Tinder... it's been around for a while (or so it seems). But what actually makes a girl swipe right or left on a guy? And how quickly is that decision made?

I asked 12 girls to give me one reason they swipe right and one reason they swipe left, based on their immediate evaluations of a guy's profile. Here's what they said.

Immediate Swipe Lefts

1. If he doesn't look good/similar in every picture (or looks good in just the first picture)

2. If every picture is a mirror picture

3. If every picture is him by himself

4. Every picture is him flexing/showing off how much he works out

5. If it says he wants a girlfriend

6. Kids - doesn't matter if they're his or not

7. Their bio is longer than 2 sentences

8. Every single picture is a group pic

...meaning you don't know which one they are because the same few guys are in every picture.

9. Every picture is them holding a huge gun/hunting/holding a dead animal

It looks a little intimidating... like are you going to be holding it when you meet up too?

10. Can immediately tell he's not your type

Sometimes, you just know.

11. Raunchy tattoos

12. Pictures with other girls - especially ones of him hanging all over another girl

Immediate Swipe Rights

1. If it looks like he likes to have fun

Girls want to see that you go out and have friends and that you're not just playing Fortnite all the time.

2. If he looks good in every picture

3. If he has a well-rounded group of pictures

4. If he has a good joke in his bio

5. If it says he's looking for something serious

Some girls are looking for that, so just make it clear.

6. Dog pictures... lots of pictures with his dog.

7. If they're involved on campus/in Greek life

8. They have a nice smile

9. Interesting bio - but not their whole life story

10. Tattoos

11. They're fit/it's easy to tell that they care enough about their appearance to look presentable

12. Height is above 5'10"