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Applying Cognitive Load Theory to Help Teach Iterative Loops in Code

On separate sticky-notes, record 4-6 examples of things that happen repetitively in your life.

Do Now:

https://bit.ly/loopypltw

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On separate sticky-notes, record 4-6 examples of things that happen repetitively in your life.

Do Now:

School Bells Ring

(Music): Song B-I-N-G-O

(App Dev) Code -> Test -> Code -> Test -> Code -> Test…

School Bus Picking Up Students

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David Czechowski (✅🏠🔑)

CSE/CSP PLTW Master Teacher

F.D.Roosevelt High School

New York's Beautiful Hudson Valley

High School of ~1,400 students, in a former-suburban district

davidczechowski@hpcsd.org

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https://bit.ly/loopypltw

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Overview

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What are the 2 general uses of loops in code?

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How does schema development improve cognitive ability?

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How can loops in code be "chunked"?

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Introduction

Loops are foundational & pervasive.

Loops are challenging.

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Loops Throughout�Computer Science

Every structured programming language will have these 3 abilities:

Sequence - Execute one command, and then another…

Selection - Executing one of two commands based on a conditional value…

Repetition - Repeatedly executing commands based on a conditional value…

(Böhm–Jacopini Structured Program Theorem, 1966)

Introduction

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Loops Throughout

the PLTW Courses

Gateway App Creators

• 4 of 14 APBs in App Creators

Computer Science Essentials (CSE)

• 23 of 32 APBs in CSE
• CSE Loops

Computer Science Principles (CSP)

• 21 of 48 APBs in CSP
• CSP Loops

AP Computer Science 'A' (CSA)

• __ of __ APBs in CSA

Introduction

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The Loop Speed Bump

Introduction

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Novice Struggles with Loops

1. Assume that each action with the loop is repeated individually rather than as a unit.

Introduction

count = 0

while count < 5:

print(count)

count = count + 1

print("Done")

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Novice Struggles with Loops

• Assume that the loop condition (while) is constantly checked, rather than at the beginning of each iteration.

Introduction

while response != answer:

print("Guess #", guesses)

response = input()

guesses = guesses + 1

print("You got it")

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Novice Struggles with Loops

• Confusing the various constructs (for, for-each, etc) with implicit incrementing.

Introduction

for count in range(10):

print(count)

print("Done")

count = 0

while count < 10:

print(count)

count = count + 1

print("Done")

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Novice Struggles with Loops

• Why is it even called 'Loop'?

Introduction

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Novice Struggles with Loops

• Poor "Inside" the loop vs "Outside" the loop examples:
• What happens repetitively?
• What happens once?

Introduction

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Novice Struggles with Loops

• Due to computer speed, assuming that a loop happens instantaneously.

Introduction

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Look-Into Loops

Deepen our CS knowledge and see how that might change classroom instruction.

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Two Types of Loops

#1 Repeat Until/While a Condition

• All we know is what causes the repetitions to end.
• Example: Alarm clock beeps until a button is pressed.

#2 Fixed Number of Repetitions

• As the repeating begin, we know how many times the repetition will occur.
• Example: Singing B-I-N-G-O

Look-Into Loops

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Two and a Half Types of Loops

#1 Repeat Until a Condition

• All we know is what causes the repetitions to end.
• Example: Alarm clock beeps until a button is pressed.

#2 Fixed Number of Repetitions

• As the repeating begin, we know how many times the repetition will occur.
• Example: Singing B-I-N-G-O

#2½ Once per item in a list. (Special Case of #2)

• The number of repetitions is dictated by a list of items.
• Example: Bus Driver repeatedly picks students up once for every name on the list.

Look-Into Loops

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Which Types of Loop are your examples?

Look-Into Loops

School Bells Ring

(Music): Song B-I-N-G-O

(App Dev) Code -> Test -> Code -> Test -> Code -> Test…

School Bus Picking Up Students

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Fixed Number of Repeats

Conditionally Repeat

Look-Into Loops

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Fixed Number of Repeats

Conditionally Repeat

Look-Into Loops

School Bells Ring

(Music): Song B-I-N-G-O

(App Dev) Code -> Test -> Code -> Test -> Code -> Test…

School Bus Picking Up Students

(Repeat Once Per Item)

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Your Loop Examples

Share your best example of each type with the person next to you.

