Principles of Human-Centered Design in App Development

Designing apps should prioritize human needs, ensuring clarity, safety, and emotional satisfaction for users.

### The Importance of Human-Centered Design
Mike Stern from Apple emphasizes the significance of using **"human interface"** instead of "user interface," highlighting the nuanced understanding of the **people designers are serving**. He discusses the **emotional and practical needs** that well-designed apps should address, such as **safety, knowledge, task accomplishment, and joy**. The session explores **universal design principles** that guide great designs, using real-world examples like **airport wayfinding systems** to illustrate the importance of **clear navigation and orientation for users**.

### The Importance of Wayfinding and Feedback in Design
Wayfinding systems help people orient themselves by providing **clear information about their current location**, options for where to go, and exit routes. The app's interface serves as a wayfinding tool, with navigation elements designed to **answer key questions and guide users**. Similarly, car manufacturers prioritize safety and provide various forms of feedback to help drivers **operate confidently, anticipate problems**, and **communicate important status information**.

### The Importance of Feedback, Visibility, and Consistency in Design
Feedback is crucial in preventing errors and guiding users, with **real-time validation and intuitive corrections** enhancing the user experience. Visibility of controls and information is essential for usability, as it allows users to **access key status information without unnecessary navigation**. Consistency in design features, symbols, and control locations helps users build familiarity and reduces the need to **re-learn how to use an app or vehicle**, making it a **vital principle for effective design**.

### The Importance of Consistency and Mental Models in Design
Consistency in design, such as using **familiar icons**, helps make apps more approachable and usable. Internal consistency, through similar visual styles and limited font variations, creates a **cohesive feel** for the app. Mental models, developed through personal experience, shape our expectations of how systems work, and when a design matches our mental model, it is perceived as **intuitive**.

### Innovative Faucet Design and Key Design Principles
Mortimer, a faucet designer, has a new concept of using **one lever for temperature** and **another for flow**, aiming to **improve user experience**. However, the mismatch between his mental model and users' expectations creates **usability problems**. The principles of **proximity, grouping, and mapping** are crucial in design, helping to **establish relationships between controls and objects**, and **reducing ambiguity in user interactions**.

### The Importance of Mapping and Affordance in Design
Mapping involves arranging controls to **mirror the layout of the objects they affect**, making it easier to understand their function. Affordance refers to the visual and tactile cues provided by an object's characteristics, indicating **possible interactions** and varying from person to person. Effective design communicates **action possibilities clearly**, using techniques like visual cues and animation to guide user interaction.

### The Principle of Progressive Disclosure
Progressive disclosure is a technique for managing complexity by **gradually guiding people from simple to more complex tasks**. It is effective in **simplifying decision-making**, but can also **hide important information**. The 80/20 rule is often used to determine which functions to prioritize, making the **most important 20% of actions easier to find**.

### The Importance of Symmetry in Design
Symmetry is a common trait in nature and human-made objects, providing **functional and aesthetic benefits**. Attractive interfaces often use a mix of **reflectional and translational symmetry** to create **balance and order**. The design principles discussed offer a framework for understanding and improving app designs, aiming to **fulfill basic human needs and enhance user experience**.

### The Importance of Human-Centric Design Principles in App Development
* 👋 Mike Stern, managing the Design Evangelism Team at Apple, emphasizes the significance of the term **"human interface"** over "user interface," highlighting its **historical roots at Apple since 1978**.
* 🧠 The term "human" encapsulates the complexities and qualities of the individuals for whom designs are created, promoting a focus on **serving their emotional and practical needs**.
* 🌍 Effective app design should address users' needs for **safety, knowledge, accomplishment, and joy**, creating interfaces that are **predictable, trustworthy, and aesthetically pleasing**.
* ✈ Using the analogy of wayfinding systems at airports, Stern illustrates how app interfaces function similarly, **guiding users through their navigation** and ensuring **clarity about their current location and available options**.
* 🚗 The design principle of feedback is crucial for user safety and confidence, as it provides **status, completion, warning, and error notifications**, ensuring users are **informed and can make decisions effectively**.
* 🔍 Visibility and consistency are also vital design principles; information must be **clearly displayed**, and similar features should be represented **consistently** to enhance usability and meet user expectations.
* 🛠 Stern advises designers to consider users' mental models—**how they perceive and interact with systems**—ensuring that designs **align with user expectations and intuitions** for seamless experiences.
* 💡 Ultimately, the session underscores that **great design is rooted in understanding human needs and behaviors**, creating interfaces that **resonate with users on a deeper level**.

### Understanding Design Principles: Enhancing User Experience through Intuition and Clarity
* 🚰 Adjusting temperature and water flow with faucet handles illustrates how **intuitive systems align with our mental models**, leading to **user satisfaction**.
* 💡 When a design, like Mortimer's innovative faucet, contradicts user expectations, it is perceived as **unintuitive**, highlighting the importance of **matching mental models** in design.
* 🔄 Proximity in design emphasizes the importance of **placing controls near their corresponding objects**, enhancing user interaction and understanding of **relationships between controls**.
* 🔗 Grouping elements together helps users **comprehend relationships** in a design, making it **easier to navigate and remember controls**, as seen in applications like Keynote and Sketch.
* 🔄 Mapping ensures controls visually represent the actions they perform, making interactions **more intuitive** and reducing the need for labels that can **complicate user experience**.
* 🍔 Progressive disclosure simplifies complex tasks by **revealing options gradually**, preventing overwhelming users while ensuring they can still **access necessary functionalities**.
* 🌊 Symmetry in design not only enhances aesthetics but also **conveys stability and order**, making interfaces **more appealing and easier to navigate**.
* 🧭 Ultimately, these design principles serve as a framework for creating **user-centered applications** that fulfill **basic human needs**, leading to a **more intuitive and enjoyable user experience**.

WWDC17: Essential Design Principles | Apple

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