An infradian cycle is a cycle completed in more than one day eg: the menstrual cycle
Stern & mclintock investigated how the menstrual cycle may synchronize as a result of the influence of pheromones.
They studied the mestrual cycle history of 29 women. They sampled pheromones with cotton pads under the armpit for 28 days. Then they were put on the top lip of another woman and then they reported the onset of their cycle.
They found that 69% women experienced changes to their cycle, bringing them closer to their ‘odour donor’
