3.5 System Input

In cybernetic communication theory and systems thinking, system input refers to any information, matter, energy, or influence that enters a communication system from its environment, crossing the system's boundary and becoming available for processing by the system's internal mechanisms. Inputs are what connect the system to its environment, providing the raw material for the system's operations and the signals to which the system must respond in order to maintain viability and pursue its goals. Understanding system inputs is essential for understanding how communication systems relate to their contexts, how they acquire the information they need to function, and how environmental changes affect system behavior.

The Concept of Input in Open Systems Theory

The distinction between system inputs and internal system processes is one of the fundamental conceptual tools of open systems theory. Closed systems, in thermodynamic theory, exchange no matter or energy with their environments; they are therefore subject to entropy increase and eventual equilibrium death. Open systems, by contrast, maintain themselves by continuously importing low-entropy resources (matter, energy, information) from their environments and exporting high-entropy outputs back to those environments.

Communication systems are paradigmatically open systems: they cannot function without continuous input from their environments. A communication system cut off from all environmental input—denied new information, new participants, new challenges, and new resources—would quickly exhaust its internal resources and collapse into communicative silence or repetitive, circular self-reference. The capacity to receive, process, and respond to environmental inputs is not incidental to communication system functioning but constitutive of it.

The concept of input does not necessarily imply passivity: communication systems actively seek inputs through environmental scanning, relationship development, and information acquisition. The system's structure and needs shape what inputs are sought, which are attended to, and how available inputs are processed. Input acquisition is itself a communicative activity.

Types of Communication System Inputs

Communication systems receive several distinct types of inputs from their environments:

Informational Inputs

Informational inputs are messages, signals, data, and representations that carry content about the state of the environment, the behavior of other systems, or the consequences of the system's own past outputs. Informational inputs are the most distinctively communicative type of input:

• External messages: communications initiated by environmental agents and directed at the system.
• Environmental signals: information available in the environment that the system's sensors detect even without active communication (ambient conditions, observable events, indirectly available data).
• Feedback signals: information about the consequences of the system's own outputs, returned from the environment to become new inputs.

The significance of any informational input depends not only on its content but on how the system interprets it relative to its existing models, expectations, and goals. The same message may be highly informative to one system (because it resolves significant uncertainty) while being trivial or unintelligible to another (because the receiver lacks the interpretive framework to decode it or because the message content is already known).

Human Inputs

In many communication systems, new participants are inputs that alter the system's composition and therefore its communicative possibilities. When a new member joins a group, a new employee joins an organization, or a new person enters a relationship, they bring new communicative repertoires, new perspectives, new relational styles, and new expectations that constitute inputs the system must process and integrate. The system responds to these human inputs by socializing new members (adjusting their behavior to fit the system's existing patterns) or by accommodating to them (adjusting the system's patterns to incorporate what the new members bring).

Resource Inputs

Communication systems require resources—time, attention, material support, legitimacy, financial resources, technical infrastructure—to maintain their communicative activity. Resource inputs are not themselves messages but they enable and constrain the system's communicative capacity. A team that loses resources (time, space, attention, tools) loses communicative capacity even if the informational inputs it receives remain unchanged.

Structural Inputs

Sometimes what enters the system across its boundary is not discrete information but structural influences—patterns, norms, practices, or frameworks from the environment that reshape the system's internal organization. Cultural diffusion, organizational isomorphism, and social influence all involve structural inputs: the system's internal structure is modified by exposure to environmental patterns without a specific discrete message causing the change.

The Processing of Inputs

System inputs do not simply enter the system and immediately become system outputs. They are processed through the system's internal mechanisms before affecting the system's state and behavior:

Filtering and Attention

The first stage of input processing is filtering: the system attends to some inputs and ignores others. No communication system has the capacity to process all available environmental signals; selective attention is both necessary and constitutive. The system's existing structure, values, and needs determine what it attends to—creating systematic patterns of attention and inattention that shape what the system knows and what remains outside its awareness.

Organizations develop formal and informal information gatekeeping mechanisms that filter environmental information before it reaches decision-makers. Families develop communication norms that specify which environmental topics are relevant and discussable within the family system. Individuals develop attentional habits and cognitive schemas that direct attention toward some environmental signals and away from others.

