As the new academic year opens, universities across the US are unveiling new steps to combat "microaggressions", from discouraging use of the phrase "you guys" to banning jokes about Harambe, the gorilla killed in May at the Cincinnati Zoo.

America's universities are attempting to adapt to an environment in which student protests are increasingly common, and perceived prejudice or insensitivity can spark near-instantaneous outrage.

To do so many have added new diversity-focused faculty positions and implemented mandatory sensitivity training for students.

Sheree Marlowe, the new chief diversity officer at Clark University in Massachusetts, recently lectured incoming students about microagressions, or behaviours that can send unintended negative signals to a particular group.