Glossary - Foundations for Designing User-Centered Systems - page 410

Figure and ground Figure is the term used to refer to the objects being focused
on; ground is the rest of the perceptual field.

Fitts' law A method used to predict the time it takes to move a pointer to a target.

Flesch reading ease score A calculated value that reflects the readability of a
selected piece of text.

Forcing function A mechanism for physically constraining actions to prevent the
user from proceeding to the next step in task performance. To start most cars,
for example, you are forced to put the key into the ignition.

Formative evaluation A type of evaluation that is used to help designers refine
and form their designs. The focus of formative evaluation is to identify prob-
lems and potential solutions.

Fovea A small area of the retina (covering about 2 of visual arc). This is the area
of clearest vision.

Framing effects Refers to the fact that the way that potential outcomes of a
particular situation are presented (framed) has a powerful influence on how
users choose between alternatives.
Functional fixedness Functional fixedness occurs when a person becomes fixated
on a particular use of an object.

Functionality What the system does. Usually specified by the functional

requirements.

Fundamental attribution error The belief that our own behavior can be
attributed to extrinsic factors in the environment, and that the behavior of others
is attributable to their intrinsic properties (e.g., they are a bad person).

Fundamental attribution error of design The belief, held by designers, that
users act and behave in the same way as designers when using technology.

Generic error modeling system (GEMS) An approach to modeling errors based
on interpretation, planning, memory, and acting.

Gestalt principles of visual grouping Can be used to explain how groups of
objects are interpreted. The principles were developed as a rebellion against the
simplistic notion that perception could be structurally analyzed into its com-
ponent parts, and that complex ideas were the result of associating together
simpler ones.

GOMS (Goals, operators, methods, and selection rules) A method of task
analysis that can be used to describe the details of error-free, expert task per-
formance using Goals, Operators (actions), Methods (procedures), and Selec-
tion rules (to choose between methods).