The Development of ShortTerm Working Memory in Young Infants

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The Development of Short-Term Working Memory in
Young Infants J. Steven Reznick, Kathryn
Cochrane, Barbara Davis Goldman, Hillary A.
Langley University of North Carolina at Chapel
Hill
ABSTRACT  We administered a delayed-response
task to 6 infants in a longitudinal, microgenetic
design, testing infants every two weeks from 5-7
months through 12 months. Each of the infants was
able to span a minimal delay by 9 months, and
many infants had a strong surge in memory
capacity at around 11 months. This developmental
timetable has implications for theories of neural
maturation and the infants underlying cognitive
architecture.

• METHOD
• Participants 6 infants (3 males, 3 females) (4
  European American and 2 African American) entered
  the study at 5-7 months of age and were tested
  every two weeks.
•  Apparatus The infant sat on a teachers lap
  facing a table with two covered wells.
•  Procedure
• The exact day and time of the test was
  determined by the infants state tests were
  conducted only when the infants teachers deemed
  the infant to be healthy and content.
• The examiner placed a desirable toy in one of
  two wells, covered both wells, imposed a delay,
  made sure that the infant had looked away from
  the wells, and then allowed the infant to search
  for the toy
• Each infant completed 10 to 20 trials in a
  session.
• The shortest delay between the toys
  disappearance and the infants search was labeled
  0 sec but in effect lasted approximately 1 sec.
  
• If the infant successfully retrieved the toy
  twice in 3 trials the delay was increased by 3
  sec increments to a maximum of 30 sec.

• RESULTS
• Each session was scored to reflect the longest
  delay attained by the infant in that session.
• All 6 infants reached criterion on the
  delayed-response task at or above a 1-sec delay
  before 9 months.
• Bi-weekly progress was gradual in the months
  that followed, but 3 of the 6 infants had a
  notable increase in memory span within a week of
  11 months.

• DISCUSSION
• These data are consistent with the claim that
  short-term working memory for the location of a
  hidden object emerges in most infants during the
  first year.
• Developmental curves suggest mostly monotonic
  change in memory span during subsequent months.
• The large boost in memory span at 11 months is
  notable.

Ongoing Replication Study
INTRODUCTION  Working memory can be defined as
the capacity to retain information such as the
identity or location of an event for seconds or
minutes and then use this information to develop
a plan, perform a task, or solve a problem.
Working memory is often assessed using a
delayed-response task in which information
specifying an objects location must be
maintained across a delay despite distraction and
must be updated trial by trial. Previous research
suggests an onset of working memory at around 6
months and rapid improvement in subsequent
months, continuing through the second year.
An x-month-old tries to find a hidden toy.