Long-term memory for speech in 2 to 4-week-old infants

Long-term auditory memory in 2-4-week-old infants was examined using speech stimuli, a longitudinal design with controls within and among groups, and behavioral indices of recognition. Fifteen infants (mean age = 14 days) divided into two experimental groups and one control group participated in the study. Mothers in both experimental groups repeated a training word to their infants 60 times per day for 13 days. Tests for recognition of the training word and the infant's first name were conducted when the infants were approximately 22, 25, 28, and 29 days of age. The average delay between training word exposure and recognition testing was 14 hours for the first three test sessions and 42 hours for the final test session. Control infants received comparable test exposure but no training word repetitions. By one month of age, experimental infants demonstrated recognition of their training word following both 14- and 42-hour delay intervals, but name recognition did not occur. Control infants failed to recognize any of the stimuli presented. The results imply a capacity for auditory long-term memory among 1-month-old infants.