Individual people can experience time differently, too. You’ve probably noticed how time seems to speed up when you’re racing against a deadline or having fun, and how it tends to drag when you’re bored. This is because when you’re focused on something, like a big work project or a party, your brain pays less attention to how time passes. But when you’re bored, or your brain is less stimulated, you become more aware of the passing of time, making it feel slower. One study proposed that dopamine—the neurotransmitter and hormone that helps us feel happy—may be an additional culprit. It showed that increased dopamine production, which happens when you’re enjoying something, may slow down your body’s internal clock, making time feel like it’s flying by.