Context Lab

Context Lab

@contextlab.bsky.social

A motley crew of science nerds trying to understand the inner workings and limits of human memory. Plus some Bayesian stuff...and ๐Ÿง. Director: @jeremyrmanning.bsky.social https://www.context-lab.com

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๐Ÿšจ HyperTools 1.1 is out! ๐Ÿšจ This is our group's Python library for working with and visualizing high-D data. v1.0 was a ground-up rewrite; 1.1 fixes lots of bugs and adds some fun/useful new features and better data handling. pip install --upgrade hypertools Read on for a tour! ๐Ÿง‘โ€๐Ÿ’ป

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๐Ÿšจ HyperTools 1.1 is out! ๐Ÿšจ This is our group's Python library for working with and visualizing high-D data. v1.0 was a ground-up rewrite; 1.1 fixes lots of bugs and adds some fun/useful new features and better data handling. pip install --upgrade hypertools Read on for a tour! ๐Ÿง‘โ€๐Ÿ’ป

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๐ŸŒ 20 cities, 1645 months of temperatures = one trajectory. We also make it simple to show complex patterns over time. Here we're showing how temperatures across 20 cities around the globe change from month to month, over 138 years (1875--2013).

We've also added "morph" animations that can interpolate between point clouds or meshes. hyp.plot(shapes, '.', color='k', animate='morph', title=names) Here's a fun little example with some of our new built-in shapes from a "point cloud zoo" ๐Ÿฐ๐ŸงŠ๐Ÿ”ฎ๐Ÿซ–๐Ÿพ

๐Ÿšจ HyperTools 1.1 is out! ๐Ÿšจ This is our group's Python library for working with and visualizing high-D data. v1.0 was a ground-up rewrite; 1.1 fixes lots of bugs and adds some fun/useful new features and better data handling. pip install --upgrade hypertools Read on for a tour! ๐Ÿง‘โ€๐Ÿ’ป

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๐ŸŽจ hypertools speaks text! Give hyp.plot a list of strings and it embeds them, projects into 2D or 3D, plots the result: hyp.plot(texts, '.') Here, descriptions of 5 paintings becomes their own clouds, drawn in colors pulled from the actual canvases (also showing off our new palette tools!).

๐Ÿ—บ๏ธ order='serial' reveals a dataset one piece at a time. Here's an example from Alice in Wonderland's Mad Tea-Party. Individual conversation segments reflect the speaker (color) and what they're talking about (position and shape). If you do research on conversations, this is a fun one!

๐Ÿšจ HyperTools 1.1 is out! ๐Ÿšจ This is our group's Python library for working with and visualizing high-D data. v1.0 was a ground-up rewrite; 1.1 fixes lots of bugs and adds some fun/useful new features and better data handling. pip install --upgrade hypertools Read on for a tour! ๐Ÿง‘โ€๐Ÿ’ป

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If there are "extra waypoints" in someone's recounting --- i.e., events inferable from their neighbors --- then we can simplify our recountings by dropping them, without losing much of the overall structure of the narrative!

This was a multi-year effort by a fantastic group of wonderful scientists from our team, including @paxt0n.bsky.social, Alishba Tahir, Jennifer Xu, and Soo Hwan Park. Check out our paper to learn more, and we hope you'll play around with our code and data too!

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Our work suggests that when we recount our experiences to other people, what we may be doing is "leading" them on a journey through a semantic representation space (approximated here using text embeddings).

But just like navigating through the woods using trail markers, not all markers are equally useful. It's necessary to put in a marker at ambiguous locations (forks in the road, overgrown parts of the trail). But markers at obvious locations (or GPS "continue straight!" instructions) are less useful.

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Second, delayed recountings looked like smoothed/simplified versions of the immediate recountings. We used the RDP algorithm, originally developed for cartographic simplification, to ask how much each "event" in people's recountings contributed to the overall trajectory shape.

Events whose removals (from the immediate recountings' trajectories) least changed the overall trajectory shapes were the most likely to be omitted in people's delayed recountings.

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We found two interesting things. First, people's second (delayed) recountings were more similar to their own first recountings than to the original episode! Distortions of the original experience (of watching the episode), as reflected in the initial recounting, carry forward to future recountings.

Check out our latest collab with Manish Saggar, @richardfbetzel.bsky.social, et al. (lead: Chunyin Siu)! We use TDA to show that 2nd-order (edge) brain interactions more distinctly segregate task connections than other kinds of network patterns. Paper/code/data: www.biorxiv.org/content/10.6...

