Cognition Rebecca W. Boren, Ph.D. IEE 437/547 October 12, 2011.

Cognition

Rebecca W. Boren, Ph.D.IEE 437/547October 12, 2011

What is a Mental Model?

Cognition

What is a Mental Model?

Cognition

Memory for procedures or how things work

Cognition

How to use an ATM or ride a bicycle.

Case Study: The Wrong Mental Model Can Kill You

Kenneth NemireProceedings of the Human Factors and

Ergonomics Society51st Annual Meeting - 2007

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What is your mental model of a roller coaster?

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Cognition

TOP GUN An inverted roller coaster

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• Hanging roller coasters have only been around for 20 years.

• They comprise 4% of the world’s roller coasters.

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• All of group 1 (118 students) and all of group 2 (31 attorneys) drew pictures of a sit-down roller coaster.

• Of the 19 people exiting the theme park (group 3), 76% drew a picture of a sit-down roller coaster. This park had a higher than usual number of inverted roller coasters – 75%.

Research ResultsResearch Results

• Mental models• Thinking• Remembering• Forgetting• Learning• Attention• Schemata• Understanding

• Comprehension• Situation awareness• Time-sharing or multi-

tasking• Knowledge in the

Head• Information

processing & storage

Cognition involves

Cognition

Every day we process large Every day we process large amounts of information.amounts of information.

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What do you see?

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What do you see?

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Mental or cognitive resources Mental or cognitive resources are of limited availability and are of limited availability and

must be allocated. This must be allocated. This requires mental effort.requires mental effort.

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Selective attention focuses on some information and not on

other information.

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Attentional CaptureAttentional Capture

The understanding of information processing is important to designing alarms and displays.

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• Bottom up: when stimulus quality is high bottom-up processing will dominate.

• Top down: we “sample” the world where we expect to find information. How long we attend to the signal depends on its value.

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Effort: we prefer to scan short distances rather than long ones. We prefer to avoid head movements to select information sources. Why fatigued drivers fail to turn their head and look behind them.

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Selective AttentionSelective Attention

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• Salience (conspicuous, unambiguous, clear, obvious) features

• Effort

• Expectancy

• Value

Perceptional ProcessesPerceptional Processes

• Extract meaning from information processed by our senses.

• Cognition compares incoming information with stored knowledge in order to categorize.

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Three Perceptional ProcessesThree Perceptional Processes

• Bottom-up feature analysis.

• Top-down processing.

• Unitization (stimuli seen as a whole). – Children see letters; adults see words.

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Do you see a letter imbedded in the lines?

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What if we put the lines closer together?

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High expectations are based on associations and context.

Turn the machine … when the red light indicates failure.

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UnderstandingUnderstanding

Comprehension relies on working memory unlike

perception.

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Working MemoryWorking Memory

• Working memory is limited in capacity: 7 ± 2 chunks.

• Working memory is limited in duration: 7 to 70 seconds.

• Working memory is also called short-term memory (STM).

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• A chunk is defined as one bit of information.

• Examples: RXF is 3 chunks, while CUP is a single chunk.

• NAT is 1 chunk because it is pronounceable.

CognitionWorking MemoryWorking Memory

• Create chunks by making spaces or grouping: (480) 965-7258.

• Social security numbers are chunked.

xxx-xx-xxxx

CognitionWorking MemoryWorking Memory


• Words are easier to remember than numbers: 1-800-FLOWERS.

• Similarly sounding letters can be more easily confused than letters that sound different. DPZETG versus JTFWRU

• Group letters and numbers together, not mixed: ABC123 rather than A1B2C3.

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Short-term MemoryShort-term Memory

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• Working memory is encoded in three ways.

–Visual

–Phonetic

–Semantic

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• Working memory is encoded in three ways.

–Visual DOG

–Phonetic “dawg”

–Semantic

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• Errors are usually acoustic rather than visual.

• E may be recalled as D rather than F

• E sounds like D rather than F, although E and F look more alike.

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• Avoid negatives. “Do not turn off the equipment” may be heard as “Turn off the equipment.”

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• Instruction should be followed by action.

–“For billing, press 1”

–“I want roast beef, 3/4 of a pound”

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• Attention can be diverted.

–Example: cell phone use while driving.

–Bathing a baby interrupted by the telephone ringing.

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For information to be transferred from STM to LTM, the person must direct their attention and make some effort.

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End of Part 1

Next time we will talk about the different memory systems and how to transfer STM into LTM

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Long-term MemoryLong-term Memory

•Lasts a lifetime. •Retrieval may pose a problem.•Unlimited capacity.

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Two types of LTM:

•General Knowledge: schemata & mental models•Event memory: episodic & prospective

Semantic MemorySemantic Memory

• Semantic memory is part of LTM.

• Knowledge is organized into semantic networks where sections of the network contains related pieces of information.

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Semantic MemorySemantic Memory

• Associations are similar to– Databases

– Networks

– Not like a filing cabinet

• Information is related in a meaningful way.

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• Information in STM is transferred to LTM by semantically encoding it.

• Reading the textbook over and over is not enough. The material needs to be related to past experience in some meaningful way.

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Organization of LTM – Organization of LTM – General KnowledgeGeneral Knowledge

• Information stored in associative networks.

• Memory we use for daily activity is semantic knowledge.

• Our knowledge is stored in semantic networks.

