This hypothesis suggests that women concealed ovulation to obtain men's aid in rearing offspring. Schoroder summarizes this hypothesis outlined in Alexander and Noonan's 1979 paper: if women no longer signaled the time of ovulation, men would be unable to detect the exact period in which they were fecund. This led to a change in men's mating strategy: rather than mating with multiple women in the hope that some of them, at least, were fecund during that period, men instead chose to mate with a particular woman repeatedly throughout her menstrual cycle. A mating would be successful in resulting in conception when it occurred during ovulation, and thus, frequent matings, necessitated by the effects of concealed ovulation, would be most evolutionarily successful. A similar hypothesis was proposed by Lovejoy in 1981 that argued that concealed ovulation, reduced canines and bipedalism evolved from a reproductive strategy where males provisioned food resources to his paired female and dependent offspring.