A promising avenue for characterizing individuals lies in an examination of the antecedents of recorded behaviors. Autobiographical information from college students was used as an alternative to traditional personality methodology to demonstrate the scientific utility of biodata. The traits selected for investigation were positive and negative emotionality. Biodata items were clustered rationally, based on their correlations with the traits in question and divided into two classes, i.e., behavioral and developmental. Hypotheses were formed about the relationship between various background variables and emotionality, independent of the clustering process. Results yielded a substantial overlap between the hypotheses and the clusters, providing evidence for the validity of the clusters and for the utility of biodata methodology in personality research. In addition, the biodata substantiated virtually all previous research findings. The findings appear to extend current knowledge of the specificity of the relationships between background and positive and negative emotionality. (Author/JAC)