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The Brain is made up ofNeurons (HIGHLY SPECIALIZED CELLS THAT GENERATE AND CONDUCT NERVE IMPULSES).

http://www.nku.edu/~dempseyd/bio208pg8.htm

http://www.nku.edu/~dempseyd/bio208pg8.htm

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The neurons interconnect to send messages through the network of brain cells.

How Memories Are Made, And RecalledScienceDaily (Sep. 16, 2008) — What makes a memory? Single cells in the brain, for one thing.

The link below will take you to an article that explains memory from a biological prospective.

http://www.sciencedaily.com/releases/2008/09/080908101651.htm




• Semantic memory is memory for concepts and meaning of words.

• A schema is the entire knowledge structure about a particular topic, e.g. cups, college professors, vacations.

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• To recall more information, it must be analyzed, compared, and related to past knowledge.

• Retrieval is sometimes difficult.

• “Forgetting” is a failure of memory retrieval.

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• Forgetting is due to

– Weak item strength

– Weak or few associations

– Interfering associations

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• “Remembering” is enhanced by frequent rehearsal in STM and by making meaningful associations with other information.

• “Thinking” involves activation of task-relevant material in working memory.

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• Scripts or mental models are memory for knowledge of procedures (dynamic schemata).

• Mental models generate a set of expectancies.

• A large number of people having the same mental model defines a population stereotype.

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• Cognitive maps are mental representation of spatial information.

• Examples:– Layout of a classroom (POV)– Geographical layout of a city

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Organization of LTM – Organization of LTM – Event MemoryEvent Memory

• Episodic memory for past events.

• Examples:

– Eyewitness testimony

– Birthdays and other special days

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• Based on visual memory, but not a faithful “video recording.”

• Memory may be biased

• Memory may be degraded

• Eyewitness testimony is generally recognized as unreliable.

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• Prospective memory for things that are supposed to happen in the future.

• Failure of prospective memory is called “absent-mindedness.”

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Semantic Network

Meaning of concepts & things

Schema

Entire knowledge

structure about a particular topic

Mental Models & Dynamic

Schemata

(Scripts)

Procedural

Cognitive Maps &

Spatial memory

Long Term Memory – General Knowledge

Memory for Events

Episodic

Memory for past events

Prospective

Memory for events that are supposed to happen in the future.

Long Term Memory – Event

Long-term Memory Long-term Memory Implications for DesignImplications for Design

• Encourage regular use of information to increase frequency and recency.

• Encourage verbalization of information that is to be recalled.

• Standardize.

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Recall TaskRecall Task

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Long-term Memory Long-term Memory Implications for DesignImplications for Design

• Use recognition rather than recall.

• Use memory aids. Knowledge in the World. Cognitive artifacts. Checklists.

• Design information to be easily remembered.

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Situation Awareness (SA)Situation Awareness (SA)

Designers, researchers, and users employ the concept of SA to characterize users’ awareness of the meaning of dynamic

changes in their environment.

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Lack of Situation AwarenessLack of Situation Awareness

• A pilot suffers a catastrophic controlled-flight into terrain.

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Lack of Situation AwarenessLack of Situation Awareness

• Control room operators at the Three Mile Island nuclear power plant lost SA when they believed the water level in the plant to be too high rather than too low.

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Situation Awareness (SA)Situation Awareness (SA)

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•Design easy-to-interpret displays of dynamic systems.•Tools for accident analysis.•Training is important (especially for attentional skills).

Three Stages of Situation AwarenessThree Stages of Situation Awareness

• Perception & selective attention

• Understanding

• Prediction

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All rely on STM and LTM.

Time-sharingTime-sharing & Attention Attention

Time-sharing is the ability to perform more than one cognitive task by attending to both at once or by rapidly switching attention back and forth between them

(divided attention).

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• Multi-tasking or time-sharing is not doing two things at the same time.

• It is switching back and forth.• It is more difficult than most people

realize.

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Four major factors determine the extent to which two or more tasks can be time-shared.

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1. The degree to which one or more of the tasks are trained to automaticity.

2. The skill in resource allocation.3. The degree of shared resources.4. The degree to which task elements

can become confused.

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Multi-taskingMulti-tasking

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What happens as we get older?

•Systems (vision, hearing, cognition) deteriorate at different rates.•Individuals undergo changes at different rates.•At what age should people stop driving cars?

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•Older drivers have more accidents per mile driven than younger drivers.•One alarming story of the deaths of 10 people because of an 89-year old driver.•It was not a visual problem, nor an aging problem. It was a perceptual problem.

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•UFOV related to attentional capture.•Little correlation between driving safety and visual acuity.

Useful Field of View (UFOV)Useful Field of View (UFOV)

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•UFOV deficits occur more often in older adults, but cut across all ages.

•Training can improve UVOF.

Useful Field of View (UFOV)Useful Field of View (UFOV)

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Review of Memory Systems

Semantic Network

Meaning of concepts & things

Schema

Entire knowledge

structure about a particular topic

Mental Models & Dynamic

Schemata

(Scripts)

Procedural

Cognitive Maps &

Spatial memory

Long Term Memory – General Knowledge

Memory for Events

Episodic

Memory for past events

Prospective

Memory for events that are supposed to happen in the future.

Long Term Memory – Event

Cognition

Questions?Questions?

Cognition Rebecca W. Boren, Ph.D. IEE 437/547 October 12, 2011.

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