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💬Communication in Extension -- Models, Elements, Barriers and Feedback

Comprehensive guide to communication in agricultural extension covering 8 models (Aristotle to Rogers-Shoemaker), 6 elements (CMCTAR), message flow, distortion types, noise, barriers, and feedback for IBPS AFO, NABARD, and RRB-SO exams.

Communication is the foundation of all extension work — without effective communication, no technology transfer, no behaviour change, and no rural development is possible. From Aristotle’s ancient model of persuasion to modern interactive frameworks, understanding how messages travel from source to receiver is essential for every extension professional.

This lesson covers:

  1. Definition and origin of communication
  2. Types — verbal and non-verbal
  3. Eight communication models — Aristotle, Lasswell, SR, Schramm, Shannon-Weaver, Berlo, Leagans, Rogers-Shoemaker
  4. Six elements of communication (Leagans’ CMCTAR)
  5. Feedback, barriers, and noise
  6. Exam-critical associations and summary

All topics are high-yield for IBPS AFO, NABARD, and RRB-SO exams.


From Farmer to Farmer: Communication in Action

When a progressive wheat farmer in Haryana tells his neighbour about a new seed-treatment method he learned from a KVK scientist, that is communication. When the neighbour tries it, gets better yields, and tells five more farmers — that is diffusion through communication. Every successful extension programme depends on effective communication.


What is Communication?

  • Derived from Latin word “communis” meaning common. At its core, communication is about establishing commonness — creating shared understanding between people.

  • According to Leagans: “Process by which two or more people exchange ideas, facts, feelings or impressions in ways of common understanding of the meaning, intent and use of messages.

  • Effective communication requires not just sending information, but ensuring the receiver understands the meaning, purpose, and application exactly as intended.


Types of Communication

TypeKey FactsAgricultural Example
VerbalAverage person spends 70% of time communicating verbally; 30% message distorted in verbal communicationExtension worker explaining fertiliser doses to a farmer group
Non-verbal40% of communication through body language (gestures, postures, facial expressions)A farmer nodding while listening but crossing arms — may indicate doubt despite verbal agreement

NOTE

Nearly one-third of verbal messages get distorted, and nearly half of all communication is non-verbal. Extension workers must master both channels.


Eight Models of Communication

Over the centuries, scholars have developed different frameworks to explain how communication works. Each model adds a new dimension — from Aristotle’s simple one-way persuasion to Rogers-Shoemaker’s focus on measurable effects. Understanding these models helps extension professionals choose the right approach for different situations.

1. Aristotle’s Model (384-322 BC)

Speaker → Speech → Audience

  • First basic persuasive communication model
  • One-way model with no feedback mechanism
  • Focuses on the speaker’s ability to persuade
Aristotle's communication model showing one-way flow from Speaker to Speech to Audience
Aristotle’s Model — the earliest persuasive communication framework with no feedback loop

2. Lasswell’s Communication Sequence (1948)

Who says → What → Which channel → To whom → What effect

  • Pioneered research into political communication, propaganda, and political symbolism
  • Identifies the five essential components of any communication act
Lasswell's communication sequence showing Who-What-Which channel-To whom-What effect
Lasswell’s Communication Sequence (1948) — five essential components of any communication act

3. Stimulus-Response Model (SR Model)

A → B = X

  • Proposed by Stevens
  • Communication is the discriminatory response of an organism to a stimulus
  • Also called interpersonal communication
  • Not all messages produce the same response in all receivers

4. Schramm’s Model (1961) — SESDD

  • Effective communication requires common field of experience between source-encoder and decoder-receiver
  • Key insight: “Each person is both an encoder and decoder” — communication is a two-way, continuous process
Schramm's communication model showing overlapping fields of experience between source and receiver
Schramm’s Model — communication requires a common field of experience between encoder and decoder
Schramm's encoding and decoding process showing two-way continuous communication
Each person acts as both encoder and decoder in Schramm’s two-way communication process

5. Shannon-Weaver’s Mathematical Theory (1949)

Source → Transmitter → Signal → Receiver → Destination (with Noise Source)

