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76 Chapter 3 Understanding users

Figure 3.2 Two different ways of struc-
turing the same information at the inter-
face: one makes it much easier to find
information than the other. Look at the
top screen and: (i) find the price for a
double room at the Quality Inn in Co-
lumbia; (ii) find the phone number of the
Days Inn in Charleston. Then look at the
bottom screen and (i) find the price of a
double room at the Holiday 1nn in
-
Bradley; (ii) find the phone number of
,,
the Quality Inn in ~edford. Which took
longer to do? In an early study Tullis
found that the two screens produced
quite different results: it took an average
of 3.2 seconds to search the top screen
and 5.5 seconds to find the same kind of
information in the bottom screen. Why is
this so, considering that both displays
have the same density of information
(31%)? The primary reason is the way
the characters are grouped in the display:
in the top they are grouped into vertical
categories of information (e.g., place,
kind of accommodation, phone number,
and rates) that have columns of space be-
tween them. In the bottom screen the in-
formation is bunched up together,
making it much harder to search through.

displays. However, it is much harder to find the information in the bottom screen
than in the top screen. The reason for this is that the information is very poorly
structured in the bottom, making it difficult to find the information. In the top the
information has been ordered into meaningful categories with blank spacing be-
tween them, making it easier to select the necessary information.
Perception refers to how information is acquired from the environment, via the
different sense organs (e.g., eyes, ears, fingers) and transformed into experiences of
objects, events, sounds, and tastes (Roth, 1986). It is a complex process, involving
other cognitive processes such as memory, attention, and language. Vision is the