Shh, here's a secret.

Depending on what side of town you are on, you are only an hour or less from a dozen colleges, and University Circle is a great place to investigate "trials"and studies too, Case Western to Oberlin, CSU to Bowling Green, etc. etc.
Most "focus groups" for marketing companies may require some digging for, but many of these gigs pay decent money AND give you some knowledge. NEOUCOM paid 50 bux an hour to be a simulated patient.

I'll check my Rolodex, what area are you in?

gjabiz

As a result of Online colleges, and Community colleges, the "laws" of Academics have changed, however, most still like to see and some still require their professors to PUBLISH as part of their path to tenure.

What do they publish? Results from studies they conduct. These studies use students and general public. Almost every department has something cooking.

I suggest a copywriter study human behavior, Psychology Depts., which seem to always be conducting studies of some sort. Or, as in the case of U. of Akron, or any private research company, eye tracking or neuroscience studies, IF that is what interests.

Even English departments, may offer a study which could be useful to a copywriter.

I once did a "color" study at Kent State school of fashion, which introduced me to the idea of DISAMBIGUITY, a hot Dress topic on the Net these days.

A persuader, a copy writer, for example, knows how to use the mind's need for clarity, and by confusing the mind temporarily, a technique perfected by Milton Erickson, can grab and direct the mind.

Add in color studies, and you see why biggest online sites use blue.

gjabiz

PS. There are offline survey companies which also pay for your opinion, but colleges offer a wide variety of opportunities.