The filtering of inputs creates the possibility of system pathology through information blindness: the systematic exclusion of inputs that would be important for system functioning but that the system's existing structure screens out. Organizations that filter out negative information create conditions for progressive disconnection from environmental reality. Relationships that filter out information about partner dissatisfaction create conditions for accumulating unaddressed grievance.

Interpretation and Decoding

Attended inputs must be interpreted: raw signals must be decoded into meanings, and meanings must be assimilated into the system's existing models of the environment. Interpretation is not passive reception but active construction: the system brings its existing knowledge, expectations, and conceptual frameworks to bear on the input and produces an interpretation that may or may not accurately reflect the environmental reality from which the input came.

Interpretation is influenced by the system's context and history. The same input receives different interpretations from systems with different histories, different relational contexts, and different current states. A message that seems critical in one relational context seems supportive in another; information that confirms existing expectations is assimilated smoothly while information that disconfirms expectations is often distorted in the direction of existing expectations.

The interpretive process can introduce error: inputs can be misinterpreted, selectively decoded, or assimilated into frameworks that distort their significance. These interpretive errors are often not random but systematic, reflecting the system's existing biases, commitments, and organizational pressures.

Integration and State Change

Successfully decoded inputs are integrated into the system's current state: they modify the system's model of its environment, trigger emotional or motivational responses, activate stored memories and associations, and prompt evaluations of the implications for the system's goals and functioning.

Integration changes the system's state. Before a piece of news is received, the system is in one state; after it is received and integrated, the system is in a different state. The degree of state change depends on the information value of the input (how much it changes the system's uncertainty about the environment) and its relevance to the system's goals and concerns. High-information, high-relevance inputs produce large state changes; low-information, low-relevance inputs produce small or negligible state changes.

Feedback as a Special Type of Input

In cybernetic communication theory, feedback occupies a special place among system inputs: it is information about the consequences of the system's own outputs, returned from the environment to become inputs for subsequent system behavior. Feedback is the mechanism through which the system learns whether its outputs are achieving their intended effects and adjusts its behavior accordingly.

The cybernetic insight is that feedback is what enables purposive, goal-directed behavior: a system that cannot receive feedback about the effects of its actions cannot correct its behavior in response to deviation from its goals. Without feedback inputs, a communication system is behaviorally blind—it must repeat the same outputs regardless of their effects.

The distinction between feedback and other inputs lies in their origin: feedback comes from the system's own environment in response to the system's outputs, creating a causal loop. Other inputs originate independently of the system's previous outputs and represent exogenous environmental events.

In human communication, feedback inputs are ubiquitous: the listener's facial expressions and backchannel vocalizations are feedback inputs to the speaker; the audience's response is feedback input to the performer; sales figures are feedback inputs to the marketing communicator; polling results are feedback inputs to the political communicator. Each of these feedback signals provides information that the communicative agent uses to evaluate and adjust subsequent communication.

Input Deprivation and Input Overload

Communication systems can experience both insufficient inputs (input deprivation) and excessive inputs (input overload), with characteristic consequences in each case:

Input deprivation: When a communication system receives insufficient environmental input, it loses the feedback signals needed for error correction, accumulates an outdated model of the environment, and may develop increasingly autistic patterns of communication—focused on internal self-referential activity rather than responsive engagement with the environment. Isolation from environmental inputs creates the conditions for distorted reality perception, rigidified communication patterns, and eventual failure of environmental adaptation.

Input overload: When a communication system receives more inputs than its processing capacity can handle, it must reduce the effective load through various strategies: filtering more aggressively (attending only to high-priority signals), processing less deeply (substituting heuristics for careful analysis), delegating processing to subsystems, or queuing inputs for delayed processing. Input overload is a characteristic problem of contemporary information environments where technological amplification of communication has vastly expanded the range of inputs available to individuals and organizations.

The management of input load—selecting the right quantity and type of inputs for effective processing—is itself a critical communicative activity that shapes what systems know, what they attend to, and what remains invisible to them.