Systemic-Structural Theory of Activity and Design
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Design is the creation of a models of artificial object in
accordance with some requirements and characteristics
with the purpose of materialization of these objects.
The notion of model and the descriptive language
employed for a model are critical for design. The whole
process of design can therefore be conceptualized as
translating one descriptive language into another.
Symbolic models are major models of design process.
Systemic-Structural Theory of Activity with carefully
developed units of analysis can be considered as a
theoretical foundation of psychological aspects of design.
Systemic-Structural Theory of Activity and Design
The concept of psychological process without action
neglects concept of structure. As in physics, where light
has both particle and wave characteristics, we understood
cognition as a process and as a system of actions or other
functional information processing units
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In our discussions we’ll bring your attention first of all to
morphological analysis and description of activity. The
morphological description of activity entails the description
of the structure of activity in which major units of analysis
are actions and their components are called operations.
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In contrast to concept of process that emphasizes what happens
strictly in psychological domain, the concept of action connects
theory to the practical domain.
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Concepts of activity and actions always assume
existence of objects as material or idealized
phenomena and processes. We understand a
process as a sequence of changes of the objects and
connected with it changes in cognitive processes
and structure of activity.
Operative units of activity are information entities
that are simultaneously perceived, actualized,
manipulated or memorized. It is material for
cognitive actions.
Classification of actions
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There are direct connection actions and
transformational actions. Direct connection mental
actions proceed without distinct differentiated
steps and require less attention. They are less
conscious and subjectively are experienced as
instantaneous. For example, recognition of a
familiar object may be seen as this kind of action.
Transformational mental actions involve more
deliberate examination and analysis of stimulus as,
for example, the perception of an unfamiliar object
in a dimly lit environment.
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Mental or cognitive actions can be classified
according to dominating psychological process.
1. The first group of actions are those of direct
connections;
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1. 1. Sensory actions are enabling detection of signal
from noise or require a decision about the signal at
the threshold level. These actions enable us to detect
objects from their background noise, obtain
information about distinct features of objects such as
color, shape, sound, etc.
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1. 2. Simultaneous perceptual actions are implicated
in the identification of clearly distinguished stimuli that
are well known to operator and are only called upon
immediate recognition. Perceptual actions enable us
to perceive whole qualities of objects or events - as
for example in the recognition of a familiar picture.
1. 3. Mnemonic (memory) actions are composed of
memory processes such as memorization of units of
information, recollection of names and events, etc.
Direct connection, mnemonic actions include
involuntary memorization without significant mental
effort.
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1. 4. We can also isolate imaginative action as for
example in mentally rotating the visual image of an
object from one position to another according to a
goal. This action involves manipulation of images
based on perceptual processes and simple memory
operations.
1. 5. Decision-making actions are actions at a
sensory-perceptual level that are involved in an
operator’s decision on sensory data.
2. 1 Reproductive transformational actions
2. 1. 1. Successive perceptual actions are involved in the
interpretation of information from unfamiliar stimuli and
require the creation of a perceptual image that is developed
during perception of external objects that are novel and
require more deliberate examination and analysis of stimuli.
During skill acquisition, one may observe the transition from
successive transformational action to simultaneous direct
connection perceptual actions.
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2. 1. 2. If after receiving information, the operator must
determine what steps are needed next, based on a logical
analysis of the situation this is a decision-making action at a
verbal thinking level.
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2. 1. 3. Recording actions are enabling an operator to
transform from one kind of information to another. For
example, transformation of meaningful verbal expression
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from one language to another.
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2. 2. Higher-order transformational
actions involved in thinking processes
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2. 2. 1. Categorization actions include information
processing resulting in the division of some signals
into a series of separate subjects or classes.
2. 2. 2. Deductive actions refer to the application of
general rules to draw novel conclusions from
existing data. (Many mathematic task-solveings
are related to deductive actions)
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2. 2. 3. Mnemonic actions entail complex manipulation of information
in working memory, extracting information from long-term memory,
storage of requisite information and maintaining information in working
memory.
3. Creative actions
These include psychological acts or operations that generate new
knowledge from old knowledge in a logical and/or intuitive way.
Creative actions are fundamentally different from reproductive actions
insofar as reproductive actions are connected with convergent
thinking. Creative actions are productive actions that implicate
divergent thinking. These actions are not further broken down within
the Theory of Activity. Creative-imaginative actions that are
empowering combinations of logical and intuitive operations on
images are examples of creative actions.
