Three lay mental models of disease inheritance

Genetics are coming to play an increasing role in biomedical understanding of common diseases. The implication of such findings is that at-risk individuals may be offered predictive genetic tests. How do individuals make decisions about predictive tests and what information do they need to make informed choices? Richards [Richards, M.P.M., 1993. The new genetics: some issues for social scientists. Sociology of Health and Illness 15, 567–586] has argued the first step in understanding and helping people to make these decisions is to investigate lay beliefs of genetics. This study examined mental models of inheritance in a sample of 72 lay people. Through analysis of open-ended questionnaires we found three mental models which loosely corresponded to three phases of historical development in the science of genetics. These we labelled the Constitutional, Mendelian and Molecular Models. Predictions for individuals holding each model are made for the comprehension of genetic information in a testing situation.