When we are tired or preoccupied - what psychologists call 'resource-depleted' - we start to economise, to conserve those resources. Higher-order thinking is more expensive. So too is doubt, scepticism, arugment. 'Resource depletion specifically disables cognitive elaboration,' wrote Harvard psychologist Daniel Gillbert...Because it takes less brain power to believe than to doublt, we are, when tired or distracted, gullible. Because we are all biased, and biases are quick and effortless, exhaustion tends to make us prefer the information we know and are comfortable with. We are too tired to do the heavier lifting of examining new or contradictory information, so we fall back on our biases the opinions and the people we already trust

Auteur: Margaret Heffernan