COM 3210, Week 6

Making sense from prior experience

TopicsTypes of reasoning that users

engage inLearning theoriesLearning modelsConclusions for interface design

1. ReasoningTwo types of reasoning:Based on analogies Based on metaphors

Analogy and MetaphorAn analogy provides an explicit,

isomorphic mapping between objects of two domains

A metaphor is a looser connection that draws on similarities, but also includes dissimilarities.

ExamplesKilling a tumor is like a general’s

army attacking a fortress surrounded by mines

Your PC’s operating systems works like a desktop

whether something is an analogy or a metaphor also depends on the scope of the comparison

Computing metaphorsNo chance for real analogies in computingcomputing metaphors use real world

objects in a computing environmentthey provide an intuitive understanding of

the computing object and initiate a process of active learning

computer metaphors are indispensable as overarching design strategies, but choose carefully

The desktop metaphorPictures of trash can Macintosh

The desktop metaphor “The use of the trash can to eject a disk was present form

the very beginning of the Macintosh interface. […] The original Mac had not hard disk. […] Because most users typically would switch back and forth between several diskettes during a session, it was deemed appropriate for the Mac to keep a memory image of the list of files of the various disks, regardless whether or not the diskette was actually inserted in the drive. […] Often, during the course of a session, the user would finish using a particular diskette, […] To reclaim vluable space, the now unwanted list of files represented by the grayed-out icon could be thrown away by dragging it into the trash…” Tom Erickson, Apple

2. Learning TheoriesMajor groups:behaviorist theories constructivist theories

Behaviorist theoriesLearning as changes of observable

external behaviorStimulus - response, selective

reinforcementhabitsProminent Behaviorist: SkinnerLearning as a reactive process

Constructivist theoriesLearning as constructing meaning in

one’s mind building of conceptual structures

through reflection and abstractionnot directly observablerequires self regulationlearning as an active processPiaget, Gestalt

Constructivist approachesPerceptionOrganizationDecision makingProblem solvingAttention Memory

3. Some practical learning modelsconcept formationlearning by explorationlearning by explanationlearning by imitationlearning by chunkingproceduralization

Concept formationCommon response to a class of stimulidiscrimination of distinctive features of

objectsconjunctive: Car - 4 wheels and enginedisjunctive: meazels - one or several of the

following symptoms: relational: rectangle - four sided object with

the two opposite sides of the same length

Concept formationUsers acquire new concepts and refine

theme.g. Children learn about dogs and

catsfirst concept: animals have four legs

(humans have two)refinement: birds are animals and

have only two legs.

Concept formationWhat kind of concept does a

computer user need to learn?How can designers support concept

formation

Learning by experimentationLearning as an active processexploration and experimentation:

“Learning by doing”experiential learning theory (Gibbs

1988): Concrete experience

Reflective observation

Abstract conceptualization

Active experimentation

Learning by experimentationHow can designers facilitate this kind

of learning?Restricted functionality at firsttraining wheelsfeedbacksafety nets‘undo’

Explanation-based learninggeneral ideas and supporting facts

such that the learning can see the relationship between them

e.g. lecturesmental modelsWhat are sources of explanation for

computer users?What makes a good explanation?

Minimalist instructionpeople rather learn by

experimentation than by explanationexplanation i.e. instruction should

support thatinstruction should be as little as

possible, but as much as necessary

Minimalist instructionFocus on real world activities of the

task domainChoose an action oriented approach

(how to do things)emphasize error recognition and

recoveryeliminate repetitions, summaries,

reviews, and exercises

Learning by imitationPiaget: three types of human adaptation:Play: assimilating objects to

predetermined activities regardless of the object’s attributes, e.g. using chair as horse

Simple Imitation: change behavior to be something else, e.g. using mam’s lipstick, but also dance lessons

Intelligent AdaptationAssimilating aspects of the environment

to the cognitive structure and accommodating cognitive structures to

the environmentguided by structures and resulting in

changed structurese.g. apprenticeship (crafts), pilot-training,

nurse training, learning to drive a car

Immitation and intelligent adaptationLearning to do things: skillscan start as imitation and may move

on to intelligent adaptationHow can this be exploited in

interface design?How can a designer support this type

of learning?

Learning by chunkingForming general rules from specific

instancesdeclarative chunking: e.g. grouping

digits of a phone number.Procedural chunking: grouping

several actions into a new action, e.g. drag and drop

Proceduralization From declarative to procedural knowledgefrom facts to how-to-do knowledgefrom knowing everything about

typewriters to learning how to typefrom knowing everything about windows

to learning how to use itConsistency is important, but can be

harmful or annoying

Exercise: answer the following questionsWhat is the tree that grows from an acorn?What is the black cover garment that one

wraps around one self?What sound does a frog make?“knock knock” stories are a kind of …What’s the term to say you’ve got no

money?What’s the clear part of an egg?

Habit intrusionUsers tend to behave in habitual

wayseven if it is not appropriateHow can designers incorporate

habitual behaviour?

4. Design principles for learnability (Dix)Predictability - help users predict future

actionsSynthesizability - help user asses effects

of past actionFamiliarity - help users to apply past

knowledgeGeneralizeability - help users to extend

knowledgeConsistency - similar behavior in similar

situations

Summary week 6Reasoning by analogy and by metaphorModels of learning:

concept formation experimentation explanation imitation and intelligent adaptation chunking proceduralization

Further reading Preece, J. et al. (1994) Human Computer

Interaction Eberts, R. (1994) User Interface Design Dix et al. (1998) Human Computer Interaction Carroll, J. (1990) The Nurnberg Funnel MIT Press Carroll, J. (1998) Minimalism: Beyond the

Nurnberg Funnel MIT Press Huthicns, E. (1995) Cognition in the Wild. MIT

Press Gibbs, G. (1988) Learning by Doing