Flights into deteriorating weather conditions : investigating cognitive biases in weather-related decision making : a thesis presented in partial fulfillment of the requirements for the degree of doctorate of Philosophy in Aviation at Massey University, Manawatu, New Zealand
In this thesis, the author‘s aim was to investigate whether the use of three cognitive heuristics may lead to systematic biases leading visual flight rules (VFR) qualified pilots to make inappropriate or ineffective decisions when faced with adverse weather and fly into instrument meteorological conditions (IMC). Although heuristics may reduce cognitive workload in weather-related decision making, they may lead VFR pilots to judge weather conditions as being better than they are in reality and continue flight into IMC conditions, when diverting or turning back would be the judicious choice.
Three cognitive biases that may potentially occur in pilot decisions to fly from VFR into IMC were identified: anchoring effect, confirmation bias and outcome bias. Three vignette-based studies found that pilots tended to anchor and under-adjust on initial information (n = 201), favour a confirmatory strategy when testing a hypothesis (n = 278) and evaluate judgments by the outcome rather than the decision process (n = 300).
Three intervention studies tested whether encouraging pilots to consider additional information rather than focusing on a narrow set of evidence when making judgments could reduce the impact of the three cognitive biases. Although a 'consider the alternative' strategy is sometimes effective, it was largely unsuccessful in reducing all three cognitive biases (n = 101). The perseverance of the biases in all six empirical studies is discussed in relation to the extant literature, as are the implications for flight-training and general aviation pilots generally.