Although hypoxia is believed to occur above altitudes of 10,000 ft, some have
suggested that effects may occur at lower altitudes. This pilot study explored risk
judgments under conditions of mild hypoxia (simulated altitude of 8,000 ft). Some
evidence of an increased optimism was found at this level, suggesting the need for a
larger scale study with more experimental power.
Gilbey, Andrew, Toby Mundel, Stephen Legg, Stephen Hill, Zac Schlander & Aaron Ramon (2010). A pilot test of the effect of mild-hypoxia on unrealistically optimistic risk judgements. Aviation Education and Research Proceedings, vol 2010, pp 7-12.