in men of sensory , genitourinary , and cardiovascular complaints with
age. These results are hardly surprising, but they do demonstrate thatthe analyses work when a true maturational effect is there to be found.
The Douglas and Arenberg (1978) study of GZTS scales and a more
recent study of NEO-PI scales provide examples of the kinds of infer -
ence that can be made when multiple analyses are conducted in the
same sample.
Longitudinal analyses of the GZTS showed that 5 of the 10 scales
declined between the first administration and the second, some 7 yearslater. But the results of other analyses indicated that only two of thesewere likely to be aging effects. Thoughtfulness and Personal Relationsshared a pattern of effects in longitudinal, cross-sequential, and time-sequential designs but not in the cross-sectional analysis. The longitudi -
nal effect may have been the result of aging, time, or practice; the cross-
sequential effect, of aging or time; and the time-sequential effect, ofcohort or time. The one common element in the three designs is time ofmeasurement, so it seems likely that during the decade of the 1960sparticipants become less thoughtful and less trusting of others. This lineof reasoning is confirmed by the failure to find any cross-sectionaldifferences in Thoughtfulness or Personal Relations: When everyone ismeasured at the same time, there are no age or cohort differences.
Friendliness shows a more complex pattern. Like Thoughtfulness
and Personal Relations, it declined in the three designs that share timeof measurement as an effect, but it also showed a cross-sectional in-
crease . Douglas and Arenberg (1978) interpreted this as evidence not of
maturation but of long-term cultural change: “Successive cohorts andindividuals became more easily aroused to hostility and tended to beless agreeable” (p. 745). Certainly we would want to see replications ofthis finding before accepting it as valid.
Only two traits survived this screening: Masculinity and General
Activity level, both of which declined with age in cross-sectional, longi -
tudinal, and cross-sequential designs but showed no effect in the time-
sequential analysis. Results were just what one would expect if therewere maturational changes in Masculinity and Activity , and the only al -
ternative explanations involved complicated and improbable combina -
tions of practice, time-of-measurement, and cohort effects.
However, the changes in both General Activity level and Masculin -
ity on the GZTS are extremely small. For the statistician, the statement
that they amount to about one-eighth of a standard deviation over 7Growth or Decline in Personality 75