There's a good reason for why your grandma keeps telling you about the terrible experience she had with the checkout lady at the grocery store who wouldn't take her coupon and so she had to call the manager, etc. Your grandma doesn't remember that she told you already. In fact, no old people do! But there's more! Take it away, Science! "'Older adults are additionally highly confident, compared to younger adults, that they have never told people particular things when they actually had,' study co-author Nigel Gopie, a cognitive scientist at the Rotman Research Institute in Toronto, said in a statement. 'This over-confidence presumably causes older adults to repeat information to people.'" I bet you didn't know that!