Age differences in understanding of disease causality: AIDS, colds, and cancer.

The development of concepts of disease causality was explored by asking 9-, 11-, and 13-year-olds and college students about risk factors for AIDS, colds, and cancer. Their knowledge became more accurate and differentiated with age. Although younger children knew a good deal about what causes each of the diseases, they lacked knowledge of what does not cause them, often inferring that risk factors for one disease, especially AIDS, cause other diseases as well. Knowledge of true risk factors for a disease was largely independent of knowledge of non-risk factors, and knowledge of one disease was largely independent of knowledge of another. These findings provide clues as to how disease understandings evolve with age and suggest that health educators must both understand students' current knowledge structures and explicitly teach students to make important differentiations between risk and non-risk factors for a given disease and between distinct diseases.