Transcript slides - ISSEP 2010

Mission to Mars –
A Study on Naming and Referring
Michael Weigend
University of Münster, Germany
Outline
1.
2.
3.
4.
5.
6.
Introduction: Naming and referring
Design of the Study “Mission to Mars”
Mission 1
Mission 2
Mission 3
Conclusion
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Introduction
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Names
Functions:
• Identifying (making it distinguishable)
• Addressing (making it accessible)
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Types of Names
Mom
E
player_1
•
•
explicit - implicit
direct - indirect
My brother’s daughter’s dog
flight.passengers[0]
sqrt(2)
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Naming and Referring
to name = to create a name
to refer = to use a name
person = flight.passengers[i]
…
print(person)
Constructing an indirect name implies referring.
Creating a name includes anticipating its usage.
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Working Memory
Baddeley (1974, …, 2006)
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Naming and Reduction of Working
Memory Load
flight.passengers[i].name[0]
Split
person = flight.passengers[i]
first_letter = person.name[0]
print(first_letter)
if first_letter in "ABCDE":
...
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Mathematical Modeling in Science
Short direct names
instead of long indirect names
“Let c0 be the concentration of
the hydrochloric acid in the beaker…”.
E = mc²
Naming
conventions
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Design of the Study
“Mission to Mars”
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Question
To what extent are students without former
informatics education able to use naming
techniques, when they have to write
algorithms?
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Workshops
•
Briefing
•
Phase 1: Interpret given instructions
•
Phase 2: Write instructions
•
Phase 3: Exchange instructions
•
Phase 4: Compare the results
•
Debriefing
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Mission 1
Naming and Referring
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direct name
Phase 1 – the Model
(1) Draw a five point star. One of the
tips points upwards. Write the letter A
in the middle of the star.
(2) Draw a four point star with four
beams a little bit below star A. One tip
of the new star points upwards. Write
the letter B at the star.
(3) Mark star A. Mark star B.
Name of an activity
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Phase 1 – the Model
indirect name
(4) Draw circles around the tips
number 1, 2 and 5 of star A.
implicit name
(6) Put your finger on the circle,
which is at tip number 5 of A. Draw a
second circle left to this circle.
(9) Write the word Sauerstoff (oxygen)
next to the right hand side of the circle,
which is at tip number 2 of A.
62% no mistake
23 % one mistake.
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Phase 2 – Writing Instructions
• 8 different problems of equal
complexity
• At a table each student has a
different problem
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Some Results
Naming Concept
percentage
Explicit direct names (like A, B)
32%
Indexing
66%
Implicit name (like “put your finger at …”)
Define a separate procedure (like “ to mark a
polygon”)
9%
17%
105 students, grade 9, average age 15.3 years,
57 male, 47 female (one person did not tell )
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Discussion
• Most students tend to avoid to create direct names,
especially for activities.
• Indexing (numbering) things is easier than creating explicit
direct names.
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Mission 2
Naming Activities
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Procedure call
Phase 1 – The Model
To draw a Mars habitat
(1) Draw a living unit in the middle of your paper.
Call it W1.
(2) Draw a second living unit below W1.
This new living unit is called W2.
(3) …
Procedure
definition
To draw a living unit
…
To draw a laboratory
…
To draw a tank
(1) Draw a circle.
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Phase 1 – Solution
75% no mistake
12 % one mistake
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Phase 2 – Writing Instructions
• 8 different problems of equal
complexity
•Three instances of an
aggregrat (highlighted)
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Some Results
Concept
Defining procedures
percentage
4%
Subheadings (like “First part of the habitat”)
29%
Numbering the instructions (1), (2), …
73%
52 students, grade 10, average age 16.1 years,
32 male, 19 female (one did not tell).
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Discussion
Students avoid structured programming
(using procedures).
Why?
• Avoid a split attention situation (Sweller).
• Extra effort to create a (and rehearse) new holistic
concept of activity.
• Easier to use an existing concept of activity (like
numbering corners).
