SYSTEM THEORY
Chapter 3
Stephen Littlejohn
Theories of Human Communication
OVERVIEW
System theory is a general theory applied to
all levels of communication;
Cybernetcs and information theory are related
to system theory;
System theory deals with the interrelated parts of
an organization; cybernetics deals with control
and regulation in the system, and information
theory focuses on organizational patterns;
SYSTEM CONCEPTS
 What is a system?
• A set of objects (elements) that interrelate to
form a whole;
• A closed system: no interchange with its
environment (doesn’t apply to social
systems);
• An open system: one that receives matter and
energy from its environment (applies to
communication);
What is a system? (continued)
 Consists of 4 things:
• Objects, or parts, elements, or members of the
system;
– These parts may be physical or abstract;
• System consists of attributes;
• Internal relationships among its objects
(mutual effects);
• An environment--they are affected by their
surroundings;
SYSTEM CONCEPTS
 Wholeness and interdependence
• In a system the whole is more than the sum of
its parts;
• It is a product of the forces or interactions
among its parts;
• It s parts cannot be understood separately;
• The interdependence creates organization in
the system (e.g., a family);
SYSTEM CONCEPTS
 Hierarchy
• Systems tend to be embedded within one
another;
• Every complex system consists of subsystems;
• Given that systems are within systems, it is
fuzzy as to where to locate the boundary
between the system and the environment ;
SYSTEM CONCEPTS
 Self-regulation and control
• Systems are often viewed as goal oriented;
• They are governed by their purposes;
• The parts operate according to guidelines and
adapt to the environment on the basis of
feedback;
• This aspect of system functioning is
cybernetics;
SYSTEM CONCEPTS
 Interchange with the environment;
• Inputs and outputs;
• The system affects and is affected by the
environment;
• Balance (homeostasis);
– Self-maintenance;
– Sensing deviations from the norm and correcting
those “faults”;
SYSTEM CONCEPTS
 Change and adaptability;
• The system must adapt to its environment;
 Equifinality:
• A particular final state may be achieved in
different ways;
CYBERNETICS
 Cybernetics is the study of regulation and
control in systems, with emphasis on
feedback;
 Cybernetics deals with the ways systems
gauge their effect and make necessary
adjustments;
 A thermostat is a good example of a simple
feedback mechanism;
TWO TYPES OF CYBERNETIC
FUNCTIONS
 Automatic response to feedback (causal
necessity);
 Actional response (with intention);
 What distinguishes system theory from
other approaches is its high level of
generality and emphasis on
interrelationships among elements, not on
the type of necessity employed;
INFORMATION THEORY
 Grows out of engineering, and is concerned
with the quantitative study of information;
 The classic work on information theory is
found in Claude Shannon’s book, The
Mathematical Theory of Communication;
BASIC CONCEPTS OF INFORMATION
THEORY
 Entropy--randomness or lack of
organization;
 Information is a measure of uncertainty or
entropy;
 The greater the uncertainty, the more the
information;
INFORMATION THEORY
 Information Transmission:
• Information theory is not concerned with
meaning, only with message transmission and
reception;
• Information theory offers a linear model of
communication, intended for electronic
communication devices (see next slide);
Signal
Information
Source
Transmitter
Signal
Received
Channel
Receiver
Destination
Noise
Source
Shannon & Weaver’s model of communication
From Mathematical Theory of Communication, 1949
YOUR THOUGHTS ON INFORMATION THEORY
AND HUMAN COMMUNICATION ???
Littlejohn suggests that Shannon & Weaver’s model,
though widely depicted, has limited relevance to human
communication. It applies to technical devices better
than to humans.
Your thoughts, please.
CRITICISM OF SYSTEM THEORY
Breadth of the theory an advantage or does it add to
ambiguity?
Does it provide flexibility in application or equivocality?
Is system theory merely a philosophical perspective or
does it provide explanation?
CRITICISM (CONTINUED)
Has system theory generated useful research?
Does the system idea reflect reality or is it an arbitrary idea?
Does system theory help to simplify or does it make things
more complicated than they really are?
CRITICISM (CONTINUED)

Littlejohn seems to
lean toward seeing
the ways in which
Information Theory
doesn’t work for
everyday
communication;
A measurement tool;
 Downplays meaning;
 Does not deal with
context;
 Does not deal with
personal factors
(learning);
 Does not deal with
perception &
processing;
