What Is Signalling Theory?
Why Humans Use Signals — and Why We Care When They Stop Meaning What They Used to Mean
Signalling theory begins with a simple but unsettling observation: we almost never evaluate people directly. Instead, we evaluate the signals they emit.
We infer intelligence from vocabulary.
We infer wealth from clothing.
We infer kindness from tone.
We infer competence from grammar.
In each case, we are not measuring the trait itself. We are interpreting an outward marker and using it as a shortcut to guess something deeper and less visible.
Signalling theory explains how and why this process works, when it breaks down, and why people react so strongly when a signal loses its reliability.
The Basic Problem: Hidden Traits
Much of what matters socially is invisible.
You cannot directly see:
Intelligence
Loyalty
Competence
Wealth
Trustworthiness
Effort
Yet social life requires rapid decisions about all of them.
Evolutionarily and socially, humans solved this problem by developing sensitivity to signals. A signal is any observable behaviour or trait that provides information about something hidden.
A degree certificate signals education.
A firm handshake signals confidence.
A wedding ring signals commitment.
A fluent paragraph signals cognitive control.
The key is that signals stand in for something else.
But they only work when observers believe the signal is meaningfully connected to the underlying trait.
Costly Signals: Why Difficulty Matters
One of the most important ideas in signalling theory is that of costly signals.
A signal becomes credible when it is difficult, expensive, or effortful to fake.
For example:
Running a marathon signals discipline partly because it requires sustained training.
Donating large sums of money signals wealth because you must actually possess the money to give it away.
Speaking with technical precision signals expertise because acquiring that vocabulary takes time and education.
The cost is what protects the signal from imitation. If anyone could run a marathon with no training, finishing one would stop signalling discipline.
This is why difficulty matters so much socially. We respect achievements not simply because they are impressive, but because they are hard to fabricate.
Grammar fluency historically functioned as a costly signal. To write clearly required years of reading, feedback, revision, and often formal education. Because it was hard to fake, it became a reliable proxy for competence.
But when technology reduces the cost of producing a signal, the signal destabilises.
And when signals destabilise, people get uneasy.
Signal Inflation and Social Instability
When a once-rare signal becomes common, its social meaning changes.
Consider academic degrees. As university attendance expanded, a bachelor’s degree shifted from elite marker to baseline expectation in many professional contexts. The signal inflated. Its relative status value dropped.
The same dynamic occurs with language fluency.
If AI tools make polished writing widely accessible, then grammatical precision is no longer a clear indicator of individual training. The signal becomes cheaper.
Observers are then forced to recalibrate. They begin asking: does this reflect ability, or assistance?
This is not just a technological issue. It is a psychological one. Humans rely on stable signals to navigate hierarchy. When stability erodes, suspicion increases because the shortcut no longer feels safe.
You can see this in accusations of artificiality. When someone produces highly structured writing in an informal setting, observers may question whether the signal still maps onto the trait it once indicated.
The discomfort comes from uncertainty, not from grammar itself.
Honest Signals vs. Manipulative Signals
Signalling theory also distinguishes between honest and deceptive signals.
An honest signal reliably indicates the underlying trait. A manipulative signal attempts to create the appearance of a trait without possessing it.
Luxury counterfeits illustrate this perfectly. A designer logo signals wealth or taste. A counterfeit replicates the signal at lower cost, which threatens the status structure attached to the original item.
This is why counterfeit markets provoke strong reactions. They blur the boundary between earned and imitated signals.
AI occupies a similar psychological space in writing culture. If someone can generate polished text without undergoing the traditional learning process, the boundary between trained fluency and assisted fluency becomes harder to detect. More on that here.
The reaction is often framed as ethical concern, but it is also about signal protection.
People care about preserving the meaning of signals because signals structure social order.
Signalling and Identity
Signals do more than convey competence. They shape identity.
Clothing signals group membership.
Language style signals political orientation.
Humour style signals cultural alignment.
