Mental Models

Joel Kline

Texas Tech University

May 23, 2007

If I give you my keys…could you drive my van?

Mental Model Theory

Originates from Scottish Psychologist Kenneth Craik’s work that suggests the mind constructs "small-scale models" of reality (1943).

Mental models can be constructed from perception, imagination, or the comprehension of discourse.

They normally underlie visual images, but can also be abstract and represent situations that cannot be visualized.

Mental models have structure that is analogous to the structure of what they represent.

Resemble the “picture” theory of language described by Ludwig Wittgenstein in 1922.

Critics of the theory argue that the mind uses inference rules not models as the basis for deductive reasoning.

Donald Norman and Richard Young (independently) were the first to devise a terminology for Mental Models for use in HCI around 1983

Definition

Representations of systems and environments derived from experience.

A mental model is accurate when the real and imagined outcomes correspond

Two Categories Models of how systems work Models of how people interact with systems

Good Design Occurs…

Results when designers have an accurate view of the system (easy) and an accurate view of the user’s interaction with the system (hard). The designer then designs a system interface that merges both models.

Designers can learn the user:

Through personal use of the system Laboratory testing (usability, focus

groups) Direct Observation of users

Where do we “get” models?

External interface conventions - come to your interface with the users

Internal interface conventions - build or break trust

For both interface users and media developers

Print model has 600 years behind it Build trust with consistency Consistency can evolve

Consistency is Contextual

MM Examples

Automobile Doors with knobs that don’t turn Any computer interface device. Have

you ever tried a Dvorak keyboard?

InDesign Examples

Folios Right to left reading Consistent Hierarchy Consistent use of bold, italics, and

underline Typically an issue with longer

documents

InDesign Interface MM

When you have no MM?