Transcript Kognitive Architekturen - ACT-R

State of ACT-R Research
Agenda:
Most
of the
Time
1. Review the ACT-R 5.0/6.0 architecture.
2. Illustrate its application to two experiments on
learning to solve equations -- one with children
and with adults.
3. Show how fMRI data provide converging data for
architectural assumptions.
4. Show off nearly parameter-free predictions.
5. Discuss future goals.
ACT-R versus ACT*
1. Common: Cognition has declarative & procedural systems.
2. Common: Each system has subsymbolic & symbolic aspects.
3. ACT-R 2.0: Rational analysis guiding the subsymbolic level.
4. ACT-R 4.0: Central cognition integrated with perceptual-motor.
5. ACT-R 4.0/5.0: Different types of learning that really work.
Declarative
Symbolic
Passive
recording
of the
Knowledge
Level Learning:
contents
of various
buffersas
Module products
recorded
aschunks
chunks
whichoncache
-- focus
instruction
results
for the future
and examples
Subsymboli c Chunk activations are
estimated by a Baye sian
algorithm reflect likelihood
that a chunk will be needed.
Procedural
Production compilation
Collapses production rules
into single rules that leads to
specialization of methods
Production utilities are
estimated by a reinforcement
learning to estimate expected
payoff of various rules
6. ACT-R 5.0: has biologically-inspired module and buffer structure.
7. ACT-R 6.0: Use of this structure to foster cumulative science.
ACT-R 5.0/6.0 Modules and Buffers
Type
x=4
Manual
Control
Retrieve Declarative
7+5=12
Memory
ACT-R
Production
System
Control
State
Parse
Visual
Perception 3x-5=7
Problem
State
“Unwinding”
“Retrieving”
Hold
3x=12
The First Experiment
Qin, Anderson, Silk, Stenger, & Carter (2004)
1. 11-14 year-olds just about to start Algebra 1
2. Day 0: Instruction, paper & pencil practice, coaching
3. Days 1 - 5: Computer-based practice
Example of eq uat ions:
st ep
equati on
0 st ep
1x + 0 =
1 st ep
3x + 0 =
1x + 9 =
2 st ep
6x + 5 =
03
12
12
23
4.Student types answer by pressing finger in data glove.
5. Imaged in fMRI scanner on Day 1 and 5.
Unwind Instructions that ACT-R Parses into
an Internal Declarative Representation
1.
2.
3.
4.
To solve an equation, encode it and
a. If the right side is a number then image that number as the result and then
focus on the left side and unwind it.
b. If the left side is a number then ..
To unwind
a. If the expression is the variable then the result is the answer.
b. If a number is on the right unwind-right
c. If a number is on the left unwind-left
To unwind-right, encode the expression and
a. If the expression is _ + 0 then focus on the left part and unwind
b. Otherwise invert the operator, image it as the operator in the result, image the
right part of the expression as the second argument in the result, evaluate the
result, and then focus on the left part and unwind
To unwind-left encode the expression and
a. If the expression is 1 * _ then focus on the right part and unwind
b. Otherwise check that the operator is symmetric, invert the operator, image it
as the operator in the result, …
ACT-R’s General Procedures for Interpreting
and Following Declarative Representations of
Procedures applied to 7x + 3 =38
Instruction 1a: Create image “=38”
Instruction 2b: Unwind-right 7*x+3
Instruction 3b: Change image to “=38-3”, this to “=35”,
and focus on 7*x
Instruction 2c: Unwind-left 7*x
Instruction 4b: Change image to “=35/7”, this to “=5”,
and focus on x
Instruction 2a: The answer is 5, key it.
1. Initially instructions are retrieved and interpreted.
2. Eventually production compilation produces taskspecific production rules.
Examples of Production Rules
General Interpretive
If one has retrieved an instruction for achieving a goal
THEN retrieve the first step of that instruction
Prior Knowledge
IF one is evaluating the expression “a operator b”
THEN try to retrieve a fact of the form “a operator b = ?”
