This is the third article of my Rock the DAT series. The first article is an overview of the DAT exam with some study materials to help prepare for it. My second article discusses the basic sciences and how I approached studying them. In this article I will offer suggestions and tips on preparing for the Perceptual Ability Test (PAT).
Perceptual Ability Test
I had almost no idea what to expect when I started studying for the PAT. I had read about T-F-E, pattern folding, and hole punches on various message boards and websites. But I did not know what any of those things were. My first order of business was to learn as much about the PAT as possible before starting with any practice tests.
I used Youtube to research each section of the PAT and learned common techniques used by others. At the time I was unaware of Ari’s DAT Bootcamp videos which actually explain common approaches to problem solving and tips for test day. I watched videos that were created by Youtube user mmglasco. I found them to be very helpful. That said, they are nowhere near as comprehensive as those provided by DAT Bootcamp.
I practiced angle ranking and pattern folding using Crack DAT PAT’s generators and problem sets. When I had a basic understanding of the PAT, I tried my hand at the first practice exam. I did terribly of course, but this served as a benchmark from which I could measure my progress. I could also practice the concepts I had not yet mastered. For the first test I did a dry run of all the PAT subjects. I did not look at the second test until I felt I was sufficiently prepared to do so. You have only so many tests to practice, so don’t want to use them up too quickly.
The hole punch section takes some time to figure out, but it will become quite easy if you practice it enough. I bought some sticky notes and a hole punch so that I could see how the hole punching worked on paper. I would draw a 4×4 grid on a sticky note and then refer to Crack DAT PAT’s first practice test to review the hole punch diagrams. Next, I folded my sticky note into the pattern shown on the practice test. I then used my hole punch to replicate what was shown on the screen.
From there, I could unfold the paper and understand how the holes would be transferred throughout the paper. You will soon recognize patterns in how holes are reflected across lines of symmetry, and this will prepare you for the more difficult 1/3 folds and such. For a video tutorial of this concept, take a look at the following DAT Bootcamp video.
The nice thing about folding paper is that each fold represents a line of symmetry which will serve as a reflection point for a hole punch. If you fold the paper in half, and then punch a hole on one side, you should expect that hole to appear in the same location reflected across the line of symmetry or fold.
DAT Bootcamp offers a free hole punching generator (shown above) which means that you don’t have to waste practice tests on hole punches.
Most PAT problems require abstract thinking
Once you are familiar with hole punches and how they work on the page, you can start working with them more abstractly. I started using my dry erase board and I would draw out enough grids before I started a practice exam so I didn’t waste time drawing them during the exam. They should look something like this:
For a good example of this, check out this video from Youtube user thelifeofadentnerd. When you take the actual PAT you should be provided with grid paper. I recommend calling your testing center to be sure that they will provide you with this. If not, you will need to draw out your grids in the few moments you have before you begin the examination!
There are many ways to solve hole punching problems using abstraction and login. Personally, I approached them as a logical game and found it to be kind of fun after a while. Before completing a problem, work backwards and follow the lines of symmetry.
If you solve these problems logically and sequentially then you will eventually be able to solve them quickly too. I used mmglasco’s video for some ideas on how to draw the patterns and solve them with pencil and paper. If you remember that lines of symmetry are the most important part of solving these problems then you will do just fine come exam day.
Remember one important detail: you want the shape that fits the keyhole the best. When working with keyholes you may find yourself thinking that there are two acceptable solutions to a problem–there aren’t. If you find yourself stuck on a problem because you think that there are two right answers, I suggest that you circle the two you believe to be correct and then move on to another problem.
Come back later with a fresh pair of eyes. Sometimes you will see something you had missed before with some time away from the problem. More often than not however, you need to get through the rest of the exam and can’t get bogged down with a few difficult problems. By the way, this rule applies to every problem on every section of the PAT!
I encountered many problems on DAT Bootcamp which I was sure had two solutions. Crack DAT PAT seemed a little easier in this regard. I believe that it still provides adequate preparation for the actual PAT. When you find yourself struggling to figure out which answer is correct, it is a good idea to look at the keyhole and eliminate your possibilities bit by bit.
Take a logical and sequential approach for the hole punch section and you will catch even the tiniest details. Sometimes it helps to compare the shapes directly to one another and then to look for their differences in the keyhole. Is one side of a shape angled but the same side of the keyhole is straight? Does one shape have a notch that the other lacks?
