went to publication.
At first, what we found was very confusing!
But when we dug in, it revealed a fascinating neural strategy for how we switch between tasks
doi.org/10.1101/2024.09.29.615736
🧵
At first, what we found was very confusing!
But when we dug in, it revealed a fascinating neural strategy for how we switch between tasks
doi.org/10.1101/2024.09.29.615736
🧵
Reposted by Harrison Ritz
Excited to share a new preprint, accepted as a spotlight at #NeurIPS2025!
Humans are imperfect decision-makers, and autonomous systems should understand how we deviate from idealized rationality
Our paper aims to address this! 👀🧠✨
arxiv.org/abs/2510.25951
a 🧵⤵️
Humans are imperfect decision-makers, and autonomous systems should understand how we deviate from idealized rationality
Our paper aims to address this! 👀🧠✨
arxiv.org/abs/2510.25951
a 🧵⤵️
Estimating cognitive biases with attention-aware inverse planning
People's goal-directed behaviors are influenced by their cognitive biases, and autonomous systems that interact with people should be aware of this. For example, people's attention to objects in their...
arxiv.org
November 13, 2025 at 1:20 PM
Excited to share a new preprint, accepted as a spotlight at #NeurIPS2025!
Humans are imperfect decision-makers, and autonomous systems should understand how we deviate from idealized rationality
Our paper aims to address this! 👀🧠✨
arxiv.org/abs/2510.25951
a 🧵⤵️
Humans are imperfect decision-makers, and autonomous systems should understand how we deviate from idealized rationality
Our paper aims to address this! 👀🧠✨
arxiv.org/abs/2510.25951
a 🧵⤵️
Reposted by Harrison Ritz
Profits from scientific publishing are eye-watering, costing us billions. In ‘The Drain of Scientific Publishing’ (arxiv.org/abs/2511.04820), (building on ‘The Strain of Scientific Publishing’ doi.org/10.1162/qss_a_00327) we show how it is harmful – and unnecessary.
The Drain of Scientific Publishing
The domination of scientific publishing in the Global North by major commercial publishers is harmful to science. We need the most powerful members of the research community, funders, governments and ...
arxiv.org
November 12, 2025 at 11:41 AM
Profits from scientific publishing are eye-watering, costing us billions. In ‘The Drain of Scientific Publishing’ (arxiv.org/abs/2511.04820), (building on ‘The Strain of Scientific Publishing’ doi.org/10.1162/qss_a_00327) we show how it is harmful – and unnecessary.
Reposted by Harrison Ritz
"Electrodes are held on the scalp of the patient by an arrangement of rubber and whalebone bars tied under the chin (fig. 1). A most suitable cap is one made for setting waves in hair. It is not necessary to shave the scalp, though the examination is easier if the hair is short and recently washed."
November 12, 2025 at 12:42 PM
"Electrodes are held on the scalp of the patient by an arrangement of rubber and whalebone bars tied under the chin (fig. 1). A most suitable cap is one made for setting waves in hair. It is not necessary to shave the scalp, though the examination is easier if the hair is short and recently washed."
Reposted by Harrison Ritz
Our next paper on comparing dynamical systems (with special interest to artificial and biological neural networks) is out!! Joint work with @annhuang42.bsky.social , as well as @satpreetsingh.bsky.social , @leokoz8.bsky.social , Ila Fiete, and @kanakarajanphd.bsky.social : arxiv.org/pdf/2510.25943
November 10, 2025 at 4:16 PM
Our next paper on comparing dynamical systems (with special interest to artificial and biological neural networks) is out!! Joint work with @annhuang42.bsky.social , as well as @satpreetsingh.bsky.social , @leokoz8.bsky.social , Ila Fiete, and @kanakarajanphd.bsky.social : arxiv.org/pdf/2510.25943
Reposted by Harrison Ritz
Delighted to see this finally out: rdcu.be/eO9oW
We tested whether brief striatal dopamine release events influence the vigor of skilled movements. Despite popular belief, we did not find any evidence linking rapid dopamine dynamics to motor vigor on a moment-by-moment basis.
