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.
What approach was being used before the multivariate?
Univariate and bivariate research approaches were more commonly used before the multivariate approach.

Question: How did the multivariate help?
Self-contained rewrite: How did the multivariate research approach help research?