[Design for whom] Affordance, does the handle invite someone to grab?

Roughly speaking

1. Is the object inducing you to do it? Affordance and Shall We Dance.
2. Human malfunction, slips and mystery.
3. How to prevent errors. Associate information.

Affordance

The most important thing to consider when designing is to create a sense of operation that you can understand even if you don't know anything.

The same goes for this blog itself. I deliberately create parts that I can push and parts that I can't push.

You'll probably have experience in the real world as well. I thought it was a push door, but it was pulling. You may even be amazed at how it was a sliding door.

When I see something like a knob, I want to sniff it. In some cases, you might want to try turning it.

It makes me want to combine the concave and the pointed part. It is well known that the theory of continental drift is that Wegener was able to "get" when he combined the South America and African continents.

In all of the above, objects induce human actions. This is called affordance. And the person who clearly defines affordances in the world of design is Donald Norman, the author of "Design for Who (D.A. Norman/Shinyosha)", which we will introduce today.

Malfunction pattern. Slip and mystery

Affordance is a concept that is easier to understand when viewed from failure cases than from success cases. For example, confusing interfaces are considered typical affordance failures.

Does it open when you press it? Does it open when you pull it?

The door on the left is clearly a failure. I'm clearly hoping that the door handle will pull, but if you look closely, it says PUSH above, and the correct answer is pressing. But the right is inherently accurate as an affordance, and this door should be pulled.

Affordances need to be used appropriately to prevent the above mentioned operational errors. To do this, it is probably necessary to first explain the patterns of human malfunctions. There are two main types of human malfunctions. It's slips and mystery.

slip, automated behavior error

A slip is an error in automated behavior. Mistakes occur during the casual process of doing things that you always do.

For example, action-based mistakes. After pouring milk into the coffee, I put the coffee cup in the fridge. This refers to the fact that a milk pack was originally meant to be put in the fridge, but the coffee cup was put in the fridge.

For example, memory lapse. After cooking dinner, I forgot to turn off the stove fan. This simply refers to forgetfulness. Among the casual behaviors, there are actions that later expect other actions (such as if you open the door and you need to close it). I forget about that action.

Mystake, if the plan itself is wrong

Mystake refers to choosing to act incorrectly even if you are looking at the situation properly.

The door case is close to here. You will notice that it is something to pull, then operate the door and push it open. The ABS features of cars are also applicable. An ABS is a mechanism that prevents the tire from locking so that it stops at the shortest distance when a car is pressed on the brakes, but uses a mechanism that automatically pushes out the brake pedal when the ABS is in operation. At this time, people who are pressing the pedal may be surprised and release the brake pedal. For ABS to work, you need to keep stepping on, but in reality it ends up not being stepped on.

How to prevent errors

Affordances has hidden hints to use this mechanism to prevent malfunctions. This suggests that appropriate affordance associations will prevent human malfunctions. The following features prevent errors:

• Visible Affordance Signifier
• Discoverability
• Immediate feedback

First, let people know in a visible way. This book calls this a signifier. The escalator has yellow lines that you should clearly not step on, but that is where the step is filled for the escalator, and it informs humans that standing there is a danger that it is trapped and dangerous.

As the name suggests, discoverability refers to being easily recognized. This is effective in preventing slips from errors. Toothpaste and face wash foam are in the same tube shape, and while affordances are working in the sense that they are pushed out and used, they probably aren't working in the sense that they can distinguish between toothpaste and face wash foam. On the other hand, what makes a big warning with the term "Don't mix with acidic and alkaline detergents is likely to work well in terms of discoverability.

It is also important to be able to get feedback immediately when you do something or change occurs. In the world of web and apps, the red circle in the top right of the icon is called a badge, which is also a great signifier that lets you know that there is an announcement or update, and will send you notifications immediately.

Failure is a derivative of research through affordances. Research is progressing in Japan in the world of engineering, and Professor Hatamura Yotaro, the creator of failure studies and authority in this field, rakes together a number of failures and systematically spins the laws of error. Looking back on failures in a positive way and thinking about measures to prevent recurrence is something Donald Norman himself had high hopes for at least Design for Who (D.A. Norman/Shinyosha), and there are many related books, so I would like to introduce them from time to time.

This book has many charming design failures. It might be a good idea to look at it first. I hope you'll read it.