The Priam IV test was a test given to cadets at Starfleet Academy in the 2340s and 2350s. It was the final test whose passing granted degree candidature and admission to the graduating class. It covered a cadet's responses to Prime Directive issues.
It took place within a holodeck and cadets undergoing it were hypnotized into believing it was real.
When Cadet Data took the test in the early 2340s, however, he could not be fooled into believing the simulation, and could even the see the holodeck walls. Instead, Data permitted computer experts to program the experience directly into his mind, an experience that he found disturbing.
Circa 2358, Cadet Tasha Yar undertook the Priam IV test. Doctor Forbus and Counselor T'Pelak hypnotized her and took part in its initial states to ease her into the simulation. There, the USS Threnody was destroyed in an ion storm and an escape pod bearing cadets Tasha Yar, Forbus, and T'Pelak crash-landed on the planet Priam IV, a Prime Directive–prohibited world. Yar was the only survivor, while Forbus and T'Pelak were "killed". Left without supplies, Yar had to journey across harsh jungle to somewhere where she could be rescued, either the permitted landing zone 100 kilometers away, or a primitive Priamite village to find some Federation researchers who dwelled amongst the natives in disguise.
After six in-game days, Yar discovered a modern boat and investigated, only to find an Orion slaving operation, with a reptilian Orion slaver taking possession of Priamite slaves—and that the Federation researchers were selling them to him. She was captured too, but escaped her own slavery to decide how to handle the situation- thanks to the addition of a loose screw to her chain, as efforts to make the test hard enough to be plausible made it so hard that Natasha couldn't escape on her own- reflecting on a range of Prime Directive–related problems and her own rescue before the test ended.
The next day she had an interview before the test invigilators, led by Commander Erdman (who'd played one of the researchers), Forbus, T'Pelak, her mentor Darryl Adin (who played the Orion), and others. After explaining her reasoning despite her indecision, Erdman passed Yar with an excellent grade.
The situation was designed to be practically unsolvable within the time allotted, its goal instead being to see how Yar considered the Prime Directive issues and handled decisions regarding them. The only wrong decisions were acting hastily, without considering all factors, or without second-thoughts; a decision made at that time would have been the wrong one, but by escaping captivity, Tasha would have given herself time to heal and plan if she had been dealing with a real scenario.
- As an unsolvable test, the Priam IV test is similar to the Kobayashi Maru scenario.