on being human
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On Being Human. ITEC 4130 Fall 2009. Understanding humans. Humans evolve much more slowly than technology There are limits to human capabilities - knowing what they are helps us understand what is going on. Three Views of Humans How to model a human!. Humans are interpreters/predictors - PowerPoint PPT PresentationTRANSCRIPT
On Being Human
ITEC 4130Fall 2009
Understanding humans
Humans evolve much more slowly than technology
There are limits to human capabilities- knowing what they are helps us understand what is going on
Three Views of Humans How to model a human!
Humans are interpreters/predictors- cog. psych. & AI
Humans are sensory processors- sensory psych., EE & CS systems
Humans are actors in environment-activity Th., ethnog., ecol. psych.
Humans as I/O machinesSenses
visionhearingtouchsmell/tasteproprioception (positional feedback)requires time to propogate back to brainkinesthesia (muscle memory)instantaneousgolf swing or catching a ball
VisionTwo stages in vision
- physical reception of the stimulus- processing and interpretation of stimulus- red arrow green arrow problem
The physical apparatus: the eye- mechanism for receiving light and transforming it into electrical energy
More about the eye
The eye:- the light it picks up is light that reflects from objects - images are focused upside-down on retina- retina contains rods for low light vision and cones for color vision- ganglia distribution on the retina varies by species (African plains vs tree dwellers)
Depth and Size PerceptionIt is a complex suite of clues
* visual angle indicates how much of field of view object occupies* Is your visual field circular?* Test this using a marker on the board
* visual acuity is ability to perceive fine detail * predatory birds have very high visual acuity
* Eagles: 600,000 cones/sq mm* Humans: 150,000 cones/ sq mm
Depth and Size PerceptionIt is a complex suite of clues
* familiar objects perceived as constant size* law of size constancy* as someone walks toward you you don’t think: Man,
that guy is getting taller by the second!
* Cues help perception of size and depth* Accommodation (lens stretches)* Occlusion* Motion parallax* Relative size (tied to size constancy)* Aerial perspective (atmospheric)
Brightness
* Brightness is a subjective reaction to levels of light
* Measured by just noticeable difference
* Visual acuity increases with luminance* Pinhole camera* Reading is improved in bright light
Color Perception
* Color made up of hue, intensity, saturation
* Cones sensitive to color wavelengths* Blue acuity is lowest* Green acuity is highest* 8% males and 1% females color blind
(Red/Green confusion most freq)
XXXXXGraphical Representation
at the InterfaceGraphical modeling and 3-DGraphical coding
Graphical coding for quantitative dataColor codingColor versus monochrome coding
Icons
Compensation & Illusions
http://blindspottest.comhttp://en.wikipedia.org/wiki/Image:Gradient-optical-illusion.svghttp://en.wikipedia.org/wiki/Same_color_illusionhttp://en.wikipedia.org/wiki/Grid_illusionhttp://en.wikipedia.org/wiki/Ponzo_illusionhttp://en.wikipedia.org/wiki/Image:Revolving_circles.svg
Reading… it’s pretty complicated
“Stage” model of reading(1) visual pattern perceived(2) decoded using internal language representation (pick out the words)(3) interpreted using knowledge of syntax, semantics, pragmatics
(what do these words mean?)
Perception in reading
* Reading involves saccades and fixations* Saccades are rapid movements of the eye* Without them, the retina would “saturate”
and you wouldn’t see anything* Fixations are the stops in that movement
* Perception occurs only during fixations* Otherwise the world would be blurred!* AKA: saccade masking
* Word shape is important to recognition.
Hearing
Two stages in hearing- physical reception of the stimulus- processing and interpretation of stimulus
-someone speaks to you-you say “what?”-but you figure out what
they said before they can answer
Hearing* Provides information about environment:
* Distance* Direction (but you can’t distinguish between directly in front
and directly behind you!)
* People can hear from 20Hz to 15kHz(I wish!)* less accurate distinguishing between high
frequencies
* Auditory system filters sounds* We can attend to sounds even in the presence of
background noise * “cocktail party phenomenon”
Touch
* Receptors in the skin:- thermoreceptors (heat and cold)
but you can’t distinguish which!- nociceptors (pain)- mechanoreceptors (pressure)
* Unevenly distributed across the body* Some areas more sensitive than others
* fingers are more sensitive than your back
6th, 7th and 8th sensesProprioception
internal awareness of your body position(Through feedback)
Kinesthesisawareness of body movement(Through muscle memory)
Balance vestibular organ of inner earvisual cues as to orientationawareness of body orientation
through proprioception
Movement & perception
Tight integration of -perception & motor planning, -movement execution-feedback
proprioceptive, kinesthetic, vestibular and visualResponse time = reaction time + movement time
-Movement time depends on age, fitness …-Reaction time depends on modality
visual: 200msauditory: 150 mspain: 700ms (slow and distance related)
The Box Model of MemorySensory memories
visiontouch
auditory
Short-term/workingmemory
Sensory buffersareconstantlyoverwritten
Driven by attention
Scratch-pad for temporary recall* rapid access (70ms)* rapid decay (200ms)* limited capacity (7 ± 2) Recency effect:
recall of recent items bestEvidence for several working memories
Semantic: facts, meanings, skills, concepts, understandings…Episodic: events, time, place, emotion…
Long-termMemory
Episodic
Semantic
The Box Model of MemoryLong-termMemory
Episodic
Semantic
Semantic memory structure
-provides access to information-represents relationships between information-supports inference-associative:
-recall based on meaning-gives rise to meaning-related
confusions-eye witness testimony…
Attention
FocusedSustainedDividedSelectiveAlternating
Attention
How to focus attention at an interface?Structure the informationOthers…
Consolidation
Moving information from STM to LTM?
Need to provide:Structure Meaning Become familiar (through rehearsal)
Forgetting
DecayInformation lost gradually but slowly
InterferenceNew information replaces old (retroactive)Old may interfere with new (proactive)
InhibitionYou can ‘choose’ to forgetExample:
Parking your car…You intentionally forget all but the most recent
episode
Retrieval
Recall* Information reproduced from memory* Can be assisted by cues, (e.g. categories, imagery, auditory input…)
Recognition* Information gives knowledge that it has been seen before
Knowledge representation
Declarative knowledge = knowing thatSemantic networksFramesScripts
Procedural knowledge = knowing howScriptsProduction rules
Semantic networks
Frame-based model of semantic memory
Knowledge is organized in data structure
Slots in structure are instantiated with particular values for a given instance of data...translation for CS people:
frames classes in the head;
slots variables/methods in the head)
General knowledge as frames
Script-based memoryScripts = using frames for stereotypical
processes (e.g. eating in a restaurant)* used for interpreting situations* generalize episodic-memory
events
Production rules
Representation of procedural knowledge
Condition/action rulesif condition is matched, rule fires
Slips and Mistakes
Slips are errors in execution of correct intention
Capture errorsErrors of attention
Mistakes are errors in selection of goal or method for accomplishing it
Errors of knowledge