Let’s do one together!
Right off the bat we can eliminate solution E. The disc surrounding the pyramid in this object encircles it entirely. Therefore, E is incorrect because it would require the disc to be only a semi-circle. It is also pretty obvious that D is incorrect because the disc in the original object is circular, not an oval. So now we are down to just three possible answers. Even a random guess would give us a 33% chance of being right.
Solutions A and B require you to determine which is larger, the base of the pyramid, or the disc that surrounds it. For B to be correct, the pyramid’s base must be slightly larger than the disc, allowing just the corners to show when viewed from top or bottom.
For A to be correct the base of the pyramid must be so much larger than the disc that we can’t see the disc at all when viewed from top or bottom. However, notice in the diagram below that the corners do not actually extend further than the edge of the disc. The corners should be the furthest point from the center of a pyramid (Pythagorean’s Theorem). We therefore conclude that the base of the pyramid is smaller than the disc’s diameter.
Looking at the image above we can conclude that both A and B are false. As we have excluded A, B, D, and E, we are left only with option C as a solution. Great, we have arrived at our initial answer! But does it make sense?
Check your answers!
Looking at the keyhole we see that the disc appears about 2/3 or 3/4 the way up the pyramid. This seems to be true for option C. We already concluded that the disc must be wider than the base of the pyramid which is also true of option C. The disc continues all the way around the object, again like option C. By deductive reasoning and visual inspection it seems that answer C is the correct answer.
When I took the PAT I was not aware that there would be rock keyholes on the exam. I had three rock problems and I had a very hard time with them. They are unlike any other keyhole I had practiced up to that point. I marked all three and moved on. When I returned I wasn’t any more confident in the answers I gave. Luckily for you, DATgenius has since created a free rock keyhole practice test!
In some cases, there may be a very slight size difference which sets the solutions apart, and you will just have to use your best judgment to determine which shape best fits through the keyhole. Other times you may see shapes that feature rounded corners while the keyhole features square ones. A careful eye for detail is crucial here, and you should be systematic in your approach to comparing the shapes to each other and to the keyhole itself. I used mmglasco’s video to better understand PAT keyholes and found it very helpful. You may also want to check out the DAT Bootcamp keyhole tutorial video.
If you asked most pre-dental students which part of the PAT they struggled with the most, it would probably be T-F-E. You will first need to figure out exactly how this section works before you can begin practicing it. Although you can figure out neat little tricks for cube counting and hole punching, top-front-end requires a lot of mental acuity and a critical eye.
I spent a lot of my time in high school with CAD software. I believe that some time spent with this kind of software can improve your T-F-E skills tremendously. Most colleges and universities offer CAD software on school computers for students to use. A good example of this software in action can be seen below:
You can generally download objects such as these pretty easily, the sample file for the image above can be found here for example.
Notice that physical features which are hidden from the perspective shown are indicated with dashed lines. In the image below, notice that there are two holes that pass all the way through the base of the object.
All features that are hidden from view are indicated with dashed lines. Correct solutions will always feature dashed lines where something is hidden from your view. Sometimes a hidden feature is directly behind a visible feature. In those cases you will see only the solid line, not the dashed line for the feature behind it.
There is only one right answer
Sometimes you will have two answers that seem plausible, just as you did with keyholes. Usually this comes down to something that is missing or is slightly different from one of the possible answers. Take the image above for example. The top view (top left of the diagram) correctly shows the biggest hole as being off-center.
One distractor on the PAT might show the hole at the center of the object. One good look at the end view (bottom right) of the image shows that the hole does not line up with the center of the object. Any option to the contrary would be wrong. Be as rational and deductive as you can be.
Imagine the missing view
With T-F-E it is important to remember that you are trying to imagine what the object looks like in the missing view. The problem may be missing the top, the front, the side, or the isometric (angled) view. In any case, it is up to you to figure out logically which answer choice best fits the object in the image. DAT Bootcamp has a great visualizer tool you can use to practice visualizing these problems.
I took a screenshot from the visualization tool to give you an example of these problems. Notice that we have a top view and an end view here. We are expected to determine what the front view should look like.
