Referees touched their heads three times to signal the procedure was under way.
The IRB wants a standardised system to deal with significant head knocks.
Part of the research involved taking advice from a French neurosurgeon and an Australian PhD graduate on the subject. New Zealand Rugby Players' Association boss Rob Nichol worked as the players' representative in recommending the system for trial. IRB chief medical officer Martin Raftery says the main objective is to ensure concussion is not assessed on the run, in the interests of player welfare.
"This system is about creating the time to make a proper assessment.
"Data from the Rugby World Cup told us that when it was suspected a player had something wrong, it took 82 seconds for the doctor to get to them and complete an assessment.
"That figure concerned us. Taking the player off the field for five minutes gives doctors a more suitable time frame for diagnosis.
"It also gives doctors a standardised tool which potentially concussed players can be assessed against."
The memory test involves what are known as the Maddox questions. They include: Who did you play last week? Did you win? What ground are you at?
That differs from past theories to test groggy players such as: What's your name? How many fingers am I holding up? What's the score?
For the balance test, players stand with one foot in front of the other while a doctor measures the number of wobbles over 20 seconds.
If a player fails any part of the test, they are replaced.
Raftery says feedback from doctors, coaches and referees has been positive: "[New Zealand under-20s coach] Rob Penney even went out of his way to say how pleased he was with the system."
If given the IRB tick, the system will be used only at rugby's top level, not lower grades.