Ch5
Understand the Human
The human
•
Information
i/o
...
•
visual, auditory, haptic, movement
•
Information stored in
memory
•
sensory, short
-term, long
-term
•
Information
processed and applied
•
reasoning, problem solving, skill, error
•
Emotion
influences human capabilities
•
Each person is different
2
Humans are limited in their capacity to process information. This has
important implications for design.
Vision (eye sight)
Two stages in vision
• physical reception of stimulus
• processing and interpretation of stimulus
We need to understanding both stages as both influence
what can and cannot be perceived visually by a human
being, which in turn directly affects the way what we
design computer systems.
The Eye -
physical reception
•
Eye is mechanism for receiving light and transforming it
into electrical energy
•
light reflects from objects
•
images are focused upside
-down on retina
•
retina contains
rods for low light vision and
cones for
colour vision
•
ganglion cells (brain!)
detect pattern and movement
Interpreting the signal
•
Size and depth
•
visual angle
indicates how much of view object occupies
(relates to size and distance from eye)
•
visual acuity
is ability to perceive detail
(limited)
•
familiar objects perceived as constant size
(in spite of changes in visual angle when far away)