The simulation serum is a drug used to induce simulations. It was designed by Jeanine Matthews and was used in aptitude test. The Dauntless use a variation in the second stage of Dauntless initiation.
Use in Aptitude Tests
In the Aptitude Tests, simulations are used to determine a child's predominant characteristics. The results are an indicator of which faction the child should choose. Test results of the Divergent are inconclusive.
The Simulation Serum is usually administered orally in liquid form for the Aptitude Tests, however, it can be injected in a vaccine-like manner if need be.
One version of the simulation is to choose between a knife and a piece of cheese. The Dauntless choose the knife, while the Amity choose the cheese. However, it is also possible to refuse both, as in a persons case, after which she submitted to the dog that occurred with an Erudite response. A child appeared, and the dog ran at her. Tris threw herself at the dog - a Dauntless and Abnegation response.
There are other scenarios in the simulation too, like cats clawing your eyes out-or something like that.
Use in Dauntless Initiation
The Simulation Serum is used in the emotional stage of the Dauntless initiation.It was also used for the fear landscape test.
The initiates are given a serum shot containing a transmitter that sends the data to a computer and connects the mind to the simulation.
The initiates are put under a simulation of their worst fears until they slow their heart rate and breathing, or do something that defies the fea
r. That is why the test is called "your fear landscape". Most initiates have 10-15 fears. Tris Prior had only 7 fears.. Tobias (Four) had 4 fears, and was given his nickname because of this. He was also Divergent and helped Tris to hide it so she wasn't targeted.
History of Fear Serum Simulation 
- The Dauntless Fear Serum origionally were not generated by a person’s individual fear, they were instead general fears like heights or spiders. (According to Zoe talking to Tris)
- Norton, the Erudite representative before Jeanine, let the Fear landscapes go on way longer than they should’ve been. Until the simulation was changed to end or move on when that persons heart rate slowed down.
- Jeanine tested a newer version of the fear serum on a factionless man in exchanged for some sort of essentials. The Factionless man was “never quite right again”
- Jeanine used a Terror Serum on Tris whilst testing on her in Insurgent, Jeanine stated it was a very potent version of the Fear Serum and she remembered how to make it.
- Many Divergents are exposed during the Fear Simulation as they ara aware and can manipulate their way through, This is how Four confirmed Tris 's and Uriah 's Divergents and how Amar found out Four was Divergent.
- Jeanine also visted Dauntless during Fours initiation as she suspected something wrong with Amar and Four 's tests, after this Four got the all clear (after being trained and spoken to by Amar) However Amar got 'caught'