Critical Thinking and The Scientific Method

Critical thinking involves constantly asking questions, examining information and evidence, and figuring out conclusions. All of these actions are the basis for the scientific method, which then gives good evidence on which to base conclusions.

fig. 1

Socrates

Critical thinking can be traced in Western thought to the Socratic method of Ancient Greece developed by Socrates.

KEY POINTS

With a scientific attitude, a person is armed for critical thinking.
Critical thinking has led to many surprising conclusions. Critical thinking has also helped to combat commonly held beliefs, such as the idea that opposites attract. In fact, people who are opposites are not usually attracted to each other.
Scientific theories account for behavior by linking and integrating observations and facts into a set of principles. These principles summarize information and should lead to testable hypotheses.
Hypotheses are testable predictions that help guide research by providing a framework for the evaluation of research results. Results are said to either confirm or not confirm a theory. On the other hand, predictions can also bias interpretations of data.
Psychologists use operational definitions that define the exact processes used in characterizing their research variables. The operational definition for "generosity" might be "the amount of money contributed." Operational definitions enable other researchers to replicate the study.
After testing hypotheses, research usually leads to revised theories and additional research.

What is Critical Thinking?

The application of logical principles, rigorous standards of evidence, and careful reasoning to the analysis and discussion of claims, beliefs, and issues. Doesn't this sound like the scientific method?

So Why do Scientists Think Critically?

Critical thinking is considered important in psychological science because it enables one to analyze, evaluate, explain, and restructure thinking, thereby decreasing the risk of adopting, acting on, or thinking with a false premise. Within the framework of the scientific method and scientific skepticism, the process of critical thinking involves acquiring information and evaluating it to reach a well-justified conclusion or answer.

To develop one's critical thinking abilities, one must acknowledge that one still has numerous blind spots, and learn the art of suspending judgment. Other ways of improving critical thinking skills are through development of intellectual empathy and intellectual humility. The first requires extensive experience in entering and accurately constructing points of view toward which one has negative feelings. In other words, it takes the willingness to look at another view from the perspective of the person who supports it. Practically, this means knowing competing models or theories as well as the one you support. It also means accepting that other people have good reasons to support their own view. The second, humility, requires the ability to identify the extent of one's own ignorance in a matter. It is at least as important to have an idea of what you don't know as to know what you do know.
Critical thinking skills, however, enable people to make decisions or judgments on what to believe or what to do in a more reflective way, thus reducing bias.
The Scientific Method- a Way to Think Critically

The scientific method, because it has a series of specific steps and actions to take, creates a way to think critically. There are other ways as previous articles in this module show, but the scientific method provides an excellent starting point. Below are some aspects of the Scientific Method that support critical thinking.

Theory
- In modern science, the term "theory" refers to scientific theory, a well-confirmed type of explanation of nature, made in a way consistent with scientific method and fulfilling the criteria required by modern science. Theories are described in such a way that any scientist in the field is in a position to understand and either provide empirical support ("verify") or empirically contradict ("falsify") them.The key is that it requires evidence to create, support, or discredit theories. If someone wants to show that Jean Piaget was wrong and two-year-olds can learn calculus, then they need to provide evidence! The best evidence here would be one, or even better several, two-year-olds who can show that they understand calculus. Scientific theories are the most reliable, rigorous, and comprehensive form of scientific knowledge, because they have the most empirical support. As you can see, this meaning of "theory" is very different from more common uses of the word "theory" that imply that something is unproven or speculative. Scientific theories are also different from hypotheses, which are much more limited. A hypothesis is just a prediction about a specific event; theory deals with many events and explains WHY those events occur.
  
  A scientific theory is also capable of both predicting future occurrences or observations. It allows a measure of control. If my theory of student learning is correct, then I can use it to create a situation where students can learn better!
- Another important characteristic of a scientific theory is that it makes falsifiable predictions. The relevance and specificity of those predictions determines how potentially useful the theory is. In practice, a body of descriptions of knowledge is usually only called a theory once it has a minimum empirical basis. Finally, a theory must be the most parsimonious explanation, which means that it must be the simplest explanation that still can explain the situation fully. A parsimonious explanation passes the Occam's Razor Test.
Hypothesis
A hypothesis is a proposed explanation for a phenomenon. To be a scientific hypothesis, it has to be testable through experiment or observation.
One possible hypothesis might be "opposites attract;" the idea that people will get in romantic relationships with their opposite. So a conservative would be attracted to a liberal, an introvert attracted to an extrovert, and so on. It is a prediction, and it can be tested.
Concepts are the basic components of hypotheses. Hypotheses connect concepts by specifying the expected relationships between concepts. So the above hypothesis specifies that it is different people (a concept) will attract each other (another concept). Now, the researcher must use an operational definition to indicate how these abstract concepts will be measured. That measurement means that we can test for the existence of the concept, and we can ensure that people test the concept the same way in different studies. So, we would have to specify what "opposite" and "attract" mean. So we might operationally define "opposite" as having opposing personalities, such as extroverted or introverted. We would take it further and define the personality test we'd use to see if someone is introverted or extroverted and the specific score we would use as a cutoff to say that a person fits in one category or the other.
A recent real effect of differing definitions occurred when millions of Americans went from normal to overweight in a day's time. The change in the theoretical definition of "overweight " was based on new theories put forth by the National Institute of Health, suggesting greater risks than originally believed. The government then changed the operational definition of "overweight" to "having a BMI over 25" (rather than 27 for women and 28 for men). Changing our understanding of when someone is "overweight" put several million more in that category, even though they had not actually gained or lost any weight.
Replication
Experimental replication-- or reproducibility-- is one of the main principles of the scientific method, and refers to the ability of a test or experiment to be accurately reproduced, or replicated, by someone else working independently. To help an experiment be repeatable, the researcher should ensure that the variables are measurable and can be measured in the same way by others. Reproducibility relates to the ability for other researchers to find the same results doing the same study. So, for instance, if a researcher discovered that tickling students improves their memory, then other researchers would have to do the same (or similar) studies and find the same result. Reproducibility contributes to scientific consensus and is considered necessary to establish the scientific validity of a theory or hypothesis.
Sometimes experimenters may make systematic errors during their experiments, unconsciously veer from a scientific method , or, in rare cases, deliberately report false results. Replication is one important way to "check" previous research for errors. When independent researchers repeat the same experiment themselves based on the original experimental methods and procedures and arrive at similar results, their results provide further validation of the hypothesis and support for a theory.
So if we found that opposites attracted, based on our study, others would want to test it several times with different groups of people to see if we were correct, or if we made a mistake. The evidence, by the way, indicates that we made a mistake, because people who get in relationships tend to be more similar on important variables than different.

Conclusion

Using and testing theory with hypotheses gives us valid evidence about a phenomenon. That evidence is then fuel for critical thinking about that phenomenon, which means we get closer and closer to a correct understanding of that phenomenon.

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Boundless curates and validates high quality, openly licensed content from around the Internet. This particular unit used the following sources:
- http://en.wikipedia.org/wiki/Critical_thinking
- http://psycnet.apa.org/journals/psp/72/3/592/
- http://psychology.wikia.com/wiki/Theory
- http://psychology.wikia.com/wiki/Depression_-_Psychological_theories
- http://psychology.wikia.com/wiki/Hypothesis
- http://en.wikibooks.org/wiki/Introduction_to_Psychology/Research_Methods_in_Psychology
- http://www.psychwiki.com/wiki/What_is_an_operational_definition%3F
- http://psychology.wikia.com/wiki/Operational_definition
- http://psychology.wikia.com/wiki/Replication