We tested whether brief striatal dopamine release events influence the vigor of skilled movements. Despite popular belief, we did not find any evidence linking rapid dopamine dynamics to motor vigor on a moment-by-moment basis.
Subsecond dopamine fluctuations do not specify the vigor of ongoing actions
Nature Neuroscience - Liu and colleagues show that the vigor (that is, speed and amplitude) of dexterous movements is not controlled by ongoing fluctuations in extracellular dopamine within the...
rdcu.be
November 10, 2025 at 3:43 PM
Delighted to see this finally out: rdcu.be/eO9oW
We tested whether brief striatal dopamine release events influence the vigor of skilled movements. Despite popular belief, we did not find any evidence linking rapid dopamine dynamics to motor vigor on a moment-by-moment basis.
We tested whether brief striatal dopamine release events influence the vigor of skilled movements. Despite popular belief, we did not find any evidence linking rapid dopamine dynamics to motor vigor on a moment-by-moment basis.
Reposted by Harrison Ritz
Now out in #ScienceAdvances: @baiweiliu.bsky.social and I ask how internal (goal) and external (sensory) selection are coordinated during visual search. The key insight: internal and external selection are not inherently serial, but may develop in parallel in the human brain: doi.org/10.1126/scia...
Concurrent selection of internal goals and external sensations during visual search
Internal and external selection processes can codevelop in time to yield efficient search behavior.
doi.org
November 10, 2025 at 12:00 PM
Now out in #ScienceAdvances: @baiweiliu.bsky.social and I ask how internal (goal) and external (sensory) selection are coordinated during visual search. The key insight: internal and external selection are not inherently serial, but may develop in parallel in the human brain: doi.org/10.1126/scia...
Reposted by Harrison Ritz
New preprint:
Neural manifolds that orchestrate walking and stopping
Here we develop a new theory for neural generation of walking and how it can stop- Next we test the theory using Neuropixels probes in the lumber spinal cord of freely moving rats. See more:
www.biorxiv.org/content/10.1...
Neural manifolds that orchestrate walking and stopping
Here we develop a new theory for neural generation of walking and how it can stop- Next we test the theory using Neuropixels probes in the lumber spinal cord of freely moving rats. See more:
www.biorxiv.org/content/10.1...
November 9, 2025 at 9:33 PM
New preprint:
Neural manifolds that orchestrate walking and stopping
Here we develop a new theory for neural generation of walking and how it can stop- Next we test the theory using Neuropixels probes in the lumber spinal cord of freely moving rats. See more:
www.biorxiv.org/content/10.1...
Neural manifolds that orchestrate walking and stopping
Here we develop a new theory for neural generation of walking and how it can stop- Next we test the theory using Neuropixels probes in the lumber spinal cord of freely moving rats. See more:
www.biorxiv.org/content/10.1...
Reposted by Harrison Ritz
New pre-print from our lab, by Lakshmi Govindarajan with help from Sagarika Alavilli, introducing a new type of model for studying sensory uncertainty. www.biorxiv.org/content/10.1...
Here is a summary. (1/n)
Here is a summary. (1/n)
Task-optimized models of sensory uncertainty reproduce human confidence judgments
Sensory input is often ambiguous, leading to uncertain interpretations of the external world. Estimates of perceptual uncertainty might be useful in guiding behavior, but it remains unclear whether hu...
www.biorxiv.org
November 9, 2025 at 9:34 PM
New pre-print from our lab, by Lakshmi Govindarajan with help from Sagarika Alavilli, introducing a new type of model for studying sensory uncertainty. www.biorxiv.org/content/10.1...
Here is a summary. (1/n)
Here is a summary. (1/n)
Reposted by Harrison Ritz
New paper in Imaging Neuroscience by C. Sainz Martinez, J. Jorge, et al:
An optimized framework for simultaneous EEG-fMRI at 7T enabling safe, high-quality human brain imaging with millisecond temporal resolution and sub-millimeter spatial resolution
doi.org/10.1162/IMAG...
