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Book summary: Designing with the Mind in Mind

This is my summary of “Designing with the Mind in Mind” by Jeff Johnson, a book about user interface design that explores the reasons why those principles work.

Introduction

How valuable are UI design guidelines depends on who applies them. They often describe goals, not actions, so they can’t be followed like a recipe. They also often conflict with each other. This book tries to give rationale to make them easier to apply.

Visual content

Expectations

Our perception is biased by our experience, current context and goals. Implications: (1) test your design to make sure different users interpret it in the same way; (2) be consistent with position, colours and font for elements that serve the same function; and (3) understand your users’ goals (they can be different, too!) and make sure you support them by making relevant information clearly visible at every stage.

Memory

We’re much better at recognising than at remembering (“see and choose” is easier than “recall and type”). Tips: (1) avoid modes, or if you can’t, show the current mode clearly; (2) show search terms when showing search results (they’re easy to forget if we get interrupted for whatever reason); (3) when showing instructions for a multi-step process, make sure the instructions are there while following the steps.

Attention and goals

When people focus their attention on their tools, it is pulled away from the details of the task. Software applications should not call attention to themselves. Short-term memory and attention are very limited, so don’t rely on them. Instead indicate what users have done versus what they have not yet done, and/or allow users to mark or move objects to indicate which ones they have worked on versus the rest.

Support people’s goal-execute-evaluate cycle: provide clear paths, including initial steps, for the goal; software concepts should be focused on the task rather than implementation, for the execution; provide feedback and status information to show users their progress towards their goal, and allow users to back out of tasks that didn’t take them toward their goal, for evaluation.

While pursuing a goal, people only notice things that seem related to it, and take familiar paths whenever possible rather than exploring new ones, esp. when working under deadlines. After they’re done, they often forget cleanup steps: design software so that users don’t need to remember, or at least to remind them.

Misc. tips:

Learning

We learn faster when operation and vocabulary is task-focused, and when risk is low:

Responsive systems

Responsiveness is not the same as performance, it can’t be fixed by having faster machines/software. Principles:

When showing progress indicators (always an operation takes longer than a few seconds): show work remaining; total progress, not progress on the current step; start percentages at 1%, not 0% (and display 100% only briefly at the end); show smooth, linear progress, not erratic bursts; use human-scale precision, not computer precision (“about 4 minutes” better than “240 seconds”).

Display important information first. Don’t wait to have all the information to show everything at once.