The strange thing about the last biscuit is not that it exists but that it works, most of the time, for most people. Put a number on memory and it becomes a target; put a target on it and the number stops meaning what it meant. The usual story is that we are careless calculators. The better story is that we are careful about the wrong things. Nobody sets out to be governed by the last biscuit, yet it shapes an astonishing share of the ordinary day.
What follows
The lesson is modest. Build for the person who exists, not the one in the model. If you want to see memory at work, watch a queue form where there is no reason for one. The textbook treats memory as a preference to be revealed. In practice it is a story we tell ourselves after the fact. The evidence here is thinner than the confident commentary suggests, and the honest position is a shrug with a direction of travel.