Acquired Task-Specific
IF the goal is to unwind an expression
and the expression is of the form “subexpression + 0”
THEN focus on the subexpression
ACT-R Modules: The first 2+ Seconds: 7x+3=38
(a) Day 1
Time
Visual
0.00
Production
Retrieval
(b) Day 5
Goal
Imaginal
Manual
Visual
Instruction
Production
Encode
Image-Right
Encode
Equation
"Exp = 38"
Focus Left
0.50
0.75
Goal
Image-Right
Solving
Unw ind
Unw inding
Encode
Equation
"Exp = 38"
Solving
Parallel module activity,
limited by long encoding
Unw ind
Unw inding
Focus Left
= 38
Encode Lef t
Side
"Exp + 3"
Encode
Test f or Skip
Unw ind
Ex + 3 = 38
Evaluate
Instruction
Unw ind
Encode
Test f or Skip
Ex + 3 = 38
Don't Skip
1.25
Retrieving
Production
Compilation
= 38 - 3
Unw ind
Convert Plus
Image Op
Inserting
Image Op
Image Arg
1.50
= 38
Encode Lef t
Side
"Exp + 3"
Instruction
1.00
Imaginal
Encode
Encode
0.25
Retrieval
Exp + 3 = 38 -
Image Arg
Evaluate
= 38 - 3
Production
Compilation
8-3=5
Evaluate
Retrieving
1.75
Retrieve Fact
2.00
2.25
8-3=5
Retrieval
Speed up
Focus Left
Continuing
Unw ind
Unw inding
Focus Left
Encode Lef t
Side
"5 * X"
= 35
Manual
ACT-R Modules: The middle 2+ Seconds: 7x+3=38
Day 1
Time
Visual
Production
Retrieval
Day 5
Goal
Imaginal
Manual
Visual
Production
Retrieval
Goal
Imaginal
Manual
2.25
Encode
Test f or Skip
2.50
Evaluate
8-3=5
2.75
Retrieving
3.25
Focus Left
Continuing
Unw ind
Unw inding
= 35
35 / 7 = 5
Encode Lef t
Side
"5 * X"
Instruction
Unw ind
Retrieve Fact
Instruction
Focus Right
Continuing
Unw ind
Unw inding
Unw ind
3.50
Encode
=5
Focus Right
Test f or Skip
7 * x = 35
Encode Right
Side
"X"
Don't Skip
Unw ind
3.75
= 35 / 7
Retrieve Fact
Focus Left
3.00
7 * x = 35
Symmetric
Invert Op
Convert Times
Press Key
Image Op
Inserting
Done
Image Op
Image Arg
4.00
7*x = 35 /
Image Arg
Evaluate
4.25
Retrieving
35 / 7 = 5
4.50
= 35 / 7
Evaluate
Press Key
ACT-R Modules: The last 2+ Seconds: 7x+3=38
Day 1
Time
Visual
Production
Retrieval
Day 5
Goal
Imaginal
Manual
4.50
35 / 7 = 5
4.75
5.00
5.25
Retrieve Fact
Focus Right
Continuing
Unw ind
Unw inding
= 35
Focus Right
5.50
5.75
Encode Right
Side
"X"
Instruction
Test Var
Press Key
Done
6.00
6.25
Press Key
Visual
Production
Retrieval
Goal
Imaginal
Manual
Learning over 6 Days of Experiment
8000
Time to Solve (msec.)
7000
6000
5000
4000
3000
2000
0 Step: Data
O Step: Theory
1000
1 Step: Data
1 Step: Theory
2 Step: Data
2 Step: Theory
0
0
1
2
3
Days
4
5
Comments on the ACT-R Model
1. Virtue: It actually does the task -- interacts with same
software as subjects.
2. Virtue: The model is not hand crafted but learns from
instruction (albeit the instructions are a little hand-crafted to
facilitate parsing).
3. Fact: Two parameters were estimated to fit the latency data
-- the latency scale for retrieval and the visual encoding
time.
4. Doubt: There is an great deal of theoretical complexity for a
rather simple set of numbers.
5. Resolution: We will use brain imaging to test for distinct
patterns predicted by different modules in the model.
