Designing interactions: Bill Verplank

Reading about the interaction design process.

Page 126-127 in Designing interactions by Bill Moggridge

Note: numbered paragraphs in 'quote marks' are copied directly from the book.

Bill Verplank: Says that the interaction designer has three questions to answer...

1. "How do you do?" - 'How do you affect the world. A human, a person that we are designing for, does something, and we provide affordances. We either present handles that they can continuously control, or we give them buttons for discrete control, pressing the button and giving up control to the machine. When you are designing the way people act, there is a choice between handles and buttons. You can grab hold of a handle and manipulate it, keeping control as you do it. Alternatively you can push a button, or click on one, delegating control to the machine.'

How does this apply to my project: This links into my concept of active and passive interaction. Where the digital artefact requires user intention to do something and where it doesn't. However, the 'handles' and 'buttons' concept differentiates between the two types of control: where you initiate something and then release control, and where you continuously control something. I did not even consider these two types of interaction. In the current prototype, you push a button and it executes a single predetermined action. As there is only one action being executes, i'd class this as being a button. If there was the option to send different messages it would be more of a handle.

 Sitting down on the chair executes an action which is fully controlled by the user: where they get up, the chair stops glowing. This is a handle as you maintain control over the interaction throughout.

This distinction is important as it defines the level of control and type of control that users have over the interface, and how much control is relinquished to the user.

2. "How do you feel"? - 'How do you get feedback? McLuhan made the distinction between what he called 'fuzzy' or 'cool' media and 'distinct' or 'hot' media. Early TV was a cool medium, with its fuzzy images. Cool medium draws you in. A book with careful printing or a gravestone is hot, or immutable-you cannot touch or change it. We design the way that the machine, or the system, gives feedback to the user, or the sign communicates. That's where a lot of feelings come from; a lot of our emotion about the world come from the sensory qualities of those media that we present things with.'

How does this apply to my project: The type of feedback and mediums used affect the feelings of the users. It is very important that these are right, as the way that a message is conveyed can affect they way it is received. This is similar cognitive psychology theory about perception: the way that something is delivered can affect how it is perceived. 

3. "How do you know?" - As we design products with computers in them, it is very difficult for a usre to know exactly what they are going to do. A map gives the knowledge that you may need if you are designing complex systems. A path offers the kind of understanding that is more about skill an doing the right thing at the right moment. It is the responsibility of the designer to help people understand what is happening by showing them a map or a path. The map shows the user an overview of how everything works, and the path shows them what to do, what they know moment by moment.

How this applies to my project: INSTRUCTIONS!

Whatever the outcome (architecture, toolkit or built system example), users will need to know exactly what to do. The designer may not always be present to explain it, so some kind of instructions will be needed. Feedback is also important.

Schneiderman’s eight golden rules

1.       Strive for consistency; show consistent commands & terminology in similar situations

2.       Enable frequent users to use shortcuts

3.       Offer informative feedback; for every operator action

4.       Design dialogue to yield closure – grouping actions and then feedback at stage completion

5.       Offer simple error handling – avoid ability to make errors  & offer simple error handling

6.       Permit easy reversal of actions

7.       Support internal locus of control; users should be in charge of the system, not vice versa

8.       Reduce short term memory load

These usability heuristics illustrate important aspects of user interface design, in particular the need to offer informative feedback. How will the user know what what they are trying to do has been done or if there has been a problem.