manVvn~-TI

Research Note 85-93

INSIGHTS ON INFORMATION AB3SORPTION AND

TRANSMISSION RATES IN C I SETTINGS

Beverly G. Knapp and Carol A. Tolbert

for r*

Battlefield Information Systems Technical Area -k

SYSTEMS RESEARCH LABORATORY D[

Franklin L. Moses, Acting Director LE C

MAY 08 S6

Research Institute for th eavrmy adScalSine

C-,

September 1985

Approved for public release; distribution uflhitec.

86a 5 6 O7
~~~~~ d' Uclassif ied

CLASSIFICATION OF THIS PAGE (WP~mi Data Entered) %

REPORT DOCUMENTATION PAGE BEFORE COSMPLTIN FOR

~,v~ 4.PORT NUMBER 2 VTACSINO..RCIPIEIT'S CATALOG NUMBER -

ARI Research Note 85-93 ________________

S TI TL E (and Subtitle) 5.T.EOF REPORT PERIOD COVERED .

'~Insights on Information Absorption and FnlRpr

2 Spt.82 -Sept. 83

Transmission Rates in C I Settings 6. PERFORMING ORG. REPORT NUMBER

7. AUTHOR(&) S. CONTRACT OR GRANT NUMBER(&)

* Beverly G. Knapp and Carol A. Tolbert

9. PERFORMING ORGANIZATION NAME AND ADDRESS 10. PROGRAM ELEMENT. PROJECT. TASK ~ ."

* U.S. Ar-my Research Institute for the Behavioral AE&WR NTNMESd~

*and Social Sciences, 5001 Eisenhower Avenue, 2Q263743A793

* Alexandria, VA 22333-5600 ______________ .

It, CONTROLLING OFFICE NAME AND ADDRESS 12. REPORT DATE

U.S. Army Research Institute for the Behavioral September 1985

and Social Sciences, 5001 Eisenhower Avenue, 13. NUMBER OF PAGES 1W JA

Alexandria, VA 22333-5600 34

14. MONITORING AGENCY NAME & AODRESS(If different fromi Controlting Offtce) IS. SECURITY CLASS. (of this report)

Unclassified

15a. DECLASSI FICATION/ DOWNGRADING A...

SCHEDULE

IS. DISTRIBUTION STATEMENT (of this Report)

Approved for public release; distribution unlimited.

17. DISTRIBUTION STATEMENT (of the abstract entered In Block 20, It different from Report)

III. SUPPLEMENTARY NOTES

III. KEY WORDS (Continueaon reverse side it necessary mid tdentify by block number) 0

Information Processing Tiansmission Rates

Information Absorption C I Automation

Cognitive Load

Time Stress

MMI

20. AEST14ACT (Cmtthnm -m teasrue aid H necesearY a" identi fy by block number)

Recent advances in automatic data processing (ADP) greatly enhance the value w

of automated support to Army operations, yet this does not elim nate the .

importance of the human role in operations. As an example, in C I settings

soldiers transmit and receive messages via computer, and these computers

offer great potential for information transmission, storage, and computation,

but the high volumes of information involved must still be interpreted by "*. ~.*'

a person for them to be useful.

(over)

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SECURITY CLASSIFICATION OF THIS PAGE(Wha, Daga Entetod) . " . % 

.~~ft _ _l k Al-..

20. (continued) ". " "'' .

-In designing automated systems, it is therefore necessary to understand the """ """ "

user's needs and limitations. Systems developers have become more concerned -

with the amount and rate of incoming information which users can successfully

comprehend. This paper addresses these concerns as a response to specific

inquiries regarding the amount of incoming information which individuals can

assimilate during a soldier-machine interface. The research note shows that . -

the information absorption rate varies widely depending on factors internal e . -

and external to the individual involved. The impact of the amount and rate . *

of incoming information on user performance is outlined by integrating the

relevant psychological research literature on information processing, using - -.

a military application for the example.

Unclassified

ii SECURITY CLASSIFICATION OF THIS PAGE(When Data Entered)

--... . -. . . .. ..... - --.- - ..

'4W" 0- -1. ''
* *T~ ' lW" TIC 17' p..*s' .A 7ia.r.~-wrai,. -- rcrrtU. S. ARMY RESEARCH INSTITUTE

FOR THE BEHAVIORAL AND SOCIAL SCIENCES

A Field Operating Agency under the Jurisdiction of the

Deputy Chief of Staff for Personnel

W. DARRYL HENDERSON

*EDGAR M. JOHNSON COL, IN

*Technical Director Commranding

This reort has been cleared for release to the Defense Technical information Center IDTIC). ft has been given no~

other primay distribution and will be available to requstors only through DTIC or other reference services such

a the National Technical Information Service INTIS). The views. opinions, end/or findings contained in thi Ireor wre tho of the outhor(s) and should not be construed as an official Department of the Army position,

policy. or decision. uninsoe designated by other official documeontatlion.
