found online by Raymond
From The Journal of Improbable Research:
It seems that a lack of sleep may prevent the brain from forgetting unimportant information. A lack of sleep may also prevent the brain from remembering important information. How can scientists make sense of this seemingly-nonsensical seeming-contradiction?
Imagine you just met your child’s teacher, who is named Gwen. The name Gwen, however, is firmly associated in your memory networks with your grandmother, who is also named Gwen.
Under such conditions, you may unintentionally think that your grandmother has no children, or that the teacher is in fact your grandmother.