If research is done to find out behaviours and attitudes by analysing existing records and other materials, it is known as

Studying behaviours and attitudes by analysing existing records and materials is archival research.

It relies on documents, registers, and stored data already produced by others.

Past research is not a recognised methodological term for this kind of inquiry.

Non-observational research is too vague and does not name this documentary method.

Non-participant research merely means the observer stays outside the group, not that records are analysed.

Archival sources are unobtrusive, so they avoid reactivity from the people being studied.