EXECUTIVE SUMMARY

As the Army's information and data flow requirements become more complex

in areas such as all-source intelligence analysis, tactical fire control,

and maneuver control, it has become crucial to understand exactly the

user's needs and limitations. In designing automated systems, system

developers have become more concerned with the amount and rate of incoming

information which users can successfully comprehend. This research note

addresses those concerns as a response to specific inquiries regarding the

rate of incoming information which individuals can assimilate in a soldiermachine interface context. It is shown that the information absorption rate

varies widely depending on factors internal and external to the individual.

The impact of the amount and rate of incoming information on user performance

is outlined by integrating the relevant psychological research literature on

information processing using a military example application.

.Aocesionl For

NTIS CRAMI

DTIC TAB 03

Unannounced

Justificatioi . ... ..

By ................ .......... .......... .....

Dist. ibution I

Availability Codes

Avail and f or DIMt special

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*. . . .. . .• .. .*. . .. .... .. . . *p.. . . . ... . . . -. . .. . .. .. ..* . . . . . . . . . .. ... : ,: . , . .. . . . . .:..
%.1,,

INSIGHTS ON INFORMATION ABSORPTION AND

TRANSMISSION RATES IN C21 SETTINGS

Beverly G. Knapp & Carol A. Tolbert

Officer Smith is sitting at a control station in the tactical operations

center, Division X. Teletype messages regarding unit location, status, crews

and fire power are coming in at an average rate of two per minute. Consider

the following example:

Alpha report as of 221800 Jul

APB7187 93YCYDPB744733

Translates to: Alpha report as of 221800 Jul:

A-1-22V (known) is located at PB718793 avid has his basic

load of ammunition between 50-75%.

B-l-22V (known) is still located at the last reported

position and his basic load is in excess of 75%.

C-1-22C (known) is at the same location but his basic

load is between 50 and 75%.

D-1-22C (known) has changed his location to PB744733

and his basic load is greater than 75% (messages are decoded using a

matrix decoding scheme, from Corps Information Flow Study, 1978).

The soldier's task is to decode the incoming line of type and produce situation reports every four hours in a format appropriate to supply the commander

,'~~.;....... ; ............-........................... ....................................... ..... . . . -......... .... ,.'._.... .... - -'..... .. "" .... ""- "" * -- ."* ,-, . ,-- "* **"""."°*"* ", ' "* ""-" ," ""•"•" .- "--" S -' " .. ,. - .." : """'.. .:.."-' .,-
-.

with knowledge of those "critical things which allow him (or her) to influence

the battle in a timely, responsive manner" (Corps Information Flow Study,

1978).

A critical question is at once raised relating to the successful accom--

plishment of the task: is the rate of incoming messages too fast or too

slow for optimal performance and accomplishment of the stated mission?

The answer clearly depends on a variety of factors impinging on the soldier

as transmission occurs, information is decoded and processed, and reports

are prepared.

Factors Influencing Information Absorption

The types of factors affecting information absorption and processing

are best understood by conceptualizing the sample soldier's task as an

example of a typical information processing system, of which the soldier is one

component. Figure 1 portrays information flow from inception to output

in such a system:

- - Information Storage

oSensing: Informtion Action information rm. -- Processing Function Outut

R ivig and: (physical | Product - Input Receiving Decision communication)

(letype) (receipt of (decode message, (record message, (transmit

message) determine priority) update report sitrep)

matrix)

Figure 1. Typical Information Flow Functions in a

generic communication system

adapted from E.J. McCormick Human Factors Engineering New York,

McGraw-Hill, 1970. with permission.

2

-°. .

:'- '. :-': - .. '' ."".". :,•;- .-. . . -",". ... .-. ".. . .-.-. '.-"."'. ' " :..-.. """..- - "". . """" ." '""". - "'" ", "-
The time from input to output is always influenced by how the information

is handled along the line. Three categories of factors or variables are

important in this regard:

1. System factors

2. User factors

3. Task variability as influenced by I and 2.

System factors. System factors include the mechanical aspects of the input/

output devices, the physical layout of the control station, and generally how

the message is presenteA and is to be transmitted. Issues of interest are:

is the message presented verbally or symbolically, visually or auditorily

how is the message formatted or coded

how much control does the receiver have over the manner of message

display and rate of influx

. how discriminable is the message from other ambient and environmental

stimuli

is the hardware easy to work with (i.e., user acceptable)

* are reporting and/or updating requirements easy to work with and "

produce.

User factors. User factors involve the vast array of qualities that constitute the human link in the system. These include experience, training,

cognitive style, motivation, internal and external stressors, etc. Issues of

importance include:

3 *:~'-* .* *~'.*'..*..:...*
-LX - U 07 W- 16L- LN 

how extensive is the soldier's training and experience in working with

the message codes

. are there sufficient incentives to produce timely and accurate reports

. is the soldier fatigued, under personal stress, physically and/or

mentally alert.

Task factors. Task factors are those elements which define the nature of the

task itself. One of the most critical factors is the amount of incoming

information per unit of time. Research indicates that whether the task is

perceived as easy or difficult depends on this and other factors, such as

required physical exertion and amount of time available to complete the task

(Moray, 1982). When a large quantity of incoming information is presented on

the terminal display, whether it is presented simultaneously or sequentially

affects the user in different ways. If it is presented all at once, user

performance deteriorates due to the great volume of visual information (Regal

& Knapp, 1984).

