I found that there are several studies of processes occurring during climbing including the cognitive deficit, emotional changes and hallucinations at high altitude.
Peter Brugger (1999) in his article “Hallucinatory experiences in extreme-altitude climbers” insisted that “there is anecdotal evidence for a high incidence of anomalous perceptual experiences during mountain climbing at high altitude” (p. 66).
He had a structured interview with eight high altitude climbers who have reached the altitude above 8500 m without supplementary oxygen. The results from interviews showed that most climbers have hallucinatory experience during climbing at high altitudes, and apart from cerebral hypoxia, social deprivation, physical exhaustion, hypothermia, dehydration, lack of sleep, hypoglycaemia from food deprivation and acute stress seem to play a role in the genesis of these experiences.
Also, many high-altitude climbers have summit fever which is an anticipation to reach the summit disregarding safety, and ethics, among other things. When the climbers get summit fever, it clouds the climbers’ the decision-making process.
Tempest and co-authors (2007) quotes Krakauer’s “Into the thin air” in their article “In the Death Zone- A study of limits in the 1996 Mount Everest disaster”
“the sort of individual who is programmed to ignore personal distress and keep pushing for the top is frequently programmed to disregard signs of grave and imminent danger as well. This forms the nub of a dilemma that every Everest climber eventually comes up against: in order to succeed you must be exceedingly driven, but if you’re too driven you’re likely to die. Above 26,000 feet . . . the line between appropriate zeal and reckless summit fever becomes grievously thin. Thus the slopes of Everest are littered with corpses.” (Krakauer, 1997: 233)
Brugger, P., Regard, M., Landis, T., & Oelz, O. (1999). Hallucinatory experiences in extreme-altitude climbers. Neuropsychiatry Neuropsychology and Behavioral Neurology, 12(1), 67-71.
Carol L. Gohm (2001). Personality in Extreme Situations: Thinking (or Not) under Acute Stress. Journal of Research in Personality 35, 388–399 doi:10.1006/jrpe.2001.2321, available online at http://www.idealibrary.com
Greig, A. (1985). Summit fever : the story of an armchair climber on the 1984 Mustagh Tower expedition (3375842). London: Hutchinson.
Greig, A. (1997). Summit fever : an armchair climber’s init[i]ation to Glencoe, mortal terror and ʻThe Himalayan Matterhornʾ (1204221, Rev. ed.). Seattle: Mountaineers.
Tempest, S., Starkey, K., & Ennew, C. (2007). In the death zone: A study of limits in the 1996 Mount Everest disaster. Human Relations, 60(7), 1039-1064. https://doi.org/10.1177/0018726707081157