Starting from the top view you see that we expect to see three different planes with no hidden facets (because there are no dashed lines). This eliminates B immediately, because that option would have only two different planes when seen from above. Option A is eliminated because the square shown sticking out to the right is not present in the top view. See the image below:
The answer is lurking in the details…
Notice that the cutout circled in blue is much smaller in option A than it is in our top view. Looking at D we can see that there is an extra piece at the top right that is not visible in our top view. It also does not appear in our end view. For that piece to have a line as shown, it would have to be a different width than the rest of what it is attached to. But in the end view there is nothing there that differs in width from the rest of the object.
By process of elimination we have determined that C is the correct solution. We can also see that it is correct just by noticing that we see three different planes, that there is a cutout at the top right which corresponds to what we see in the top view and the end view, and because it has a small face sticking out at 90 degrees from the rest of the object.
Some people really just have an eye for this, and then there’s me. I was pretty average with this section of the PAT during my preparation. I really struggled with angles that differed by only 3°. One important thing I did was write down my rankings and then see if my answer appeared in the possible solutions. Although not foolproof, this ensures that you arrived at your answer independently from the answer choices.
I also started by writing down which angle I thought was largest, and which was smallest. This way, if I was unable to determine the two angles which were intermediate, I could at least refer to the solutions and see if only one answer choice agreed with me. Of course you should strive to rank all of the angles, but when the differences are exceptionally small this can be very difficult. Narrowing the results will increase your odds of getting the problem right, and also help you to reach a solution.
In the example above you see that only 3 or 4 can be the largest, and only 1 or 2 can be the smallest. If you had determined that 4 was the largest, and 1 was the smallest, then you would have been able to determine that answer D was correct without knowing which was 2nd or 3rd in the order. Sometimes it is helpful to identify which problems are setup this way and then look only for the smallest and largest angles. This will save you precious time in a section of the PAT that should take no longer than five minutes or so.
Practice, practice, practice!
Really, more than any other section I think that angle ranking comes down to sheer volume of practice. The more you expose yourself to angle rankings, the better you will become to a point. I did plateau at some point during my own practice, and I found that with difficult 3° angles I would only ever average about 75% accuracy.
The good news is that the vast majority of angle rankings on the actual PAT are larger than 3°. It may not seem like much but remember that 4° is 33% larger than 3°!
Sometimes it can be helpful to turn difficult things like angle ranking into a game. I started playing The Eyeball Game after seeing it recommended by another pre-dental student. Although it seems unrelated, you will probably benefit more from it than you would imagine.
I saw good results with my angle rankings after playing The Eyeball Game for a few days. I worked really hard just to try and earn the top score, because I’m a nerd. Another great tool for practicing angle rankings is the DAT Bootcamp angle ranking generator as well as the angle generator that comes with the Crack DAT PAT software.
Cube counting really isn’t too difficult. The key is to remember that there might be cubes you can’t see beneath cubes that you can. Also, if there is no visible evidence of a cube’s existence, then you should assume that it is not there.
For example, if there is a tower of cubes rising from behind a wall of cubes then assume that there are hidden cubes supporting the tower. I have given a short set of rules further down below which should help to guide you in solving these problems.
Before starting an exam, I made certain to mark my scratch paper with five separate sections like so:
Doing this before the exam will save you precious time. Be sure to mark your cube counting charts along with your hole punching grids before starting the exam! There is a demonstration and instructional period before the exam starts that you can use to prepare.
Be careful, the problem may be harder than it seems!
Some cube counting diagrams are deceptively easy. Take this one for instance:
Many people look at this and think that the two closest cubes are hanging beneath all of the others. If asked how many cubes they see, they will respond that they can see only 10 cubes. The problem is, there are actually 12 cubes!
This is a tricky diagram, because you can see it two possible ways: either two cubes are hanging lower than the others or they are all on the same plane. One hard and fast rule you should know is that the cubes are resting on an even surface like so:
In this image I have highlighted the actual footprint of the diagram. Remember again that your first assumption should be that the entire object is resting on a flat surface like a table. Also, do not count the sides of the cubes that are resting on the imaginary table when you are asked to count how many sides of the cubes are painted.
