ORBING to Sumner (1906) "the mores can make anything right," and he went on to illustrate with a chapter on sacral harlotry and child sacrifice. According to Tarde (1903) "imitation is the key to the social mystery," "society is imitation," "social man is a veritable somnambulist." Such quotations indicate the late 19th century awareness of the power of culture to perpetuate arbitrary beliefs. Less drastically expressed, some such perspective permeates present day social science, although tempered somewhat by functionalism in anthropology and sociology. In social psychology, for example, cultural tradition tends to be invoked primarily as an "explanation" for social evils, prejudice, resistance to ameliorative social change, and the like. The current emphasis upon conformity reinforces this view, in spite of Asch's (1952) demurrer. Yet there are, no doubt, restraints upon a complete arbitrariness to culture, particularly with regard to beliefs that lie within people's direct range of observation. Thus arbitrary and erroneous superstitions about the shape of fishhooks probably would not long survive the systematic drift pressures resulting from continual minor variations some of which are in the direction of noticeably more effective form. Here lies the problem in the theory of culture for which a laboratory analogue was sought.Since Sherif's (1936) classic studies on the formation of "social norms" in laboratory groups, there have been sporadic efforts to bring the process of cultural transmission into the laboratory. While much small group research might be so interpreted, the present study was in particular inspired by Sherif's studies, by Rose and Felton's (1955) "experimental histories of culture," and by the preliminary report of experiments on the evolution of "microcultures" by Gerard, Kluckhohn, and Rapoport (1956). In the

Objectives: To determine if the relative distance between the acetabular teardrops on unstressed and lateral compressive stress examination under anesthesia (EUA) pelvic fluoroscopic images is reproducible between independent reviewers. Design: Retrospective database review.Setting: Level 1 trauma center.Patients/Intervention: Fifty-eight patients with a lateral compression type 1 pelvic ring injury who underwent EUA.Main Outcome Measure: Validation of EUA objective measurements between blinded, independent reviewers using interclass and intraclass correlation coefficients.Results: There was excellent interobserver and intraobserver reliability between all reviewers. Values for each intraclass correlation coefficients (including 95% confidence intervals) were between 0.96 (0.95-0.098) and 0.99 (0.99-0.99) for all measurements. P values were ,0.0001 for all measured parameters. Conclusions:The relative change in distance between the acetabular tear drops during lateral compressive EUA of lateral compression type 1 pelvic injuries is reliable between independent reviewers. This allows for accurate, objective measurement of pelvic motion independent of patient size or body habitus.