Summary:

- The article discusses a new study that found men have a daily hormone cycle, with their testosterone levels peaking in the morning and declining throughout the day.
- This daily fluctuation in testosterone is linked to changes in the size of the brain's hippocampus, which is responsible for memory and spatial navigation.
- The findings suggest that men's cognitive abilities and behavior may vary throughout the day due to these natural hormonal changes, which could have implications for work and daily activities.