Did you have examples for both types?

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Look-Into Loops

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Fixed Number of Repeats

Conditionally Repeat

Look-Into Loops

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Fixed Number of Repeats

Conditionally Repeat

Look-Into Loops

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Fixed Number of Repeats

Conditionally Repeat

Look-Into Loops

for i in range( __ ):

#

#

while _______:

#

#

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Fixed Number of Repeats

Conditionally Repeat

Look-Into Loops

for(int i=0; i<__; i++)

{

// ...

}

while( ______ )

{

// ...

}

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Other Loops

Look-Into Loops

for( Object o : objects )

{

// ...

}

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Disadvantage of Other Loops (for novices)

Confusing the various constructs (for, for-each, etc) with implicit incrementing.

for count in range(10):

print(count)

print("Done")

count = 0

while count < 10:

print(count)

count = count + 1

print("Done")

Look-Into Loops

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Cognitive Load

Assessing the mental demands for completing a task.

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Cognitive Load Theory

Long-Term Memory

• Possibly unlimited
• "Memories" / "Knowledge"
• Organized by collections of related information

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Short-Term Working Memory

• Extremely limited – three to nine “information elements”
• "Schema" only count as a single element

Cognitive Load

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Cognitive Load Demo

Demonstration

Cognitive Load

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Cognitive Load on Learning

Extrinsic Load

• Cognitive burden not related to the learning

Intrinsic Load

• Complexity of the concept

Schema

• Structured collections of prior learning recalled from long-term memory

Cognitive Load

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Cognitive Load in Chess

In 5 seconds, a novice player could memorize the placement of only 4 pieces on a chess board, while a Chess Master could memorize 16 pieces.

(1973 "Perception in chess.")

Cognitive Load

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Schema in Chess

The Chess Master wasn't seeing individual pieces, but rather recognizing common patterns… chunks!

(1973 "Perception in chess.")

Cognitive Load

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Schema Demo

Demonstration

Cognitive Load

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Cognitive Load of Loops

It is easy to say: "Jump 3 times" but it can require 5 or more blocks/lines of code to implement.

High Cognitive Load!

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Cognitive Load

for(int i=0; i<10; i++)

{

jump();

}

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A "Schema" for Loops

Help students establish a schema for loops.

Show them the 'patterns' in the code.

Reduce the intrinsic cognitive load.

Cognitive Load

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An App Inventor Loop Schema

Cognitive Load

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A VEXcode Loop Schema

Cognitive Load

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A Python Loop Schema

Cognitive Load

count = 0

while count < :

#

#

#

#

count = count + 1

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A Java Loop Schema

Cognitive Load

int count = 0;

while(count < )

{

​

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count = count + 1;

}

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General Loop Schema

While loop is in nearly every imperative programming language.

It looks very similar in most programming languages.

Can be used in both applications of a loop in code.

Cognitive Load

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Known Number of Repeats

Repeat While Condition

Cognitive Load

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In Practice

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Careful around Loops

You are an 'expert'.

Tread lightly around loops with novices, it is cognitively dense.

Show students the pattern.

Teach students the pattern.

Require students to find the pattern.

In Practice

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Example: CSE Activity 1.1.5

Sample Code for generating a random number of a specified length.

In Practice

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Example: CSE Activity 1.1.5

See it with a schema…

In Practice

Repeating this many times:

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The Loop Schema in Class

Poster

Website

Modeling

Externalizing It

In Practice

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The Loop Schema in Class

Poster

Website

Modeling

Externalizing It

In Practice

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The Loop Schema in Class

Poster

Website

Modeling

Externalizing It

In Practice

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The Loop Schema in Class

Poster

Website

Modeling

Externalizing It

​

In Practice

"Ok, we need a loop. Let's put together the "oop chunk…"

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Put it into Practice

What are you teaching next? (Or choose an Activity from one of the CS courses.)

Which "type" of loop is it?

How can you help students develop a loop "schema" to support their success?

In Practice

https://pltw.read.inkling.com/read/

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What are the 2 general uses of loops in code?

​

How does schema development improve cognitive ability?

​

How can loops in code be "chunked"?

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Thank You!

Questions?

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