  • Best suited for broadcast of farm information
  • Mathematical/Information Theory of communication
  • Introduced the concept of noise in communication
Shannon-Weaver mathematical model showing Source-Transmitter-Signal-Noise-Receiver-Destination
Shannon-Weaver’s Mathematical Theory (1949) — introduced the concept of noise in communication

Three Levels of Problems:

LevelProblemMeaning
1TechnicalAccuracy of information transfer from sender to receiver
2SemanticPeople attach different meanings to words and language
3InfluenceWhether the message leads to desired behaviour change

Key Concepts by Shannon-Weaver:

ConceptDefinition
EntropyDegree of randomness or freedom to select a message; higher entropy = more information content
RedundancyInformation that could be omitted without losing meaning; English language is ~50% redundant; helpful in noisy channels
NoiseAny distortion not intended by communicator — physical (background sounds), psychological (prejudices), or semantic (misunderstood terms)
Channel CapacityAmount of information transmittable per unit time

6. Berlo’s Model (1960) — SMCR

Source → Message → Channel → Receiver

  • Berlo is known as Father of Communication
  • Six elements: Source, Encoder, Message, Channel, Decoder, Receiver
  • Purpose of communication should be behaviour control
  • Effectiveness depends on communication skills, attitudes, knowledge, social system, and culture of both source and receiver
Berlo's SMCR model showing Source-Message-Channel-Receiver with sub-components
Berlo’s SMCR Model (1960) — Berlo is known as the Father of Communication

7. Leagans’ Model (1963) — CMCTAR

Communicator → Message → Channel → Treatment → Audience → Response

  • The Communicator is the characteristic element
  • Best described for field extension work
  • Unique features: includes Treatment (how message is packaged) and Response (audience’s reaction)
Leagans' CMCTAR model showing Communicator-Message-Channel-Treatment-Audience-Response
Leagans’ Model (1963) — best described for field extension work, includes Treatment and Response

8. Rogers and Shoemaker’s Model (1971) — SMCRE

Source → Message → Channel → Receiver → Effects

  • Added the concept of Effects — what changes occur in the receiver
  • Definition: “The process by which messages are transferred from a source to a receiver”

Comparison of Communication Models

ModelYearKey ElementBest For
Aristotle384-322 BCSpeakerFirst persuasive model
Lasswell1948Who-What-Which-Whom-EffectPolitical communication
Shannon-Weaver1949NoiseBroadcasting farm information
Schramm1961Common field of experienceTwo-way communication
Berlo (SMCR)1960Encoding/DecodingFather of Communication
Leagans (CMCTAR)1963Communicator + TreatmentField extension work
Rogers-Shoemaker (SMCRE)1971EffectsChange measurement

TIP

Quick Model Summary: Aristotle (first persuasive) | Lasswell (Who-What-Which-Whom-Effect) | Shannon-Weaver (best for broadcast, mathematical) | Berlo/SMCR (Father of Communication) | Leagans/CMCTAR (best for field extension) | Rogers-Shoemaker/SMCRE (Effects).


Six Elements of Communication (Leagans)

While models give us the overall framework, understanding the individual elements of communication is equally important. Leagans identified six elements that make up any communication act — mastering each element is key to effective extension work.

Basic elements: Source, Message, Channel, Receiver. According to Leagans, there are 6 elements:

Leagans' six elements of communication diagram showing the complete communication process
Six Elements of Communication according to Leagans — the foundation of extension communication

I. Communicator

  • Person who initiates the communication process (source/sender)
  • Attitude matters towards: Self, audience, and content
  • Berlo identified 5 verbal communication skills: Writing, Speaking (encoding), Reading, Listening (decoding), and Thought/Reasoning (master skill for both)

II. Message

  • Physical product of source-encounter
  • Berlo’s dimensions: Message Code, Message Content, Message Treatment
  • Phonemes = basic speech sounds; Morphemes = smallest meaningful unit of speech; Syntax = rules for word order

