Escaping the laboratory: the rodent experiment of John B. Calhoun and their cultural influence

In John B. Calhoun’s early crowding experiments, rats were supplied with everything they needed – except space. The result was a population boom, followed by such severe psychological disruption that the animals died off to extinction. The take-home message was that crowding resulted in pathological behaviour – in rats and by extension in humans. For those pessimistic about Earth’s “carrying capacity,” the macabre spectacle of this “behavioural sink” was a compelling symbol of the problems awaiting overpopulation. Calhoun’s work enjoyed considerable popular success. But cultural influence can run both ways. In this paper, we look at how the cultural impact of Calhoun’s experiments resulted in a simplified, popular version of his work coming to overshadow the more nuanced and positive message he wanted to spread, and how his professional reputation was affected by this popular “success.”