The promises of positive change for women on screen that followed her role in the groundbreaking film Thelma and Louise have failed to materialise, leaving girls today with few role models, according to the actor Geena Davis.

The media continue to have a huge influence on how the world views women and girls, and how they view themselves, she said. But few current roles show women in powerful positions, and continue to reinforce damaging gender stereotypes.

Davis was speaking to the Guardian as research into the film industry showed that of characters in leadership positions, women were four times more likely than men to be shown completely naked. The study also found that 42% of men were shown in leadership roles, compared with 27% of women.