Theory of cognitive load and
optimal complicacy of textbooks
Jaan Mikk
04.12.2013
Cognitive load theory
• Information is processed in working memory.
• The working memory capacity is restricted by
7+/-2 units, which may have a different size.
• If the working memory is overloaded, then
learning is rather slow.
• Filling in a carafe with a narrow hole.
• The content of the units is not restricted.
Beginners and specialists
• Experienced chess player can learn the
positions of twenty chessman in some
seconds. He remembers several thousands of
positions.
• Experienced players and beginners have the
same mental abilities but specialists have
huge experiense.
• It is not needed to learn by hearth; I can look
in textbook???
Mental schemas
• Knowledge is stored as schemas in long term
memory (read only memory).
• Mental schemas reduce the load of working
memory.
• Mental schemas are formed as a result of
training. For example, learning to read or solve
some simple mathematical problems.
• Thinking is subject specific.
• The aim of education is the creation and
automation of mental schemas.
Reducing the cognitive load
• Tasks from real life are too complicated.
• It is important to support the learner
– From simple to complicated,
– Hints for solving problems
– fedback
Goal free problems
• Data and the question: What can be
calculated.
• The load to working memory is smaller
because aim is not fixed and there is no need
to find the way to the aim
Worked examples
• The load on working memory is smaller.
• worked examples facilitate learning mental
schemas more than problem based learning.
• worked examples facilitate meta-cognition
and transfer but reduce motivation.
• In one study, worked examples enabled to
acquire three year math course in two years.
• First give overview of complicated task and
then practice solving parts of it.
Partly worked examples
• Some steps in the solution are missing and
students have to add these steps.
• Cognitive load is smaller than in solving the
whole problem.
Recommendations
from dual coding theory
• Use words and graphics in explanations.
• Place print words near corresponding graphics
(maps, illustrations with words on them).
• Words should be presented as speech rather
than onscreen text (teacher explaining
graphics at blackboard, multimedia).
• Avoid words as narrations and identical text
on graphics.
Redundant information
• Redundant information raises the cognitive
load because learners have to elaborate
also the information retrieved from longterm memory.
• Peoples’ learning is hindered when
extraneous sound, pictures, and words are
used in teaching.
Cognitive load reversal effect
• Novice learners facilitate from worked
examples, experts learn more while solving
problems.
• Auditory explanations of illustrations may
hinder learning by experts.
• Integrated explanatory notes increased the
cognitive load of high ability students.
The cognitive load
in sentence comprehension
• Too long sentences overload the working
memory and hindere learning.
• Text written in too short sentences is
redundant and therefore not the most
effective in learning.
• There should be some optimal length of
sentences for students.
Rationale
• We do not know the optimal value of
sentence length.
• Let us try different borderlines between the
short and long sentences in calculations .
• The borderline by which the correlation
between the percentage of too long
sentences and text acquiring is maximal is
the sentence length for CLT reversal effect
Method
• 37 students 17-18 years old interested in
depth study of chemistry.
• 30 texts from popular-scientific books. The
average length of the texts was 170 words.
• Every student filled in the blanks in every
text (cloze procedure).
• The coefficients of correlation between the
cloze test results and the percentage of text
in long sentences was calculated.
Results
Long sentences boundary
line
in characters with spaces
Coefficient of linear
correlation
with cloze test results
120
0.42
130
0.52
140
0.55
150
0.49
160
0.46
170
0.45
Figure 7.4. The dividing line between the short and oversized sentences plotted
against the correlation between the percentage of oversized sentences and the
results of the content test. 124 students from 7th, 8th and 10th grade.
0,75
0,7
Correlation
0,65
0,6
0,55
0,5
0,45
0,4
0,35
20
40
60
80
100
120
140
Dividing line
160
180
200
220
Number of unknown words
per hour
Figure 7.2. Relationship between the percentage of unknown words in a text and
the number of unknown words read in an hour (Kondrateva, 1974).
40
35
30
25
20
15
10
5
0
0
1
2
3
4
5
6
7
8
9
Percentage of unknown words in the text
10
11
Optimality criteria I
Grade
3.
4.
5.
6.
7.
8.
9.
Sentence
length
Abstractness
Complicacy
7
8
9
10
11
12
13
1,0
1,1
1,1
1,2
1,2
1,3
1,3
11
13
14
15
16
17
18
Optimality criteria II
• One new concept in an hour
• In foreign language, 5new words for active acquering
in an hour.
• 3,6 % of new words in foreign language text for
independent reading
• Up to 3 (5) words between connected words
• Every new for students idea in a separate sentence
• New words should be repeated 7 times in the
textbook.
• Up to 3 operations in physics tasks.
Students are very different!
• In PISA 2009 reading test, one fifth of Estonian
schools achieved 530 points or more and one
fifth of Estonian schools below 470 points. The
difference 60 points corresponds to one and
half year in students’ development.
• Individual differences of students are larger.
• On the next slide, we see the average results
and SD of a verbal test carried out with 2. – 8.
grade students in Estonia.
2. grade
Number of students
3.
0
4.
5.
7.
6.
5
10
8.
15
Number of words written in a minute
20
Different textbooks are needed
•
•
•
•
Textbooks on different level of difficulty
Textbooks with tasks on different level
Textbooks with different content
Additional materials in internet