AGRICULTURAL EXTENSION HAS LONG ASSUMED THAT IF FARMERS ARE GIVEN INFORMATION, SOME WILL USE IT, AND THAT IDEAS WILL DIFFUSE FROM INNOVATORS TO OTHER FARMERS. HOWEVER, RESEARCH FINDINGS INDICATE THAT ABOUT 16 PERCENT OF FARMING POPULATIONS USE THE INFORMATION PROVIDED AND THAT WIDESPREAD DIFFUSION MAY TAKE UP TO 10 YEARS. DIFFERING VALUES AND BELIEFS HELD BY EXTENSION AGENTS AND FARMERS MAY IMPEDE COMMUNICATION. WHILE THE AGENT MAY ACCEPT EVIDENCE, SUPPORTED BY EXPERIMENTAL DATA, CALLING FOR CERTAIN CORRECTIVE MEASURES, THE FARMERS MAY MISINTERPRET THE PROBLEM OR THE INFORMATION, AND REGARD THE NEW PRACTICE AS IRRELEVANT, UNFEASIBLE, OR INEFFECTIVE. MOREOVER, THE INFLUENCE OF REFERENCE GROUPS (FACE-TO-FACE GROUPS WITH THEIR OWN SYSTEMS AND NORMS AND SOCIAL SANCTIONS TO ENFORCE THEM) MAY IMPEDE BOTH DIFFUSION AND ADOPTION. RURAL GROUPS, WHETHER BASED ON NEIGHBORHOODS OR ON WIDER AREAS, TEND TO BE MEMBERSHIP REFERENCE GROUPS. THE WORK OF PARSONS AND BALES SUGGESTS THAT VALUES, BELIEFS, AND ATTITUDES ARE FORMED AND CHANGED WITHIN REFERENCE GROUPS, AND THAT CHANGE REQUIRES FACTUAL, EFFECTIVE COMMUNICATION AND INTERACTION AMONG THE MAJORITY OF MEMBERS. THE DOCUMENT INCLUDES 17 REFERENCES. THIS ARTICLE WAS PUBLISHED IN "HUMAN RELATIONS," VOLUME 19, NUMBER 4, 1966, PUBLISHED BY THE TAVISTOCK INSTITUTE OF HUMAN RELATIONS, LONDON, ENGLAND. (LY)