[M2]classical theoriescognitive modeling

roles of theory

theory as paradigm

that which underpins research design

theory as a lens

that which may inform our understanding of the phenomenon under

investigation

theory as new knowledge

that which may emerge from our study

roles of theory in HCI

descriptiveexplanatorypredictive

prescriptivegenerative

what other conceptualisations did you find when going over your

assignments?

classical theories

(raw) cognitive psychology(applied) basic research

cognitive modeling

but let’s focus on cognitive modeling

direct manipulation

direct manipulation relates to distance and engagement

distance between one’s thoughts and the

requirements of the system under use

engagement as in the feeling that one is directly

manipulating the objects of interest

theory of action

gulf of execution

gulf of evaluation

the gulf of execution represents the difficulty the

user has in translating a psychological goal into a

physical action

for example, the goal learn more about avocados is purely psychological

the user of a hypertext system on the WWW will need to see the available links, recognize the

appropriate choice, and use the mouse to point and click on that link

thus, in order to learn more about avocados, the user needs to execute a set of physical steps

the gulf of evaluation represents the user's difficulty in evaluating

whether the response of the computer system meets the

desired goal

in the previous example, the user would need to perceive the system response, examine the

resulting node, and assess whether it presented the proper information about avocados

Keystroke-Level Model

KLM quantifies operations such as…

K Press a key or buttonP Point to a target on the displayH Home hands on input deviceD Draw a line segmentM Mentally prepare for an actionR (system response time)

Goals, Operators,Methods, Selectors

goals are what the user wants to achieve and can be broken down into subgoals

operators are actions performed in service of a goal and can be perceptual,

cognitive or motor acts

methods are sequences of operators and subgoal invocations accomplishing

a specific goal

selection rules represent the user’s knowledge of which method should be applied

GOMS is good atmodeling goal-directed

tasks

GOMS is good for…comparing different designs

building a help systemparametric analysis

profiling

GOAL: DELETE-FILE. GOAL: SELECT-FILE. . [select: GOAL: KEYBOARD-TAB-METHOD. . GOAL: MOUSE-METHOD]. . VERIFY-SELECTION. GOAL: ISSUE-DELETE-COMMAND. . [select*: GOAL: KEYBOARD-DELETE-METHOD. . . PRESS-DELETE. . . GOAL: CONFIRM-DELETE. . GOAL: DROP-DOWN-MENU-METHOD. . . MOVE-MOUSE-OVER-FILE-ICON. . . CLICK-RIGHT-MOUSE-BUTTON. . . LOCATE-DELETE-COMMAND. . . MOVE-MOUSE-TO-DELETE-COMMAND. . . CLICK-LEFT-MOUSE-BUTTON. . . GOAL: CONFIRM-DELETE. . GOAL: DRAG-AND-DROP-METHOD. . . MOVE-MOUSE-OVER-FILE-ICON. . . PRESS-LEFT-MOUSE-BUTTON. . . LOCATE-RECYCLING-BIN. . . MOVE-MOUSE-TO-RECYCLING-BIN. . . RELEASE-LEFT-MOUSE-BUTTON]

*Selection rule for GOAL: ISSUE-DELETE-COMMAND If hands are on keyboard, use KEYBOARD-DELETE-METHOD, else if Recycle bin is visible, use DRAG-AND-DROP-METHOD, else use DROP-DOWN-MENU-METHOD