Conversation so far:
What is multivariate research?
Raymond Cattell pioneered the use of multivariate experimental psychology (the analysis of several variables simultaneously).
What else can you tell me about multivariate research?
The multivariate approach allowed psychologists to study the whole and their unique combination of traits within a natural environmental context.

Question: What was being used before the multivariate?
Self-contained rewrite: What approach was being used before the multivariate?