An optimized framework for simultaneous EEG-fMRI at 7T enabling safe, high-quality human brain imaging with millisecond temporal resolution and sub-millimeter spatial resolution
doi.org/10.1162/IMAG...
November 6, 2025 at 3:55 PM
New paper in Imaging Neuroscience by C. Sainz Martinez, J. Jorge, et al:
An optimized framework for simultaneous EEG-fMRI at 7T enabling safe, high-quality human brain imaging with millisecond temporal resolution and sub-millimeter spatial resolution
doi.org/10.1162/IMAG...
An optimized framework for simultaneous EEG-fMRI at 7T enabling safe, high-quality human brain imaging with millisecond temporal resolution and sub-millimeter spatial resolution
doi.org/10.1162/IMAG...
Reposted by Harrison Ritz
If you're interested in dynamical systems analysis for neuroscience, definitely check out @oliviercodol.bsky.social 's revised version of our RL paper! Very cool results in the new Fig 6, worth it regardless of if you saw our previous version or if it's all new.
www.biorxiv.org/content/10.1...
www.biorxiv.org/content/10.1...
November 6, 2025 at 5:58 PM
If you're interested in dynamical systems analysis for neuroscience, definitely check out @oliviercodol.bsky.social 's revised version of our RL paper! Very cool results in the new Fig 6, worth it regardless of if you saw our previous version or if it's all new.
www.biorxiv.org/content/10.1...
www.biorxiv.org/content/10.1...
Reposted by Harrison Ritz
Do you like RSA analysis, M/EEG and Bayes? Then you'll love Variational RSA for M/EEG, by recently completed PhD student @alexlepauvre.bsky.social from Lucia Melloni's group. It's a method and SPM toolbox for multivariate analysis of M/EEG data. arxiv.org/pdf/2511.01784 . 🧵 [1/4]
November 6, 2025 at 2:03 PM
Do you like RSA analysis, M/EEG and Bayes? Then you'll love Variational RSA for M/EEG, by recently completed PhD student @alexlepauvre.bsky.social from Lucia Melloni's group. It's a method and SPM toolbox for multivariate analysis of M/EEG data. arxiv.org/pdf/2511.01784 . 🧵 [1/4]
Reposted by Harrison Ritz
Looks great! arxiv.org/abs/2511.02063
Neural dynamics of cognitive control: Current tensions and future promise
Cognitive control is a suite of processes that helps individuals pursue goals despite resistance or uncertainty about what to do. Although cognitive control has been extensively studied as a dynamic f...
arxiv.org
November 6, 2025 at 1:34 AM
Looks great! arxiv.org/abs/2511.02063
The best post genre, by far, is people patching their first cell
November 6, 2025 at 1:45 AM
The best post genre, by far, is people patching their first cell
Reposted by Harrison Ritz
Western study reveals brain’s predictive power.
Researchers find neurons don’t wait for challenges to arise, they plan how to react. news.westernu.ca/2025/10/sens... #CdnPSE @westernu.ca
Researchers find neurons don’t wait for challenges to arise, they plan how to react. news.westernu.ca/2025/10/sens... #CdnPSE @westernu.ca
Study reveals brain’s predictive power
New study reveals that we rely on sensory expectations to get prepared for unexpected disturbances, helping us react faster and more accurately.
news.westernu.ca
November 3, 2025 at 4:03 PM
Western study reveals brain’s predictive power.
Researchers find neurons don’t wait for challenges to arise, they plan how to react. news.westernu.ca/2025/10/sens... #CdnPSE @westernu.ca
Researchers find neurons don’t wait for challenges to arise, they plan how to react. news.westernu.ca/2025/10/sens... #CdnPSE @westernu.ca
If we’re talking about ‘generational investment’, Canada needs faculty positions for postdocs.
There have been virtually no cog psych/neuro jobs in the past three years.
There have been virtually no cog psych/neuro jobs in the past three years.
November 5, 2025 at 2:22 PM
If we’re talking about ‘generational investment’, Canada needs faculty positions for postdocs.
