Herding under real-fire and simulated-fire conditions: A heuristic strategy

Abstract

This study compared herding behavior in mice under real-fire and simulated-fire conditions from the view of eco-rationality. Study 1 used 80 mice and adopted a 2 (conditions: Real-fire or Simulated-fire)×2 (learning: Naive or Trained) inter-group design. The trained group consisted of 16 mice that learned escape routes through training and the Naive group consisted of 16 untrained mice. The remaining 48 mice were false subjects (crowd) and were also trained to learn the escape routes. Study 2 used 64 trained mice and adopted a 2 (conditions: Real-fire or Simulated-fire)×2 (individual mouses memory: Remembered or Forgotten) mixed design. Sixteen of these mice were randomly assigned to the remembered experimental group before receiving treatment that made them forgot the escape routes (memory-loss treatment) and to the forgotten experimental group after receiving the treatment. The remaining 48 trained mice were the crowd (false subjects). Study 3 used 80 trained mice and adopted a 2 (Real-fire or Simulated-fire)×2 (crowds memory: Remembered or Forgotten) inter-group design. The remembered crowd (false subjects) consisted of 48 mice that did not undergo memory-loss treatment. Sixteen mice were randomly assigned to the remembered experimental group. The forgotten crowd consisted of 48 mice that received the memory-loss treatment. An additional 16 randomly chosen mice received the memory-loss treatment and were assigned to the forgotten experimental group. Mice in each study were randomly and equally distributed between the real-fire and simulated-fire conditions. The dependent variable for all studies was the escape strategy of the mice in the experimental groups, which was assessed by measuring escape time and exit choice. The main findings were: (1) when mice did not know an escape route and the crowd did, they tended to follow the crowd; (2) when mice knew an escape route, they preferred to choose this route rather than follow the majority, even if the crowd clearly knew how to escape; and (3) when mice had forgotten an escape route and escape-related information obtained from the crowd was no longer clear, herding behavior occurred under the real-fire condition but not under the simulated-fire condition. In conclusion, herding is a heuristic strategy that corresponds to ecological rationality. During a real fire, if the individual has an implicit memory associated with escape, priority is given to this knowledge instead of the herding heuristic.