Decision Making / 1 / 1.5 / 1.5.3

1.5.3 Human Decision Making—When We Get It Wrong

Klein (1998) argues that heuristics, particularly the recognition heuristic, bounded rationality, and mental simulation of selected strategy or strategies, play critical roles in decision making. Klein argues that whilst heuristics are generally associated with decision making under pressure of time, they are used in deliberate decision making much more frequently than many decision makers would admit.

Gigerenzer, et al., (1999) join Klein in suggesting that the use of heuristics is not confined to situations where time and information are limited. Indeed, it seems there is surprisingly little use of detailed analysis and comparison of alternative strategies, despite the institutionalised teaching of such approaches; analysis of options by consideration and weighting of all relevant factors is known as Franklin’s Rule⁵ (Gigerenzer, et al., 1999: 26-7). In many situations involving recognition, heuristics such as Minimalist or Take-the-best outperformed Franklin’s Rule, and performed as well as multiple linear regression (Gigerenzer, et al., 1998: 87-91). Despite the apparent strengths and utility of heuristics, there are threats to decision making in complex environments that come from inappropriate reliance on heuristics, judgement and intuition, or gut feeling. To make this point I often tell the following story:

‘An engineer friend, who maintained the old car his wife drove, tried to explain to her that the car was likely to stall on a hot day when the engine temperature rose and the fuel in the carburettor vaporised. In old cars this particular problem was generally exacerbated by an inefficient cooling system. His wife developed her own way of dealing with the overheating and stalling problems. On every occasion when the car hesitated and the temperature gauge indicated rising temperature, she stopped, raised the bonnet and allowed the engine to cool. When the radiator had cooled sufficiently to permit safe removal of the radiator cap, she filled the radiator from the ample supply of water she always carried. She looked for the familiar cues—a warm day—hesitation or frequent misses in the engine—increasing engine temperature—steam coming from the engine or the smell of oil from the over-hot engine. This was treated in the same way—stopping when it was safe to do so, raising the bonnet, and etc. This worked every time—well almost. The last time it happened, except that it was a comparatively cool day, the other cues presented and the normal remedial actions were taken. However, they proved totally ineffective. The radiator was refilled, but the engine could not be restarted. It could not even be cranked over by the starter motor. Subsequent inspection by a mechanic revealed that the engine had seized from lack of oil. Indeed, my friend’s wife claimed, in her adamant defence, that she was totally reliant upon him to check the oil level: she argued that she never had a need to check the oil level.

On every occasion, her search for cues ceased when she had filled the radiator. On reflection, the heuristics she called upon under these circumstances should have included consideration of one additional cue, the presence of sufficient engine oil. In this case:

• the mental models my friend’s wife had of the workings of the engine were inappropriate and incomplete,
• the set of heuristics she invoked were not appropriate to all circumstances she might encounter, and
• satisficing ceased too early for the given problem situation.

A mechanically inclined person would have noted the absence of reference in this story to the oil pressure warning lamp, which lights when oil pressure is low. This lamp was operational, but its intermittent flashing was ignored. Weeks beforehand the alternator lamp which is adjacent the oil pressure warning lamp had behaved in a similar way, but the alternator had since been overhauled. This time, an intermittently flashing lamp was registering low oil pressure. It was ignored in much the same way as the alternator lamp had been over previous weeks.’