Generally speaking, any interactive product should provide good usability. But what do we mean when we say it is ‘usable’? Over the years interaction designers have identified a number of specific qualities, which are aimed at during the design process and referred to as ‘usability goals. 

Typically, these are:

·        Effectiveness: does the product enable the user to easily accomplish the task for which it is designed?

·        Efficiency: does the product enable the user to accomplish a task quickly with a minimum number of steps?

·        Safety: does the product minimise opportunities for users to make errors and, if they do make errors, can they recover easily?

·        Utility: does the product offer the functionalities that users need to complete a particular task?

·        Learnability: is it easy to learn how to use the product?

·        Memorability: is it easy to remember how to use the product?

But what is usability?

“The extent to which a product can be used by specified users to achieve specified goals with effectiveness, efficiency and satisfaction in a specified context of use” — according to ISO 9241

Different businesses have different ultimate design objectives, but the process objectives to be followed in the process of interaction design are universal, it can be said that they can be applied everywhere. I summarize these more general process objectives as four words: less, faster, better and saving

How to understand these four words?

The so-called less means that the information feature should be refined and clear at a glance, and unnecessary features and information should be reduced as much as possible.

The so-called faster, both performance and efficiency, refers to responding to user actions as quickly as possible and helping users achieve their goals as quickly as possible.

The so-called better is that the design of the product must meet the industry-leading design standards, so that users feel easy to use, and like to use.

The so-called saving means saving time, effort, and energy, helping user reduce action and cognitive costs.

1. Less

As humans, we have 86 billion sensory neurons, and about 40 billion sensory information inputs per second, but the human consciousness can only notice 40 of them at a time, while the human short-term memory can really process only 4±1.

Therefore, we should do the subtraction as much as possible in the interaction design, and use the four strategies of interaction design: reasonable deletion, hierarchical organization, timely hiding, and clever transfer, so as to reduce the complexity of interface information as much as possible.

2. Faster

If you make an input and the system gives you an output within 0.14s, you will think that the output is caused by your input. For example, if you click a button and it makes your expected response within 0.14s, you will feel very smooth (or insensitive, it should be), but if it has no feedback after 0.14s, you may frown and feel a little stuck. If it doesn’t give feedback for more than 1 second, I’m afraid you can’t help clicking again.

For interaction design, the user’s sense of control is very important, so we must make our product as fast as possible to meet the user’s need for a sense of control.

3. Better

People like the feeling of familiarity, and the evolutionary explanation for this is simple, if you recognize a recurring thing, it is safe, because it has not killed you, so the familiar will give people a natural sense of security and Favourite, people will like familiar actions and familiar elements.

Therefore, when we conduct interaction design, we must conduct competitive product analysis and study the design habits of the industry, because the design habits of the industry will shape the cognition and usage habits of users.

4. Saving

This makes our body mechanisms prefer energy-efficient products and designs. In the final analysis, it is the design of lazy people. For example, when many people stay at home on weekends, their nature is revealed. Basically, they don’t sit down when they can lie down That’s why smart furniture, smart appliances, and smart cameras are so popular.