Short- and long-term memory contributions to immediate serial recognition: evidence from serial position effects.
A long-standing body of research supports the existence of separable short- and long-term memory systems, relying on phonological and semantic codes, respectively. The aim of the current study was to measure the contribution of long-term knowledge to short-term memory performance by looking for evidence of phonologically and semantically coded storage within a short-term recognition task, among developmental samples. Each experimental trial presented 4-item lists. In Experiment 1 typically developing children aged 5 to 6 years old showed evidence of phonologically coded storage across all 4 serial positions, but evidence of semantically coded storage at Serial Positions 1 and 2. In a further experiment, a group of individuals with Down syndrome was investigated as a test case that might be expected to use semantic coding to support short-term storage, but these participants showed no evidence of semantically coded storage and evidenced phonologically coded storage only at Serial Position 4, suggesting that individuals with Down syndrome have a verbal short-term memory capacity of 1 item. Our results suggest that previous evidence of semantic effects on "short-term memory performance" does not reflect semantic coding in short-term memory itself, and provide an experimental method for researchers wishing to take a relatively pure measure of verbal short-term memory capacity, in cases where rehearsal is unlikely.
Purser
Harry
H
Developmental Neurocognition Lab, School of Psychology, Birkbeck College, University of London, London, UK. h.purser@bbk.ac.uk
Jarrold
Christopher
C
D002648:Child; D002675:Child, Preschool; D006801:Humans; D008037:Linguistics; D008297:Male; D008570:Memory, Short-Term; D010700:Phonetics; D021641:Recognition, Psychology; D012660:Semantics