If incoming information is presented sequentially, however, the nature of

the task is changed. For example, in the sample message transcription task,

effective performance may proceed indefinitely if the task were simply to

decode and post incoming data. However, this is almost never the case. As

certain messages will have a greater import than others, they will necessitate

other kinds of actions than mere postings. A decision-making process must

ensue, other actions must be taken and then succeeding messages become part of

a queue. This introduces an element of stress into the information flow

system. The soldier is no longer free to maintain the routine pace established, but must deal with priority items or other imposed demands. Thus, the

simple transcription task never exists in isolation, continuing indefinitely,

4
but is always subject to modification and interference due to the various user

and system factors (as per examples cited above) which continuously change its

nature.

Considering the effects of the interplay of user and system factors on

the information flow process, the rate at which information is absorbed will

then be dependent upon what factors are operating at any given time. To

illustrate this system, figure 2 represents a modification of the information

flow process cited in figure 1, by including the influence of impinging user/

system factors in a time-based model.

Note the time line on the left and the user/system factors on the right.

This portrayal demonstrates that the time from t (input of message) to time

t (transmission of sitrep) is roughly 30 seconds (hypothetical estimation for

the purposes of example). However, the influences from the user/system

factors in the right column can subject the time line of subtasks to perturbation and delays. The maintenance of the consistent 30-second time cycle for

message processing will only occur if there is no perturbation to the basic

flow. When a user/system factor has direct bearing on a subtask, the result

will be to either speed up or delay information processing and product output.

The system depicted in figure 2 has been studied extensively. In fact, a

similar notion has recently been incorporated into a model of human-computer

interaction. The model, which is more fully outlined in the Appendix section

of this paper, entitled "Technical Background", has proved to be a useful

method of studying and understanding the human-computer interaction.

5

. . . . . . .* - U*6 ~- - *- .- .. .
Time/ information Flow Typical User-System Factors

seconds by Subtask Impinging upon Task Performance

to Input: message imprinting on * alertness

TTY terminal USER * previous message handling

* previous task loading

SYSTEM S * terminal hardware characteristics 

maintenance I

status

ti Sensing: receipt of information/ attentional capacity

officer detects message USER * visual acuity

* alerting mechanism

SYSTEM 9 ambient conditions:

* luminence level, legibility

t2 Information Processing: e training

decoding, translating/trans- USER 0 experience

scribing written text e skill level

a coding strategies

SYSTEM * interactive features -

a acceptability of features

t3 Decision Making: determine * training

message priority/formulate U experience

response *cognitive strategies *net cognitive load

SYSTEM * time pressure * urgency-priority

t4 Take Action perform * skill level

maneuver/update sitrep matrix/ USER, psychomotor capabilities

phone call. etc. : access to communication channels

SYSTEM, feedback from environment/superiors -

subordinates

Output. transmission of ,itrep U familiarity with transmission protocol

through chain USER readiness

30 seconds * type of transmission channels

(hypothetical) SYSTEM * protocol for transmission

* * readiness of transmission channels

to new message

entry

Figure 2. User-system factors influencing rate of information flow

in a time-based system for a simple transcription task.

6

- 4
* ~ .--

It is within the above context that the rate of information absorption is

best considered. To say that a human operator may absorb "2 Hz per second" is

simply to use a term from acoustics which refers to frequency of occurrence in

cycles per second. In this case a "cycle" is an undisturbed occasion of

message input to report output, with smooth accomplishment of intervening

subtasks. The fact that this almost never happens affects how accurately the

rate of information absorption can be determined. In the present example, an

incoming rate of two messages per minute may be optimal on one occasion, too

slow in another instance and overwhelmingly fast in a following instance. A

well-trained, experienced soldier who is not fatigued or imposed upon with

other demands may be able to allow several minutes worth of messages to form a

queue. With a glance, the message series may then be perused, a sitrep matrix

updated, leaving time to spare. A soldier who is just learning and faces a

command directive to provide immediate, current status information to an

intermediary, will be overwhelmed by the influx of messages while trying to

respond to the additional tasks. What is automatic and even routine to one

controller is going to be consciously difficult for another.

Let us now suppose that in addition to receiving and interpreting incoming messages, the soldier must also actively reply to the incoming information. In other words, he must formulate a reply and find the correct means of

sending it. His specific task is to decide how to respond and to type the

response into the terminal. The two critical issues at this point are (1)

ensuring that the correct reply is obtained and (2) ensuring that the reply is

correctly typed in. Again, many factors influence the rate and accuracy with

which outgoing responses are transmitted.

7
^0

Factors Influencing Information Transmission

In order to actively reply to an incoming message, it must be decoded and

processed, as explained earlier. Thus, the transmission of information

becomes the next step in the human-computer interaction. Because of the

sequential relationship among the steps in processing incoming information,

the factors which influenced information absorption rate will also influence

the information transmission rate. Consequently, the discussion which accompanied figures 1 and 2 also applies to information transmission. Specifically, system factors, user factors, and task variability affect the rate

and accuracy of information transmission.