biorxiv.orgGlobal topology of brain-wide co-fluctuations links task states, personality, and behavioral symptom dimensionsFunctional connectivity in network neuroscience is traditionally characterized using time-averaged correlations between brain regions. While these summaries capture stable large-scale organization, they do not fully reflect the temporal structure of moment-to-moment interactions. Here, we investigate how the order of interaction used to represent brain dynamics shapes the organization recovered from neural data. We compare three interaction representations of fMRI dynamics: regional activation (node time series), pairwise co-fluctuations (edge time series), and higher-order triplet interactions (triangle time series); within a common topological framework using Mapper from topological data analysis (TDA). Across task and resting-state data, Mapper representations derived from pairwise co-fluctuations more distinctly segregate task conditions than activation-based or higher-order representations. This organization reflects structured coordination patterns beyond activation polarity and is driven by high-amplitude interaction events. Beyond task states, modularity quality computed across all Mapper representations is highest for edge time series and selectively associated with stable individual differences: higher modularity relates to higher conscientiousness and lower internalizing and externalizing symptom dimensions. Together, these findings suggest that behaviorally relevant information is reflected in the topology of moment-to-moment brain interactions. Topological analysis of interaction-level dynamics therefore provides a complementary and interpretable framework for linking large-scale neural coordination to cognition, personality, and mental health. ### Competing Interest Statement The authors have declared no competing interest. National Institute of Mental Health, https://ror.org/04xeg9z08, MH127608 Stanford Maternal and Child Health Research Institute, https://ror.org/00yt0ea73, Faculty Scholar Award
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Great human tutors intuitively build up an understanding of what their students know, and leverage that in their teaching. The knowledge models we've built can give AI tutors the power to do something similar by explicitly modeling (and interrogating) a personalized model of the learner's knowledge.

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Eventually, for concepts that are too far apart, predictive accuracy falls to "chance" and the model ends up predicting that your chances of answering a question correctly are equal to whatever your overall average performance is, across all questions (regardless of content).

We also found that each person has a unique knowledge map, which can be revealed by asking just a few multiple-choice questions. We're excited about what this unlocks: imagine matching up study partners, conversation partners, or even social relationships by studying how people's maps align!

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So these tests showed that the maps we get out using this approach reflect people's actual conceptual understanding of real course content! Next, we looked at the geometric properties of the maps. We found a bunch of interesting things.

One finding is that knowledge is fundamentally *smooth*. Given that you've answered a question correctly, the probability of answering another question correctly falls off smoothly with distance. (Same with *incorrect* responses.)

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Harder is: construct a map using domain X and predict performance on questions from domain Y. This tests the model's ability to *generalize* to unseen, unrelated content.

And even harder: construct a map using all but one question about domain X, and predict performance on the held-out domain X question. This is a highly conservative test of the model's *specificity*, because it requires the predictive model to distinguish between very similar concepts.

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First, and most importantly: given that someone's knowledge map shows that they have X level of knowledge about some concept, does that correspond to their actual knowledge? We show that the predicted knowledge track closely with people's chances of correctly answering held-out quiz questions.

We tested this in a few different ways, and all of the tests indicated that the maps were predictive of quiz performance! The simplest test is: given a map constructed from all but one question, can we predict how you'll answer that last question?

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We developed a process for efficiently building a "map" of one person's knowledge using responses to short multiple-choice quizzes. In our paper, we tested two things: (1) the quality of those maps and (2) their geometric properties.

We use text embeddings to define a coordinate system for human knowledge. Any text (video transcripts, quiz questions, etc.) can be localized in the embedding space, which lets us capture the idea that knowing about one concept also increases the chances that you know about other related concepts.

With our v1.0 release, dream-stream now comes in Android ๐Ÿค–! context-lab.com/dream-stream...

context-lab.comcontext-lab.com
Jeremy Manning@jeremyrmanning.bsky.social

I made a quirky little web app to help guide your lucid dreams: context-lab.com/dream-stream/ It's kind of like a "netflix" or "spotify" for lucid dreaming-- you select different narratives to form a playlist, and then it uses your device's microphone to start playing when it detects you're in REM.

Remember when grinding leetcode was still a thing? If you'd like to hone your coding skills, or even just return to that simpler time for nostalgia's sake, you might enjoy this project from our group: github.com/ContextLab/l... Happy hacking! ๐Ÿ‘ฉโ€๐Ÿ’ป

github.comGitHub - ContextLab/leetcode-solutions: Leetcode discussions, brainstorming, musings, and solutionsLeetcode discussions, brainstorming, musings, and solutions - ContextLab/leetcode-solutions

Context Lab reposted

Just finished a draft of my Models of Memory (grad) course that I'm teaching this spring! Please share/borrow/re-use/follow along as desired, and if you have feedback or suggestions I'd really love to hear (especially while I can still change it)! All materials are here: github.com/ContextLab/m...

github.comGitHub - ContextLab/memory-models-course: Dartmouth graduate course (PSYC 133) on computational memory modelsDartmouth graduate course (PSYC 133) on computational memory models - ContextLab/memory-models-course
Jeremy Manning@jeremyrmanning.bsky.social

Memory-sky: I'm going to be teaching a new (open!) grad course in the spring, where we read about and implement some memory models (and ideally for them to some small datasets). Looking for suggestions to include! I could go "classic" (Hopfield nets, SAM, TCM, etc.), or "modern" with newer stuff ๐Ÿค”

Excited to have this out in @natureportfolio.bsky.social! We found that real & fictional people communicate roughly 1.5x more about the past than the future. In turn, this influences the interferences we make about past & future events in *other* people's lives. www.nature.com/articles/s41...

nature.comTemporal asymmetries in inferring unobserved past and future events - Nature CommunicationsMemories of our past experiences enable us to reconstruct (in the present) our past better than our future. Here, the authors show that we are also able to better reconstruct the pasts (versus futures...
Context Lab@contextlab.bsky.social

๐Ÿšจ Updated preprint (lead: @xxming.bsky.social) on how inferences about unobserved past/future events are informed by conversations! osf.io/yp2qu/ ๐Ÿšจ This update includes a new pre-registered replication + meta analysis. We think we've found some neat fundamental properties of human conversation! ๐Ÿงช๐Ÿง