The effects of mild hypoxia on a logical reasoning task.

In an attempt to replicate the findings of Crow and Kelman (1969) and Denison et al. (1966), which suggest that the performance of novel tasks can be impaired at altitudes below 3,050 m, 150 subjects were divided into five independent groups and their performance tested on a logical reasoning task. One group was tested at ground level in a lecture room; the remaining groups were tested in a decompression chamber, one at 305 m, one at 2,440 m, one at 3,050 m and one at 3,660 m. Significant differences were identified between the 'lecture room' and 'chamber' groups in both speed of work and error rate (p less than 0.05); this finding is interpreted as the effect of apprehension on the naive subjects. A significant difference was found between the group tested at 3660 m and the remaining groups for error rate (p less than 0.05); this finding is interpreted as the effect of apprehension on the naive subjects. A significant difference was found between the group tested at 3660 m and the remaining groups for error rate (p less than 0.05) but not for speed of work. However, no effect of altitude on the way in which the task was learned could be demonstrated.