Message Flow Models

  1. Hypodermic Needle Model — information flows directly to masses with nothing intervening; assumes direct, immediate, powerful effects (later proved simplistic)
  2. Two-step Flow Model — ideas flow from media to key communicators (opinion leaders), then from them to less active members

Message Distortion (Explained by Kirk)

TypeWhat HappensInformation StatusMemory Aid
Systematic (Stretch)Message stretched/expanded systematicallyNo information lostStretch = Safe
FogParts become unclearInformation lost (partially)Fog = Faded
MirageExtra/unwanted information addedExtra and unwanted; loss is maximumMirage = More than needed

III. Channel

  • According to Leagans: a physical bridge between sender and receiver
  • Controlling flow of information through a channel is called gate keeping

Rogers & Shoemaker’s Generalisations:

Channel TypeBest ForWhen More Important
InterpersonalPersuading individuals to accept new ideasPersuasion function
Mass mediaCreating awareness/knowledge about innovationsKnowledge function; for early adopters
Cosmopolite (external: radio, newspapers)Knowledge functionFor early adopters
Localite (local: leaders, neighbours)Persuasion functionFor later adopters

IV. Treatment

  • How the message is handled before placing in the channel — packaging, organisation, and presentation

V. Audience

  • The most important element in communication
  • Active audience is suited for the communication process
  • Audience segmentation = identifying sub-audiences and conveying special messages to each

VI. Audience Response

  • Terminating element in communication
  • Ultimate objective of any communication = audience response
  • Feedback = carrying significant response back to the communicator

Feedback

Feedback is what transforms one-way information delivery into a genuine two-way communication process. Without feedback, the communicator has no way to know whether the message was received, understood, or acted upon.

  • Concept given by Berlo
  • Action-reaction interdependence in communication
  • It stabilises the communication process
  • Acceptance and rejection are types of feedback
  • Feedback is source-oriented — it travels back to inform the communicator

Barriers in Communication

Even well-designed communication can fail if barriers intervene. These barriers can originate from the communicator, the channel, or the receiver — and recognising them is the first step to overcoming them.

BarrierTypeExample
Too much information (communication overload)Communicator-relatedExtension worker explaining 15 new practices in one session
Accuracy of information transferTechnical problemStatic on a radio broadcast
Different meanings attached to thingsSemantic barrier”Urea” meaning fertiliser to a farmer but chemical compound to a chemist

Noise

  • An obstruction in communication that interferes with or distorts the message
  • Main disadvantage: Wastage of time and energy (forces repetition)
  • Also causes: environmental pollution, attention diversion, message distortion

Exam Tips

IMPORTANT

Most frequently tested facts:

  • Communication derived from Latin “communis” = common
  • Aristotle = first persuasive model
  • Shannon-Weaver = best for broadcast; introduced noise
  • Berlo = Father of Communication; SMCR model
  • Leagans = best for field extension work; CMCTAR
  • Receiver/Audience = most important element
  • Feedback concept by Berlo
  • Extension teaching is Horizontal
  • Verbal distortion = 30%
  • Non-verbal communication = 40% of total
  • Only Complexity has negative correlation with adoption (from diffusion chapter)

Summary Cheat Sheet

ConceptKey Fact
Word originLatin “communis” = common
Verbal time spent70%
Verbal distortion30%
Non-verbal share40% (body language)
First persuasive modelAristotle
Best for broadcastShannon-Weaver (1949)
Father of CommunicationBerlo (1960)
Best for field extensionLeagans’ CMCTAR (1963)
Most important elementReceiver/Audience
Terminating elementAudience Response
Feedback concept byBerlo
Extension teaching typeHorizontal
Gate keepingControlling information flow through channel
Distortion typesSystematic (safe), Fog (faded), Mirage (more)
FidelityFaithful performance by all elements
EmpathyUnderstanding other’s internal frame of mind
Communication gapDifference between sent and received message

TIP

Next: The next lesson covers Diffusion and Adoption of Innovations — how new ideas spread from a single source to millions of adopters through communication channels.

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