When signals shift, identities feel threatened.
If grammar no longer reliably signals intelligence, then individuals who built identity around writing skill may experience subtle destabilisation. The trait that once differentiated them now appears replicable.
This helps explain why debates about AI often feel emotionally charged even when the practical stakes are small. The issue is rarely just productivity. It is about symbolic territory.
When a signal that once marked “us” becomes widely accessible, group boundaries blur. Humans tend to respond to blurred boundaries with defence mechanisms, sometimes subtle, sometimes aggressive.
Accusing someone of using AI can therefore function as boundary policing. It restores the distinction between authentic skill and mechanical output, even when that distinction is difficult to verify.
The Role of Audience Perception
A signal only works if the audience recognises it.
Writing fluency signals competence in environments that value clarity, such as academia or professional communication. In casual social media contexts that value spontaneity, the same fluency may signal detachment or artificiality.
Signals are context dependent.
This is crucial. There is no universal meaning attached to polished grammar. Its interpretation depends on the norms of the environment and the expectations of the audience.
If the audience values authenticity expressed through imperfection, then excessive polish may violate that norm. The signal is reinterpreted not as competence but as inauthentic performance.
The same behaviour, different cultural lens.
Signalling theory helps us understand that the behaviour itself did not change. The social reading of the behaviour did.
When Signals Break Down
Signal breakdown occurs when:
The cost of producing the signal decreases.
The audience becomes uncertain about its meaning.
Alternative explanations become plausible.
Once breakdown begins, trust declines.
Observers become hypervigilant. They look for inconsistencies. They rely on additional cues. They may accuse others of manipulation even in ambiguous cases.
This is a rational response to uncertainty. If a signal can no longer be trusted, people look for ways to protect themselves from misinterpretation.
However, hypervigilance can overshoot. When suspicion becomes default, even honest signals are treated as deceptive.
That is where social tension emerges.
Beyond Writing: Everyday Examples
Signalling theory extends far beyond grammar and AI.
Fitness culture is full of signals. Visible muscle mass signals discipline and health, but performance-enhancing drugs complicate the meaning of that signal.
Environmental concern signals moral commitment, but accusations of “virtue signalling” reflect suspicion that the signal is being used strategically rather than sincerely.
Professional titles signal expertise, but inflated job titles dilute their informational value.
In each case, the pattern is consistent: when a signal’s cost decreases or its authenticity becomes uncertain, people question it more aggressively.
The emotional charge attached to these debates is not irrational. It reflects the importance of reliable signals in maintaining social coordination.
The Deeper Function of Signalling
At a broader level, signalling theory reminds us that social life depends on inference. We cannot escape signalling because we cannot directly access internal traits.
The goal is not to eliminate signals but to understand their limitations.
When a signal becomes easier to produce, societies adjust by elevating new signals. Depth of insight may replace surface fluency. Demonstrated expertise may replace stylistic polish. Transparency about tool use may become its own signal of integrity.
Signals evolve. The anxiety occurs during the transition.
Simply Put: Why This Matters Now
Signalling theory offers a powerful framework for understanding contemporary debates about writing, authenticity, and AI.
It explains why grammar once conferred status and why that status feels unstable now. It clarifies why accusations of artificiality emerge when observers suspect a signal has become cheap. It shows that the emotional intensity of these reactions is not simply technophobia, but a response to signal ambiguity.
Most importantly, it reframes the issue away from morality and toward structure.
People are not merely panicking. They are navigating a shift in the informational landscape.
When signals lose clarity, trust wobbles.
When trust wobbles, suspicion rises.
When suspicion rises, social friction follows.
Understanding signalling theory does not resolve the friction immediately, but it does make the pattern visible.
And once you can see the pattern, you can stop mistaking it for something else.
References
Berger, J. (2013). Contagious: Why things catch on. Simon & Schuster.
Goffman, E. (1959). The presentation of self in everyday life. Anchor Books.
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