Deductive reasoning is one of the most basic forms of logical processing. That is to say that deduction, is one of the fundamental ways we as humans form conclusions based on the information available to us.
Many employers choose to administer psychometric deductive reasoning exams to interested job-seekers to see how well they can process information and solve problems. Even if the position to which you’re applying isn’t related to philosophy in the slightest, your prospective supervisors will want to know whether you can handle this abstract, advanced form of thinking.
If you’ve been asked to take a pre-employment deductive logical thinking test, you should make sure that you have an idea of what to expect. Deductive reasoning is, uncoincidentally, quite logical. However, it’s not necessarily simple. If you want to have the best chance of succeeding on the assessment, you’ll want to read through our short review. When you’re done, make sure to try our free deductive reasoning aptitude test to see how well you understand the material.
What Is Deductive Reasoning?
Deductive reasoning is sometimes known as top-down logic, which means that it requires you to draw a conclusion about a specific case based on a general rule. The word deduce, as a matter of fact, comes from the Latin word deducere, which means “to lead from.”
In deductive reasoning exercises, you’ll be expected to take a law given in a premise and show it applies in varies instances. Deductive reasoning employs certain facts and established patterns; therefore, it allows us to formulate definite conclusions as you would in science or mathematics where a specific solution is guaranteed.
Deductive logical thinking is really less about problem-solving and more about interpreting and applying rules. Because you must base each step of your argument on the premises, there’s not much room for creativity and exploration.
Deductive vs. Inductive Reasoning vs. Abductive Reasoning
Deductive reasoning is very different from inductive reasoning and abductive reasoning. As explained above, deductive questions ask you to apply a universal rule to a specific case.
You won’t use deductive reasoning to accuse someone of a crime, for instance, because you would have no way to be absolutely sure that someone did a crime solely based on convincing evidence. Accusing someone of a crime requires inductive logic. Inductive logic is what we call bottom-up logic because, as opposed to deductive reasoning questions, inductive problems start with the particulars and work toward a universal.
For example, you might use deductive logic if you were given the following premises and asked to draw a conclusion:
Wednesday it is going to rain.
I am sad when it rains.
If I am sad every time it rains and it will rain on Wednesdays, I can assume that I will be sad on Wednesday. This is an example of deductive logic because there’s no room for error. The conclusion follows directly from the premises, and there are no other possible conclusions. Of course, if the premises are not true, then the conclusion, while still logical, won’t be true.
By contrast, take a look at the following argument.
When Linda stopped eating oil, her skin cleared up.
Oil causes acne.
Notice how we make a general statement about health based on a particular case. It’s possible that Linda is simply particularly sensitive to oil. It’s also possible that Linda’s skin cleared up because she started washing it more thoroughly. We cannot be absolutely certain that Linda’s dietary change improved her skin, nor can we be completely sure that consuming oil causes acne in the overall population. However, using inductive logic, we can eventually make generalisations if we compile enough evidence.
We use deductive and inductive logic to come closer to the truth. Inductive logic allows us to develop a theory based on previous experiments. Deductive logic, on the other hand, permits us to apply that theory to different cases. Meanwhile, abductive logic helps us to interpret a certain situation using the data provided.
Abductive logic is slightly different. When using abductive logic, we draw a conclusion based on the evidence available. Doctors use abductive logic to diagnose a disease just like judges use abductive logic to determine the verdict of a case. Take the following example.
Jenny has chocolate all over her face.
The plate of chocolate chip cookies is empty.
Now, we can reasonably assume that Jenny did, in fact, eat the plate of chocolate chip cookies. However, we cannot prove that Jenny did solely based on the evidence in front of us. Perhaps her brother Johnny passed by just a moment ago and loaded the cookies into a container to bring to his friends. Poor Jenny happened to stop by to snack on the chocolate bar she had left in the cabinet only to have her mother walk in a moment later. While the first explanation makes more sense, the second is nonetheless plausible.
How to Prepare for a Deductive Logical Thinking Test?
You can succeed on a deductive reasoning test without studying, but if you’re nervous and want to make sure you come prepared, then you should look over practice questions. If you want to learn more about deductive reasoning, then you need to see how it works in action.
The deductive reasoning examples on the next tab will help you prepare for the real test. Take note of the structure of the questions, and make sure you understand each of the answers.
Syllogisms are one of the most popular types of deductive reasoning problems. In a syllogism, both of the two premises share something with the conclusion, and each of the two premises share another term. Below, you’ll find the three different types of syllogisms you’re likely to find on a deductive test.
- Categorical: A categorical syllogism lists the qualities of a certain category and then provides an item that contains those qualities. For this type of syllogism, you’ll be expected to come to the conclusion that the item does, in fact, belong to the largerAll cats are mammals.Molly is a cat.Therefore, Molly is a mammal.
- Conditional: A conditional syllogism provides two if-then statements. The conclusion of the first premise is the condition for the second. You’ll be expected to combine the two statements as follows:If Jason fails chemistry, he won’t graduate.If Jason doesn’t graduate, he won’t get a job.Therefore, if Jason fails chemistry, he won’t get a job.
- Disjunctive: A disjunctive syllogism presents two possible outcomes and then determines which of the two possible outcomes came to pass. You’ll have to state that the events in the other outcome will not, in fact, take place.Either John McCain or Barack Obama will become president.Barack Obama became president.John McCain did not become President of the United States
SHL’s Deductive Reasoning Test
SHL is a psychometric test company that offers employers online aptitude assessments designed to screen graduates and job-seekers. Their online deductive reasoning test contains 20 questions, which must be completed within 18 minutes.
Deductive Reasoning Tips
Deductive reasoning tests aren’t always easy. Make sure to check out our deductive reasoning test tips before heading out to the assessment center!
- Don’t Read Between the Lines: You want to make sure that you’re taking the question at face value. Remember that the process of deduction allows you to come to a definite conclusion based on a certain set of premises. If you make assumptions or base your answer on irrelevant information, you won’t come to the correct answer.
- Don’t Question the Validity of the Premises: On deductive skills tests, you can assume that all of the premises are true. It’s possible that some of them are untrue, but your job is not to determine the truth value of the premises. Remember, an argument doesn’t necessarily need to be sound to be logical.
- Pay Attention to Key Words: Qualifiers like all, so, most, never, some, and sometimes can change the meaning of a statement. Make sure to pay careful attention to these words when answering questions.
Deductive Reasoning Final Thoughts
Need some extra deductive reasoning practice? Make sure to check out our free deductive reasoning test in the questions tab to flex your logic muscles and prepare for the exam.