System factors include those presented in the previous section. In

addition, however, they also include a number of additional system specifications. These include, for instance, the location of the keys on the keyboard,

and the separate aspects of the terminal display which, in unison, yield the

display of the user's response. Research has shown, for example, that the

typing rate of expert typists on a conventional Sholes (QWERTY) keyboard was

found to be 8% faster than on an alphabetic keyboard (Underwood & Schulz,

1960). Another study (Barmack & Sinaiko, 1966) found that performance was

improved when the user was provided with feedback and when the lag between his

response and the display was reduced. Taken together, these studies demonstrate the critical importance of carefully considering human variables when

designing a system and evaluating user performance.

Of the previously mentioned user factors, the most important one in

information transmission is user experience. Evidence has long supported the

notion that the time to perform a task decreases with practice (Snoddy, 1926).

An experienced typist inputs information much faster than does a novice.

8
oP v

However, many other factors contribute to performance other than the user's

level of experience. One of the more pertinent ones is the role of attention

in transmitting information. Research has shown (Haber, 1932; Sipowicz &

Baker, 1961) that people have relatively short attention spans, that they get

bored with repetitive tasks, and that their past experience colors their

perceptions. This results in decreased performance accuracy. Consequently,

computer tasks should be designed to maintain the user's vigilance.

Task factors were also described in the previous section. Probably the

most relevant one in information transmission is the exact amount of time

allotted for the task. It is especially critical in information transmission

because it affects both the accuracy of the outgoing message and the user's

perception of task difficulty. Studies have shown that a speed-accuracy

trade-off operates in many tasks, and that users perceive the task as more

difficult as its allotted time decreases (Darjanian & Sheridan, 1980).

Another time variable is when the user is presented with numerous messages to be transmitted within a very short period of time. In our example,

this situation prevails if the soldier is required to send multiple responses

in a brief period of time. He must decide the order of priority of outgoing

messages and then send them in that order as quickly as possible. The order

of outgoing messages thus forms a queue. (The notion of a queue is discussed

in the Appendix.)

The complex interplay of user, system, and task factors is also evident

in information transmission tasks. The rate of accuracy of transmitted information is contingent upon a number of simultaneous variables, as shown in

figure 2. The actual information transmission occurs in the last two steps of

the figure. Again, note that it is tempting and commonplace to refer to an

9
- - -

information transmitter's task as simply "sending messages." Holding this W, ..P

simplistic view, however, one cannot account for why one soldier transmits

information quicker and more accurately than another. To understand and

adequately evaluate the situation, it is imperative to be aware of the various

user/system/task factors. Rather than conclude that the second soldier is less

competent than the first, the two situations should be compared and contrasted

in light of user/system/task factors. For example, it may be found that: the

second soldier's attention span is shorter than the first one's, or that the

second soldier's psychomotor capabilities are not as coordinated as the first

one's, or that the time allotted for transmission is too short for the second

soldier to adequately perform, or that the terminal being used by the second

soldier is internally set to operate at a slower rate. The first two possibilities are user factors, the third is a task factor, and the fourth is a

system factor. Yet any one or more than one of these possibilities may be

operating at any given time. Once the problem source has been found, it is

then possible to take remedial action.

The transcription task described above is an example of a very simplistic

task in which incoming messages are automatically typed on a printer/terminal

and the soldier works directly with the printed page to decode, process, and

respond. In a computer-based command center, however, incoming 02 information

typically enters an automatic memory storage unit first. This capability

potentially changes the task scenario dramatically. Note the block labelled

"information storage" in figure 1, the simple communication system. This

descriptor can apply to the hardware component responsible for accumulating

messages and allowing an operator to access and reply to these in a controlled

way. Some prior programming may also allow transcribing, aggregating, and

* 10

......... !

. . . *

,,,:.-.- ,-" ,,' .,.., -:,."< .... ',.', .... '..-....:......'..'..-...... ... ...- -: ,', ..-. .,. .... .7.

.. ,,r ., ,t,., . , L , .L_ ... r.._.. , .. -., ¢,. .< ... .. ... ... .. ... ... . . .. . .. . .. ,.' ,'. '....' . .. ..- ...
recording functions to be performed by the machine. In this situation, the

soldier may be viewing only summaries of many reports, or records of change

over time, or be alerted to critical changes only if they meet certain preestablished criteria. In this case, there would not necessarily be a decision

regarding the order in which to transmit messages; the storage unit would

handle this.

However, even with this task transformation, the issue of information

absorption and transmission remains. New questions are raised regarding the

use and access of stored information, the ease with which one responds to

automatically highlighted critical elements, and how the order of entering

information is determined. Regardless, information must still be received and

processed, decisions made and actions taken, all in a time-sensitive manner.

Questions of information format and display, user training and experience, and

determination of desired outputs will still pertain to the rate of information

absorption and transmission.

