Epilogue

Abstract

Cronbach (1957) has differentiated between two major disciplines of scientific psychology, namely between experimental psychology and correlation psychology. In experimental psychology the scientist changes conditions systematically in order to observe their consequences. The psychophysical studies in Wundt’s laboratory in Leipzig a century ago started experimental psychology (Wundt 1888). In correlation psychology the scientist studies “correlations presented by Nature (…) and the correlator finds his interest in the already existing variation between individuals, social groups, and species. By ‘correlation psychology’I do not refer to studies relying on one statistical procedure only…” (Cronbach 1957).