I__. - International Military Testing Association

ABSTRACT
DIETARY EFFECTS ON TEST PERFORMANCE
Charles A. Salter
Laurie S. Lester
Susan M. Luther
Theresa A. Luisi
U.S. Army Natick Research, Development & Engineering Center
Natick, MA
Previous research suggests that meal composition may affect performance
on the automated Memory and Search Task (MAST). The purpose of this study
was to determine if lunch protein or carbohydrate would interact with caffeine to
affect performance and mood as assessed by the MAST, the Automated Portable
Test System (APTS), and visual-analogue mood scales. Male subjects were
assigned either to a protein lunch (5 g/kg turkey breast) or a carbohydrate lunch (5
g/kg sorbet) group so that normal caffeine intakes were equivalent. Within each
group, subjects rotated through two caffeine conditions in a counterbalanced order,
drinking two cups of either caffeinated or decaffeinated coffee with lunch. Caffeine
use was prohibited at other times during the study. The APTS was consistent with
the MAST in showing no performance effects of protein and caffeine, though
protein did correlate with some self-reported moods. The protein group reported
increased hunger over time (p=.OO2) and felt less dejected (p=.O4) than did the
carbohydrate group, while caffeine produced no significant effects. Greater
carbohydrate intake was associated with lower MAST scores, though the direction
of causation is unclear, and it had no effect on the APTS. It is concluded that
performance on the MAST and APTS are relatively unaffected by dietary
differences of this type and magnitude.
INTRODUCTION
The automated Memory and Search Task (MAST) uses a hand-held
computer to present stimuli consisting of randomized sequences of 16 alphabetic
characters each along with randomized targets of 2, 4, or 6 letters that the subject
identifies as being present within or absent from each stimulus (Salter et al, 1988).
The first studies with the MAST used it as a tool to assess dietary effects on
performance (Salter et al, 1988). These studies indicated a significant post-lunch
slump in MAST scores followed by recovery later in the afternoon. Salter and Rock
(1989) did not find a post-meal decrement in performance on the MAST when
slightly different times were used for testing. This latter study did find, however, that
the more protein subjects ate at lunch, the better they scored on the MAST
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