Methodological limitations in synchronisation studies

• Criticisms have been made of early synchronisation studies and the methods employed
• commentators argue that there are many factors that may effect change in a woman’s menstrual cycle , including stress, changes in diet , exercise et cetera that might act as confounding variables
• This means that any supposed pattern of synchronisation as seen in the studies by McClintock and others is no more than would have been expected to occur by chance
• in addition research typically involves small samples of women and relies on participants self reporting the onset of their own cycle
• other studies have failed to find any evidence of menstrual synchrony in all female samples (Trevathan et al 1993)