jacobs

• Jacobs (1887) conducted an experiment using a digit span test, to examine the capacity of short-term memory for numbers and letters.
• sample: 443 female students (aged from 8-19) from the North London Collegiate School. 
• Participants had to repeat back a string of numbers or letters in the same order and the number of digits/letters was gradually increased, until the participants could no longer recall the sequence.
• Findings: The student had an average span of 7.3 letters and 9.3 words, which supports Miller’s notion of 7 ± 2.