Telling people how things work.

Although it is the aim of ergonomists to make the operation of machines and systems as self-evident as possible, instructions usually have to be provided since the cost of completely self-explanatory apparatus may be excessive or its complexity may make it impracticable. When a person meets a novel piece of apparatus he will have expectations about how it may work. People tend to read instructions to confirm their expectations, so that anything unexpected in the operation of the apparatus must be emphasised in the instructions if it cannot be avoided in the design. It is important to determine exactly who will use the instructions and design them accordingly. The best combination of pictorial and verbal materials must be found to make the instructions as easy to understand as possible. Not everyone automatically looks for the instructions when they cannot make something work the first time they meet it. It is the responsibility of the designer to ensure operating instructions attract attention.