ACT-R Modules and Buffers
Type
x=4
Manual
Motor
Control
Cortex
Retrieve Declarative
Prefrontal
7+5=12
Memory
Cortex
ACT-R
Production
Basal
System
Ganglia
Control
Anterior
State
Cingulate
Parse
Visual
Fusiform
3x-5=7
Perception
Gyrus
Problem
Parietal
State
Cortex
“Unwinding”
“Retrieving”
Hold
3x=12
Our Modules (all left lateralized)
as 100 (5x5x4) Voxel Regions
Motor/Manual: BA 3/4
(x = -37, y = -25, z = 47)
Prefrontal/Retrieval: BA 45/46
(x = -40, y = 21, z = 21)
Parietal/Imaginal: BA 39/40
(x = -23, y = -64, z = 34)
Our Modules (all left lateralized)
as 100 (5x5x4) Voxel Regions
Ant Cing/Goal:BA 24/32
(x = -5, y = 10, z = 38)
Caudate/Procedural: (x = -5, y
= 9, z = 2) Actually 4 x 4 x 4
21.6 Second Structure of fMRI Trial
Prompt
Equation
ITI
+
3x+2=17
*
1.2 s
1 scan
12 s
10 scans
8.4 s
7 scans
Mapping Module Activity onto
the BOLD Response
0.8
fMRI Response to Events
0.7
First
0.6
Second
Third
Activation
Activation
0.5
Total
0.4
0.3
0.2
Module
Activity
0.1
0
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21
Time (sec.)
1 .0 0
0 .9 0
Proportion Engaged
0 .8 0
0 .7 0
Procedural
Retrieval
Goal
Imaginal
Manual
Day 1: f(t)
2 steps
0 .6 0
0 .5 0
0 .4 0
0 .3 0
0 .2 0
0 .1 0
0 .0 0
0 .0
1 .0 0
Proportion Engagement
0 .9 0
0 .8 0
0 .7 0
1 .0
2 .0
Day 5: f(t)
2 steps
3 .0
4 .0
5 .0
6 .0
Time during Trial (Sec.)
7 .0
8 .0
Procedural
Retrieval
Goal
Imaginal
Manual
0 .6 0
0 .5 0
0 .4 0
0 .3 0
0 .2 0
0 .1 0
0 .0 0
0 .0
1 .0
2 .0
3 .0
4 .0
5 .0
Time during Trial (sec.)
6 .0
7 .0
8 .0
t

BOLD
Function
Proportion of Maximum
CB(t) 
f (x)B(t  x)dx
1 .0 0
0 .9 0
0 .8 0
0 .7 0
s =1.5, a =3
s=3, a = 3
s=0.75,a=6
s=1.5, a =6
0.8
0.6
0.4
0.2
0.0
0
Proportion Engagement

Predicted
BOLD Response
1.0
0
5
Module Demand
Day 5: f(t) Function
2 steps
10
15
Time
20
25
30
Procedural
Retrieval
Goal
Imaginal
Manual
0 .6 0
0 .5 0
0 .4 0
0 .3 0
0 .2 0
0 .1 0
0 .0 0
0 .0
1 .0
2 .0
3 .0
4 .0
5 .0
Time during Trial (sec.)
6 .0
7 .0
8 .0
Density
0.6
1 2
Distribution of
Responses
0.4
0.2
0
0
3
6
9
12
Time (sec)
15
18
Motor/Manual: BA 3/4
(x = -37, y = -25, z = 47)
21
0
1
2
0
1
2
Motor: r = .975
0.3
Operation
Operation
Operation
Operation
Operation
Operation
Response
Delay
0.2
0.1
0.0
0
-0.1
0.4
Percent Change in Bold
Response
0
0.8
Percent Change in Bold
Response
0.4
1
3
6
9
12
15
18
21
Day
Day
Day
Day
Time During Trial (Sec.)
Motor: r = .972
0.3
1
5
1
5
0.2
0.1
0.0
0
3
6
9
12
15
-0.1
Time during Trial (sec.)
18
21
Percent Change in Bold
Response
0.4
Prefrontal/Retrieval: BA 45/46
(x = -40, y = 21, z = 21)
0.3
Operation
Operation
Operation
Operation
Operation
Operation
0.2
0.1
0.0
0
-0.1
0.4
Percent Change in Bold
Response
0
1
2
0
1
2
Prefrontal: r = .963
3
6
9
12
Almost no Effect
15
18
Day
Day
Day
Day
Prefrontal: r = Time
.935 During Trial (Sec.)
0.3
21
1
5
1
5
0.2
0.1
0.0
0
3
6
9
12
15
-0.1
Time during Trial (sec.)
18
21
0
1
2
0
1
2
Anterior Cingulate:
r = .981
0.3
Operation
Operation
Operation
Operation
Operation
Operation
0.2
0.1
0.0
0
-0.1
0.4
Percent Change in Bold
Response
Ant Cing/Goal:BA 24/32
(x = -5, y = 10, z = 38)
Percent Change in Bold
Response
0.4
3
6
9
12
15
18
21
Day
Day
Day
Day
Time rDuring
Anterior Cingulate:
= .982Trial (Sec.)
