Thought has a narrow desk

Working memory holds only a few items at once — on the order of four chunks in typical adults, not an inner theatre of unlimited space.

Miller’s famous ‘seven plus or minus two’ (1956) described a span for certain tasks. Cowan’s later work, and much that followed, puts the pure working-memory capacity nearer to three or four chunks when rehearsal and grouping are controlled.

That limit is why we write, why we diagram, why we talk to ourselves. External memory is not a crutch. It is how a four-slot machine builds cathedrals and proofs. Attention selects; the rest waits outside.

Load the desk and reasoning collapses: more errors, more reliance on habit, more susceptibility to the biases in the neighbouring entries. Education that ignores the limit — walls of undigested information — is a design failure.