Psychological research was in a kind of rut in 1955 when George
A. Miller, a professor at Harvard, delivered a paper titled "The
Magical Number Seven, Plus or Minus Two," which helped set off an
explosion of new thinking about thinking and opened a new field of
research known as cognitive psychology.
The dominant form of psychological study at the time,
behaviorism, had rejected Freud's theories of "the mind" as too
intangible, untestable and vaguely mystical. Its researchers instead
studied behavior in laboratories, observing and recording test
subjects' responses to carefully administered stimuli. Mainly, they
Mr. Miller, who died on July 22 at his home in Plainsboro, N.J.,
at the age of 92, revolutionized the world of psychology by showing
in his paper that the human mind, though invisible, could also be
observed and tested in the lab.
"George Miller, more than anyone else, deserves credit for the
existence of the modern science of mind," said Steven Pinker, a
Harvard psychologist and author. "He was certainly among the most
influential experimental psychologists of the 20th century."
Mr. Miller borrowed a testing model from the emerging science of
computer programming in the early 1950s to show that humans' short-
term memory, when encountering the unfamiliar, could absorb roughly
seven new things at a time.
When asked to repeat a random list of letters, words or numbers,
he wrote, people got stuck "somewhere in the neighborhood of seven."
Some people could recall nine items on the list, some fewer than
seven. But regardless of the things being recalled -- color-words,
food-words, numbers with decimals, numbers without decimals,
consonants, vowels -- seven was the statistical average for short-
term storage. (Long-term memory, which followed another cognitive
formula, was virtually unlimited.)
Mr. Miller could not say why it was seven. He speculated that
survival might have favored early humans who could retain "a little
information about a lot of things" rather than "a lot of information
about a small segment of the environment."
But that, he concluded, was beside the point. He had articulated
an idea that was to become a touchstone of cognitive science: that
whatever else the brain might be, it was an information processor,
with systems that obeyed mathematical rules, that could be studied.
Mr. Miller, who was trained in behaviorism, was among the first
of many researchers and theorists to challenge its scientific
principles during the 1950s. Mr. Miller and a colleague, Jerome S. …