The GMAT is an exam that students generally study for over a few months, but it can be argued that students have been preparing for it their entire lives. From mastering addition in elementary school to understanding geometric properties and reading Shakespeare sonnets, your whole life has arguably been a prelude to your success on the GMAT. You might not need everything you’ve ever learnt on this one exam, but you will already have been exposed to everything you need to be successful.

However, there are times when all the information you’ve spent a lifetime accumulating can hinder you on the GMAT. For example, everyone has been influenced to some degree by their upbringing, their experiences and their personal biases. This is unavoidable, but knowing that many GMAT questions will try to exploit this gap can help you prepare for it. Remember that outside knowledge can only hinder you on the test as everyone has to be able to solve the question with only the information in front of them. Anything less would constitute an unfair advantage of one test taker over another (and be uncivilized).

The GMAT is based on logical facts mentioned in the question, not reader bias or preconceived notions formed long before you ever set foot in the test center. However it’s important to understand how our brain takes information and compares it to what we expect to see.

Let’s look at a Critical Reasoning question and try to identify the answer choices that are completed with subconscious information from our own preconceptions:

From 1994 to 2001, violent crime in New York City steadily decreased by over 50% from a rate of 1,861 violent crimes per 100,000 people in 1994 down to 851 violent crimes per 100,000 people in 2001. Criminologists have partially attributed this drop to proactive policing tactics such as “broken window policing”, wherein city officials immediately fixed small acts of vandalism and, as a result, lowered other types of criminal behavior. During this same period, the rate of violent crime in the United States steadily decreased by 28% (down to 500 violent crimes per 100,000 people).

Which of the following conclusions is best supported by the information above?

(A)   The decrease in the total crime rate in the United States caused the decrease in New York City’s crime rate.

(B)   New York City spends more per capita on law enforcement than does the rest of the United States.

(C)   If the rest of the United States were to adopt law enforcement tactics similar to those of New York City, national violent crime rates would continue to fall.

(D)   Between 1994 and 2001, the violent crime rate in New York City was consistently higher than the national average.

(E)    The violent crime rate in New York City will soon be below the national average.

The first tactic used by the GMAT to bring to mind students’ beliefs is using topics that evoke strong opinions. Many people have strong opinions on crime, based primarily on their first hand experiences. If your sister’s house got broken into last year, you might have very strong opinions on crime that you didn’t have two years ago. When you see topics that evoke strong emotions, the GMAT may be trying to blind side you (so remember to stand your ground).

This question is specifically asking about which answer choice is supported by the text, which means that it’s an inference question. The important thing to remember about inference questions is that the answer must always be true. However, the downside is that we can’t easily predict the correct answer because many different choices could all conceivably be correct. We’ll have to approach these one by one and determine whether they always have to be true.

Answer choice A states that the decrease in the total crime rate in the United States caused the decrease in New York City’s crime rate. This is a classic causality trap. If the crime rate went down in one place and another place at the same time, is there necessarily causation? Did one cause the other? Were they both caused by some third element? We simply cannot tell with the information provided. Answer choice A is incorrect.

Answer choice B postulates that New York City spends more on law enforcement per capita than the rest of the US. This may very well be true, and our brains probably start thinking that this is a likely scenario given that New York is the biggest city in the US, but there is no discussion of this in the text. This is one scenario that your brain might start filling in the blanks for you, but don’t be fooled. Inference questions must always be true, and at best this is “likely” (like a Justin Bieber scandal). Answer choice B is not supported by the information above.

Answer choice C hypothesizes about what would happen if the rest of the country adopted the New York City strategy. This is conjecture in its purest form. We don’t know what would happen if the rest of the country followed NYC’s example. (Where’s Miss Cleo when we need her?) The tempting aspect of this answer is that it seems to give a larger context to the passage as a strategy to reduce crime across the country. No such blanket policy was advocated, but our brains sometimes try and make the leap in logic on their own. This answer is incorrect, even if on some level we want it to be relevant.

Answer choice D offers that the violent crime rate in New York City was consistently higher than the national average during the timeframe being examined. This plays into our preconceived notion about answer choice B (spending more money per capita) in that New York is a relatively dangerous place. The difference is, in this case, the claim is absolutely backed up by the numbers in the passage. New York City is at 851 incidents per 100,000 people in 2001 whereas the national average is 500 for the same number of people. Clearly New York City was above the average in 2001. Furthermore, since 1994, New York City has decreased by over 50% whereas the national average only dropped by 28%. If NYC dropped by a bigger percentage and still ended up higher than the average, I must have been even higher above the average back in the mid 1990s. Answer choice D must therefore be correct based on actual numbers in the text.

Answer choice E again theorizes about what might happen in the future if various things happen (but only if Pisces is in Aquarius). There is no backing for this answer choice in the text, and this hypothetical must also be discarded.

The nature of inference questions helps isolate the faulty premises being used on many answer choices designed to confuse and trap test takers. However it’s important to be on the lookout for answers that have purposeful gaps designed to get test takers to fill in with their own opinions. You have spent a lifetime preparing for this test, and your accumulated knowledge from years of experience will help you maximize your score. Just make sure your knowledge doesn’t override what’s written on the page in front of you.

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Ron Awad is a GMAT instructor for Veritas Prep based in Montreal, bringing you weekly advice for success on your exam.  After graduating from McGill and receiving his MBA from Concordia, Ron started teaching GMAT prep and his Veritas Prep students have given him rave reviews ever since.