The "Jensen effect" results from the correlation between the g factor and a
huge number of psychological and biological variables, Although Rushton (R
ushton, J. P. (1999). Secular gains in IQ not related to the g factor and i
nbreding depression - unlike Black-White differences: a reply to Flynn. Per
sonality and Individual Differences, 26, 381-389) proposed that the secular
increase in test scores is not a "Jensen effect", the present study demons
trates that this is true for crystallized tests but not fluid tests. A flui
d g factor is correlated with the generational changes observed in two succ
essive Spanish standardizations of the DAT battery. Contrary to Rushton's (
1999) findings - based on a crystallised g there is a positive correlation
between a fluid g and the generational cognitive change. There is one stron
g implication of the generational cognitive difference observed in the pres
ent study for the comparison of contemporary human populations: an environm
ental explanation of the current cognitive gap between some populations nee
d only posit that the current average environment for population A (with a
lower average score) marches the quality of the average environment for pop
ulation B (with a higher average score) a generation ago. (C) 2001 Elsevier
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