This study, conducted on a sample of 403 adult subjects, set out to explore
the relationships between measures of digit span (forward and reversed), m
otor and spatial span, and their dependence on a broad range of measures of
cognitive function. The results revealed that measures of digit span are c
losely related, as are measures of motor and spatial span, but these pairs
of memory span measures are relatively independent of each other. Furthermo
re, reverse digit span, motor span, and spatial span appear to rely on what
might be regarded as intellectual or executive cognitive functions. As suc
h, the results provide little support for accounts of serial recall, which
suggest that order and/or item information are more adequately modelled in
a modality-independent form.