04 Cognitive Aspects Flashcards
Definition Cognition
Mental action or process of acquiring knowledge and understanding through thought, experience, and the senses.
- > Refers to all stages of human information processing
- > Cognitive processes underlie how users process system output and how they perform input
Important Cognitive Processes
perception, attention, memory, judgment, evaluation, comprehension, language production, learning, problem solving, decision making, planning, creativity
Perception definition
The process of recognizing and interpreting sensory stimuli
-> governed by the five sensory modalities: vision, hearing, tactile sensation, taste, olfaction
Types of perception
Visual,
Auditory,
Tactile
Visual search - Attentive vs preattentive
Attentive Perception
- Visual scanning of view
- Sequentially identify objects
- Compare each object with target
- > SLOW
Preattentive Perception
- Certain visual features (color, shape, texture) are processed in parallel
- Subconscious accumulation of information from the environment
- An object that differs from surrounding objects in one feature is immediately recognized
- > < 0.25 sec, subconcious
Gestalt Laws
- Good Shape (clear, simple shapes)
- Proximity (spatially close objects belong together)
- Closure (tendency to see complete figures amidst discontinuities)
- Similarity (similar shapes appear as belonging together)
- Continuity (cintinuous shapes belong together)
Perception: Design Implications
Use techniques that make important elements stand out
Bordering & spacing are effective visual ways of grouping information
Avoid cluttering the interface with too much information
Tactile feedback can offer subtle output from computers
Perceptual illusions can be utilized to increase the efficiency and improve the quality of user experience
Processing in Memory
Encoding is the first stage of memory. It processes and combines received information.
Storing creates a record of the encoded information in memory.
Recall retrieves information from the past.
Types of Memory
Sensory memory
Very brief recall of a sensory experience (visual, tactile, auditory, …)
Holds data 0.2-1.5s; high capacity
Working memory
Mostly encodes symbolic (verbal) data using visual or acoustic encoding
Typical capacity of of working memory is limited to around 4-7 chunks
Was believed to be 7 +/- 2 chunks of information (Miller‘s rule)
Holds data approx. 15 seconds (can be extended using repetition or shortened using interference by other information)
Long-term memory
Semantic and episodic encoding (associations)
Almost „infinite“ capacity (both capacity and duration)
Fast recall, slow encoding
How to deal with human memory
don’t overload users’ memory
support recognition rather than recall
help user remember
Fitts’ Law
Time to select a target is a function of the distance and width (size) of the target.
It furthermore depends on device-specific constants.
t = a + b log(D/W)
D: the distance
W: the width (size) of the target
a: time required to start/stop moving the device
b: the inherent speed of the device
4 Cognitive Models for HCI
- Mental Models
- Gulfs of Execution and Evaluation
- Human Processor Model
- External Cognition
Mental Models
Mental models are internal constructions of some aspect of the external world. These enable a human to make predictions
mental model = understanding of a system
Done through learning and system use
Shallow mental models vs. deep mental models
Gulf of Execution
the distance from the user to the physical system
the difference between actions the user intends, and actions required by the system
Gulf of Evaluation
the distance from the physical system to the user
psychological gap that must be crossed
to interpret a user interface display
