Working memory limits
🧩EXPLANATION
Working memory is what a person can hold in mind and use at one moment, and it is small. George Miller's 1956 paper, 🔬 The Magical Number Seven, Plus or Minus Two, is where the famous seven comes from. Two things I had wrong about it for years:
- He was counting chunks, not items. A phone number is ten digits or three groups.
- He was half joking about the number. Later work puts the span nearer four chunks for most material.
The way to stretch the limit is recoding: packing items into larger meaningful units. The limit on the number of units does not move.
Example from work, and why 214 exceptions is not a list: in Rotterdam a dispatcher had 214 open exceptions before nine. Nobody reads 214 of anything. They read the top of the screen and carry an anxious feeling about the remainder. That is where 🔍 Exceptions digest by e-mail comes from: five things at 07:00.
Often confused with: short-term memory as a store. Working memory is the store plus the work being done on it.
Notes: 📖 Miller on the limits of working memory. Claim: 💎 Working memory holds a handful of things so the list must hold the rest.