Although many real-world networks are thought to be scale-free, the evidence remains inconclusive, primarily because the generative mechanisms proposed have not been rigorously validated against the real-world data.
A 2012 Psychological Bulletin article suggests that at least 8 seemingly unrelated biases can be produced by the same information-theoretic generative mechanism.
A recent study suggests that the belief revising conservatism can be explained by an information-theoretic generative mechanism and that assumes a noisy conversion of objective evidence (observation) into subjective estimates (judgment).
Barabási and Albert proposed a generative mechanism to explain the appearance of power-law distributions, which they called "preferential attachment" and which is essentially the same as that proposed by Price.
At present, the more specific characteristics of scale-free networks vary with the generative mechanism used to create them.
A mediator, as defined by Baron and Kenny (1986), "represents the generative mechanism through which the focal independent variable is able to influence the dependent variable of interest" (p. 1173).
They bear an appearance and generative mechanism highly similar to that of waterspouts, usually taking the form of a translucent and highly laminar helical tube.
For example, Muller and Newman have proposed that physical laws of structure govern the genesis of major diversifications (such as in the Cambrian explosion) with successful structures co-opting genetic generative mechanisms later.
This book on evolutionary developmental biology is a collection of papers on generative mechanisms that were plausibly involved in the origination of disparate body forms during the Ediacaran and early Cambrian periods.
One method to validate a power-law relation tests many orthogonal predictions of a particular generative mechanism against data.