0.3
1
5
1
5
Almost no
Learning
0.2
0.1
0.0
0
3
6
9
12
15
-0.1
Time during Trial (sec.)
18
21
0.4
0.3
Operation
Operation
Operation
Operation
Operation
Operation
0.2
0.1
0.0
0
-0.1
0.4
Percent Change in Bold
Response
Parietal/Imaginal: BA 39/40
(x = -23, y = -64, z = 34)
Percent Change in Bold
Response
Rather directly
reflects time because
of skipping steps in
equation
representation
0
1
2
0
1
2
Parietal: r = .969
3
6
9
12
15
18
Day
Day
Day
Day
Time During Trial (Sec.)
Parietal: r = .955
0.3
21
1
5
1
5
0.2
0.1
0.0
0
3
6
9
12
15
-0.1
Time during Trial (sec.)
18
21
Rather directly
reflects time because
of production rule
collapsing
Percent Change in Bold
Response
0.4
Operation
Operation
Operation
Operation
Operation
Operation
0.2
0.1
0.0
0
3
6
9
12
15
18
Time During Trial (Sec.)
Caudate: r = .973
Day
Day
Day
Day
0.3
21
1
5
1
5
0.2
0.1
0.0
0
Caudate/Procedural:
(x = -5, y = 9, z = 2)
0
1
2
0
1
2
0.3
-0.1
0.4
Percent Change in Bold
Response
Caudate: r = .975
3
6
9
12
15
-0.1
Time during Trial (sec.)
18
21
c2 measures of Match between Regions and
Modules--small is good (<130 nonsignificant)
M anual
Retrieval
G oal
I maginal
P roc edural
M otor
8 8 .9 3
4 9 3 .2 2
2 5 5 .9 1
3 8 4 .6 6
3 4 7 .0 5
P refrontal
4 5 2 .0 5
8 2 .6 0
1 9 4 .9 4
1 2 5 .6 6
1 6 3 .7 6
C ingulate
7 2 4 .6 6
3 5 0 .3 2
1 2 3 .2 7
2 1 0 .4 7
2 8 6 .2 8
P arietal
4 2 6 .4 0
1 0 1 .8 8
1 7 1 .7 4
9 5 .2 1
1 1 4 .9 3
C audate
3 3 3 .8 9
1 3 3 .1 3
1 1 1 .0 1
1 0 1 .8 2
8 1 .0 3
Identical
Little
Operation Operation Operation
Response Response
Large
Medium
Medium
Different
in 0
Learning
Learning
Learning
Peaks
Operation
Weak
Medium
Medium
Observations about fMRI and Modeling
1. While the analysis has been about ACT-R fitting the learning of
algebra the same methods can be used to relate many different
information-processing theories to many tasks.
2. The unifying concept in all cases is that the BOLD response in a
region reflects time a module is engaged. This allows us to map
between an information-processing model and the BOLD response
and so to track individual components of the model.
3. The same prespecified areas behave as predicted in many adult
studies.
4. There is no claim one way or another about whether the modules
are implemented in these regions.
5. The critical fact is that we have a measure of the activity of
specific modules rather than just the overall behavior.
6. Challenge: Can we take this same model and fit it to another
experiment.
The Second Experiment-- Qin, Sohn, Anderson,
Stenger, Fissel, Goode, & Carter (2003)
Example of eq uat ions:
st ep
equati on
0 st ep
P <-> 4 5
1 st ep
2 st ep
1.
2.
3.
4.
answer
P <-> 4 5
P <-> 4 5 P <-> 4 5
P 4< -> 5 P <-> 5 4
Adults
Day 0: Instruction and general practice
Days 1 - 5: Computer-based practice
Subject types answer by pressing thumb and then
quickly keying 4 terms.
5. Scanned on Days 1 & 5.
18 Second Structure of fMRI Trial
Prior
Equation
Give
Answer
Px4<->5 1-3-5-3-4
1.5 Second Scans
Blank
Period
Instructions for ACT-R
1.
2.
3.
4.
5.
6.
To solve an equation, first find the “<->”, then encode the first pair that follows, then
shift attention to the next pair if there is one, then encode the second pair.
If this is a simple equation output it; otherwise process the left side.
To process the left side, first find the “P”.
If “<->” immediately follows then work on the operator that precedes the P;
otherwise first encode the pair that follows, then invert the operator, and then work
on the operator that precedes the P.
