Date of Award


Document Type


Degree Name

Master of Arts (MA)




Previous work has documented that cognitive deficits were observed in subjects tested at high altitudes (15,000 ft to 25,000 ft). Controversy remains as to whether cognitive deficits are observed at altitudes below 15,000 ft. The present study focused on this controversy, looking at the effects of moderate altitudes, 12,500 ft and 15,000 ft, on short term memory and compared them to a control altitude of 2,000 ft. Subjects were 72 students and instructors from the Department of Aviation Sciences at the University of North Dakota. After a series of pretests, including the Vocabulary Subtest of the Wechsler Adult Intelligence Scale-Revised, the Digit Span subtest from the Wechsler Memory Scale-Revised, the Vandenbcrg Mental Rotation Test, the Digit Symbol subtest of the Wechsler Adult Intelligence Scale-Revised, and the near-contrast sensitivity portion of the Vistech VCTS 6000 chart, subjects were assigned to one of three altitude groups and spent an hour and a half at their designated altitude for cognitive testing. One of the tasks administered was the Sternberg (Salthouse & Somberg, 1982) memory task. The second task was a dual attention task in which subjects performed a 30 min vigilance task while simultaneously listening to an audio tape with instructions to recall and read back a radio call prefaced by their assigned call sign. The audio tape of the radio calls contained four different call signs and half of the radio calls were high memory loads (at least 4 pieces of information) and half were low memory loads (no more than 2 pieces of information).

Analysis of variance was used to analyze the data. No consistent and interpretable effects were found in the Sternberg task. No effects of altitude were found in the vigilance task. The analysis of the readbacks revealed no significant difference for readbacks with low memory loads. However, for recall of readbacks with high memory loads, significant deficits in recall observed at 12,500 ft and 15,000 ft.