The stereotype of Polish people having inferior intelligence was introduced to the American public by anti-Polish Hollywood during WWII, by portraying Polish people as being backward and having inferior intelligence. This was part of Hollywood’s War on Poland during and after WWII. This was the precursor to the actual introduction of Nazi German subhuman intelligence jokes about Polish people that Hollywood and NBC-TV would RENAME as "Polish jokes".

Hollywood and the TV networks beefed up their anti-Polish bigotry when they then turned their negative stereotype of Polish people into “Polish jokes” in the late 1950's/early 1960’s. The origin of “Polish jokes” is actually Nazi German propaganda. Hollywood/NBC-TV RENAMED Nazi subhuman intelligence jokes about Polish people as “Polish jokes” and introduced them to the American public in the 1960’s to condition the American public to have the same anti-Polish prejudice that they have. They made sure not to reveal the Nazi origin of subhuman intelligence jokes of Polish people, because otherwise these hate jokes would have been rejected by the American public.
HOLLYWOOD'S WAR ON POLISH PEOPLE during WWII........was the first step of motion picture/TV anti-Polish Bigotry in America