Reported two studies investigating the relationship between the extent
of children's experience with illness and their level of understandin
g about the causes of illness, Both studies compared children with exp
erience of a major chronic illness (cystic fibrosis in Study I and can
cer in Study 2) with children whose illness experience was relatively
minor and acute. The age range of the children in Study 1 was 4.6 to 1
0.6 years; in Study 2 it was 7 to 14 years. The measure of understandi
ng of illness was the Bibace and Walsh (1980, 1981) Piagetian-based te
st. To determine the specificity of illness experience effects, perfor
mance on this test was considered against a second measure of cognitiv
e functioning: conservation of amount and volume in Study 1; the Peabo
dy Picture Vocabulary rest-Revised in Study 2. Results point to both a
ge and experience as contributing to children's understanding of illne
ss. Methodological issues and implications for future research are dis
cussed.