article_snippet: The study tested 33 healthy women.
article_snippet: When the films were over, scientists took samples of the women's immune cells, known as natural killer cells, and mixed the women with cancer cells to see how effectively the women attacked the disease.
article_snippet: And she believes far more research needs to be done on this cultural tic. '
article_snippet: I think it's a fascinating social behaviour, it is essential to study.'