A processing approach to the working memory/long-term memory distinction: Evidence from the levels-of-processing span task

Rose, N. S. & Craik, F. I. M. (2012). A processing approach to the working memory/long-term memory distinction: Evidence from the levels-of-processing span task. Journal of Experimental Psychology: Learning, Memory, and Cognition, 38, 1019-1029.

This paper examined whether long-term memory (LTM) can have effects on working memory (WM). LTM is a system for permanent knowledge, while WM is described as the ability to attend to relevant information while completing a task. Many models have been proposed to clarify the division between WM and LTM (e.g., multicomponent model, Baddeley, 1986; embedded models, Cowan, 1999). 

Perhaps one way to clarify the influence of LTM on WM is to examine how phenomena that have been known to impact LTM, also effect WM. For example, one hallmark finding related to LTM is that items are recalled better when they have been more deeply processed. Shallow processing might include repeating an item (phonological processing) whereas deep processing would involve making a connection with the meaning of a word (semantic processing). The present study investigated the influences of these Levels of Processing (LOP) on WM performance. In two studies, participants were first presented with questions cueing either a phonological judgment, “Does the following word RHYME with X?”, or a semantic judgement, “Is the following word a member of the CATEGORY X?" Participants were then shown a to-be-remembered word, about which they answered the question. After 4 to 8 items, participants had to recall all the to-be-remembered words, which was either a surprise (Exp. 2) or not (Exp. 1). This WM measure was compared for items to which rhyme or category judgments were made, which was considered to reflect either intermediate or deep processing, respectively. LTM was also measured in Exp. 1 by asking participants to choose the to-be-remembered words after a 10-min delay period. 

Not surprisingly, LTM benefited from LOP conditions, with better recognition for words processed semantically than phonologically. LOP effects in WM were mixed, however. A WM advantage was observed only for the immediate recall of 8-item lists in Exp. 2. Given that the test was a surprise in Exp. 2, participants might not have actively maintained the words by rehearsing them. As a result, those having been processed more deeply at initial encoding could have been recalled from LTM. 

These results suggest WM and LTM can be supported by the depth of processing of items in similar and different ways depending on encoding, maintenance and retrieval processes. Both phonological and semantic processing make contributions to WM and LTM. The findings suggest that encouraging deeper processing of a word at encoding will facilitate retention in the long term.  

Baddeley, A. D. (1986). Working memory. New York, NY: Clarendon Press/Oxford University Press.

Cowan, N. (1999). An embedded-processes model of working memory. In A. Miyake & P. Shah (Eds.), Models of working memory: Mechanisms of active maintenance and executive control (pp. 62–101). New York, NY: Cambridge University Press.

Blogger: Theresa is a MClSc/PhD Candidate, supervised by Dr. Lisa Archibald. Theresa’s work examines the learning of phonological (speech sound) and semantic (meaning) aspects of words.