How do you feel at sunset? Maybe lonesome, cheerless, or sad? Otherwise, you might feel a little agitated.
It is known that aggressive behaviors in patients with dementia are increased at the sunset time. Indeed, I have experienced that some inpatients cause trouble mainly at twilight compared to daytime. I thought the main reason is delirium, as well as a fewer number of caregivers at night.
But, recent studies suggest the circadian rhythm is influential on controlling aggressive behaviors. The experiments with mice proved that they become more hostile to intruders at night. Furthermore, mice whose parts of the brain accountable for the circadian rhythm had been destroyed showed no significant difference in aggressive behaviors during the day.
Independent: Aggressive behaviour reaches highest levels at sunset, finds body-clock study
Thus, it is estimated that our aggressiveness is partially controlled by the time. At the same time, we are rational so that we can suppress the impulse derived from the instinct. But once the antagonistic function is impaired due to neurological diseases such as dementia, we would be controlled by the body-clock.
Chronopsychology is a new region of the brain science. I expect many interesting findings will be reported soon.