(CNN)For a group of radical anti-Western militants, ISIS is pretty good at luring Westerners to its ranks.

The latest is an American teen from suburban Chicago who was allegedly on his way to join ISIS. Mohammed Hamzah Khan was stopped just before he was supposed to board a plane to Turkey, authorities said.

But he's far from alone.

Last month, U.S. authorities detailed their case against a New York food store owner accused of funding ISIS and plotting to gun down American troops who had served in Iraq.

And a French man told his mother that he and his half-brother were going on vacation -- only to tell her later that they were fighting in Syria.

"Some of the foreign fighters may not return as terrorists to their respective countries, but all of them will have been exposed to an environment of sustained radicalization and violence with unknowable but worrying consequences," Richard Barrett of The Soufan Group wrote in a report called "Foreign fighters in Syria" this summer.

So what is it about ISIS and its uncanny ability to recruit Westerners? Here are five methods the group employs:

It preys on a recruit's sense of identity

The recruits are often young -- sometimes disillusioned teenagers trying to find purpose and make their mark.

For many, it boils down to a lack of a sense of identity or belonging, Barrett said.

"The general picture provided by foreign fighters of their lives in Syria suggests camaraderie, good morale and purposeful activity, all mixed in with a sense of understated heroism, designed to attract their friends as well as to boost their own self-esteem," he wrote.

Answer the following questions:
1. Where was Mohammed Hamzah Khan going?
2. How was he going to travel
3. What was he planning to do?
4. Is he a youngster?
5. From where?
6. Does he live in the inner city?
7. Which part then?
8. How many ways are known for ISIS to gather recruits?
9. Do they go after older people
10. What group do they try to get?
11. What are they counting on them lacking?
12. What group of people is ISIS against?
13. Do they let them join?
14. Where was a food store owner from that tried to help ISIS?
15. What was he accused of?
16. Was he going to attack anyone?
17. Who
18. Which ones?
19. Is this problem only in the U.S.?
20. What other country has it?

Numbered answers:
1. Turkey
2. by plane
3. join ISIS
4. yes
5. Chicago
6. no
7. the suburbs
8. five
9. no
10. disillusioned teenagers
11. a sense of identity or belonging
12. Westerners
13. yes
14. New York
15. funding ISIS
16. yes
17. American Troops
18. who had served in Iraq.
19. no
20. France