What are the key principles behind the human-centered design system as discussed in The Design of Everyday Things?

Some common mistakes designers make that prevent users from intuitively understanding how to use their products include:

1. Lack of clear instructions: Users should not have to guess or remember complex steps to use a product. Instructions should be clear, concise, and easily accessible.

2. Poorly designed user interface: The user interface should be intuitive and easy to navigate. Complex or confusing interfaces can deter users.

3. Ignoring user feedback: Designers should always take into account the feedback from users. Ignoring this can lead to design flaws and user dissatisfaction.

4. Not considering user diversity: Designers should consider the diverse needs and abilities of users. A product that is not accessible or usable by a wide range of users can be seen as a design failure.

The principles of psychology, cognitive science, and art can significantly improve product design across industries by enhancing user experience and interaction. Psychology helps in understanding user behavior, needs, and motivations, which can inform the design process to create more intuitive and user-friendly products. Cognitive science can contribute by providing insights into how users process information, make decisions, and interact with products. This can help in designing products that align with the user's cognitive processes, reducing cognitive load and improving usability. Art, on the other hand, can enhance the aesthetic appeal of products, making them more attractive and engaging for users. It can also aid in conveying the product's purpose and functionality through visual cues.