Summary: Putting It All Together - Foundations for Designing User-Centered Systems - page 379

this? It would have to record actions while it was doing them. Users are basically
like this as well. It is very hard to remember what you are doing when you are busy
doing it. Ericsson and Simon ( 1993 ) laid out a fairly good theory of when users can
talk aloud about what they are doing. It is even more difficult to talk about what
you have done and be completely accurate. That said, sometimes the only data we
can afford to gather is how users think they think, and sometimes users will choose
systems based on such judgments, so we will often have to work with these
judgements. You might wish to be more skeptical in the future about users' (and
untrained designers') reports about how they do a task or whether they learn or not.
14.2.4 Social
Most tasks are carried out by teams of people interacting with one another.
Sometimes they will be working directly with co-located people, but in other cases
they may be working distally as a team. Individual users have limitations on how
well they work together in teams: some people are natural leaders, whilst some are
natural followers.
Chapters 8 and 9 note social factors that influence users, including distributed
responsibility, and social influence on teams. For example, users (and system
developers) will often misjudge social relationships. They will often send out one
blanket email to ten people asking for one of them to volunteer, rather than
sending out ten individual emails. The sorts of variations in performance that you
see across users can sometimes be attributed to the context they are working in, as
well as their own capabilities and limitations. If you put the same user in the same
task and physical situation but vary the environmental conditions by increasing the
temperature, or reducing the lightinglevels, for example, this may affect their
performance.
14.2.5 The Role of Tasks and Environments
Knowing users' tasks will help design systems to perform these tasks in numerous
ways as presented in Chap. 11 . There are a wide range of uses and applications,
and of ways to represent users' tasks and activities. Good designers can choose
appropriately based on what is needed for a given design project.
Users' tasks are not always directly understandable by designers using their
own intuitions, but there are ways to find what tasks users do and what tasks they
want to do. However, there will still be surprises because it is difficult to know
everything, particularly for new tasks and unexpected uses.
It is also important to understand the environment in which users perform their
tasks. Usability studies help to provide a way to understand the tasks, the users, the
environments, and how they interact.