Control your approach
Have you noticed the different ways experimental data appears in MCAT passages? They have a repertoire. There are other forms of presentation in MCAT passages. Have you noticed how they throw you into paragraphs of dense molecular biology details. That's another genre. AAMC has a characteristic way they do that. That's part of their repertoire. Another kind of passage section is the smorgasbord, which moves from science topic to topic ranging widely in a kind of free for all. All the ways information may be presented in MCAT science passages. For each type of presentation, there is a different way it should be approached. Try to be conscious that you are always deciding how you are approaching things. You could decide to just stumble through the passage. You are not doing that. You are consciously finding the best way to approach each passage element.
Organic mechanisms, dense molecular biology language, enzyme studies, tables of growth data, spectroscopy results, complicated looking structural formulas, mathematical equations. You decide how you are going to approach each thing. Learn to play with each a different way. The sense you are orienting yourself will develop into a conscious art. Sometimes you step back and put the pieces together. Sometimes you approach from the perimeter, reading the caption and the legend. You know the figure will clear if you give your brain a little time to acclimatize to it. You always make sure to get a good handle of the experimental variables. You have the ways that you approach things. With dense molecular biology language, you scout the whole paragraph from start to finish and then study it all together to understand it. The MCAT is trying to rush you at the start, so don't let it rush you. The exam will be trying to slow you down with a table with eight columns and fifteen rows later. Always do what it takes to get the gist and keep moving. You have your own repertoire of approaches to things.
Interpreting experimental data
AAMC is writing the MCAT as a big book that is continuously expanding into unfamiliar territory. The most important thing you can do to prepare for the variation in what AAMC may pull out of their hat is to have a disciplined general approach. Notice that you have to get oriented a certain way to the experimental data in an MCAT passage. Make that stage of orientation a figure of merit you pay attention to. After a while you will have a general approach to interpreting experimental data.
Make sense of the science first
Think of how quickly you can form a clear idea of the experimental procedures and results in an MCAT passage. You may not realize it, but this game is often won or lost earlier in the passage. The general tendency is for the experimental portion of the passage to follow after a paragraph or two of underlying science. It seems obvious, but the experimental section will make much better sense if you take the time to study and understand the underlying science. Don't let the MCAT rush you through that part. You get the time you spend back later. Rush the start and the experiment doesn't make sense and you get stuck on questions. You lose more time than you saved moving quickly through the beginning. Aim to reach the experimental portion having built a mental state of ideas that you have established, kept active and sustained from the beginning. When you read the experimental procedures you understand its rationale of the researchers. You'll be able to anticipate and interpret their data. Always give yourself permission to take a little extra time to put the pieces together at the start of any MCAT passage. Light the lamp you need for the whole passage then. The time you invest at the beginning comes back to you.
Walk around the data
Walk around graphs and data and get a picture of the perimeter first. Make it a careful mission as if you were in the last stages of a plan to enter the facility through the fence in Stranger Things. Read the caption and axes labels. Think about what they are measuring in their system, what they are manipulating, how they are operationalizing their variables. Then you look at the data. Graphs and data tables don't come clear if you stare straight into them. In fact, it's worse than that. They have a way of projecting whatever gestalt you want if you're not careful. A general approach for experimental data is careful and systematic, working first from the outside and then looking in towards the actual data only after coming to understand what variables are being manipulated and which are being measured.
Now that you've figured out the table, try to get the table to speak to you. A good strategy is to pick a combination of a manipulated variables you think should produce a particularly high or low result in the table based on your understanding of the experiment. You will be surprised how often you are correct about this prediction. The act of testing the table this way will confirm you understand the rationale for the experiment and how to read the table.
There is a decision to make next about how much of the table to read. One big factor to consider is the volume of data. Can you scan it quickly? Do it. Would looking through the data become time-consuming and repetitive, then it's a trap set for you. Get out of there. You know already how to read the table. Wait for them to ask you something specific.
The approach to uncertainty
On rare occasions an experimental result may seem counter-intuitive or unexplainable. You might be misunderstanding something. Then again, it may be purposeful. It may be an unsolvable riddle put into the passage on purpose by AAMC. Real life can be unexplainable or unpredictable, but when it is in an MCAT passage, it is always intended to be there. The first approach is to turn this uncertain thing into an intelligent open question. Now it is something in a queue you are keeping track of. This is the minimum necessary approach so that you don't lose the thread of the passage.
You have made the passage as clear as you could have up to now. It was satisfactory until you ran into this unclearable element. Know that there will be a few unclearable elements in the passages in your exam. They may take the form of advanced, specialized terminology. It may be counter-intuitive or difficult to explain laboratory data. It may be noisy data saying nothing. Wherever you find yourself, you can still make a coherent mental picture of it. Turn the uncertainty into your best guess. Does it make sense in the light of the rest? You have just solved the puzzle as it was intended by AAMC. Your mental state still is in the unbroken flow of attention you have maintained from the start. There was a black box. You could not figure out how to open it. You accommodated it. It is the out-of-scope thing or the unknowable thing. Make the best guess you can. You're probably right! Keep track of the uncertainty. Many open questions resolve themselves later if you keep track of them.
The molecular biology laboratory
The workflow of an experiment, as described in the passage, may involve core techniques such as SDS-PAGE, size exclusion chromatography or RT-PCR. A question is usually coming about technique mentioned in the passage. Sometimes you have to adjust to a technique being employed that is high level or very specialized. You may not know exactly how the technique works, but at least you can piece it together in terms of inputs and outputs.
A common type of question asks you to infer the purpose of an experimental control. Think through the purpose of an experimental control when you first come across it. The question you ask is, "What confounding variable you are sorting out for us?" Approach it ambitiously and figure out its purpose when you first meet the control in the passage. The more more clear you are about it before you even reach the question the better.
Sometimes graphs or tables seem complicated because you haven't given yourself a complete sense of the identity of the manipulated variables. Imagine an experiment with three manipulated variables, such as genotype, pH, and presence of an inhibitor. This type of thing may easily result in two tables with multiple sets of bars in each table. The height of a bar represents the magnitude of the measurement. The position of the bar represents a unique combination of the manipulated variables. These tables are not hard if you carefully account for the variables under manipulation and observation.