You've put your keys somewhere and now they appear to be nowhere, certainly not in the basket by the door they're supposed to go in and now you're 20 minutes late for work. Kitchen counter, night stand, book shelf, work bag: Wait, finally, there they are under the mail you brought in last night.

Losing things is irritating and yet we are a forgetful people. The average person misplaces up to nine items a day, and one-third of respondents in a poll said they spend an average of 15 minutes each day searching for items—cellphones,...