Katz, Elihu2023-05-222023-05-2219782011-04-19https://repository.upenn.edu/handle/20.500.14332/1911This is the accepted version of the article which has been published in final form at http://dx.doi.org/10.1111/j.1460-2466.1978.tb01608.xCommunicationSocial and Behavioral SciencesArticle