Scientific Inquiry & Reasoning Skills - Skill 3: Reasoning about the Design and Execution of Research

Questions that test reasoning about the design and execution of research will ask you to demonstrate your scientific inquiry skills by showing you can “do” science. They will ask you to demonstrate your understanding of important components of scientific methodology. These questions will ask you to demonstrate your knowledge of the ways natural, behavioral, and social scientists conduct research to test and extend scientific knowledge.

As you work on these questions, you may be asked to show how scientists use theory, past research findings, and observations to ask testable questions and pose hypotheses. Questions that test this skill may ask you to use reasoning to identify the best way for scientists to gather data from samples of members of the population they would like to draw inferences about. They may ask you to identify how scientists manipulate and control variables to test their hypotheses or to identify and determine different ways scientists take measurements and record results. The questions may ask you to identify faulty research logic or point out the limitations of the research studies that are described. Or they may ask you to identify factors that might confuse or confound the inferences you can draw from the results.

These questions may also ask you to demonstrate and use your understanding of the ways scientists adhere to ethical guidelines to protect the rights, safety, and privacy of research participants, the integrity of the scientists’ work, and the interests of research consumers.

For example, questions that test this skill will ask you to use your knowledge of important components of scientific methodology by:

  • Identifying the role of theory, past findings, and observations in scientific questioning.
  • Identifying testable research questions and hypotheses.
  • Distinguishing between samples and populations and between results that support and fail to support generalizations about populations.
  • Identifying the relationships among the variables in a study (e.g., independent versus dependent variables; control and confounding variables).
  • Using reasoning to evaluate the appropriateness, precision, and accuracy of tools used to conduct research in the natural sciences.
  • Using reasoning to evaluate or determine the appropriateness, reliability, and validity of tools used to conduct research in the behavioral and social sciences.
  • Using reasoning to determine which features of research studies suggest associations between variables or causal relationships between them (e.g., temporality, random assignment).
  • Using reasoning to evaluate ethical issues when given information about a study.
  • Determining which molecule is a product of two other molecules without rearrangement.

For example, questions from the Psychological, Social, and Biological Foundations of Behavior section may ask you to reason about the design and execution of research by:

  • Identifying the basic components of survey methods, ethnographic methods, experimental methods, or other types of research designs in psychology and sociology.
  • Selecting a hypothesis about semantic activation.
  • Identifying the extent to which a finding can be generalized to the population when given details about how participants were recruited for an experiment in language development.
  • Identifying the experimental setup in which researchers manipulate self-confidence.
  • Identifying the most appropriate way to assess prejudice in a study on implicit bias.
  • Using reasoning to determine or evaluate the implications of relying on self-report measures for a specific study.
  • Identifying the third variable that may be confounding the findings from a correlational study.
  • Making judgments about the reliability and validity of specific measures when given information about the response patterns of participants.
  • Identifying whether researchers violated any ethical codes when given information about a study.

The three sample questions that follow illustrate Skill 3 questions from, respectively, the Psychological, Social, and Biological Foundations of Behavior section; the Biological and Biochemical Foundations of Living Systems section; and the Chemical and Physical Foundations of Biological Systems section of the MCAT exam.

Skill 3 Example From the Psychological, Social, and Biological Foundations of Behavior Section

Researchers conducted an experiment to test social loafing. They asked participants to prepare an annual report or a tax return. Some participants performed the task individually and others performed it as a group. What are the independent and dependent variables?

  1. The independent variable is the overall productivity of the group, and the dependent variable is each participant’s contribution to the task.
  2. The independent variable is the type of task, and the dependent variable is whether the participants worked alone or in a group.
  3. The independent variable is whether the participant worked alone or in a group, and the dependent variable is each participant’s contribution to the task.
  4. The independent variable is whether the participant worked alone or in a group, and the dependent variable is the type of the task.

The correct answer is C. This Skill 3 question assesses knowledge of Content Category 7B, Social processes that influence human behavior. This question is a Skill 3 question because it requires you to use reasoning skills in research design. This question requires you to understand social loafing and draw inferences about the dependent and independent variables based on this concept and the description of the experimental design.

Skill 3 Example from the Biological and Biochemical Foundations of Living Systems Section

Sodium dodecyl sulfate (SDS) contains a 12-carbon tail attached to a sulfate group and is used in denaturing gel electrophoresis of proteins. Numerous SDS molecules will bind to the exposed hydrophobic regions of denatured proteins. How does the use of SDS in this experiment allow for the separation of proteins?

A.   by charge

B.   by molecular weight

C.   by shape

D.   by solubility

The correct answer is B. This is a Skill 3 question and requires knowledge from Content Category 1A, Structure and function of proteins and their constituent amino acids. It is a Skill 3 question because it requires you to understand the design of a denaturing gel electrophoresis experiment and the role that SDS plays in this technique. Based on this understanding, you will be able to determine that proteins will be separated only by molecular weight.

Skill 3 Example From the Chemical and Physical Foundations of Biological Systems Section

A test for proteins in urine involves precipitation but is often complicated by precipitation of calcium phosphate. Which procedure prevents precipitation of the salt?

A.   addition of buffer to maintain high pH

B.   addition of buffer to maintain neutral pH

C.   addition of calcium hydroxide

D.   addition of sodium phosphate

 

The correct answer is B. This is a Skill 3 question and relates to Content Category 5B, Nature of molecules and intermolecular interactions. In this Skill 3 question, you must identify a change in an experimental approach that would eliminate a frequently encountered complication. The complication in this case is related to the test for protein-involving precipitation. The test will give a false positive if calcium phosphate precipitates. To answer this Skill 3 question, you need to use reasoning skills to determine how changing experimental parameters will eliminate the complication.

The three sample questions that follow illustrate Skill 3 questions from, respectively, the Psychological, Social, and Biological Foundations of Behavior section; the Biological and Biochemical Foundations of Living Systems section; and the Chemical and Physical Foundations of Biological Systems section of the MCAT exam.