Summary and Conclusions

The foregoing presentation of a sample task has illustrated the impact of

user and system factors as impinging upon the rate of flow of information in

the accomplishment of the task. Emphasis was placed on showing examples of

the knowledge base available relating to the nature of human processing.

While there is considerable literature available to offer guidance in the

design of system elements (e.g., McCormick, 1970; Van Cott & Kinkade, 1972),

the human is viewed as the critical element which determines rate of information flow in task performance. This is because the effective design of system -

elements is really based on an understanding of human processing capabilities

%-

*• *,**"" * . . .. - . . . w . .~. . . . .'o.•,O. ' ' ' ° 4 4- .. .-.. :_':. .,..:? . .. . . . " "" '" " " ," " ,,",""", . . .'"- 0 " "" , , - """" . -"
and limitations. In any dynamic system involving objects and humans configured together, the human is really a system within the larger total network. Figure 3 illustrates this simple concept.

:'en

Figure 3. The human operator is represented an an organic

data-transmission/information-processing link in

input-throughput-output communication cycling of information flow

from E.J. McCormick Human Factors Engineering New York: McGrawHill, 1970. reprinted with permission.

Given the above premise stressing the importance of comprehending the

nature of human processing, rate of information absorption and transmission by

the human may be determined by applying what is known to specific task contexts. Consider the command and control setting as an example of how the

process of knowledge application and task specification may lead to determining information absorption and transmission rates. Referring back to

figure 2, there is a flowchart of subtasks for a particular task from start to

12
finish. At each time (to, t,... t ) the relevant user/system factors are

0 5

listed extensively. These specify the exact parameters of the environment,

hardware, message format, etc. For each subtask, an estimate could be given

for the time required to execute it. The rate of information absorption and

transmission is then simply the cumulative time from to to t This is

strictly an analytical process, using given task, user, and system specifications and applying general estimates of processing time from the knowledge

base. The exercise does not stop here, though. It is likely that the cumulative time estimates will not be accurate, either because some element has not

been clearly specified, or a knowledge gap does not allow precise determination of a time. However, the preliminary work for test and evaluation to

determine precise times has already been accomplished by the analytical

process. Now it remains only to select methodological techniques from the

knowledge base to test specific subtask skills in an experimental situation.

Since the task, scenario, and user have already been specified, testing is a

relatively straightforward matter. With the trend toward computer reception

of a highly speeded influx of information from a variety of sensors and other

G2 sources, the command and control posts will have access to large amounts of

time-sensitive inputs. It is important that the rate at which humans can

process and absorb these data be assessed, so that the benefits of the automated collection, storage, and display components will not be lost. The

preceding description is one such assessment technique.

Conclusion

This report was in response to a specific request from the Army system

development community to ascertain whether specific data are available for

how much information an individual can absorb per unit time. It has shown

13

* .. .. . . * . . .. * . . * * . . ... . * A. 

-7 °
Ie

that in fact, no specific human data processing rates are available because

each situation is accompanied by internal and external factors unique to the

individual and system components being considered. A simple task was developed

and described, showing how a specific data processing rate might be computed,

- given that factors impacting the task under consideration could be clearly

specified. Also included is an appendix providing more detailed background of

the behavioral science literature on information processing, for readers who

wish to pursue technologies specific to their own system application.

1 .4

* - .

S.". .
Appendix: Technical Background in Human Information Processing

This section is a detailed discussion of psychological concepts and of

illustrative studies conducted in the area of information processing. What

was illustrated in the body of the report by means of the message transcription task is that user and system factors determine the rate of information

flow in a communication sequence (input-processing-output). Absorption rate

. is a function of user reception of information at any given point in the

cycle; transmission rate is a function of information acquisition at a particular time.

A technical knowledge base has been developed in the area of cognitive

psychology which addresses the processing capabilities of individuals as they

* acquire, modify, manipulate, store, and use information. Models have been

constructed (see a summary diagram, figure 4) to conceptualize human processing as information proceeds through various internal structures or levels

(e.g., Neisser, 1967; Craik & Lockhart, 1972; Norman, 1980). Research

findings lend insight into how well and how quickly information is represented

and transferred in a given processing activity. In specified tasks, human

performance has been measured to record speed and accuracy in identifying

targets, recognizing objects, comprehending texts, etc. Each of these is

contingent upon the various formats of the information and internal/external

conditions in that situation. While some general principles are known regarding processing capabilities, no general rates of absorbing or transmitting

information may be developed until applied to specific tasks with their

attendant parameters.

In the case example of message transcription, the following questions

would need to be answered before pertinent knowledge could be applied:

15

V.. .-... ...- ,. - .- .-
torch AlocaIioentions.

emory Process

interpretation Attentional.

structuring Thought Processes Resources construcion

Memory Structures

Long-term - secondary memory

Short-term - primary memory

activated concepts

working storage _

Pattern Recognition Motor Programs .

