> USE OF SOCIAL INFORMATION

Many animals, including humans, seem to collect information on the behavior of other organisms. Observed organisms, in turn, seem to modify their behavior when visual clues, such as a pair of eyes, indicate that they are being watched. Observers may then "spy" from concealed vantage point to detect unbiased behavior. The value of the social information is reflected in the responses and counter-responses (Dally et al 2006; Milinski and Rockenbach 2007).

Ultimately, social information allows image scoring, or evaluating of other organisms' behavior patterns. Reputation can matter. Cooperation can be guided by status, or reputation, rather than instances of direct reciprocity. Indirect reciprocity can evolve in a group with image scoring (Nowak and Sigmund 1998, 2005) — and can also effectively solve the problem of the tragedy of the commons (Milinski et al 2002).