Classification of actions based on the nature of tools
employed for actions.
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1) object-practical action that are performed with real
objects;
2) object-mental action that are performed mentally with
images of objects;
3) sign-practical action performed with real signs such as
receiving symbolic information from different devices as
well as the transformation of them;
4) sign-mental action are performed mentally by
manipulating symbols.
Criteria for
Classification
Specific Nature of
Object of Action
Real
Object
ObjectPractical
Action
Sign
(Sign System)
ObjectMental
Action
Method of Action
Performance
Practical
Performance
SignPractical
Action
Mental
Performance
Sign-Mental
Action
Motor actions
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Actions, performed by an individual through his skeletonmuscular system, that can change the state of objects in
the external world are called object-practical-actions or
simply “motor actions” or “object-actions”. These actions
include distinct motions that are motor operations. Verbal
actions are a particular class of motor actions that include
motor components
Standardized motor action is a complex of standardized
motions, performed by the body, unified by a single goal
and a constant set of objects and work tools. Under
standardized motion we understand a single motion of
body, leg, hand, wrist and fingers that has different
purposes in work processes and correspond to rules of
standardized description. For example, “move arm and
grasp lever” is considered a standardized motor action that
is comprised of two standardized motions, “move arm” and
“grasp”.
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When deploying MTM-I for Activity Theory we do not build
up holistic activity out of the elements. Rather, holistic
activity is the point of departure for analysis of the
separate elements of activity into sequential decomposition
of activity. If required by feedback, we can re-visit the
holistic activity implying that analysis of design of
performance has a recursive, loop structure.
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Any motor action includes within itself cognitive
components: a) The programming block (i.e., the block of
motor instructions); b) executive block (i.e.,
implementation of motion); c) evaluative block (i.e.
corrections). The first and third function blocks of motion
are cognitive in nature, whereas the second block is motor
in nature.
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The purpose of these micro-shiftings are not execution or
implementation of motion, but rather they play a cognitive role of
exploring the space of movement. The micro-motions are not
conscious to the subject. They perform cognitive functions. This is an
evidence that external behavior and internal cognitive activity are
interdependent. Therefore, the Theory of Activity posits the principle
of “unity of consciousness and behavior” or “unity of cognition and
behavior” in general.
Verbal action is another category of actions that within ergonomics is
addressed in terms of communicative functions. According to Activity
Theory, speech also performs regulative function in human behavior.
Speech is treated as a system of verbal actions.
Verbal actions may either be the minimal verbal expression that a
subject voluntarily expresses for the transmission of meaningful
information aligned with the desired goal, or as the minimal expression
of the verbal actions corresponding to real actions.
The task “Check Spelling”
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1. Reach and grasp mouse with the right hand.
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2. Move the pointer to the initial position preceding misspelled
word and press it with the index finger.
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3. Highlight the required word by moving the pointer and
dragging it from the beginning of the word to the end, release
the mouse button.
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4. Move the pointer to the spelling icon, press the button with
the index finger, then release it.
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5. Examine the list in the drop down menu.
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6. Select the appropriate item.
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7. Move the pointer to the desired spelling option, then press
the button with the index finger.
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8. Hit the OK button, then release it.
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When a subject performs the first action, the mouse is the object to be
engaged by the subject. When the subject performs the second action,
the mouse becomes a tool through which the subject implements the
movement of the pointer to the start position. When the subject
performs the third action, tools become more complicated. It includes
both the mouse and the pointer as the word to be replaceed assumes
the role of the object.
The actions can be described in terms of typical elements of a task
(technological units) or in terms of typical elements of an activity in
psychological units.
Example: 1. Reach and grasp mouse with right hand. This is
description of action by using technological units of analysis.
R30A + G1A is description of the same action by using psychological
units of analysis.
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1. “Reach and grasp mouse with right
hand” is object practical action.
5.”Examine the list in the drop down
menu.” and 6. “Select the appropriate
item”. are sign practical action.
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Action 5 is simultaneous perceptual
action. Action 6 is decision making
action at verbal thinking level ( Select
the appropriate item).
Qualitative Stage of analysis.
