30-Second Psychology: The 50 Most Thought-provoking Psychology Theories, Each Explained in Half a Minute - Christian Jarrett 2011
Thoughts & Language
Quick, try to memorize this sequence of letters: UPSBMWCIAIOC. It’s a daunting task until you notice that it’s actually made up of four well-known acronyms: UPS and BMW are companies, and CIA and IOC are organizations. Without breaking the sequence of twelve letters into chunks, you’d have a hard time remembering them all. In 1956, US psychologist George Miller noticed that, although we can remember tens of thousands of items over the long term, the limit for short-term memory tasks such as this one seems to fall consistently around seven items - whether they are numbers, letters, words or even musical tones. But amazingly, Miller’s student, Sidney Smith, was able to teach himself to recall forty random binary digits (zeros and ones) by combining them into chunks eight digits long. Each sequence of digits was like a separate ’word’ to Smith, so he could remember many more digits than an untrained person. Similarly, we can remember long telephone numbers by chunking the digits into groups. We can quickly learn songs by chunking words into lines and rhyming pairs of lines - and the number of chunks that we can recall over the short term, Miller found, is nearly always very close to seven.
Under ordinary circumstances, we can remember about seven items at a time - but if we group them together into ’chunks’, we can remember many more.
While Miller’s work is quite robust, recent studies have questioned it. Are you really remembering seven chunks, or are you just grouping those chunks into even bigger chunks? In 2001, American psychologist Nelson Cowan argued that the capacity of short-term memory is much less than seven. When we are prevented from making new chunks by working simultaneously on another task, the number of chunks that we can remember is closer to four.
THE COGNITIVE REVOLUTION
The astonishing feats of performers at the annual World Memory Championships show how mnemonics can be used to extend short-term memory way beyond just seven items.