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CS 102 Human-Computer Interaction

Lecture 3: Cognition (2)

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AdministriviaHope you completed the reading assignment

Reminder: If you miss a class, you must review the alternate reading within a week to get attendance credit. Also review lecture material (the alternate reading is not a substitute.)

Some reference books are held under course reserve in the library

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ProjectsPlease post in Moodle about project ideas. Do some research and decide teams and rough outline of project by next Monday.

Some sources of ideas:

Your personal interests/experiences

Things to improve campus

Scan recent conferences (ACM CHI, UIST or CSCW)

Talk to us

Be realistic in scoping out the project

skills, hardware, test subjects, time, …

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As we may think

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As we may thinkWritten in 1945, after 50-60 years of tech. inventions (Electricity distribution, automobiles, airplanes, movies, TV, telephone, atomic bomb…)

“[Man] has built a civilization so complex that he needs to mechanize his records more fully if he is to push his experiment to its logical conclusion and not merely become bogged down part way there by overtaxing his limited memory.”

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Memex“A memex is a device in which an individual stores all his books, records, and communications, and which is mechanized so that it may be consulted with exceeding speed and flexibility. It is an enlarged intimate supplement to his memory.”

What’s in the memex vision that’s not on the web today?

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CS102: Monsoon 20157 http://trevor.smith.name/memex/

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L2: Recap

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Elements of Cognition

• Attention

• Perception, recognition

• Memory

• Language, reading, listening, etc.

• Problem-solving, decision making, planning, …

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Transactive memory

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human

Externalized memory to other repositories like other people, paper or written materials, tangible objects, etc.

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Memory in the Internet age

People forget items they think will be stored on a computer, and remember those they think will not available.

Participants asked to enter trivia facts under 2 conditions: they were told it would be either saved or erased

Mean recall in “erase” condition: 31% vs. “save” condition: 22%

11 Google effects on memory: Cognitive consequences...

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Memory in the Internet age

If people know where to find information, they are less likely to remember it

Participants asked to enter trivia facts and shown one of 3 messages: “erased”, “saved”, “saved in folder X”

Mean correct answer to true/false question:

93% (erased), 88% (saved), 85% (saved to a folder)

12 Google effects on memory: Cognitive consequences...

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Memory in the Internet age

People are primed to turn to the Internet when faced with gaps in knowledge

Demonstrated with a modified Stroop test

13 Google effects on memory: Cognitive consequences...

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Stroop testing

Invented by J.R. Stroop in 1935

Uses interference as a way to study access

A more accessible word will cause more interference

Test interference by asking people to name the color a word is written in

14 Studies of interference in serial verbal reactions

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Stroop testing: let’s try it

15 Studies of interference in serial verbal reactions

http://cognitivefun.net/test/2

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Memory in the Internet age

Comparing interference of (e.g.) Google/Yahoo to Nike/Target

Mean 712 ms vs. 591 ms after hard questions

Mean 603 ms vs. 559 ms after easy questions

16 Google effects on memory: Cognitive consequences...

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Memory in the Internet age

“We are becoming symbiotic with our computer tools, growing into interconnected systems that remember less by knowing information than by knowing where the information can be found.”

17 https://www.youtube.com/watch?v=ihgXRWaIlVE

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Augmenting Cognition

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Scanning a web page

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Using personal history

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1010100110101001010101010111010101001010101010101010100101010101010010100100101001010000#

Email history

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Experience-infused browser

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Experience-infused browser

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Experience-infused browser

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Experience-infused browser

The browser is like a second brain with unlimited capacity, and responds within a few seconds.

Provides simple, private personalization of web pages

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Memory Testing

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The memory problem3.8M patients in U.S. have Alzheimer’s, 5.4M MCI

Cost of dementia expected to exceed cancer or heart disease by 2030

Current ways of testing memory are basic

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CELL: Cognitive Evaluation with Life-Logs

• Use digital life-logs to establish ground truth for memory tests

• Automatically generate questions from sent email

• If successful, much more accurate and inexpensive way of testing

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CELL research issuesDo older people remember less?

(How) does memory drop off over time?

Are more frequently mentioned items better remembered?

Are people names better remembered than other names?

etc…

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Example CELL question

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Location History

30 http://google.com/locationhistory

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Cognitive biases

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Judgment under Uncertainty: Heuristics and Biases

Psychology of Intelligence Analysis

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Cognitive biases

3 (major) types

• Representativeness

• Availability

• Anchoring and adjustment

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Representativeness70% of people are engineers and 30% are lawyers.

"Dick is a 30-year old man. He is married with no children. A man of high ability and high motivation, he promises to be quite successful in his field.”

Judge: Is Dick a lawyer or an engineer?

Leads to base-rate fallacy

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Misconceptions of chance

A fair coin is tossed 6 times.

Judge: Which one is more likely?

T H T H H T

H H H H H H

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Effect of sample size

2 hospitals:

• 15 children born per day

• 45 children born per day

Babies are 50% boys, 50% girls (on avg.)

Judge: Which hospital (if any) is more likely to have days where > 60% children born are boys?

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Effect of sample size

Consider the difference between avg. word length of:

(a) successive pages

(b) successive lines

Which varies more?

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Regression to the mean

An extreme instance will likely be followed by an instance that is less so.

For example, after a really bad performance, a better one is likely to follow, and after a really good performance, a worse one is likely to follow.

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Causal explanationsWe bias towards causal explanations

But in reality, cause may be due to regression to the mean, external, or not explicitly intended

We bias towards estimating similar sizes of cause and effect

Intuitive to bang on the elevator buttons to summon it faster

A tennis star’s career simply peters out

We overestimate the role of internal factors and underestimate the role of external factors

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Oversensitivity to Consistency

Unwarranted generalizations from small sample sizes, e.g.

The train is always late…

Russians are generally….

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Availability biasIn the dictionary, does ‘r’ appear more often as the first letter or the third letter?

How many ways to pick 2 members out of 10 vs. 8 members out of 10?

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Vividness criterionVivid cases outweigh a much larger body of statistical evidence

“Man-who syndrome”, e.g.

I know a man who had cancer…

I know a man who ran the ultra-marathon…

Leads to an over-estimate of the actual probability

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Out of sight, out of mindCorollary: People fail to correct for lack of information

“The average person eats 3 pizzas a year”

Immediacy effect:

“This is the best movie I’ve ever watched.”

“Yesterday was a historic moment!”

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Anchoring and adjustmentEstimate

1 x 2 x 3 x 4 x 5 x 6 x 7 x 8

8 x 7 x 6 x 5 x 4 x 3 x 2 x 1

In studies, median judgement was 512 vs 2250

Adjustments are usually not enough

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Anchoring and adjustmentDiscredited evidence persists even after it is debunked

e.g. “academic urban legend” of decimal point error about the iron content of spinach

44 http://sss.sagepub.com/content/44/4/638.full.pdf+html