Introduction
We raise the question of whether an escaping crowd can benefit from a mixture (or heterogeneity) of direction-choice-making strategies, and if so, how would an optimal composition of strategies be like.
Methods
We perform extensive computer simulation analyses and examine crowds of evacuees composed of two different behavioural classes in terms of their direction-choice strategies. We examine three possible strategies: (I) follow the majority (II) follow the minority without the possibility of decision update and (III) follow the minority with the possibility of decision update.
Findings
Results showed that the types of escape decision strategy and their composition in the crowd vastly impacted on the efficiency of the evacuation process. The numerical analyses showed the followings: (1) The highest degree of optimality was achieved from a homogenous crowd of minority followers with the possibility of decision update. (2) The magnitude of the detriment resulted from greater concentrations of the follow-the-majority strategy in the crowd was much larger than the benefit of having more of the follow-the-minority strategy. (3) The marginal benefit of increasing the concentration of the follow-the-minority strategy largely diminished once this strategy became dominant in the crowd. A substantial portion of this benefit was realised at about 50% concentration level. (4) The system's efficiency was more sensitive to the behavioural strategy when there was only a one-off chance of direction-choice making.
Applications
These findings have implications for evacuation management. They offer quantitative evidence on how training or modifying individuals' decision-making behaviour can potentially facilitate evacuation processes. They provide insight into ideal (or optimum) forms of behaviour.