Human-Computer Interaction 3e Dix, Finlay, Abowd, Beale

exercises  -  3. the interaction

EXERCISE 3.5

3.5 Using your function groupings from Exercise 3.4, count the number of items in your menus.

(a) What is the average?
What is the disadvantage of putting all the functions on the screen at once?
What is the problem with using lots of menu headings?
What is the problem of using very few menu headings?

Consider the following: I can group my functions either into 3 menus, with lots of functions in each one, or into 8 menus with fewer in each. Which will be easier to use? Why?

(b) Optional experiment
Design an experiment to test your answers. Perform the experiment and report on your results.

answer

(a) The answer depends on the answer to Question 3.4. The problem with putting all functions on the screen at once is that they will occupy too much screen space, leaving little room for anything else. Too many menu headings will make it difficult for the user to decide under which heading a desired command resides. Too few menu headings means that each menu will consist of many menu items, complicating the visual search task to locate the menu item and increasing the average length of time it takes to drag the mouse and select an options. Fitts' Law gives us a way to understand the impact of length of menu items and selection times.

We would tend to go for a larger number of smaller menus, under the assumption that it is possible to create clear conceptual boundaries between menu categories. If the eight categories lead to an easy to understand decomposition of the commands, then it would be easier to decide which menu to select and then would be quick to select a menu item among a small number of options. A small number of menus might result in an unclear decision on where to place some menu items.

(b) Open-ended experiment


Other exercises in this chapter

ex.3.1 (ans), ex.3.2 (ans), ex.3.3 (ans), ex.3.4 (open), ex.3.5 (open), ex.3.6 (tut), ex.3.7 (tut), ex.3.8 (open)

all exercises for this chapter


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