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This stage of analysis includes broad number of methods. They can be
classified according to different criteria.
Parametric method of study - allows concentration on distinct aspects
of activity.
Functional analysis – it is systemic method of study. This method
considered activity as self – regulative system. Major unit of analysis is
functional mechanism or functional block.
Objectively logical analysis – integrates broad number of methods
including verbal and graphical description of task, description of
technological processes, tools, equipment, conditions of work etc.
Socio – cultural methods of study pay attention to social context under
which task is performed.
Individual – psychological methods – personal requirements for job
performance, individual features of personality, training, individual
style of activity performance etc. are related to this category.
Algorithmic analysis
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Morphological analysis refers to the division of activity into
actions and operations, algorithmic descriptions of activity,
developing time structure of activity.
It consists of the subdivision of activity into qualitatively
distinct psychological units and determination of the logic
of their organization and sequence. These units are
formulated as elements of activity with a specific logical
structure.
Typically, such elements, called members of an algorithm,
are made of actions with their associated sub-goals,
integrated through supervening goals. Due to limits on the
capacity of working memory, each member of an algorithm
is limited to between one to three actions.
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As units of activity, the members of algorithms are termed
‘operators’ and ‘logical conditions’.
Operators consist of actions that transform objects, energy
and information. For example, operators that are
implicated in receiving information, analyzing a situation
and comprehending it, performing such executive activity
as shifting of gears, levers, etc. can be described as
efferent operators.
Logical conditions are members of the algorithm that
determine logic of selection and realization of different
members of an algorithm, and include a decision-making
process.
Human algorithms are the algorithms that are defined by
associated units of analysis made up of human actions.
Actions as units of analysis constitute the distinctive
features of human algorithm in flow-charts widely used to
represent human performance.
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The tabular form of an algorithm is read top to bottom.
The left column with symbolic description is called the
formula of algorithm, and is presented in a vertical
orientation. In some cases, a formula for the algorithm
may be presented separately as a horizontal line of
symbols (we do not use this method of symbolic
presentation of algorithm at present time).
Following the development of the algorithm, experts then
perform psychological analysis of the algorithm, returning
to a qualitative stage of analysis. Each member of an
algorithm can be evaluated as a whole from qualitative and
quantitative points of view.
SYMBOLIC DESCRIPTION OF HUMAN ALGORITHM
All operators involved in reception of information are
categorized as afferent operators and are designated with the
superscript a, as in “0 a“.
If the operator is involved in extracting information from longterm memory, the symbol m is used as in 0m. The symbol 0 m w
is associated with keeping information in working memory.
The symbol 0 e is associated with the executive components
of activity, such as the movement of a gear. Operators with
the symbol 0e are efferent operators.
In deterministic algorithms, the logical conditions designated
with “l” have two values, zero or one. Logical condition in this
case has two outputs with probabilities of occurrence 0.5. In
such a case the logical condition can be designated as l1 1
which possesses two potential values.
SYMBOLIC DESCRIPTION OF HUMAN ALGORITHM
In some cases logical conditions can be a combination of simpler
ones. These simple logical conditions are connected through
“and,” “or,” “if-then,” etc. rules. Complex logical conditions are
designated by a capital “L,” while simple logical conditions are
designated by a small “l”.
In a probabilistic algorithm, logical conditions may have two or
more outputs with a probability between zero and one.
Suppose algorithm has logical condition with three outputs with
distinct probabilities of occurrence. In such a case the logical
condition can be designated as L1 1 (1-3) which possesses not two
potential values, but three. In this case there are three versions of
output  1 (1),  1(2),  1 (3) with different probability. For example the
first output has the probability 0.2, the second 0.3 and the third
0.5.
SYMBOLIC DESCRIPTION OF HUMAN ALGORITHM
Frequently in algorithmic description, an always-false logical
condition is used, which is defined by the symbol . This
logical condition is introduced only to make it easier to write
the algorithm.
The symbols “l” or “L” for logical conditions in the left column
include an associated arrow, numbered with a superscript, such
as 2. An arrow with the same number, but a reversed position
must be presented in front of another member of the algorithm
to which the arrow makes reference, 2. An upward pointing of a
logical state of simple logical conditions, “l” when, “l” = 1,
requires skipping the following members of the algorithm until
the next appearance of the superscripted number with a
downward arrow (e.g. 11).
