Oh man. Everybody, the Xbox One and Playstation 4 consoles are launching within a matter of days, at least where I live. But like most people who don’t string their hammocks up between two money trees, I can really only afford to buy one this year.

But which one? I know that I myself tried to prepare for this decision by listing the features of each console in two columns: one titled “Reasons to buy a PS4” and the other “Reasons to buy an Xbone.” Maybe you’ve done something similar, even if you’ve got a column on there for “Buy new PC instead, you console babies.”

But there are pitfalls to this kind of approach, because it makes us susceptible to certain biases and errors in logic. I thought it would be interesting to highlight a couple to help you make your last minute deliberations.

One: The Justification Effect

Let’s start with a simple thought exercise. Think of five types of chips. Any kind of chips –potato chips, corn chips, tortilla chips, whatever. Now, rank order those chips in terms of your preference. Done? Great. NOW, turn to the person on your left and explain your rankings. Tell this probably bewildered person why you put Doritos above Pringles and Ruffles above Fritos or whatever.

Congratulations, you’ve probably just fallen prey to the kind of error in judgement in thinking that may reduce the quality of your your decision about which console to buy.

Researchers Timothy Wilson and Jonathan Schooler were interested in whether or not this kind of introspection and explanation process could affect the quality of decisions people make when choosing among various alternatives. They gave subjects five different kinds of jam, asked them to taste each one, and then had them rank them. The researchers then compared those rankings with objective ratings of quality from a Consumer Reports study where professional food tasters ranked the same foodstuffs.

Wilson and Schooler had half their subjects explain their jam rankings in great detail, and those people went on about things like aroma, spreadability, and chunkiness. But compared to a control group that just ranked the jams without being forced to think too much about it, those in the “explain yourself” group made ratings that were further off from the professional tasters at Consumer Reports. They were, the researchers argued, less accurate ratings.

Why? Because the subjects started focusing on factors that didn’t really matter. Smucker’s had more chunks of fruit in it, so it gets a higher rating. Wait, what? Is chunkiness really important for jam? Doesn’t matter; it sounds plausible so it got factored in.

And that’s the key point: when asked to think about and justify our preferences, we kick off a search for possible reasons that are both salient (that is, obvious) and easy to communicate. The fact that some of these reasons might not make sense for us in our particular circumstances can get shoved to the sidelines if it makes it easier to explain our otherwise unexplainable preferences. Thus those of us pondering which console to buy and trying to lengthen that that two-column list may put “Remote play with PS Vita” down in the PS4’s favor even though we don’t own a PS Vita and don’t think we’ll ever buy one. Or maybe you’ll put down “Gamerscore ports over” under the “Reasons to Buy an Xbone” column even though just five minutes before starting the process you’d have said you don’t care at all about gamerscores.

Why? Because those are salient and easy to communicate reasons that make your introspection and justification tasks easier, even though they won’t improve the quality of your decision. How do you combat this? Think carefully about everything you put on that list in terms of whether it’s really a benefit to you or not, then strike it if not. For myself, I mitigated this potential error by weighting each console feature as a big, medium, or small reason to buy. This let me keep them on the list, but also let me compare options more realistically.

Two: The Misuse of Missing Information Effect

Most of the decisions we make involve some amount of uncertainty, and backing a player in the console wars is no exception. We don’t always have certain information available, or if it is out there we have to go through some effort to track it down. But be careful, because we tend to pursue and overvalue information that really should be useless to us –just because we went to the trouble of getting it.

Researchers Anthony Bastardi and Eldar Shafir were interested in how decision-makers would value information that they had to wait to get. In a series of experiments they had people pretend to be in various roles such as a college admissions officer, a student registering for a class, a bank loan officer, or just an average Joe shopping for some new electronics. Half of the subjects –the ones in the control group– were given a complete set of information to make their decision. For example, in one study they read this:

Imagine that you are on the admissions committee of Princeton University. You are reviewing the file of an applicant who plays varsity soccer, has supportive letters of recommendation, and is editor of the school newspaper. The applicant has a combined SAT score of 1250 and a high school average of B. Do you… a) accept the applicant?

b) reject the applicant?

The other half of the subjects, though, were in the “uncertainty condition.” They had most of the same info, but with this difference at the end:

You have two conflicting reports of the applicant’s high school average grade. The guidance counselor’s report indicates a B average, while the school office reported an A average. The school has notified you that the records are being checked, and that you will be informed within a few days which of the averages is the correct one. Do you… a) accept the applicant?

b) reject the applicant?

c) wait for clarification from the applicant’s school before deciding?

Unsurprisingly, most study participants opted to wait for clarification and it turned out that the average grade was a B. This made the candidate’s profile identical to the one that those in the control group, except that subjects in the uncertainty condition had to imagine waiting a few days to get one missing piece.

What happened? Some of those in the uncertainty condition ended up putting more weight on the average grade data point, and the group rejected the candidate about 10% more often as a result. Across several other experiments the researchers found evidence that when information is missing and then made available, we put more emphasis on it while making decisions. You think “Hell, I went through the trouble of getting this information, I’d better use it.” And in doing so, we calibrate wrongly and overvalue it.

So don’t do this with the new consoles. Say that after hearing the news about how the PS4 won’t act as a DLNA server and won’t play or stream music from your network, you wonder if the Xbone will. That information isn’t readily available, so you have to wait for the information to come out a few days later in a FAQ from Microsoft or from reviews in the press. You’re might very well overvalue that feature in your decision.

Or let’s take another example. Imagine that the cross-platform Call of Duty: Ghosts is on your must-buy list, so you’ll be getting it on whatever console you guy. But the reviews on the Xbone version of that game are under embargo for a week longer than those for the PS4. When the PS4 reviewer mentions frame rate dips, you wonder if that’s as big a problem on the Xbone but you can’t find out. You have to wait a week for that version’s reviews to come out, and as a result you may overvalue frame rate as a criteria against which to judge that version of the game and the console, relative to other factors.

So be careful when you have to wait for or work for information. Think about each piece individually and either discard it if it’s irrelevant or weight it appropriately. Or, better yet, wait until most of the information is available –such as after launch and after press embargoes– before putting on your thinking cap.

So there you have it: common errors in judgement that may specifically arise because you made bulleted lists comparing the new consoles from Sony and Microsoft. It’s good that we think carefully and base our decisions on hard data, but brains don’t always work how we expect them to.

That said, though, I have to ask: which are you going to buy? Or, if you are from the future, which did you buy? And how did you make that decision?