Lecture2 Human

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CS374 Human-Computer Interaction

Human Perception

Monvorath Phongpaibul

Prapaporn Rattanatamrong

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InputOutput Channels

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?

?

HelloHi,

there


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Input Input in the human occurs mainly through the senses

Sight

Hearing

Touch

Taste

Smell

Number of effectors to aid the input mechanism

Limbs Fingers

Eyes

Head

Vocal system


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Vision Primary source of

information

There are 2 stages of visualperception

Physical reception of the

stimulus

Processing and interpretation

of the stimulus


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Visual Perception Perceiving size and depth

Visual Angle - the angle a viewed

object subtends at the eye

Size Constancythe tendency ofobjects to keep the same apparent

size regardless of distance.

Depth

Distance

Familiarity


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Visual Perception Perceiving brightnessreaction to levels of light

Luminancethe amount of light falling on the objects surface

and its reflective properties

Contrasta function of the luminance of an object and theluminance of its background

The capabilities and limitations of visual processing


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Which one is longer?


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Which one is longer?


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Is the text correct?

The Quick Brown

Fox jumps over the

the lazy dog.


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Visual Perception Perceiving color

Color made of 3 components:

Huethe spectral wavelength of the

light (S - blue, M - green, L - red)

Intensitythe brightness of the color

Saturationthe amount of the

whiteness in the color

The combination of color components

can make up of 7 million different

colors.

Human can perceive about 10 different colors without training

8% of males and 1% of females are color blindness. Mostly due to

unable to discriminate between red and green


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Reading 3 Stages of reading process

Perceive the visual pattern of the word

Reference to a representation of language

Syntactic and semantic analysis and operate on phases orsentences

Some facts about reading

Adults read approximately 150 words / minute Standard front that readable is 912 points

2.35.2 inches of line lengths are readable

Reading from a computer screen is slower than from a book

Negative contrast displays are preferred and results in more

accurate reading performance


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Hearing The human ear Outer ear

Middle ear

Inner ear

Processing sound

Pitchthe frequency

of the sound

Loudnessproportional

to the amplitude of the sound Timbretype of the sound

Human ear can hear frequencies from 20 Hz15 kHz.

Human ear can distinguish frequency changes of less than

1.5 Hz. at low frequencies

http://www.youtube.com/watch?v

=1FFDvhGjMDo


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Touch Skin contains 3 types of sensory receptors

Thermoreceptorsrespond to temperature

Nociceptorsrespond to intense pressure, heat and pain

Mechanoreceptors respond to pressure Rapidly adapting mechanoreceptors

Slowly adapting mechanoreceptors

Two point threshold test

Related to Human-Computer Interaction


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Movement

Computer Human I/O Brain

Display TextReceive Text

Process andgenerate response

Respond to the

text

Transmit

Signal

Receive respond

What happen when you

see this window?


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Movement

Speed VS. Accuracy of

movement

Typing

Shooting game

Pie Menu vs. Linear Menu


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Human Memory: Structure of MemorySensory memories

Iconic

EchoicHaptic

Short-term memory

or

Working memory

Long-term memory

Attention

Rehearsal

Cocktail Party

phenomenon


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Sensory Memory Buffers for stimuli received the senses

There is a sensory memory for each sensory channel

Iconic memoryvisual stimuli Echoic memoryaural stimuli

Haptic memorytouch stimuli

Constantly overwritten by new information coming in on

sensory channels

TestMoving the finger in front of you. How many finger did

you see?


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Short-term Memory Acts as a Scratch-paper for temporary recall

information.

Try 35 x 6which part of the memory is working?

Average people can remember 7 +/- 2

2653076208

071 242 6378


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Long-term Memory Main memory resource, huge and no capacity limit but

slow access

Two type of long-term memory

Episodic memory

represents our memory of events and experiences in a serial form

Construct the actual events that took place at a given point in ones

live Semantic memory

Structured record of facts, concepts and skills that we have

acquired

Structured in the way that allow access to information

representation of relationships between pieces of information and

inference


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Lecture2 Human