Forget that seven-year itch

A SYDNEY scientist has challenged the long held wisdom that seven is the ''magical'' number of new things the brain can process at one time.

More than 50 year ago, American psychologist George Miller published a study that measured people's recall of lists of new information.

Dr Miller concluded the brain's short-term memory capacity could absorb roughly seven pieces of information.

But when University of NSW psychiatry professor Gordon Parker asked people to repeat random lists of letters, words or numbers, confusion set in after four, he found.

"To remember a seven numeral phone number, say 6458937, we need to break it into four chunks: 64. 58. 93. 7,'' he said.

And when Professor Parker examined Miller's original data he found the results of his experiments showed the brain could handle only four chunks of information, not seven.

While there are plenty of examples of groupings of seven - the seven wonders of the world, the seven deadly sins and the seven days of the week - there are just as many references to four - four seasons, four Gospels, four card suits in a pack and the World Cup, Olympic Games and Rugby World Cup every four years.

The scientific consensus supported the four over seven for the amount of information the brain could absorb, Professor Parker said.

''There may be no limit in storage capacity per se but [there is] a limit to the duration in which items can remain active in short-term memory.''

This story Forget that seven-year itch first appeared on The Sydney Morning Herald.