communicoupling

The crowd can hide
what it knows.

The first diner chooses the wrong restaurant. The second has weak private evidence and follows. By the fifth choice, the line outside looks more informative than anyone's own clue. Each person may be responding rationally to the visible sequence, yet the sequence contains less independent evidence than it appears to.

An information cascade begins when observed actions outweigh a person's private signal. From that point, later signals stop entering public knowledge because their owners copy the crowd. Agreement rises while information stops accumulating.

signal accuracychance each private clue is correct

66%

sequence lengthpeople choosing in order

signal disclosurepeople revealing evidence as well as choice

correct choices

—

agents selecting the true state

cascade onset

—

first choice that ignores its signal

hidden signals

—

private clues never added to public evidence

Confidence after each visible choice

green: cumulative correct choices · violet: public confidence; a cascade can make confidence rise after learning has stopped

run 1

Set the conditions

what to try

Separate visible agreement from independent evidence.

Start a cascade

Choose Opaque choices and request several runs. Early accidents sometimes determine a long, confident sequence.

Expose the clues

Choose Show the evidence. Public belief can now absorb contrary information even after actions align.

Strengthen private evidence

Raise signal accuracy. Individuals need a larger action history before it becomes reasonable to ignore their own clue.

the mechanism

Actions reveal less than the evidence behind them.

Agents choose sequentially between two states. Each receives an independent signal with known accuracy and observes the accumulated public record. If signals are disclosed, the record receives the clue directly. Otherwise it sees only the choice—a censored product of private evidence and prior public belief.

Once public evidence becomes strong enough, both possible private signals produce the same action. That action then contains almost no new information, although later observers may count it as another independent vote. The crowd becomes unanimous precisely because its hidden evidence is no longer being expressed.

the social payoff

A line is not a sample if everyone saw the line.

Hiring fashions, investment runs, medical practice, product adoption, and online pile-ons all mix private evidence with observation of prior action. Agreement can be informative early and redundant later.

Asking people to state evidence before seeing others, collecting judgments simultaneously, or displaying confidence and reasons changes the channel. The intervention works by preserving independence, not by celebrating disagreement for its own sake.

the mapping

Mechanism ↔ social life.

In the model	In the world
private signal	A clue, estimate, diagnosis, or firsthand observation.
visible action	The restaurant chosen, candidate hired, asset bought, or answer endorsed.
public belief	What later actors infer from the ordered history.
cascade onset	The point at which either possible private clue yields the same public action.
signal disclosure	Showing reasons or estimates rather than only the final choice.

where it tears

Limits.

People do not update identically.

Real actors differ in priors, confidence, incentives, and ability. The Bayesian agents here isolate information loss, not human psychology.

Actions may change payoffs.

A crowded restaurant can become better or worse because it is crowded. Network effects and congestion turn observational learning into a different game.

Disclosure can correlate the evidence.

Many stated reasons may descend from the same source. Making evidence visible helps only when provenance remains legible.