If you follow the footprint outline above and assume that there is continuity between all of the blocks (which there must be in these problems) then you will count 12 total blocks. Notice that instead of having two blocks hanging down on the side closest to us, we actually have one block that appears above all of the others. That block and the one beneath it obscure our view of the two blocks behind them. But we assume that there is continuity and so we count them as being there. Another way to look at this problem would be as follows:
Make a table and tally the cubes
I counted how many painted sides are visible and then placed them into the table below:
Simply count how many unpainted sides there are of each type on the diagram and fill out each of your tables. After you have done this you can answer the questions. When you finish counting the unpainted sides you should count how many blocks you ended up with and see if that matches up with how many blocks you expected there to be.
I counted 12 blocks on the diagram and I have 12 tallies in the table above. Don’t go backwards and try to find out how many cubes have X number of sides. You might miss some cubes without realizing it and then you won’t be able to double check your total.
In summary, when approaching cube counting problems I use the following rules:
- Assume that the blocks are resting on a flat surface.
- The diagram is continuous and does not have gaps.
- Do not count hidden blocks except when this violates rule #2.
So I found this section to be easier on the actual PAT than it was on the practice materials. Most of my recommendations in studying for this portion of the PAT are the same that I had for T-F-E and hole punches. Try to unfold the object with your imagination. It can be very helpful to use deductive logic. For the examples below I am using examples from this video on mmglasco’s Youtube page.
With the problem you are given a three-dimensional object with blank faces. When working a problem like this, I try to find the face that appears to be the most unique. Next I look for that face in the answer choices. Keep in mind that it might not be directly visible because it can be facing away from you.
In this case, the red face is obscured from our view because it is on the side facing away from us. This adds another level of complexity to the problem. Notice that none of the other possible solutions could possibly contain the red face. We probably finished this problem already. In the interest of being absolutely certain that I am correct though, I will go through the other answer choices.
Let’s choose another side to be sure
Notice that I have chosen a second face for my comparison. You can choose any face really, I just chose this one for reasons that will become clear in a moment. The next step is to imagine how the pattern will fold and then which edges are connected to each other.
As the pattern is folded, we expect the edges to come together as shown in the diagram above. Also, the small cutout we see in the blue face should correspond with a similar cutout we see in the red face as follows:
I have circled the regions that will appear opposite from each other with blue circles. Finally, I check to see if the red face and the blue face are separated from each other with the correct faces or not.
Notice that the face labeled with the number “1” in the diagram above should appear at the bottom of our blue face? Also notice that face number “2” should appear on the smaller side of the blue face? This all corresponds with solution D, which is the correct answer.
Hopefully you found that problem to be pretty easy. If my explanation didn’t help or confused you, take a look at the video I linked to above. Next we’ll take a look at a folding problem which involves actual pattern matching, as in patterned faces.
Folding patterns are fun!
In a problem like this I see which shapes I can eliminate immediately. I tend to start with solutions that have three patterned sides showing. Starting with solution A then, notice that it has two faces that feature a stripe down the center. Our problem pattern only features one side that has a stripe down the center, so we can eliminate solution A immediately.
Next look at solution D. It also features three striped sides next to each other which makes it easier to discern right from wrong quickly. Notice that it can’t be correct. When the faces with a stripe on the edge are folded together then the blank face should appear at the top. The face with the stripe on it should therefore appear on the bottom. See for yourself:
Looking at options B and C, it is apparent that option C is correct. If you fold the edges together as shown in the image above then the blank face should show up on top. Although I am reasonably certain that answer C is the correct solution to the problem, I want to be sure and so I will eliminate B.
Try to eliminate all of the wrong answer choices if you can
Notice that the face with a stripe down the middle has to appear opposite the blank face no matter how you fold the pattern. Also, every face surrounding the blank face features a stripe on the edge and not down the center. Because solution B shows the face with a stripe down the center being next to the blank face, we know that it must be wrong.
Some people might start with the blank face because it is the most unique of the six sides. I chose to go with the answer choices featuring three patterned faces. It is really up to you how you want to solve problems like this. Mine is certainly not the only way to solve this problem.
You may see some more difficult pattern folding problems than what I covered here. But the principles are still the same. Be deductive in your approach, and think logically.
Trying to imagine how a complex shape folds is difficult and time consuming. You are better off selecting key features which will help you to eliminate your options. Remember that practice tests are harder than the real thing to prepare you for test day!
I hope that this article on the PAT section of the DAT proves useful to someone. I will cover reading comprehension and quantitative reasoning in the last article of this series.