nd Sensory Memory System Motor Control System

Sensory 1Effectors:j Transduction speech, muscles, limbs

Physical signals Sound and movement

Figure 4. A modern version of the conventional flow chart of the human information

processing system. The basic components are a series of processing mechanisms that

take in information about the environment, perform general central processing operations, and control motor output. The central processing is complex, with various

sources of knowledge interacting with one another, controlled by an as-yet little

understood processing structure which allows for some simultaneous operation, self

awareness, consciousness of some of the processes. The stuff in the central part

of the figure is sufficiently vague as to allow for a large number of interpreta- N.

tions of its nature

from D.A. Norman "Twelve Issues For Cognitive Science" in Cognitive

Science. 1980, 4 (1) pp. 1-32 reprinted with permission of Ablex

Publishing Corporation, Norwood, N.J.

16

• .. -,'. . . , ..... . . .. , . . . .,.. . . . . . . , . . , , , . .. . .. ' . . , .
o" (1) who is the user (MOS, skill level)

(2) what is the mode of incoming information (visual/auditory; verbal!

Symbolic; printers, CRTs, etc.)

(3) what is the nature of the information extraction required (i.e.,

target detection; pattern recognition; verbal comprehension; decoding; decision making, etc.)

(4) What is the desired outcome of the task (i.e., target identification

and reporting; report preparation and transmission; situational analysis;

initiate engagements; command decision).

Once a given task scenario has been specified, information rate and ease

of information handling can be evaluated and tested by an application of -

current knowledge and empirical methodology.

Sensing and detecting. As evidenced in figure 4, sensors in the human nervous

system feed a steady stream of information about the environment to some

central processing structures where that information is analyzed, interpreted, V.

and fed to a response system (Norman, 1980). A common task is to detect the

presence or location of particular signals in a visual or auditory field. In

this task, the structure or characteristics of the signals, the field, and

their interactions have received extensive study. For example, in visual

perception, heterogeneity of the field in terms of hue, form, size, and

brightness is a significant factor in search time. Search time in general was

found to increase with increasing heterogeneity of the field (Eriksen, 1953). .Y.

Besides heterogeneity on various dimensions, a display or perceptual field can

vary in terms of other characteristics. One is the amount of information it

contains. A field may be saturated with signals or the signals may be few but

17
widely scattered. Perceptually this variable is known as the "figure-toground" ratio, or "signal-to-noise ratio" (Eriksen, 1955). The speed with

by this ratio. Research findings indicate that (a) as the number of signals

or objects in a field is increased, the time required for location of a

constant number of specific signals also increased; (b) when the field was

partitioned or formatted in some way, search time decreased; (c) if the target

signal complexity is enhanced, detection will be facilitated; and (d) if the I

noise background complexity is enhanced (increased), a progressive decrement

in target recognition will occur (French, 1954).

In a study by Banks and Prinzmetal (1976), using a detection paradigm of

signal-to-noise, the hypothesis entertained was that the mutual interference

between target and noise items is increased when they are perceptually clustered

together in the same group and decreased when they are perceptually clustered

in different groups. A single generalization characterizes all of the effects

of organization on processing: the more the target is perceptually grouped

with noise, the more it is interfered with by the noise. If the noise and

target come in on different "channels," they will interfere less with each

other. The separation of signals from noise implies some sort of elementary

processing or grouping operations in the sensory/perceptual system, even

before it reaches a central processing network. These findings and others

similar to them (e.g. Neisser, 1976; Reicher, 1969) indicate the importance of

configuring the incoming targets or messages to be compatible with the preliminary perceptual processing exercised by sensory receptors. "d

.

18

I %
Comprehending verbal messages. Criteria for the spatial arrangement of words

on the printed page have been investigated for almost a century. Extensive

research, reviewed by Tinker (1963), has evaluated such issues as vertical

versus horizontal layouts and line widths for best reading performance.

Cornog and Rose (1967) report some 140 studies that have examined the layout

of alphanumeric text materials. These types of tasks have noted the interaction of these factors on reading speed or time on task for different sorts

of displays, testing for or assuming equivalence of comprehension. Other I

studies (i.e., Levy-Schoen & O'Regan 1979; Rayner, 1978) have used eye movement measures of reading performance. It has been found that difficulty,

discriminability, comprehensibility and related features of text processing

reveal themselves through changes in frequency, duration, and location of eye

fixations (Kolers et al., 1981).

Huchingson et al. (1981) found that message formatting was a critical

variable in rate of message assimilation and comprehension. "Format" refers

to the manner in which words are arrayed. Arrays of words tested included

vertical alignments, compact arrangements, and "chunking" according to meaningful groups. In addition, some messages were presented in sequential

fashion, that is, a series of discrete word or chunk presentations were shown

over time to relay the entire message. Findings indicate that dividing

messages into one word per sequence or vertically led to poorest comprehension. Chunk and chunk sequencing were the most satisfactory for message

comprehension and recall.

P 19

"1d

. ............................ ......................-.
