"In response to first names, the high and low recallers produced different waves," Perrine Ruby, the study's lead author, told PopularScience.com. "The high recallers seem to be much more reactive to the environment. Low recallers seem to be much more resistant [to sounds interfering with the task at hand]," she says. This high reactivity could be related to why the high recallers woke up more often during their sleep, a process that probably explains why they remember more in the morning. "There is a strong hypothesis that awakening during sleep facilitates [encoding a] dream in memory," she explains.