Yes, let's talk about each one separately.
Sexism in psychology has it's roots as far back as Sigmund Freud. Freud originally felt that males were superior to females and evidence of this goes into his theory of psychosexual development where he talked about females having penis envy and general jealousy over the superior male. Even AlXXXXX XXXXX identified masculine and feminine protests by indicating that strong traits where males and weaker traits were female. Even Karen Horney geared her theory to support what she thought was rampant sexism.
Psychology's implications in cultural imperialism were shown through many different facets of history. None more prevalent than Adolf Hitler who attempted to use even obscure psychological theory such as evolutionary psychology to show that Jews, Gypsies and other "undesirables" were cranially deficient and inferior. Social psychology was used especially used to influence hundreds of thousands of German citizens to believe that they were a superior race and that others were inferior. This allowed extreme actions including mass murder, showing both cultural imperialism and racism.
This is also true of racism in psychology where cognitive theory was twisted in an attempt to show that the intellect and abilities of African Americans were inferior to that of other cultures. This occurred as recently as the 1950's when segregation was resisted and prejudiced groups used psychology in an attempt to prove their opinions.
I hope this helped,Kate