Introducing Experience Notation: A New Language for Human-Centred Design

by The Cato Bot Team 2 min read
experience-notation open-source dsl human-centred-design

Experience Notation emerged from a simple problem: how do you model complex human behavior in a way that both people and machines can understand?

The Challenge

Traditional user journey mapping tools fall short when modeling the nuanced decisions, environmental factors, and behavioral patterns that shape real human experience. Flowcharts capture linear processes, but human behavior is rarely linear. Personas describe static characteristics, but people adapt and change.

We needed something that could:

  • Model complexity without losing clarity
  • Work with AI systems for simulation and analysis
  • Remain human-readable for design teams and stakeholders
  • Support real-world constraints like time, resources, and disruptions

Designing the Language

Experience Notation is built around several core concepts:

Events and Steps

Every human experience can be broken down into discrete Events containing Steps. But unlike traditional process mapping, these aren’t just actions—they’re decision points influenced by context, emotion, and constraints.

Event: "Booking a medical appointment"
  Step: "Patient recognises need for care"
    Context: urgency=high, previous_experience=positive
  Step: "Patient searches for available slots"
    Conditional: IF urgency=high THEN prefer_earliest_slot
  Step: "Patient selects appointment time"
    Disruption: "System shows no availability for 3 weeks"

Personas with Depth

Our personas aren’t just demographics—they’re behavioral models that can adapt and learn:

Persona: "Sarah, Working Parent"
  Experience-Level: intermediate
  Interaction-Preference: mobile-first
  Adaptation-Rate: high
  Context: time_constrained=true, multitasking=frequent

Environmental Factors

Real experiences happen in real contexts. Experience Notation captures the environmental pressures that influence decisions:

Environmental-Factors:
  - system_load=high
  - staff_availability=limited  
  - peak_hours=09:00-11:00

Why Open Source?

We built Experience Notation as an open standard because human experience is too important to lock behind proprietary formats. When healthcare teams, policy makers, and service designers can all use the same language to model human behavior, we get:

  • Better collaboration across disciplines
  • Reproducible insights that teams can verify and build upon
  • Shared learning that improves simulation models over time

What’s Next

Experience Notation is already powering Demoscope.ai for synthetic user feedback and integrating with our Text2Sim simulation engine. But we’re just getting started.

We’re working on:

  • Visual editors for non-technical team members
  • Import/export tools for existing journey mapping software
  • AI safety applications for modeling edge cases and failure modes
  • Government pilots for policy impact assessment

Try It Yourself

Experience Notation is available now:

Whether you’re designing services, building AI systems, or studying human behavior, Experience Notation gives you a structured way to capture and reason about the complexity of human experience.

Have questions or want to collaborate? Get in touch or join the conversation on GitHub.