HCI Course: The Human

Stephen GilbertJune 20, 2014SPIRE-EIT

Inputs & Outputs

VisionHearingTouchMovement

Vision

Vision

Visual Angle / Visual Acuity

Spaces detectable at

30 sec – 1 min of visual arc

Brightness

Luminance is physical (photometer)Brightness is a perceptionMeasured in JNDs

– just noticeable difference in luminance

Higher luminance – Higher acuity– Higher flicker ( > 50 Hz, periphery)

Color

HUE

SAT.

VALUE / BRIGHTNESS

Low Blue Acuity

3%blue

Colorblindness

Protanopia – no red

Deuteranopia – no green

Tritanopia – no bluerare

~ 8% of males~ 1% of females

Some Illusions

Some Illusions

Some Illusions

Some Illusions

The quick brownfox jumps over

the the lazy dog.

Some Illusions

http://persci.mit.edu/gallery

YouTube, esp. recent OK Go videoandVideos by Brusspup

Design Ideas

Reading: line lengths 2.3” – 5.2” are goodDark characters on light screen

– Negative contrast gives higher luminance

Motion in periphery is eye-catching

Hearing

PitchLoudness (percept of amplitude)Timbre

Cocktail party effect

Touch

Thermoreceptors (heat /cold)Nociceptors (pressure & pain)Mechanoreceptors

– Rapidly adapting (poke)– Slowly adapting (hold)

Kinesthesis

Try:Two-point Discrimination Threshold

Touch: HomunculusSomatosenory Motor

Movement

Hick-Hyman law – time to choose

Fitts’ law – time to move

Reaction Time = a + b log2(distance/size + 1)

Selection Time = a + b log2N

Info Processing Model

x

x

PUSH-YES

PUSH-YES

Stroop

BLACK

RED

GREEN

BLACK

BLUE

RED

BLACK

GREEN

BLUE

RED

RED

BLACK

BLUE

GREEN

RED

BLUE

RED

BLACK

GREEN

BLACK

Memory Demo

#

Dog

Umbrella

Hat

iPhone

Shoelace

Justice

Lawnmower

Hamster

Contract

Eggs

Book

Accordion

Javelin

Zebra

Bat

Peg

#

Memory Demo 2

#

KEF

LAK

NEL

VEK

NER

LON

NEM

BEB

SAR

FIF

#

Expected Results

Word Position

% RecallAverage # recalled

words = 8

Chess

Who is winning?

Chess

Who is winning?How do you know?

Chess

Who is winning?How do you know?What do you remember?

Experts vs. Amateurs

Memory

Memory

7 +/- 2

Chunks

L Q R A Z J N P M

Discre

dite

d

7 +/- 2

Chunks

A B C I B M F B I

Discre

dite

d

Mental Representations

Semantic NetworkFramesScripts

Semantic Network

Frames

ScriptsEntry conditions• dog ill• vet open• owner has money

Props• exam table• medicine• instruments

Roles• vet examines• owner brings dog

Scenes• arrive at reception• wait in room• examination• pay

We are not logical…

Reasoning ala Wason

Fact: – All cards have letter on one side and number on the other

Rule: – If there’s a vowel on one side, there’s an odd number on the

other side.Question:

– Which card(s) do you turn over to verify the rule?

Reasoning (2)

Fact: – All cards represent people - the person’s drink is on one side, age

is on the other.

Rule: – If the person is drinking alcohol, he or she must be over 21

Question: – Which card(s) do you turn over to verify the rule?