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Parallel processing / Divided attention. What is parallel processing? items are processed all at once. Example: letters in a word are processed all at once, not one-at-a-time. Early vision / perceptual organization.
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Parallel processing / Divided attention • What is parallel processing? • items are processed all at once. • Example: letters in a word are processed all at once, not one-at-a-time.
Early vision / perceptual organization • Early in the visual system, information is extracted and organized in parallel. • much of this is effortless, automatic, and does not require attention. • extracts features and organizes them into objects. • e.g. Biederman, Geons, and Recognition by compenents
Gestalt grouping principles • Proximity:
Gestalt grouping principles • Similarity:
Gestalt grouping principles • Common fate:
Gestalt grouping principles • Good Continuation:
Gestalt grouping principles • Closure:
Global Precedence • Items are examined at several different scales • Large is examined before small EEEEEEEE E E E E E E EEEEEEE E E E E E E E E
Emergent Features • A global property of a set of stimuli that is not apparent by examining the stimuli in isolation
Overlapping views & HUDs • Logic: it’s easier to extract information from two items when they are close together than when they are farther apart.
Problems • Allows, but does not guarantee parallel processing. • The two displays might be treated as 2 different sources of information • Pay too much attention to the HUD (cognitive tunneling).
Costs & Benefits • Bad: Can clutter the display, making items less easy to detect or process. • Good: Works particularly well when the observer expects the stimulus • conformal symbology is an extreme example of this.
Focused Attention • Tight spacing makes it easier for us to share our attention between two items. • However, if items are too close, it becomes difficult to focus on a single item. • How tightly can we focus our attention???
Focused Attention • Flanker Task: • respond to middle item (L or R), ignore the other items (“flankers”). • 3 spaces, 3 flanker/target compatibilities. compatible incompatible neutral • LLL LRL XRX • R R R R L R X L X • L L L L R L X R X
Focused attention Response Competition Redundancy Gain
Object based attention • When you attend to part of an object, you attend to all of the object. Demo: “Name this word”
Stroop Effect • The reason that the Stroop task is so difficult (at least when the names and colors mismatch), is because you automatically process all parts of the object (color, form).
Proximity-Compatibility Principle • Items that have close processing proximity should have close display proximity. • Display proximity - how close are two components? • distance • other properties, e.g. same color • Gestalt grouping or part of the same object
Proximity-Compatibility Principle • processing proximity - • the extent to which 2 sources of information are used in the same task. • example: altimeter & rate of climb gauge
Proximity-Compatibility Principle • Moving items close together increases the likelihood that they will be processed together, as does making them part of the same object
Proximity-Compatibility Principle • Moving items close together increases the likelihood that they will be processed together, as does making them part of the same object • Close proximity can cause emergent features to occur. If the emergent feature is not part of the task or is unintended, this can hurt performance.
Proximity-Compatibility Principle • Moving items close together increases the likelihood that they will be processed together, as does making them part of the same object • Close proximity can cause emergent features to occur. If the emergent feature is not part of the task or is unintended, this can hurt performance. • Close proximity can create clutter or response conflict. If the task is likely to call for focused attention on only a single item at a time, then avoid close proximity
Color coding For the 97% of the population who are not color blind, color coding can be of great benefit: • highlighting - if the color is significantly different from the rest of the display. • stereotypical meanings: red = stop red = hot yellow = cautionblue = cold green = go
Color coding For the 97% of the population who are not color blind, color coding can be of great benefit: • highlighting - if the color is significantly different from the rest of the display. • stereotypical meanings • used to tie together spatially separate objects • mixing board • Redundant coding • a traffic light uses color and location
Color coding Limitations of color coding: • Sensory • limit the number of colors to 5 or 6 Most people can only easily discriminate between 5 and 6 colors. • color is not perceptible under low-light conditions
Color coding Limitations of color coding: • Sensory • limit the number of colors to 5 or 6 • color is not perceptible under low-light conditions • Cognitive • Color does not imply an ordered continuum • Is red ‘more’ than green?
Color coding Limitations of color coding: • Stereotypes red-yellow-green stoplight pattern might not have the same meaning in different parts of the world
Color coding Limitations of color coding: • Stereotypes red-yellow-green stoplight pattern might not have the same meaning in different parts of the world • Coding color coding should be relevant and consistent.