Scientists collected data on the date of onset of the menstrual cycles in a group of women who moved into a college dormitory together in the fall. The y-axis of the graph shows the mean difference (in days) between the onset of a woman's cycle and the average onset date of the rest of the women. Evaluate whether these data provide evidence for the existence of a human pheromone.

Video transcript

Hi everyone. Let's look for our next problem, pheromones are subdivided into several categories depending on the purpose of their production, identify which of the following pairs is matched incorrectly. So let's go through these answer choices looking for the one that is an incorrect match. So we've got choice A says territorial pheromones marking of boundaries. Well this is a correct match. That's what territorial pheromones are for many animals use them um prevents fights by marking their boundaries so another animal doesn't come in. But that is a correct pairing. So choice A. Is not our answer. Choice B. Says trail pheromones marking of paths. That is correct also um used by ants and bees and termites to mark paths to food sources so that other animals can follow them. So not our answer. Since we're looking for an incorrect match choice C says alarm pheromones trigger aggression among members of the same species. This is correct, triggers aggression as part of a protection factor. So for instance, bees when they sting a predator release these alarm pheromones kind of letting the other bees know to come and join and protect their hive. So that's a correct match and not our answer. And finally we're down to choice. The sex pheromones uh That says trigger change and developmental events. Um This is not correct sex pheromones help in the location and courtship during meeting. They can signal female receptivity and allow individuals to find each other locating a mate. And then in the courtship process. So that is not a correct match and the other part here. It's matched incorrectly matched to triggering changes in developmental effect events. Um That is caused by a different set of hormones our pheromones, I'm sorry and those are called primer pheromones. So primer pheromones trigger changes in developmental events. Sex pheromones signal female receptivity and help in location and courtship during mating. So choice D. Is the one that's matched incorrectly and therefore is our answer in the next video.