T. Bates et C. Stough, PROCESSING SPEED, ATTENTION, AND INTELLIGENCE - EFFECTS OF SPATIAL ATTENTION ON DECISION TIME IN HIGH AND LOW IQ SUBJECTS, Personality and individual differences, 23(5), 1997, pp. 861-868
Mental-speed theories of intelligence (Spearman, The abilities of man,
1927; Lemmon, Archives of Psychology, 15, 5-38, 1927-28; Jensen, Jour
nal of Social and Biological Structures, 3, 103-122, 1980; Jensen, Spe
ed of information processing and intelligence, 1987) are challenged by
the finding that, in some methods, bright subjects do not appear to p
rocess information at an increased speed. The present experiment was d
esigned to explore new RT measures which might relate more strongly to
IQ while possessing a clear theoretical relationship to biological th
eories of intelligence. One direct measure of information processing s
peed is the rate at which choice reaction time (RT) increases with inc
reasing stimulus information content (RT slope). While RT slope is a c
ritical variable in mental-speed models of intelligence, the results o
f several experiments, since Jensen proposed his model, suggest that s
lope does not correlate strongly with intelligence. We investigated th
e possibility that spatial attention affects the relationship between
RT and re in the traditional Jensen paradigm. Thirty-five subjects per
formed an RT task with two and four choice stimuli presented in narrow
and wide spatial configurations. Correlations between Raven's Advance
d Progressive Matrices (APM) scores and RT were in line with previous
reports of a moderate negative relationship between IQ and RT. However
, a much stronger effect was found in the relative speed in the narrow
and wide spatial display conditions. The wide minus narrow RT differe
nce in the two-choice condition correlated 0.71 with APM scores. This
result suggests that the processing speed advantage of high IQ subject
s is best revealed under optimal attentional conditions. It is suggest
ed that this result supports the speed of processing model of intellig
ence. Paradoxically, the traditional Jensen paradigm confounds the hig
h choice orders with increased spatial attention demands, thus artifac
tually increasing the RT slope in high, but not in low, IQ subjects. E
xplicit control of spatial attention requirements indicates that indiv
idual differences in intelligence are substantially underpinned by dif
ferences in the speed of information processing mechanisms which, in h
igh IQ subjects, require focused attention if they are to be deployed
adequately. (C) 1997 Elsevier Science Ltd.