There have been virtually no cog psych/neuro jobs in the past three years.
There have been virtually no cog psych/neuro jobs in the past three years.
Reposted by Harrison Ritz
Now in PRX: Theory linking connectivity structure to collective activity in nonlinear RNNs!
For neuro fans: conn. structure can be invisible in single neurons but shape pop. activity
For low-rank RNN fans: a theory of rank=O(N)
For physics fans: fluctuations around DMFT saddle⇒dimension of activity
For neuro fans: conn. structure can be invisible in single neurons but shape pop. activity
For low-rank RNN fans: a theory of rank=O(N)
For physics fans: fluctuations around DMFT saddle⇒dimension of activity
Connectivity Structure and Dynamics of Nonlinear Recurrent Neural Networks
The structure of brain connectivity predicts collective neural activity, with a small number of connectivity features determining activity dimensionality, linking circuit architecture to network-level...
journals.aps.org
November 3, 2025 at 9:47 PM
Now in PRX: Theory linking connectivity structure to collective activity in nonlinear RNNs!
For neuro fans: conn. structure can be invisible in single neurons but shape pop. activity
For low-rank RNN fans: a theory of rank=O(N)
For physics fans: fluctuations around DMFT saddle⇒dimension of activity
For neuro fans: conn. structure can be invisible in single neurons but shape pop. activity
For low-rank RNN fans: a theory of rank=O(N)
For physics fans: fluctuations around DMFT saddle⇒dimension of activity
Reposted by Harrison Ritz
We've been told by Finance that the 2024 budget commitments are intact, minus the $83 million. This is much better than I had been expecting.
2/ This matters enormously for granting councils. is the announced $83M cut from the 2024-25 baseline (which would be a real cut) or from the fiscal framework in which big instance were promised building up out to 2027-28 (which would mean a smaller rate of increase but not a cut)?
November 4, 2025 at 11:49 PM
We've been told by Finance that the 2024 budget commitments are intact, minus the $83 million. This is much better than I had been expecting.
Reposted by Harrison Ritz
The best write up on the state of AI in a while, from James Somers, with input from my Princeton colleagues Ken Norman, Uri Hasson, Jon Cohen, and many others. Coding with LLMs was a striking moment for me too www.newyorker.com/magazine/202...
The Case That A.I. Is Thinking
ChatGPT does not have an inner life. Yet it seems to know what it’s talking about.
www.newyorker.com
November 4, 2025 at 3:10 PM
The best write up on the state of AI in a while, from James Somers, with input from my Princeton colleagues Ken Norman, Uri Hasson, Jon Cohen, and many others. Coding with LLMs was a striking moment for me too www.newyorker.com/magazine/202...
Reposted by Harrison Ritz
Happy Tuesday after the first Monday in November! For those who are eligible and haven’t yet, please exercise your right to VOTE!!!! 🇺🇸
November 4, 2025 at 11:46 AM
Happy Tuesday after the first Monday in November! For those who are eligible and haven’t yet, please exercise your right to VOTE!!!! 🇺🇸
Reposted by Harrison Ritz
a gross parliamentary overreach — article by @picardonhealth.bsky.social in the globe and mail; #academicsky #neuroskyence #psychscisky www.theglobeandmail.com/gift/91587b9...
How much are MPs entitled to know about research grants? Not as much as they think
A parliamentary committee is asking for academics’ private information on a strange anti-DEI crusade
www.theglobeandmail.com
November 4, 2025 at 11:30 AM
a gross parliamentary overreach — article by @picardonhealth.bsky.social in the globe and mail; #academicsky #neuroskyence #psychscisky www.theglobeandmail.com/gift/91587b9...
Reposted by Harrison Ritz
Brace yourself: neural and computational insights into
the experience of mental effort! Now out in @cerebralcortex.bsky.social Led by Gaia Corlazzoli.
Paper: desenderlab.com/wp-content/u.... Thread ↓↓↓
the experience of mental effort! Now out in @cerebralcortex.bsky.social Led by Gaia Corlazzoli.