To process the operator that preceded the P, first retrieve the transformation
associated with that operator, then apply the transformation, and then output.
To output press 1, then output the first, then output the next, then output the next,
and then output the next
+ Knowledge of inverses (2-3, 4-5) and transformation rules for
getting rid of 2,3,4, & 5 prefixes.
(a) Day 1
Time
Visual
81.00
Production
Retrieval
(a) Day 5
Goal
Imaginal
Manual
Visual
Instruction
Production
Goal
First-Pair
Encode
Encode
Equation
"4 <-> 2 5"
First-Pair
Encode
Equation
"4 <-> 2 5"
Find Next
Second-Pair
Encoding
First Pair
81.50
Imaginal
Instruction
Find <->
81.25
Retrieval
Find-Next
Encoding
Find Next
"2 5"
"2 5"
Encode Null
Right
Second-Pair
81.75
Encode Null
Right
Encode
Test For <->
Encode
Equation
"2 P 3 4"
Right Done
Next?
82.00
Instruction
Process-left
Fail Test
Go On
Second Pair
Subgoal
Second-Pair
Instruction
82.25
Retrieving
Find P
"2 5 3 4"
Encode
Invert 3
Test For <->
82.50
Encode
Equation
"2 P 3 4"
Fail Test
82.75
Go On
Instruction
Second-Pair
Second Pair
Invert
83.00
Encoding
Invert1
Retrieving
Invert 3
83.25
"2 5 3 4"
ACT-R Modules: 2 P 3 4 <-> 2 5
Encoding
(a) Day 1
Time
Visual
Production
Retrieval
(a) Day 5
Goal
Imaginal
Manual
Visual
Production
Invert 3
86.75
Retrieval
Imaginal
Encoding
"2 5 2 4"
Invert 3
Invert2
Invert2
Focus-Lef t
Encoding
"2 5 2 4"
Subgoal
Focus-Lef t
Tranf orm1
Go On
87.00
Goal
Retrieving
Instruction
Test-Lef t
Test Lef t
2 Transf orm
Transf orm
Tranf orm1
Retrieving
87.25
Transf ormx
Output
Encoding
"3 5 3 4"
Output
87.50
87.75
2 Transf orm
88.00
ACT-R Modules: 2 P 3 4 <-> 2 5
Transforming
88.25
Transf orm2
Apply
Encoding
Transf orm3
88.50
Output
"3 5 3 4"
Day 1 or Day 5
Time
Visual
Production
Retrieval
Goal
Output
88.50
Imaginal
Manual
"3 5 3 4"
Output
Press-Key 1
Type
Output-First
88.75
ACT-R Modules:
2 P 3 4 <-> 2 5 89.00
Output
Second
Press Thumb
Output
Output-Next
Third
Press Middle
89.25
Output
Output-Next
Fourth
89.50
89.75
Press Little
Output
Output-Next
Fif th
Press Middle
90.00
Output
Done
90.25
Press Ring
Learning over 6 Days of Experiment
12
0 Step: Data
O Step: Theory
1 Step: Data
1 Step: Theory
2 Step: Data
2 Step: Theory
Time to Solve (sec.)
10
8
6
4
2
0
0
1
2
3
Days
4
5
Motor/Manual: BA 3/4
(x = -37, y = -25, z = 47)
0
1
2
0
1
2
Motor: r = .977
0.5
0.4
Operation
Operation
Operation
Operation
Operation
Operation
0.3
0.2
0.1
0.0
0
3
6
9
12
15
18
-0.1
0.6
Percent Change in BOLD
Response
As before, BOLD
response tracks
response timing
Percent Change in BOLD Response
0.6
Time During Trial (Sec.)
Motor: r = .979
Day
Day
Day
Day
0.5
1
5
1
5
0.4
0.3
0.2
0.1
0.0
0
3
6
9
12
-0.1
Time during Trial (sec.)
15
18
Percent Change in BOLD
Response
As before, large
effects of both
factors -- weak
response for 0
0.4
0
1
2
0
1
2
Prefrontal: r = .971
0.3
Operation
Operation
Operation
Operation
Operation
Operation
0.2
0.1
Prefrontal/Retrieval: BA 45/46
(x = -40, y = 21, z = 21)
0.0
0
Percent Change in BOLD
Response
-0.1
0.4
3
6
9
Almost no Effect
12
15
Prefrontal: r =Time
.978During Trial (Sec.)
18
Day
Day
Day
Day
0.3
1
5
1
5
0.2
0.1
0.0
0
3
6
9
12
-0.1
Time during Trial (sec.)
