bu makaleden "RESULTS
Test of Heterogeneity
Effect sizes were found to range from 0.9 to 6.4, and showed sufficient heterogeneity, Q(100)  1,028, p  .00001, to justify further examination.
Effects of Exercise
Point estimates for effect size on all cognitive tasks were 0.164
(SE  0.028, n  96, p  .05) for control groups and 0.478 (SE
0.029, n  101, p  .01) for exercisers, suggesting that both groups
improved between Times 1 and 2. However, the control groups’ improvement was about 1/8 a standard deviation, whereas the exercise
groups’ improvement was nearly 1/2 a standard deviation, on average.
Both values are significantly different from zero, and from each other
(see Table 1).
Exercisers
Theoretical variables
An examination of the estimates for each task-process category revealed
that exercise had the greatest effect on executive processes (g  0.68,
1. Another option when coding the tasks would be to use a subtractive approach, in which, when possible, the more complex executive or controlled processes would be estimated by subtracting presumably lower-order processes (e.g.,
speed) from the higher-order ones. In this manner, we could presumably have reduced the contamination of basic speed of processing within controlled and executive processes. However, the logic of “pure insertion” required under such an
approach is somewhat suspect, and, moreover, the extant data would not allow
such a procedure to be uniformly applied to all studies or tasks. As a result, we
opted for the more conservative, but uniform procedure described here.
2. Dividing the effects in this manner yielded 42 in the mostly male group,
and 53 in the mostly female group. Although a finer-grained examination of
these effects would be desirable (e.g., 25%, 26–50%, 51–75%, 76–100%),
the available data were not amenable to such analyses.
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PSYCHOLOGICAL SCIENCE
Fitness and Cognition
128 VOL. 14, NO. 2, MARCH 2003
SE  0.052, n  37, p  .05); this effect was significantly greater
than the effect of exercise on any other type of cognitive process.
However, as is evident in Figure 1, exercisers also improved reliably
more than control subjects on controlled (g  0.461, SE  0.035,
n  74, p  .05), spatial (g  0.426, SE  0.062, n  23, p  .05),
and speed tasks (g  0.274, SE  0.050, n  32, p  .05). Given the
high degree of overlap among the executive, controlled, and spatial
task categorizations, an exploratory analysis was conducted on spatial
and controlled tasks, holding out executive tasks. Controlled tasks in
isolation still showed a reliable nonzero effect size (g  0.17, SE
0.048, n  31, p  .01), but spatial tasks did not (g  0.203, SE  0.111,
n  6, n.s.). However, the nonsignificant results in the spatial tasks may result largely from a lack of power and should be interpreted with caution.
Training characteristics
Interestingly, participants in combined strength and aerobic training regimens improved to a reliably greater degree than those in aerobic training alone (0.59 vs. 0.41, SE  0.043, n  101, p  .05). Also,
participation in relatively brief training programs provided at least as
much benefit as moderate training, but not quite as much as long-term
training programs. Finally, short bouts of exercise (30 min) had very
little impact on cognitive function; the effect at this training duration
was not significantly different from zero (see Table 1).
Participants’ characteristics
The meta-analysis revealed that when the participant population
was more than half female, the group as a whole showed greater benefit than if the population was at least half male. Additionally, participants in the mid-old category seemed to benefit most from exercise.
Interestingly, clinical and nonclinical populations showed similar
improvements with exercise (g  0.47 for clinical, g  0.48 for nonclinical), suggesting that exercise interventions can be equally efficacious for clinical and nonclinical populations.
Control Participants
There were no reliable effects of theoretical variables on effect size
for control participants, nor were there many reliable effects of the
moderator variables. However, one finding is worth noting. In the control group, performance of the young-old (g  0.108, SE  0.053, n  23,
p  .05) and middle-old (g  0.258, SE  0.045, n  48, p  .05)
increased much more than performance of the old-old (g  0.076, SE
0.058, n  25, n.s.)." bu başlıkkların altını doldur B. Nörogörüntüleme Çalışmaları:
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