Paper: desenderlab.com/wp-content/u.... Thread ↓↓↓
November 4, 2025 at 12:37 PM
Brace yourself: neural and computational insights into
the experience of mental effort! Now out in @cerebralcortex.bsky.social Led by Gaia Corlazzoli.
Paper: desenderlab.com/wp-content/u.... Thread ↓↓↓
the experience of mental effort! Now out in @cerebralcortex.bsky.social Led by Gaia Corlazzoli.
Paper: desenderlab.com/wp-content/u.... Thread ↓↓↓
Reposted by Harrison Ritz
Kazuki Irie has a forthcoming paper in NeurIPS that studies the following idea:
Linear attention has cheap, unbounded memory but low precision, whereas softmax attention has expensive, bounded memory but high precision. These can be combined to build better transformers.
arxiv.org/abs/2506.00744
Linear attention has cheap, unbounded memory but low precision, whereas softmax attention has expensive, bounded memory but high precision. These can be combined to build better transformers.
arxiv.org/abs/2506.00744
Blending Complementary Memory Systems in Hybrid Quadratic-Linear Transformers
We develop hybrid memory architectures for general-purpose sequence processing neural networks, that combine key-value memory using softmax attention (KV-memory) with fast weight memory through dynami...
arxiv.org
November 4, 2025 at 10:33 AM
Kazuki Irie has a forthcoming paper in NeurIPS that studies the following idea:
Linear attention has cheap, unbounded memory but low precision, whereas softmax attention has expensive, bounded memory but high precision. These can be combined to build better transformers.
arxiv.org/abs/2506.00744
Linear attention has cheap, unbounded memory but low precision, whereas softmax attention has expensive, bounded memory but high precision. These can be combined to build better transformers.
arxiv.org/abs/2506.00744
Reposted by Harrison Ritz
I uploaded the lecture I gave on hidden multivariate pattern methods in M/EEG at the #practicalMEEG2025 conference (wonderfully organized by @cuttingeeg.bsky.social).
youtu.be/MgrqA7jMSBw
It's just an introduction but maybe some will find it useful :)
youtu.be/MgrqA7jMSBw
It's just an introduction but maybe some will find it useful :)
HMP lecture #practicalMEEG2025
YouTube video by Gabriel Weindel
youtu.be
November 4, 2025 at 11:07 AM
I uploaded the lecture I gave on hidden multivariate pattern methods in M/EEG at the #practicalMEEG2025 conference (wonderfully organized by @cuttingeeg.bsky.social).
youtu.be/MgrqA7jMSBw
It's just an introduction but maybe some will find it useful :)
youtu.be/MgrqA7jMSBw
It's just an introduction but maybe some will find it useful :)
Reposted by Harrison Ritz
it's this service, collaborative Markdown documents: hackmd.io
Marijn said it's more stable with 100s of participants compared to something like Google docs.
Marijn said it's more stable with 100s of participants compared to something like Google docs.
HackMD: Your Collaborative Markdown Workspace for Knowledge Sharing
HackMD gives you a real-time Markdown editor for collaborative work. Working with Markdown files in HackMD is simple, straightforward, and fun.
hackmd.io
November 3, 2025 at 1:23 PM
it's this service, collaborative Markdown documents: hackmd.io
Marijn said it's more stable with 100s of participants compared to something like Google docs.
Marijn said it's more stable with 100s of participants compared to something like Google docs.
Reposted by Harrison Ritz
What is the representation underlying cognition? Formal models rely on multidimensional scaling of similarity judgments to derive the representation. In this preprint with @mdlbayes.bsky.social, we take an alternative approach; we build Bayesian generative models for three cognitive tasks. /1
Similarity judgments and visual working memory do not share the same cognitive representation: https://osf.io/fm9vz
November 3, 2025 at 7:34 AM
What is the representation underlying cognition? Formal models rely on multidimensional scaling of similarity judgments to derive the representation. In this preprint with @mdlbayes.bsky.social, we take an alternative approach; we build Bayesian generative models for three cognitive tasks. /1