NEURAL SLUMP: The brain is less responsive to rewards received in the afternoon, compared with morning or evening, a study suggests.© ISTOCK.COM/G-STOCKSTUDIO

EDITOR'S CHOICE IN NEUROSCIENCE

The paper
J.E.M. Byrne et al., “Time of day differences in neural reward functioning in healthy young men,” J Neurosci, 37:8895-900, 2017.

Afternoon delight?
People report being happiest in the early afternoon. One idea is that the brain’s mood-influencing reward system varies diurnally for evolutionary reasons. According to this hypothesis, “at certain times of day, we’re more likely to want to engage with the environment,” says psychologist Jamie Byrne of Swinburne University of Technology in Australia. As hunters with poor night vision, we’d have “our best chance of catching Bambi . . . at about two in the afternoon.”

Cash for BOLD
To look for diurnal changes in reward functioning, Byrne and colleagues had 16 men guess the correct value of a...