Page 33 - Biobehavioral Resilence to Stress

10 Biobehavioral Resilience to Stress

The ASVAB, consisting of a number of scales (or subtests), is given to all

personnel entering the U.S. military. The Armed Forces Qualifi cation Test

(AFQT) is calculated from four scales of the ASVAB: (1) word knowledge,
(2) paragraph comprehension, (3) arithmetic reasoning, and (4) mathematics

knowledge. The AFQT is a good measure of intelligence, and, in fact, was
used as a measure of intelligence by the Centers for Disease Control (CDC)
for its Vietnam Experiences Study (1988).
Higher AFQT scores are modestly associated with lower attrition,
meaning that those endowed with good intelligence are likely to do relatively
well in the military (this assertion is based on the results from more than
two dozen studies; see Knapik et al., 2004, p. 10). When high school graduate
status is controlled for, AFQT is still a modestly successful predictor of attri-
tion, suggesting that the reason intelligence is a relatively good predictor of
attrition is not simply because recruits with more education do better on the
AFQT. On the other hand, high school graduation status is a more powerful

predictor of attrition than is the AFQT composite. Th is difference is probably
due to the additional relevance of other psychosocial variables. Presumably,
successful high school graduation represents some degree of perseverance,
generally appropriate behavior, and ability to function cooperatively with
teachers and peers (Knapik et al., 2004, pp. 6–7).
Several studies have reported higher rates and increased severity of
PTSD symptoms among individuals with lower intelligence scores (Kaplan
et al., 2002; Macklin et al., 1998; McNally & Shin, 1995; Silva et al., 2000;
Vasterling et al., 2002). Among military personnel, this correlation (r = –0.25;

McNally & Shin, 1995) remains significant even after adjustment for com-

bat exposure and education level. Intelligence measures gathered before and

after combat exposure (using the AFQT and a standardized intelligence test
given at a Veterans Administration Medical Center) indicate that lower intel-
ligence increases the likelihood of developing PTSD. Th ese findings do not

support the hypothesis that PTSD symptoms negatively aff ect performance
on intelligence tests. Rather, intellectual ability may be a protective factor
for several reasons. It may allow individuals to better (1) comprehend their
symptoms, (2) express themselves when talking about their symptoms, and
(3) engage in flexible and creative problem solving.

Criminal History

Preservice antisocial behavior has been identified as one possible predictor
of military attrition (Knapik et al., 2004). Unfortunately, many recruits enter
military service with a history of antisocial or criminal behavior. For exam-
ple, in one survey of 1891 male U.S. Navy recruits, 15% reported that they had
either attempted or completed a rape (Merrill et al., 1998). Among these indi-
viduals, 14.6% reported using force or the threat of force; 57.7% attempted or

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