The concept of compartmentalized brain functions acting either in concert or in conflict has been a core idea of evolutionary psychology since the early 1990s. According to University of Pennsylvania evolutionary psychologist Robert Kurzban in Why Everyone (Else) Is a Hypocrite (Princeton University Press, 2010), the brain evolved as a modular, multitasking problem-solving organ—a Swiss Army knife of practical tools in the old metaphor or an app-loaded iPhone in Kurzban's upgrade. There is no unified “self” that generates internally consistent and seamlessly coherent beliefs devoid of conflict. Instead we are a collection of distinct but interacting modules often at odds with one another. The module that leads us to crave sweet and fatty foods in the short term is in conflict with the module that monitors our body image and health in the long term. The module for cooperation is in conflict with the one for competition, as are the modules for altruism and avarice or the modules for truth telling and lying.

Compartmentalization is also at work when new scientific theories conflict with older and more naive beliefs. In the 2012 paper “Scientific Knowledge Suppresses but Does Not Supplant Earlier Intuitions” in the journal Cognition, Occidental College psychologists Andrew Shtulman and Joshua Valcarcel found that subjects more quickly verified the validity of scientific statements when those statements agreed with their prior naive beliefs. Contradictory scientific statements were processed more slowly and less accurately, suggesting that “naive theories survive the acquisition of a mutually incompatible scientific theory, coexisting with that theory for many years to follow.”