Nazlita@fsktm.um.edu.my1 General Human Factors. nazlita@fsktm.um.edu.my2 Human major senses : Vision Hearing Touch Taste Smell The central senses : Vision.

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General Human Factors

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Human major senses : Vision Hearing Touch Taste Smell

The central senses : Vision Hearing Touch

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4 stages of human information processing

Encoding Comparison Response selection Response execution

plus The processes of attention and

memory

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The perceptual system

Visual Perception - use in design of visual interfaces Perceiving size and depth -visual

angle, visual acuity perceiving brightness - the amount of

light emitted by an object Perceiving colour - hue, intensity and

saturation

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2 approaches in explaining visual perception

The constructivist – perception involves the intervention of representation and memories

The ecological – perception is a direct process, information is simply detected rather than being constructed

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The capabilities and limitation of visual processing

Visual processing involves the transformation and interpretation of image

Our expectation is an important factor in what will be interprated Eg. Ambiguous shapes, Muller-Lyer, Ponzo, text

Perception - the process of becoming aware of objects representation - appearance of things

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How do you interpret figure a and b?

a

b

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Reading

Steps of reading: 1) visual pattern perceived 2) decoded to an internal representation 3) syntactic and semantic analysis Eye, jerky movements (saccades), fixation

(during which perception occurs) Adults read 250 word/minute Words are recognize as quickly as a single

character Capitalizing words will effect speed and

accuracy

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RED BLACKYELLOWBLUEREDGREENYELLOWBLACKBLUEBLACKREDYELLOWGREENBLUEGREEN

ZYPQLEKFSUWRGXCIDBWOPRZYPQLEKFXCIDB SUWRGWOPR SUWRGZYPXCIDB QLEKFWOPR

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PadasuatuhariyanggelapAhmadtelahpergikepasarmalamuntukmembeliikanyuSampaiDipasarmalamitudiatidakdapatmenjumpaiikanyutetapitejumpadenganikanbilislalumembelinyadenganhatiyangriangria

PadasuatuhariyanggelapAhmadtelahpergikepasarmalamuntukmembeliikanyuSampaiDipasarmalamitudiatidakdapatmenjumpaiikanyutetapitejumpadenganikanbilislalumembelinyadenganhatiyangriangria.

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Hearing

The human ear outer ear (protect and amplify) -

processing sound middle ear (vibration occurs and

transmit to inner ear) inner ear (send impulses to the

auditory nerves) We can determine what and where 20 Hz < Frequency < 15 kHz

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Others

Touch - hot, cold, feeling of action such as picking up a glass, pressing the keys on the keyboard Important means of feedback

Movement = reaction time + movement time movement time depends on the

physical abilities ( age, fitness) reaction time (speed of senses)

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Memory

Sensory - iconic, echoic and haptic memory Short-term - scratch-pad for temporary

recall 35*6 examples number sequence, chunking,

meaning Long-term - episodic memory (events)

semantic memory (facts, concepts and skills)

remember, forgetting and retrieval

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3 types of memory

Sensory store – holds information for a very brief period of time (a few tenth of a second)

Short-term memory store - holds limited information for a short period of time (a few seconds)

Permanent long-term memory store - holds information indefinitely

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Thinking

Reasoning - deductive, inductive and abductive

Problem-Solving

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Examples

If the light is on then the day is getting darker

The light is on Therefore…. ????

Some people are criminals Some criminals are murderers So.. ????

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Statement: If a card has a vowel in one side it has an even number on the other.

Which card will you need to pick up to test the statement?

4 E 7 K

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Examples

There are 8 glasses of water in the kitchen. You need to carry them to the dinner table in the dining room.

How would you go about doing the above task?

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Learning

Learning by doing, like driving a car Computer systems - manual, steps

written in such a way that make user feel overloaded users use prior knowledge to use a new system

Errors Skill acquisition

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Errors

2 types : Mistakes : occur through conscious deliberation Slips : done unintentionally

A captured error -frequent activity to intended action description error - action on wrong object data-driven error - external data interruption of action associative-activation error - internal thoughts

interruption of action loss of activation error -forgetting something in the

middle of action mode error - being in a state without knowing it

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Skill acquisition

Declarative - facts about the world Procedural - how we do things inability to absorb and put into action

declarative instruction will lead to problems in learning how to use a system

offer few options so declarative knowledge small

later on can use more complicated systems

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Mental-models, knowledge

Knowledge - analogical, propositional, distributed network of general knowledge - the schemata

Mental-models - the model people have of themselves, others, the environment and the things with which they interact

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Why mental-models are important?

To design interfaces that match user’s mental models >> not easy since actual mental model experiments are difficult to find

What is the difference between images and mental models?Analogy of a movie, the frame and the short snippets of a movie

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Structural and Functional models

Structural - describes how devices and systems works

Functional - describes how to use devices and systems

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Metaphors

What are metaphors? Descriptions of an abstract concept in a

familiar form Verbal, Interface metaphors

eg. Describing using the save and find files system in a word processor

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Conceptual model A model of how human understand things

around them.

Cognitive model A representation of some aspect of the mind,

involving the acquisition of knowledge (understanding, remembering, reasoning, learning)

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Traditional cognitive framework in HCI Incomplete -individual user performing various

tasks at the interface in an inadequate conceptual framework.

More practical view of the cognitive framework

The design of real systems for real people to carry out real work activities in real organizational settings.

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2 approaches in cognitive psychology describing the activity of the brain

Computational approaches – conceptualize the cognitive system in terms of goals, planning and action involve in task performance

Connectionist approaches – simulate behaviour through using programming models

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Distributed cognitionA theory whose goal is to provide an explanation that goes beyond the individual.

In distributed cognition “functional systems” isThe collection of actorsComputer systems and technologyThe environmental setting

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Social and Organizational Aspects

Group commnunications: face-to-face, multi-party conversations computer-mediated multi-party

communication constraints such as the images and

sound that can be transmitted across the communication line

appearance of users Organization - paperles, automated office,

electronic cottage, global village