Systemic-Structural Theory of Activity and Design

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.

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 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.

In contrast to concept of process that emphasizes what happens strictly in psychological domain, the concept of action connects theory to the practical domain.

Systemic-Structural Theory of Activity and Design

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

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.

Mental or cognitive actions can be classified according to dominating psychological process.

1. The first group of actions are those of direct connections;

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.

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.

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.

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.

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 from one language to another. 2. 2. Higher-order transformational

actions involved in thinking processes 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)

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.

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

Method of Action Performance

Practical Performance

Mental Performance

Sign (Sign System)

Real Object

Object-Practical Action

Object-Mental Action

Sign-Practical Action

Sign-Mental Action

Motor actions

Actions, performed by an individual through his skeleton-muscular 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”.

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. 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.

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”

1. Reach and grasp mouse with the right hand.

2. Move the pointer to the initial position preceding misspelled word and press it with the index finger.

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.

4. Move the pointer to the spelling icon, press the button with the index finger, then release it.

5. Examine the list in the drop down menu.

6. Select the appropriate item.

7. Move the pointer to the desired spelling option, then press the button with the index finger.

8. Hit the OK button, then release it.

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.

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.

Action 5 is simultaneous perceptual action. Action 6 is decision making action at verbal thinking level ( Select the appropriate item).

Qualitative Stage of analysis.

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

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.

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.

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.

All operators involved in reception of information are categorized as afferent operators and are designated with the superscript a, as in “0 “.

If the operator is involved in extracting information from long-term memory, the symbol m is used as in 0. The symbol 0 w is associated with keeping information in working memory.

The symbol 0 is associated with the executive components of activity, such as the movement of a gear. Operators with the symbol 0 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. 11).

SYMBOLIC DESCRIPTION OF HUMAN ALGORITHM

Practical example 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.

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.

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.

Receiving Puttingaway

Pick up Delivery to workshop

Production process

Out

In

 

“Receiving” Task

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.

 O

33 

 Look at the screen message. (see fig. 2)

12

l 12 

 If screen displays a message, “work-in-process (Y/N)” and the answer is ‘Y’ go to O

34, otherwise, go to O37

 O

34 

 Type ‘Y’, hit “enter” to print out a label, and put label on the part.

 O

35 

 Look at the label to determine which department within the plant the item will be shipped to.

13 (1-3)

l 13

 

 If it goes to department 1, go to 1O36, if it goes to department 2, go to

2O36, otherwise, go to 3O

36.

13 (1)

1 O36

 

 Put the part in box 1.

1 1

 Always falls logical condition (see O28 ).

13 (2)

2 O36

 

 

Put the part in box 2.

2 2 Always falls logical condition (see O28 ).

13 (3)

2O36

 

Put the part in box 3. 

3 3

 

  

Always falls logical condition (see O28 ).

 

12

O37

 

 

Check if there is a bin for this item.

*** O27

th

 

 Compare new price with ordered price.

9

l 9 

 If new price is smaller, go to 1O31.

If new price is greater go to

O28

th

 

O28th

 

 Mentally calculate the price difference.

Please recreate the figure below in the dotted area on the right. Please do not use cut copy and paste

2a 2b

TASK

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.

Functional Analysis

The algorithm was derived from eye movement registration data, retrospective protocol and the observation and expert analysis of the video.

Morphological Analysis (2nd stage –algorithmic description)

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 3Development 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.