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Mission 3
Referring to Entities
within a Complex Geometry
49 students, grade 9
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Phase 1 – the Model
(1) The pyramid in the
right corner of the
platform is called corner
pyramid. Write number
1 on the corner pyramid.
(100% correct)
Explicit direct name
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Phase 1 – the Model
(5) When you move from
the corner pyramid
along the edge of the
platform to the left, you
reach a cube. Write 6 on
this cube.
(92% correct)
Path-oriented reference
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Phase 1 – the Model
(5) A Cylsphe is a
cylinder with a sphere on
top. Write a 5 on the
cube, which is on top of
the Cylsphe, which is in
front of a pyramid.
(92% correct)
Name for a type of
aggregates
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Phase 1 – the Model
(8) Put your finger on
the big sphere in the
middle of the platform. At
this sphere there is an
arrow pointing to a
pyramid. Write an 8 on
this pyramid.
(100% correct)
Implicit direct name
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Phase 2 – Writing Instructions
Different structure.
Parts with numbers must be
replaced . Write instructions!
Different sets of 6 parts.
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Some Results - Naming
Concept
Some kind of naming (including implicit)
Introducing and using explicit entity name (like corner
pyramid or X)
Percentage
47%
6%
Number of an entity (“Put your finger on part 3 …”)
10%
Using corner pyramid (phase 1) without introducing it
24%
Implicit naming (“Put your finger at …”)
27%
Introducing and using new aggregate types
(“Würzel”/”Cuder” for cube/zylinder)
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6%
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Some Results - Referring
Concept
Attribute oriented references
Percentage
55%
“The cube is glued at a cylinder, which is on top of a bigger
grey cube, which stands upon four white cylinders.
Additionally there are two white pyramids on top of the big
cube.”
Path-oriented references
90%
“The arrow points to a small cube. This is in front of a
bigger cube. On the bigger cube there is a sphere. Write
number 5 on this sphere.”
Aggregate-oriented references
“You see a row of cubes. On top of each cube there is a
sphere. Beside one cube with a sphere on top there is
another sphere. Write number 6 on the sphere, which is on
top of this cube.
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57%
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Some Results - Referring
Concept
Attribute oriented references
Percentage
55%
“The cube is glued at a cylinder, which is on top of a bigger
grey cube, which stands upon four white cylinders.
Additionally there are two white pyramids on top of the big
cube.”
Path-oriented references
90%
“The arrow points to a small cube. This is in front of a
bigger cube. On the bigger cube there is a sphere. Write
number 5 on this sphere.”
Aggregate-oriented references
“You see a row of cubes. On top of each cube there is a
sphere. Beside one cube with a sphere on top there is
another sphere. Write number 6 on the sphere, which is on
top of this cube.
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57%
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Conclusion
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Conclusion
• Students (grades 9 and 10, without specific training)
avoid creating explicit and direct names.
• Naming and referring are essential facets of modeling,
algorithm development and communication.
• For this competence we need informatics education!
Thank you for your attention!
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Reste (please ignore the following)
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Algorithm Comprehension
“Draw thing number
Ups + 1 in the middle of
Main Road.”
53% correct
7 questions
149 children, 3rd and 4th grade (age 9-10),
Weigend 2009
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Phonological Loop –
Word Length Effect
Number of stored items =
Number of Items that can be articulated in 2 secs
Baddeley 2003:
Recall of a five-words-sequence:
One syllable each: 90%
Five syllables each: 50%
Ellis & Hennelley 1980:
Digit span of Welsh speaking children is lower.
Welsh digits (385ms) take longer to articulate than their English equivalents
(321ms)
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Phase 1 – the Model
(3) A Threesphe consists of
three spheres, which are
connected vertically. One of
the Threesphes has got a
dark sphere in the middle.
Write number 3 on the cube,
which
is
beside
this
Threesphe on the platform.
(96% correct)
Names
for
aggregates
types
of
Aggregate-oriented
reference
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Naming and Typing
A name may be connected to a type  inducing semantics
Java
int add(int a, int b)
{
int r;
r = a + b;
return r;
}
Everyday life
• Mister Jones
• A streetcar named Desire
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