Short Term Memory

• Capacity of STM is 7+/-2
• Duration of STM is 18-30 seconds
• Encoding of STM is acoustic
• Short term memory is a unitary store
• Miller conducted the Magic Number 7 experiment to test capacity of STM
• The Magic Number 7 experiment used number lists to test the digit span of participants
• Jacobs measured capacity of STM by using digit span for both letters and numbers
• Jacobs found that the mean span for numbers is 9.3 and letters is 7.3
• The 3 stages of memory is acquisition, storage, and retrieval
• Synaptic pruning is where memories decay from lack of maintenance rehearsal
• Miller found that chunking increases capacity
• Acquisition is the early stage of the learning process where a response is first established
• Storage is the nature of the memory store e.g how and where a memory is stored
• Retrieval is the process of getting information out of storage
• Baddeley investigated the encoding of STM & LTM by using of lists of acoustically & semantically similar/dissimilar words and getting participants to recall immediately and after 20 minutes
• Baddeley found that immediate retrieval was more accurate for semantically similar words because they are encoded accoustically
• Baddeley found the long-term retrieval was more accurate for acoustically similar words because they are encoded semantically
• Peterson and Peterson investigated the duration of STM by preventing rehearsal for various periods of time before recalling
• Peterson and Peterson found that at 3 seconds 80% recalled accurately, but at 18 seconds 10% recalled accurately
• Peterson and Peterson's experiment used 24 psychology students in a lab
• Peterson and Peterson's experiment supports the multi-store model