15
18
0
1
2
0
1
2
Cingulate: r = .984
0.3
Operation
Operation
Operation
Operation
Operation
Operation
0.2
0.1
0.0
0
3
-0.1
0.4
Percent Change in BOLD
Response
Ant Cing/Goal:BA 24/32
(x = -5, y = 10, z = 38)
Percent Change in BOLD
Response
As before, large
effect for
complexity, little
for learning
0.4
6
9
12
15
Time
Cingulate: r =
.981During Trial (Sec.)
0.3
18
Day
Day
Day
Day
1
5
1
5
Almost no
Learning
0.2
0.1
0.0
0
3
6
9
12
-0.1
Time during Trial (sec.)
15
18
0
1
2
0
1
2
Parietal: r = .983
0.5
0.4
Operation
Operation
Operation
Operation
Operation
Operation
0.3
0.2
0.1
0.0
-0.1
0.6
Percent Change in BOLD
Response
Parietal/Imaginal: BA 39/40
(x = -23, y = -64, z = 34)
Percent Change in BOLD
Response
Large effect
complexity,
learning largely
complete by Day 1
0.6
0
3
6
9
12
15
Time During Trial (Sec.)
Parietal: r = .987
18
Day
Day
Day
Day
0.5
1
5
1
5
0.4
0.3
0.2
0.1
0.0
0
3
6
9
12
-0.1
Time during Trial (sec.)
15
18
Very Weak
Response in this
Experiment -yielding poor
signal to noise
ratio.
Percent Change in BOLD Response
0.3
0
1
2
0
1
2
Caudate: r = .834
0.2
Operation
Operation
Operation
Operation
Operation
Operation
0.1
0.0
0
3
6
9
12
15
18
-0.1
Time During Trial (Sec.)
Percent Change in BOLD
Response
0.3
Caudate/Procedural:
(x = -5, y = 9, z = 2)
Day
Day
Day
Day
Caudate: r = .760
1
5
1
5
0.2
0.1
0.0
0
3
6
9
12
-0.1
Time during Trial (sec.)
15
18
c2 measures of Match between Regions and
Modules--small is good (<90 nonsignificant)
M anual
Retrieval
G oal
I maginal
P roc edural
M otor
7 0 .4 2
7 1 4 .1 0
1 9 7 .7 6
3 1 1 .6 7
3 3 6 .2 2
P refrontal
4 0 3 .1 1
4 6 .9 1
2 1 4 .9 3
2 0 0 .8 3
1 6 2 .8 0
C ingulate
2 0 9 .4 1
2 7 7 .6 3
4 8 .2 5
7 2 .1 3
9 7 .5 7
P arietal
6 9 5 .1 1
2 5 9 .4 0
1 3 1 .6 7
8 8 .8 6
8 0 .2 3
C audate
1 4 3 .8 3
6 9 .1 2
1 0 3 .8 2
9 0 .5 3
9 9 .5 6
Identical
Little
Operation Operation Poor Signal
Response Response
Large
Medium
to Noise
Different
in 0
Learning
Learning Weak Day 5
Peaks
Operation Near Zero
Weak
Response
Parameters Estimated and Fits to the Bold Response
Shape
Magnitude
t a (t / s)
B(t)  m  e
Time to Peak -- a x s


s
Larger Operations?
Motor Saturation?
Motor/
Prefrontal/
Parietal/
Cingulate/
Caudate/
Manual
Retrieval
Imaginal
Goal
Procedur al

Children
0.531
0.073
0.231
0.258
0.207
Adults
0.197
0.078
0.906
0.321
0.120
3
3
3
3
3
Children
1.241
1.545
1.645
1.590
1.230
Adults
1.360
1.299
1.825
1.269
1.153
Magn(m)
Exponent(a)
Scale(s)
10 Future Directions for ACT-R
Local
Science
Shared
Science
1. Increased stress on parameter-free predictions.
2. Increased effort to anchor the module structure of
ACT-R with brain correlations.
3. Focus on instruction -- starting our models from the
beginning.
4. Goal of producing a simulated student.
5. Focus on reasoning and metacognitive processing.
6. Continued effort at community support.
7. Greater emphasis on re-use of components/models
8. Including making knowledge basis available to
community -- for instance, a middle-school math
module.
9. Finally get concerned with representational
assumptions.
10. Facilitate exchange of components between
architectures.