',--- - .- . . . - - -

Detecting and comprehending symbolic vs. word messages. The previous two

sections have highlighted research areas in the perceptual identification

and comprehension of targets of word messages. In some cases, comparisons

have been made between the use of symbolic or pictographic elements and

alphanumeric or verbal presentations of the same concepts, in order to determine speed and ease of discrimination. The premise in some of these

studies was that a "picture was worth a thousand words" and could more easily

depict a key concept or bit of information. The fact that a symbol is pictorial does not always guarantee its connection with its intended associate.

Kolers (1969) has shown that information conveyed by a symbol will depend on a

viewer's previous experience and knowledge, as well as specific training and

expectancies. In general, though, the appropriate use of symbols has shown

major advantages in being perceived more rapidly (Janda & Volk, 1934), more

accurately (Walker, Nicolay, & Stearns, 1965), and at a greater distance

(Dewar & Ells, 1974) than words. Reaction time to symbols may be shorter

(Ells & Dewar, 1979), even under visual degradation. Symbol meanings can

often be rapidly learned and accurately remembered (Walker et al., 1965), with

minimal confusion among alternatives (Green & Pew, 1978).

Cognitive processing of information. Once information has been transduced by

sensory receptors (visual, auditory, etc.), the incoming information is somehow matched and encoded by mechanisms or structures further along the cognitive system: Referring again to figure 4, the processes of pattern recognition of sensory stimuli are then followed by manipulations within various

types of memory, which are in turn influenced by thought processes, emotions,

attention, etc.

20

, '. ' . .. , .- , - .,. ,, - . . - .*-. .. . , - . - , '. "- . , -, - : , . . -. , , , , .. , . . .
One of the most recent models to assimilate the information processing

approach is called the Model Human Processor (Card, Moran, & Newell, 1983),

depicted in figure 5. The model may be interpreted as a functional analog of

the human components necessary to process incoming information. The components of the model work together to form three interacting subsystems: The

perceptual system, the cognitive system, and the motor system. The perceptual

system consists of an initial processor and of memories, the two main ones

being the Visual Image Store and the Auditory Image Store. The cognitive

system receives information from the sensory system and places it in Working

Memory while previously stored information is retrieved from Long-Term Memory

to aid in making a decision about the incoming information. The motor system

actually carries out the decision in the form of a response.

To illustrate the model with an example, we return to the message transcription task. The soldier sees the message on the display. The visual image

of the message enters the Perceptual Processor; next, it is temporarily stored

in the Visual Image Store. At this time, previously stored information which

is relevant to the message is recalled from Long-Term Memory. The Cognitive

Processor uses the Visual Image Store information and the Long-Term Memory

information as a data base of pertinent information to initiate the decisionmaking process. When a decision is reached, it is relegated to the Motor

Processor, which executes the response. The soldier responds by typing the

appropriate key(s).

The model incorporates a number of principles of operation, which are

mathematical laws defining the parameters of performance. The principles of

operation quantify the manner in which performance will be affected by numerous variables, many of which were presented earlier in this paper. It is

21

-"""." .".
.

LONG-TERM MEMORY

<UX

WORKING MEMORY .~

VISUAL IMAGE AUDITORY IMAGE -M a 54

STORE STORE 7 15-.1 dMA

2w rm17-0001 wc IN PM00 MM)0 "OK X"Ma (I Chaf) . 73 r3-M SK

OL~ - 17 17-171' Wa. 6 S 4-4.21 lw kwm (3 cihmns) - 115-361 w

-w F4 - ACOUNC Of VQgA.

JODI -no]

Figure 5. The Model Human Processor--memories and processors.

Sensory information flows into Working Memory through the

Perceptual Processor. Working Memory consists of activated

chunks in Long-Term Memory. The Motor Processor is set In

motion through activation of chunks in Working Memory.

* 22
474

possible, for instance, to solve the following problem: "A user sits before a "

computer display terminal. Whenever any symbol appears, he is to press the

space bar. What is the time between signal and response?" (p. 66). Many

other realistic problems can be solved which allow us to make knowledgeable

decisions regarding the effects of certain factors on user performance.

The model also offers a principle which takes into account varying

amounts of incoming information. It is possible to estimate how each subsystem will respond to these differences, because the model specifies the

storage capability of each of its components. In sum, the model is valuable

because it is a framework in which the entire information-processing sequence

can be conceptualized, and because it provides a method whereby practical

problems can be solved.

Whether or not these memory structures and mechanisms are actual structures, or simply ways of conceptualizing levels of processing occurring for

different stimuli, is the subject of some controversy (Craik & Lockhart, 1972;

Baddeley, 1978). However, the idea is that the resulting information is

relegated to central processing and thereby brought to "consciousness" for

active labelling, that is, what we are immediately thinking about, working

with, and may incite us to act. Most studies in this area have come from

verbal learning investigations, confined to the use of verbal materials. It

has been suggested that the processing occurring at this level has limits -'.

(e.g. Miller, 1956; Broadbent, 1958; Shiffrin, 1975) because it demands our .

attention, and therefore sensory information must either be filtered and

ignored, or queued until attention may be devoted to it. Miller's article

(1956) "The magical number seven + two", was one of the first to create aware- ,-.

ness of a limited capacity to retain and process sensory items. The principal

- .

'.

