Spring 2006 Human Performance 1H2 RevisionDr. C. Baber

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Human Performance:Revision

1H2

Chris Baber

Spring 2006 Human Performance 1H2 RevisionDr. C. Baber

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Module Objectives

• Relate cognitive psychology to human-centred system design;

• Employ basic concepts from cognitive psychology;

• Describe the use of products in terms of the requisite cognitive activities.

Spring 2006 Human Performance 1H2 RevisionDr. C. Baber

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Assessment

• Course-work (50%)– ONE lab report (45%)

• 2500 words• to be handed in THURSDAY week 11• to describe data collection and apply principles

from lectures

– Attendance of sessions (5%)

• Examination (50%)– 2 questions from 3– 1½ hours

Spring 2006 Human Performance 1H2 RevisionDr. C. Baber

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Seven Stage Action Model[Norman, 1990]

Form intentionDevelop plan

Perform action

Object in world

Evaluate against goalInterpret object

Perceive state of object

GOAL OF PERSON

Spring 2006 Human Performance 1H2 RevisionDr. C. Baber

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Solving Problems

Spring 2006 Human Performance 1H2 RevisionDr. C. Baber

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Problem Solving• A problem is something that doesn’t solve easily

• A problem doesn’t solve easily because:– you don’t have the necessary knowledge or,– you have misrepresented part of the problem

• If at first you don’t succeed, try something else

• Tackle one part of the problem and other parts may fall into place

Spring 2006 Human Performance 1H2 RevisionDr. C. Baber

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Conclusion

• More than one solution

• Solution limited by boundary conditions

• Active involvement and testing

Spring 2006 Human Performance 1H2 RevisionDr. C. Baber

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Conclusion

• Means-ends analysis:

• To modify representation• Break problem into sub-problems• To test hypothesis through ‘trial and error’

Spring 2006 Human Performance 1H2 RevisionDr. C. Baber

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Describing Problem Solving

• Initial State• Goal State• All possible

intervening states– Problem Space

• Path Constraints• State Action Tree

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Spring 2006 Human Performance 1H2 RevisionDr. C. Baber

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Key issues

• Insight in some problems– Framing– Recognition of ‘affordances’

• Reframing of problem • Through representation• Through changing states• Through analogy

Spring 2006 Human Performance 1H2 RevisionDr. C. Baber

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Perception

Spring 2006 Human Performance 1H2 RevisionDr. C. Baber

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Data-driven perception

Activation of neural structures of sensory system by pattern of stimulation from environment

Spring 2006 Human Performance 1H2 RevisionDr. C. Baber

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Theory-driven perception

Perception driven by memories and expectations about incoming information.

Spring 2006 Human Performance 1H2 RevisionDr. C. Baber

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KEYPOINT

PERCEPTION involves a set of active processes that impose:

STRUCTURE, STABILITY,

and MEANING on the world

Spring 2006 Human Performance 1H2 RevisionDr. C. Baber

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Visual Illusions

http://www.genesishci.com/illusions2.htm

Müller-Lyer Illusion

Gestalt: Grouping of parts to forma perceptual ‘whole’

Spring 2006 Human Performance 1H2 RevisionDr. C. Baber

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KEYPOINT

• Perception limits are set by sensory / neural mechanisms; but beyond these limits, perception can be cognitively controlled;

• Sensory experiences interpreted in a CONTEXT and derive from a variety of sources

Spring 2006 Human Performance 1H2 RevisionDr. C. Baber

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Memory

Spring 2006 Human Performance 1H2 RevisionDr. C. Baber

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Forgetting

• Encoding failure– Failure of consolidation

• Storage failure– Disruption by new or existing

information– Associative interference

• Two responses associated with same stimulus

• Retrieval failure

Spring 2006 Human Performance 1H2 RevisionDr. C. Baber

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Retrieval Failure

• Context• Intrinsic / Interactive: integral to stimulus• Extrinsic / Non-interactive: appear during

presentation but not part of stimulus

• Environment• Classroom learning affected when testing took

place in different room and reduced further in presence of different teacher

• State• Affect of drugs on memory task show:

– Affect for free-recall when matched– No affect for cued recall or recognition

Spring 2006 Human Performance 1H2 RevisionDr. C. Baber

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Amnesia [1]

• Infantile amnesia• Inability to remember events from before aged 4

years

• Anterograde amnesia• Inability to remember new information• HM learnt handful of words since 1950

• Retrograde amnesia• Inability to remember events from just before

injury / illness• Ribot’s law: person aged 60 can remember

childhood events and early adult life, but increasingly vague for later life

Spring 2006 Human Performance 1H2 RevisionDr. C. Baber

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Amnesia [2]

• Evidence that declarative knowledge affected but procedural knowledge intact

• Amnesiacs find it difficult to form new episodic or semantic memories

• Amnesiacs often acquire motor skills as fast as normals