You remember old phone numbers but not the client you called yesterday, because your brain lets Google do the storing. Here’s an oddity: I can easily recite the land-line numbers of childhood friends Mike, Randy, and Louis. I have not dialled those sequences, or really even thought of them in over four decades. They’re useless, obsolete information. But they are there. And then somehow I cannot recall my sister’s phone number, or even the prefix of the client number I called yesterday. That...