McClintock demonstrates the potential role of EST on menstrual synchronicity. For example, over time the cycles of the women aligned. This is important because, as EST is a modulator pheromone, it may have had an effect on the women living in close proximity and caused a change in bodily functions such as menstruation. However, repeated studies have never identified the same conclusion as this, meaning the findings are questionable and other factors may have affected the behaviour. Therefore, pheromones may have a potential role on behaviour.