I am majoring in psychology.

He is known as an expert in criminology.

He engaged in psychological warfare in the chess match.

We conducted a psychological test in today's class.

He is a world-renowned bacteriologist.

He is a world-renowned biologist.

He is traveling around the world as an ecologist.

He is a world-famous archaeologist.

He is a beginner in Japanese.

He is a renowned criminologist who has contributed to many crime analyses.