23

....
assumption of the limited-capacity view is that attention demanding (or

cognitive processing) can be distinguished from another type of processing,

automatic processing. f. An automatic t process is one that can handle as much

information as is presented--for example, ears automatically register sound

waves whether one, two, three, or more sounds are presented. Although thesensory response to stimulation is automatic, at some point the system becomes

unable to process all of its inputs because of limitations in its capacity.

This is the point at which attention occurs.

Note that the point at which attention occurs will vary in different

situations depending on rehearsal of subtasks, training, experience, incentives, etc. (Klatzky, 1980). An example will clarify this point. Consider

what happens when you first learn to drive an automobile. The instructions

. you receive emphasize the actions and the mechanics; hold the steering this

way, synchronize foot (for clutch) and hand (for gearshift) that way. As you

progress, the point of view changes. Now you are turning the wheel, not

moving your hands clockwise. Then you are turning the car, later you are

entering that driveway. Eventually, as a truly expert driver, you drive to

the bank, go shopping. The differences in qualitative feeling are vast. At

the expert level, you are no longer "aware" or conscious of all the subsidiary

operations that you perform: you look at the driveway, form the intention to

enter, and the car responds. Driving the car becomes natural and subordinate

to other attentional demands (Norman, 1980).

The processing of information in the military scenario will be much the

' same as developing a driving skill. Experienced soldiers will handle messages J

and generate responses in an almost automatic manner, except when critical,

novel elements demand attention. Novice soldiers will be overwhelmed by

24

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- - - - . -V 1 7,7j, - W . . . F .RI FEW.. 

.0

,

message processing, until their skills have become separable from the cognitive learning that must occur. The pressure of time and the rate at which

information can be absorbed will be a function of the degree to which the

assimilation of messages is an automatic process.

Development of cognitive decision-making skills. A final area of the knowledge base of information to be described is cognitive skill development, or

* decision making. In some cases, a soldier in command is involved in decision

tasks that have high attentional demands, requiring the aggregation and assimilation of many information sources in order to derive plans of action.

Studies in this area have examined such concepts as the cognitive management

of information, and decision strategies to reduce "cognitive load" (cf.

Kibler, Watson, & Kelly, 1978; Katter, Montgomery, & Thompson, 1979; Katter,

Montgomery, & Thompson, 1979a; Phelps et al., 1980). The goal of these studies

was to determine the most effective way to allocate attention, assess cognitive

. load, and develop strategies or aids to reduce the load (Donnell & Patterson,

1981). Once net cognitive load is beyond a given capacity, the human must

either shed some of the load, or suffer a deterioration, if not a breakdown,

in performance. With excessive load, the rate at which information can be

absorbed and processed for effective decisions will be decreased. Several

concepts have been proposed to counteract this, including selective attention

techniques, task simplification, and task delegation (Donnell & Patterson,

1981). Careful attention to how information is presented, in terms of reports, displays, sensor updates, etc., will have a bearing on how easy it is

to integrate information and thus produce effective, timely decisions.

25

'S..'

' .5 ... ... ... ".. . .- S 2-
"r. r. 1.*.T - TN

Mentally loading a person has the effect of destabilizing the processes

that use anticipation to regulate automatic processing and allow attention

allocation for complex decision tasks. Hacker et al. (1978) state that

properly coded knowledge of the task can save time by increasing the efficiency of processing, hence reducing cognitive load. Work in time stress and

decision analysis has been based on certain mathematical principles and

theory, and has been revealing regarding what factors interfere with and

facilitate decision making. The study of time stress relates the problem of

time to mental workload (Moray, 1982). Attempts have been made to measure the

relationship between the two. Senders (1979) asserts that unless there is

time stress in a task, there is by definition no mental load. The mathematical/conceptual framework for this work is queuing theory, which predicts

"load" based on the probability that the human will be busy at the time a

signal or message arrives. The overall conclusions indicate that difficulty

of task execution (and thereby rate of processing) is a function of the need

to generate lead time in task performance so as to keep up with incoming

information. In a similar vein, statistical decision theory has been used to

derive decision analysis techniques to reduce judgmental errors. Complex

decisions are partitioned into more basic elements in order to allow subjective assessments of incoming chunks of information to be dealt with separately. Then a means is provided through formal, logical algorithms to

arrive at a formal choice (Kibler, Watson, & Kelly, 1978).

These types of studies allow the explicit understanding of elements of

the decision-making process, so that decision aids and effective training may

"' be developed in applied situations where the rapid processing of large amounts

I.

S26 F
of information is required. In the intelligence area, for example, the

analytic operations of intelligence analysts have received extensive study

(Katter, Montgomery, & Thompson 1979, 197 9a). Here an extensive cognitive

model of the analyst was developed, based on a more general assessment of

human information processing, and then relating it to the specific tasks of G2

analysts. This application resulted in the actual explication of cognitive

tasks within analysis, and provided the basis for a field training circular to

teach these tasks (INTACT, 1984) to new analysts.

SI..

I

27 P

5, 5,.~~~ * **.***'

.° 5 ° .,, 
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31

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