knowledge of natural sciences like biology is also basic Marxism. Marxists must be materialists , which is to say have a scientific world outlook . Can't have a scientific world outlook and not know literally the FIRST THING about biology , which is the principle of sexual reproduction. It's appalling ignorance instituted by capitalist sexual repression in the Freudian sense.
Marxists critique , but engage Freud; the post mod psychologists have taken Bourgeois psychology a big step backwards from Freud, who as I say , was not perfect at all.
There is a need for focused Marxist psychology; in analyzing advertising and other bourgeois methods of brainwashing and even healing some of the proletariat . Marxist psychology would be rooted in Marx's theory of alienation.