From Page 7
(1) You're right.
affected by extreme cold.
On the other end of the continuum, heat also affects performance.
Performance under conditions of heat is affected by the amount of heavy work
to be done, the humidity level, and the amount of fluid lost from the body.
In general, heat stress takes its greatest toll in performance in physical
However, mental activities may be impaired if the
temperature is above 85F and the duration is longer than 1 hour.
Otherwise, people can function adequately in heat if they must.
Besides the effects on performance of temperature extremes, various
atmospheric gases can adversely affect man's ability to adequately perform a
task. For instance, carbon monoxide and carbon dioxide, among others, can
result in performance defects and even death, if man is exposed to too much
for too long.
In addition, Lesson 18 also discussed other atmospheric
effects, such as radiation and atmospheric pressure, which impact on
The point here is that the human factors specialist must be
aware of these variables and make sure they're dealt with in any system that
It should also be noted that man's ability to stay alert over extended
periods of time and monitor the occurrence of signals has been an important
area of study for HF specialists. It has been shown that, with the passage
of time, we find an increase in the number of missed or incorrectly
A key fact to be aware of is when this performance
decrement is greatest.
During a watch period, when would performance
(1) Very little decrement in performance occurs at all, unless the watch
period is extremely lengthy. Turn to Page 9.
(2) The greatest performance decrement occurs during the first 30-60 minutes
of watch. Turn to Page 66.
(3) Performance decrement occurs at a constant, gradual level through the
entire watch period. Turn to Page 33.
(4) None of these answers are correct. Turn to Page 6.