Evan Lin

AIHCIReinforcement LearningUX DesignEntrepreneurshipResearch

Beyond Traditional HCI: Building AI Agents That Can Evaluate User Experience Through Reinforcement Learning

12 min read

## The Ground Truth Problem in UX Design

As someone passionate about both AI and HCI, I've been fascinated by a fundamental challenge: while UI design has relatively clear ground truths (a button should be clickable, a form should be submitable), UX design lacks objective metrics. What makes one user experience "better" than another? How do we quantify "frustration" or "delight"?

## My Solution: RL-Based UX Evaluation Agents

The breakthrough came when I realized we could use reinforcement learning to create "AI users" that simulate real human behavior. Here's the core concept:

### The Environment We create a digital environment where AI agents can interact with websites or apps, just like real users. The environment provides: - **State representation**: What the agent "sees" (DOM elements, page structure, or visual screenshots) - **Action space**: What the agent can do (click, type, scroll, navigate) - **Reward function**: How we quantify "good" vs "bad" user experiences

### The Reward Function: Quantifying UX This is where the magic happens. We design a reward system that captures what makes UX good or bad:

```python # Positive rewards (success) +100 points: Successfully complete the target task (e.g., checkout) +5 points: Make progress toward goal (e.g., add item to cart)

# Small negative rewards (friction) -1 point: Every click or action taken (effort cost) -0.5 points: Every second of thinking time (patience cost)

# Medium negative rewards (errors) -5 points: Click non-interactive elements (confusion) -10 points: Attempt invalid actions (e.g., checkout with empty cart)

# Large negative rewards (failure) -50 points: Give up or timeout (total failure) ```

### The Training Process Using frameworks like Gymnasium and stable-baselines3, we can train AI agents through millions of simulated interactions:

```python import gymnasium as gym from stable_baselines3 import PPO

# Create custom UX environment class UXEnv(gym.Env): def __init__(self): self.action_space = spaces.Discrete(10) # 10 clickable elements self.observation_space = spaces.MultiDiscrete([4, 2]) # page + cart state

def step(self, action): # Update state based on action # Calculate reward based on UX principles # Return observation, reward, done, info pass

# Train the AI agent env = UXEnv() model = PPO("MlpPolicy", env, verbose=1) model.learn(total_timesteps=100_000) ```

## The Entrepreneurial Vision

This isn't just a research project—it's a startup opportunity. Imagine a SaaS platform where developers can: 1. Upload their app prototype 2. Select target user personas 3. Get instant UX evaluation reports 4. Identify friction points before real users testing

The market need is clear: current UX testing is expensive, time-consuming, and requires real human participants. An AI-powered solution could democratize access to professional UX evaluation.

## Addressing the Innovation Question

When I first considered this idea, I worried: "Has someone already done this?" After research, I found that while GenUI (generative UI) tools exist, they focus on creating interfaces, not evaluating experiences. Most existing solutions use A/B testing with real users or heuristic evaluations.

The innovation here is using reinforcement learning to create **synthetic user behavior** that can **predict UX problems** before they affect real users. This is genuinely novel and valuable.

## The Future: GenUX and Human-AI Collaboration

While GenUI focuses on generating interfaces, the real frontier is GenUX—generative user experiences that adapt in real-time to individual users. Imagine an interface that: - Learns your preferences and adapts accordingly - Anticipates your needs before you express them - Optimizes itself for your specific context and goals

Our RL-based evaluation system is the first step toward measuring and understanding such adaptive experiences.

## Call to Action

The field of Human-Computer Interaction is evolving rapidly, and there's enormous opportunity for those who can bridge the gap between technical AI capabilities and practical human needs. Whether your goal is research, entrepreneurship, or both, the time to start building is now.

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*This project is currently in development. If you're interested in collaborating or learning more about the technical implementation, feel free to reach out. Together, we can shape the future of how humans and AI collaborate to create better digital experiences.*

👨‍💻

Evanlin

Interested in AI and its future.