Hope and rats
Curt Richter conducted a series of experiments looking at how long rats survive drowning. It is an interesting, albeit a bit sick, paper.
Most wild rats dies between 1 and 15 minutes after being placed in the water. But incredibly if the researcher extracted the rat prior to drowning. Dried it and held it for a few minutes before placing back in the water. The rat would then survive for 60+ hours.
Richter concludes that the death is caused by hopelessness and this hopelessness causing death can be seen in humans.
I would argue that our most important responsibility as leaders is to build hope in the communities we serve.