Declarative Knowledge vs. Complex Task Performance
In Assessing Adult Literacy

Research by Ackerman suggests that declarative knowledge is a major contributor to the growth of "verbal intelligence" of literacy during the adult years.

The checklist approach to knowledge assessment developed by Stanovich and associates lends itself readily to the assessment of declarative knowledge. The use of simple items such as names or single vocabulary words, with each yes/no decision made independently of the other does not overload working memory.

This is an especially important factor when assessing the literacy of elderly adults. In the U.S. National Adult Literacy Survey (NALS), data for performance on prose, document, or quantitative scales indicate that, depending on which scale is discussed, performance gradually improved by about .16 to .36 standard deviations as aged increased from 16-18 through 40-54 years. However, above the age 54, there was a rapid decline of about half standard deviation for those 55-64 years, and over one standard deviation for those 65 years and older. Since it is well established that working memory becomes increasingly less efficient with advanced age, these findings strongly suggest that the NALS tasks derive a great deal of their difficulty from the load they place upon working memory. hence that may seriously underestimate the breadth of materials that older adults can read and comprehend using their knowledge base and the tasks they can perform in working memory given sufficient time to study materials and without the pressure for efficiency that is typical of test-taking situations.

The figure above compares performance of adults on tests of declarative knowledge using the checklist approach and the performance of complex tasks on the NALS. Clearly, growth in declarative knowledge continues beyond age 54 while performance on the NALS drops off rapidly above that age.