Even if memories fade when not recalled for a long time, they also change when retrieved and stored again. Since memories are stored in the same neurons, when we have similar experiences, memories don't get stored separately but merge together. That's why treating painful memories isn't about forgetting them, but rather diluting them by overlaying positive experiences (). A year of life represents 100% of a one-year-old's experience but only 2.5% of a forty-year-old's consciousness, which is why it occupies a smaller portion in our memory as well. This is why time seems to pass more quickly as we age.