ELI5: Explain Like I'm 5

Birthday effect

Okay kiddo, have you ever noticed that when you go to school or daycare, some kids in your class have the same birthday? That's because of something called the "birthday effect."

The birthday effect is a strange thing that happens where people tend to be more likely to have something in common with others who were born around the same time as them. This could be things like having the same favorite color or hobby, but it also can be things like being good at a certain subject in school or even having the same personality traits.

Scientists think that one reason for the birthday effect is that people who are born close together in time often end up going through similar experiences. For example, if you and your friend were born only a few days apart, you might end up going to the same schools and having the same teachers. This can make you both more likely to have similar interests and skills.

It's important to remember, though, that not everyone born around the same time will have everything in common. Just like how you and your siblings might all have different personalities and interests, people born around the same time will still be individuals with their own unique qualities.