I arrive home to a message on the answer machine. It's from Mum. She talks about how she's had a phone call from a relative and how she told her all about me and what's going on (I dread to think what sort of garbled message she passed on). Then how she went to see D (the Warden) this morning and sat outside his office door to talk to him and how he made her a cup of tea and gave her a biscuit and how special it made her feel. She ended the call by saying, "anyway, I'll get off now, so good-bye.........oh....hello?....hello? ooo [piqued]"
It dawns on me that, in the time it took her to leave the message, Mum forgot that she was talking to an answer machine, and was somewhat surprised and indignant not to get a "good-bye" from me at the end. Suddenly the 16 messages left on my machine a couple of weeks back make sense to me. The reason she was increasingly angry and kept calling out "hello" and asking "Why won't you talk to me?" that day was that she had forgotten that she was talking to a machine.
By my calculation, that puts Mum's short-term memory around one or two minutes.