Human Factors Flashcards
What is Human Diversity?
It is how we work
Our physical attributes
Our ages
Our cultures
How can how we work be measured?
Time taken to learn
Speed of performance
Rate of errors
Retention over time
Subjective satisfaction
What is the connection between input-output channels of humans and computers?
Human output becomes computer input and vice versa
What are the examples and effectors of human input?
Examples are sight, hearing, touch, taste and smell
The effectors are limbs, fingers, eyes, head, vocal system and ears.
What is an example of human output?
A computer can observe eyes to see where the user is fixated, measure body temperature, voice recognition, hand manipulating an input device
What is the Physical Nature of a human?
Vision, hearing, touch, movement, memory
What factors must be taken into consideration when discussing vision?
Size and Depth
Brightness
Colour
Colour blindness
Describe the attributes of size and depth
Visual angle determines how much of the field of view is occupied by the object being observed
Describe the attributes of brightness
Luminance is the amount of light emitted by the surface of an object.
Contrast is the luminance of the object compared to the luminance of its background or the difference between colour hues
Describe the attributes of vision
Colour is the major one
Hue is the measure of how similar or different a colour is from these primary colours (rgb)
Intensity: The brightness or dull ness of a colour
Saturation: amount of whiteness in the colour or the intensity and purity of the colour
Colour blindness - cannot tell the difference between red and green (and other colour combinations)
What are the limitations of visual processing?
Perception of size - expectations affect how we perceive an image
What are the attributes of Computer Vision?
Biometrics which use facial recognition for security purposes.
The irises of the eyes are also used
Unique features of your face are the input
Masks, glasses and other facial accessories can thwart these systems
What affects hearing?
Outer ear, middle ear, inner ear
Pitch (frequency of sound)
Loudness (proportional to amplitude)
Timbre (type of sound)
What are the features of hearing?
Two ears allow the location of the origin of the sound
Can detect sound in the range 20Hz - 15KHz
We can filter some background noise but becomes more difficult as noise level increases.
What are features of touch?
Haptic perception is achieved via the skin
Can detect hot or cold, pressure and pain
Can pick up delicate objects without breaking them
Good for virtual reality
Provides feedback in the gloves
Provides feedback in some touch interfaces
Provides feedback in joysticks/handheld game consoles
Vibration
Provided in joysticks and mobile devices
Biometrics - Fingerprints
What are features of movement?
Movement time
Reaction time
Speed and Accuracy
What affects movement time?
Physical characteristics such as age and fitness
What affects reaction time?
The sensory channel that received the stimulus. Auditory takes about 150 ms, Visual takes 200 ms, Pain takes 700 ms
What affects speed and accuracy?
Increased reaction time can reduce accuracy
Distance and size of target
Bigger targets and shorter distances are advantageous to speed and accuracy
What are the various types of memory?
Sensory Memory
Short-Term Memory
Long-Term Memory
What is sensory memory?
It is a buffer for stimuli received through the senses.
What is short term memory?
A scratch pad for temporary recall. Rapid access takes about 70 ms, Rapid decay takes 200ms and short term has limited capacity.
What optimizes short term memory?
Chunks, they make it easier to remember if information is broken into manageable blocks
What is long term memory?
This is where you store factual information, experiential knowledge, procedural rules of behaviour, essentially everything you know.
What are features of long term memory?
Very little decay takes place
Reasoning
Problem solving
Skill acquisition
Errors and Mental Models