Practical example
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An inventory-receiving task was selected as an object of study. Any
inventory process may be presented in terms of three subsystems:
1) stocking; 2) record keeping; 3) work-in-process.
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The first subsystem refers to the physical movement of items into
(In) and out (Out) of stock generating a physical quantity of items
on hand. “In” increases stock and “Out” decreases stock.
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The second sub-system, “work-in-process” (WIP) is a value adding
manufacturing process in which diverse raw materials or
intermediate products are transformed into ready product.
The third sub-system is the record keeping process, that is a
complex computerized system that must track all physical
movements of parts, purchases, intermediate production, etc.
The current study pertains to the first task, called “Inventory
receiving task” which entails the reception of parts from different
vendors to re-stock the warehouse. However, this task should be
studied in connection with other tasks because they are
interdependent. Figure 7 demonstrates the sequence of tasks
before improvement.
Out
In
Receiving
Putting
away
Pick up
Delivery to
workshop
Production
process
“Receiving” Task
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Description of the task in question.
The receiver opens the box from the vendor and
reads a packing slip. Then the receiver uses a
computerized management system. He enters PO
(purchase order) number listed on a packing slip
and hits an F8 key to check what is still open on the
PO. The receiver takes the parts out of the box and
compares the order quantity with received quantity.
He enters the sequence number of the item on the
PO, then changes or confirms the quantity and the
price. He assigns allocation if necessary. If
allocation is already reserved for the item, the
system will select it automatically. All required
information is exhibited on the screen. Later this
information is printed on the label. As many other
tasks that include use of computer, this task is
subject to many variations and therefore not readily
describable.
Oa33
12
l 12
Oe34
Oa35
13 (1-3)
l 13 
13 (1)
 1 Oe36
1 1
13 (2)

2
Oe36
2 2
13 (3)
 2Oe36
3 3
12
 Oa37
Look at the screen message. (see fig. 2)
If screen displays a message, “work-in-process (Y/N)” and the answer
is ‘Y’ go to Oe34, otherwise, go to Oe37
Type ‘Y’, hit “enter” to print out a label, and put label on the part.
Look at the label to determine which department within the plant the
item will be shipped to.
If it goes to department 1, go to 1Oe36, if it goes to department 2, go to
e
e
2O 36, otherwise, go to 3O 36.
Put the part in box 1.
Always falls logical condition (see Oa28 ).
Put the part in box 2.
Always falls logical condition (see Oa28 ).
Put the part in box 3.
Always falls logical condition (see Oa28 ).
Check if there is a bin for this item.
***
O27 a th
9
l 9
O28th m
Compare new price with ordered price.
If new price is smaller, go to 1Oe31. If new price is greater go
to O
28
th m
Mentally calculate the price difference.
TASK
Please recreate the figure
below in the dotted area on the
right. Please do not use cut
copy and paste
2a
2b
Functional Analysis
In this experiments it was clearly defined that in spite of same instruction
presented in figure 1 different subjects developed their own subjectively
accepted goal, and this significantly influenced the strategies of
performance and the obtained results.
The difference is not significant for the subjects as reported by them in the
retrospective analysis. However, according to instruction this is error
produced by goal formation and goal acceptance processes.
These errors in task performance are derived from orientational
components of activity but not from executive components of task. These
mistakes are therefore attributed to the goal formation stage.
Morphological Analysis (2
nd
stage –algorithmic description)
The algorithm was derived from eye movement registration data, retrospective
protocol and the observation and expert analysis of the video.
This stage of analysis demonstrates the structure of activity. The major
units of analysis taken into considerations are the actions and operations
integrated in the member of algorithm.
Morphological Analysis –Stage 3
Development of the
Time Structure
The time structure analysis shown in figure 3
demonstrates how activity unfolds in time and
how these different substructures of activity
logically interrelated in time.
Knowledge about time structure of human
computer interaction task can provide insight in
to the complexity of the various subtasks that a
subject has to perform.
The nature of the time structure helps to depict
the ease of use of the software and thereby
gives a fair measure of the usability of the
particular task. The complexity measures as
mentioned previously in time structure analysis
can be developed through the proportion of
time used for actions and operations or
adjustment for the analysis of interaction.
Regular tasks for software or equipment
can then be standardized and simplified
according to the nature of interaction.