The test-makers say that this is a myth.
From the GMAT Official Guide:
It is true that computer-adaptive testing algorithm uses the first 10 questions to obtain an initial estimate of your ability; however, that is only an initial estimate. As you continue to answer questions, the algorithm self-corrects by computing an updated estimate on the basis of all the questions you have answered, and then administers items that are closely matched to this new estimate of your ability. Your final score is based on all your responses and considers the difficulty of all the questions you answered. Taking additional time on the first 10 questions will not game the system and can hurt your ability to finish the test.
Cheers,
Brent
Brent Hanneson - Creator of GMATPrepNow.com
