Traditional chivalry is a subtle form of sexism despite its “seemingly positive” qualities, according to the authors of a new psychological study.

The study, published in the Psychology of Women Quarterly journal, uses examples of “benevolent sexism” that include using “he” to refer to a person of unknown gender, helping a woman by carrying shopping bags, or offering to drive on long-distance journeys.

Such acts imply a woman cannot perform the task without help from a man, the report’s authors argue.

Other examples include paying for dinner, seeing a woman safely home and “paternalistic treatment” that they describe as “a woman being cherished or protected by men”.

The study asked both male and female students in Germany and the United States to keep diaries of events in their lives. One group was specifically asked about sexist incidents, while another was asked about more general social interactions. Neither knew about the purpose of the study.

“Women endorse sexist beliefs, at least in part, because they do not attend to subtle, aggregate forms of sexism in their personal lives,” the report concluded.

“Many men not only lack attention to such incidents but also are less likely to perceive sexist incidents as being discriminatory and potentially harmful for women.”

The report’s authors said that “benevolent sexism” is not recognised as a problem, despite "its negative implications and consequences".

“The seemingly positive and flattering qualities, embedded within normative and therefore unnoticed or unacknowledged unequal gender relations, hides the harm benevolent sexism can promote and encourages its endorsement,” they wrote.