Infradian rhythms AO3

• strength - research supporting endogenous pacemakers and exogenous zeitgebers - McClintock (explain) - supprts both factors entraining the rhythm - however small sample of only 29 participants
• strength - further support in evolutionary basis - would have been advantageous for women to menstruate together bc they would get pregnant at same time. new-borns could be cared for collectively - suggests infradian rhythms would have been evolutionarily advantageous - however, critics say this isn't advantageous because it leads to too much competition for high quality males
• weakness - methodological shortcomings - many factors can influence menstrual cycle like stress which are confounding variables - any supposed pattern of synchronisation could be by chance which is why other studies failed to replicate findings of Stern and McClintock - menstrual synchrony studies like McClintock's are flawed and lack reliability
• weakness - a lot of it is based on animal studies - most knowledge of pheromones come from animal studies. e.g., sea urchins release pheromones into surrounding water so others will eject sex cells. results for human behaviour are inconclusive - findings lack external validity as animals are often kept in cages - not generaliseable
• Strength- practical application to treatment for SAD - phototherapy is an effective treatment for SAD where a lightbox simulates strong light in the morning and evening - research led to successful therapy and therefore increasing validity of the theory - on the other hand, there is doubts against phototherapy