Distinctiveness of disease prototypes in lay illness diagnosis: An exploratory observational study

Research on disease prototypes has revealed that lay illness diagnosis is influenced by symptom typicality, suggesting that it represents a "prototype-matching process". This study further investigates the role of disease prototypes by examining associations of prototype distinctiveness with diagnostic expectancies. One hundred and eight lay participants rated the typicality of 30 symptoms for nine common physical diseases. On this basis, two structural features of individual disease prototypes were calculated: (a) distinctiveness, that is, the dissimilarity of a prototype relative to the others (Euclidean distance measure), and (b) richness, that is, the sum of symptoms' typicality. Moreover, prototype confidence and illness experience were assessed. Finally, as a proxy to diagnostic behaviour, diagnostic expectancies, that is, prospective beliefs actually to diagnose a disease when experiencing relevant symptoms, were measured. Multiple regression analyses revealed prototype confidence as strongest predictor of diagnostic expectancies. However, positive and partly significant associations were also found with prototype distinctiveness on all levels of data aggregation (disease-specific, disease-cluster-specific, and overall). Results are discussed as to their implications for studies in lay illness diagnosis and designing health education materials. Specifically, it is concluded that such materials should include symptomatic information not only as to symptoms' typicality, but also their distinctiveness, that is, information aiding in distinguishing different diseases.

Keywords:

• Illness Representations
• Disease Prototypes
• Distinctiveness Of Prototypes
• Richness Of Prototypes
• Lay Illness Diagnosis