Plural Cities: Modeling Diverse Public Space Preferences at Scale

A benchmark for public-space images that refuses to pretend one point of view can stand in for everyone.

Read on arXiv · OpenReview (ICML 2025) · Project & Dataset

The Big Idea

LIVS (Local Intersectional Visual Spaces) is a people-in-the-loop benchmark for multi-criteria alignment of text-to-image models in urban planning. It asks:

How do different communities actually want public spaces to look and feel—and can models reflect that?

Over two years, I worked with 30 community organizations in Montréal to gather local ideas of inclusive design and turn them into structured preferences that can steer generative models toward context-aware outputs.

Why This Matters

Global, single-objective alignment often flattens local norms. Pluralistic alignment keeps multiple, sometimes conflicting, values in play, including Accessibility, Safety, Comfort, Invitingness, Inclusivity, and Diversity. That makes room for a more honest question: not just what a place contains, but who it appears to welcome.

How I Built It

Participants & Process: Two years with 30 orgs; workshops, interviews, and participatory prompt design.
From concepts to criteria: 634 community-defined ideas distilled into six criteria.
Images & Annotations: 13,462 images, 37,710 pairwise comparisons (multi-criteria sliders).
Modeling: Fine-tuned Stable Diffusion XL with Direct Preference Optimization (DPO) using multi-criteria signals.
Evaluation: In 2,200 new comparisons, annotators preferred the DPO-aligned model more often where annotation volume was higher; about half of judgments were neutral—evidence that values are heterogeneous and sometimes visually subtle.

What I Found

• No single “best” image: Improvements varied by criterion; Comfort/Invitingness benefited most from data volume; Inclusivity/Diversity remained harder to judge and to render consistently.
• Identity matters: Preference patterns differed across participant identities—supporting intersectional data over an “average user.”
• Prompts matter, too: Human-authored prompts produced more distinctive outputs—and more decisive annotations—than LLM-generated ones.
• Neutral is a signal: High neutrality often meant subtle trade-offs or ambiguous visuals, not noise—pointing to richer objective formulations beyond single binary labels.

Where This Can Be Used

• Public engagement: Generate options that mirror local priorities and surface trade-offs in workshops.
• Design iteration: Rapidly visualize accessibility, comfort, or safety tweaks grounded in multi-criteria feedback.
• Policy & research: Compare criteria across groups; explore steerable or personalized alignment strategies for different communities.

Visuals

A two-year co-creation process, from outreach and criteria-building to prompt design, comparison, and model tuning.

The distillation pipeline that reduced hundreds of community concepts into six working criteria.

A reminder that intersectional groups often continue to evaluate generated spaces differently from majority groups.

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More: arXiv · OpenReview / ICML 2025 · Project & Dataset (mid-space.one)

Tags: Pluralistic Alignment · Text-to-Image · Inclusive Urbanism · Multi-Criteria Preferences · Accessibility · Montréal