Reputational cascade

informational (or information) cascades happen when Internet users start passing on information they assume to be true, but cannot know to be true, based on information on what other users are doing. Information cascades can be accelerated by search engines' ranking technologies and their tendency to return results relevant to a user's previous interests. This type of information spreading is hard to stop. Information cascades over social media and the Internet may also be harmless, and may contain truthful information.

An information cascade is generally accepted as a two-step process. For a cascade to begin an individual must encounter a scenario with a decision, typically a binary one. Second, outside factors can influence this decision (typically, through the observation of actions and their outcomes of other individuals in similar scenarios). Due to this influence, researchers have drawn comparisons between information cascades and herd behavior.

The two-step process of an informational cascade can be broken down into five basic components:

1. There is a decision to be made – for example; whether to adopt a new technology, wear a new style of clothing, eat in a new restaurant, or support a particular political position

2. A limited action space exists (e.g. an adopt/reject decision)

3. People make the decision sequentially, and each person can observe the choices made by those who acted earlier

4. Each person has some information aside from their own that helps guide their decision

5. A person can't directly observe the outside information that other people know, but he or she can make inferences about this information from what they do

Social perspectives of cascades, which suggest that agents may act irrationally (e.g., against what they think is optimal) when social pressures are great, exist as complements to the concept of information cascades. More often the problem is that the concept of an information cascade is confused with ideas that do not match the two key conditions of the process, such as social proof, information diffusion, and social influence. Indeed, the term information cascade has even been used to refer to such processes.

Information cascades occur when external information obtained from previous participants in an event overrides one's own private signal, irrespective of the correctness of the former over the latter. The experiment conducted in is a useful example of this process. The experiment consisted of two urns labeled A and B. Urn A contains two balls labeled "a" and one labeled "b". Urn B contains one ball labeled "a" and two labeled "b". The urn from which a ball must be drawn during each run is determined randomly and with equal probabilities (from the throw of a die). The contents of the chosen urn are emptied into a neutral container. The participants are then asked in random order to draw a marble from this container. This entire process may be termed a "run", and a number of such runs are performed.

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