Intelligence isn’t about your world knowledge, but is instead the speed at which you learn new information. Unfortunately, studies in the past have found that IQ is fixed, so you’re essentially stuck with it for the rest of your life.

To be honest, so many of us don’t even know if we’re smart or not. You can’t exactly measure it unless you’re willing to spend a heap of money with a trained professional.

But there are some interesting signs that science says might be common for many intelligent people.

1. You’re anxious.

Nobody likes having anxiety, but science has consistently found that those who experience anxiety to be smarter. One study found that the worse the symptoms of people with anxiety disorders, the more intelligent they were. What’s more, another study found that anxious participants were more focused and effective at executing tasks. So if you’re worried about worrying, maybe you don’t have to worry anymore.

2. You were an early reader.

A British study found that the earlier one started reading, the more intelligent they were. The researchers said that reading early clearly had a developmental impact. So if you’re smarter than average, it’s highly likely you read earlier than others.

3. You’re left-handed.

Lefties tend to be playfully insulted growing up, but till this date, there continues to be an unexplained correlation between being left-handed and being more intelligent. This correlation is particularly pronounced in males.

4. You took music lessons as a kid.

A number of studies show that musical training enhances intelligence and executive function – a skill critical for self-control. The studies tend to show that young children who received musical training are on average more intelligent.

5. You’re funny.

If you’re witty, then you can celebrate. A study has shown a correlation between being funny and high verbal intelligence and abstract reasoning. And that’s no joke.