Simulating human reasoning in open-ended tasks has long been a central aspiration in AI and cognitive science. While large language models now approximate human responses at scale, they remain tuned to population-level consensus, often erasing the individuality of reasoning styles and belief trajectories. To advance the vision of more human-like reasoning in machines, we introduce HugAgent (HUman-Grounded AGENT Benchmark), which rethinks human reasoning simulation along three dimensions: (i) from averaged to individualized reasoning, (ii) from behavioral mimicry to cognitive alignment, and (iii) from vignette-based to open-ended data. The benchmark evaluates whether a model can predict a specific person’s behavioral responses and the underlying reasoning dynamics in out-of-distribution scenarios, given partial evidence of their prior views. HugAgent combines structured questionnaires with semi-structured think-aloud interviews to collect ecologically valid belief states, belief updates, and reasoning traces from human participants. Our experiments reveal a clear asymmetry: models recover a person’s belief state from their own context reasonably well, but struggle to predict belief updates under intervention. Cross-person and cross-domain controls trace this gap to associative matching within a topic rather than identity-consistent reasoning, suggesting that progress requires better-calibrated change detection, not simply more context. We scope the benchmark to self-reported belief reasoning in three policy domains: healthcare, surveillance, and zoning. The benchmark, along with its complete data collection pipeline and companion chatbot, is open-sourced as HugAgent (https://github.com/jajamoa/HugAgent) and TraceYourThinking (https://github.com/jajamoa/trace-your-thinking).

Vision-language models (VLMs) excel in many downstream tasks but struggle with spatial reasoning, which is crucial for navigation and interaction with physical environments. Specifically, many spatial reasoning tasks rely on fundamental two-dimensional (2D) capabilities, yet our evaluation shows that state-of-the-art VLMs often produce implausible or incorrect solutions for composite spatial problems, including simple pathfinding tasks that humans solve effortlessly at a glance. To address this, we explore an effective approach to enhance 2D spatial reasoning in VLMs by training them solely on basic spatial capabilities. We first disentangle 2D spatial reasoning into three core components: direction comprehension, distance estimation, and localization. Our central hypothesis is that mastering these basic capabilities will significantly boost performance on more complex spatial tasks requiring advanced reasoning and combinatorial problem-solving, as well as generalize to real-world visual-spatial scenarios. To test this hypothesis, we introduce Sparkle, a framework that generates synthetic data to provide targeted supervision for VLMs across these three basic spatial capabilities, producing an instruction dataset for each capability. Our experiments demonstrate that VLMs fine-tuned with Sparkle achieve substantial improvements, not only on basic tasks but also in generalizing to composite and out-of-distribution real-world spatial reasoning tasks. These findings highlight that enhancing basic spatial capabilities through synthetic generalization effectively improves complex spatial reasoning, offering insights into systematic strategies for boosting VLMs’ spatial understanding. Source codes of Sparkle are available at https://github.com/YihongT/Sparkle.

Citywalk, a recently popular form of urban travel, requires genuine personalization and understanding of fine-grained requests compared to traditional itinerary planning. In this paper, we introduce the novel task of Open-domain Urban Itinerary Planning (OUIP), which generates personalized urban itineraries from user requests in natural language. We then present ItiNera, an OUIP system that integrates spatial optimization with large language models to provide customized urban itineraries based on user needs. This involves decomposing user requests, selecting candidate points of interest (POIs), ordering the POIs based on cluster-aware spatial optimization, and generating the itinerary. Experiments on real-world datasets and the performance of the deployed system demonstrate our system’s capacity to deliver personalized and spatially coherent itineraries compared to current solutions. Source codes of ItiNera are available at https://github.com/YihongT/ITINERA.