Posted May 25, 2008
The Construct Validity of Memory Span
as a Measure of Intelligence
A Presentation at the North
Carolina Cognition Conference
Chapel Hill, NC
Bruce L. Bachelder, PhD
Independent Practice of Psychology,
Morganton, NC 28655
One point of view in working memory research is that memory span
measures merely storage, not intelligence. That interpretation,
however, is challenged by a century of research data and intelligence
assessment. Limited storage capacity is only one of several
interpretations of memory span (Bachelder, 2005). Memory span is
more closely related to
intelligence than is commonly thought (Bachelder & Denny, 1977a, b;
Jensen, 1970). As a measure of intelligence, memory span has poor face
but excellent construct validity.
(1) summarized competing interpretations of memory span as due to a
limit on storage, attention, or the ability to cope with span load
(“complex stimulus control”);
(2) reviewed the psychometric concepts of face and construct validity;
(3) presented the empirical features of memory span which parallel the
characteristics of intelligence; and
(4) discussed how a prominent point of view could conflict so sharply
with a century of data and practice.
Bachelder, B. L. (2005). The spans
question: Challenges to the memory interpretation of the "memory" span
test. Paper presented at the Annual North
Carolina Cognition Conference.
Bachelder, B. L. and Denny, M. R. (1977). A theory of intelligence: I.
Span and the complexity of stimulus control. Intelligence, 1(2), 127-150.
Bachelder, B. L. and Denny, M. R. (1977). A theory of intelligence: II.
The role of span in a variety of intellectual tasks. Intelligence, 1(3), 237-256.
Jensen, A. R. (1970). A theory of primary and secondary familial mental
retardation. In N. R. Ellis. (Ed.), International
review of research in mental
New York, Academic Press.