FOP - The Scientific Method Lesson

 

The Scientific Method

Let's Take a Look at the Science

Psychologists have four basic goals: to describe, explain, predict, and control behavior. How can they do that?

It's vital to remember that psychology is a science! When psychologists want to propose new theories, they must first do some research through the use of the scientific method. The scientific method is a method of investigation that consists of systematically observing, measuring, and experimenting in order to test a hypothesis. You have probably studied the scientific method in your science classes since early in your educational career!

Here are the steps to the scientific method:

1. Ask a Question
2. Read the Existing Research
3. Create a Hypothesis
4. Test the Hypothesis
5. Analyze Data and Draw Conclusions
6. Confirm or Edit Hypothesis
7. Communicate Results

In order to create a new theory and confirm that it is trustworthy, a scientist must repeat the same experiment repeatedly. If psychologists get the same information every time, they can be sure the experiment was valid, that the results are real, and that the theory is true.

The Need for Science

But do we really need the scientific method to investigate human behavior and thought processes? Don't humans just naturally understand how humans work? The answer to this question is NO! Experiments have shown that humans are too confident in their abilities to tell when someone is lying, to judge someone based on a first impression, to predict a person's behavior, and many other areas. We cannot depend on our common sense to understand humans because we too often fool ourselves. Here are some explanations of why we need the scientific method:

• Hindsight Bias - This is our tendency to believe, after learning an outcome, that we would have foreseen it. It's also known as the I-knew-it-all-along phenomenon. This is why we need a hypothesis: so we can remember that we didn't actually know the outcome before.
• Confirmation Bias - This is our tendency to search for or interpret information in a way that confirms what we already believe.
• False Consensus Effect - This is our tendency to overestimate the extent to which other people share our beliefs and behaviors. We tend to assume that everyone has the same thought processes and behaviors, but there is a lot of variety in humanity!
• Illusory Correlation - This is our tendency to find a relationship between variables where none actually exists. We might notice something bad happened once after a black cat crossed our path, but that doesn't mean the black cat caused the bad event. Only the scientific method can prove the existence of that relationship.

How to Test a Hypothesis  

 Psychologists can test their hypotheses in various ways:

• Descriptive methods describe behaviors by using case studies, surveys, or naturalistic observation.
• Correlational methods show an association or relationship between variables.
• Experimental methods use control and experimental groups to manipulate variables and discover their effects.

These methods have their own strengths and weaknesses, so psychologists must choose the method that best works for the theory they need to test.

Descriptive Research is research focused on describing who, what, when, where and how. Descriptive research cannot tell us the cause though.

One type of descriptive research is a case study. Case studies are useful because they give a great deal of detail about a behavior. In cases of a rare, unusual, or extreme condition, a case study would be a great tool. The problem, however, is that a case study cannot explain the underlying reason for the behavior.

Correlational Research is research focused on exploring the relationship between variables. This type of research cannot prove that one variable causes the other, but it can show a relationship. This relationship is called correlation. Please remember that correlation is not the same thing as causation. Correlational research does not prove that one variable causes another; it only shows that the variables are related in some way, which could be because another unknown variable is acting in an unknown way.

The most common type of correlational research is the survey. Psychologists call people at home to ask their opinions, stop people in the mall to find out their habits, and even use pop up windows on websites to get information. All of these methods have one thing in common: asking questions.

Surveys are great testing tools because they're so inexpensive and so easy to distribute. The problems, however, are that most people ignore them (the response rate is very low) and that people have a tendency not to be truthful with their answers. For example, social desirability bias leads people to give answers that they think are socially acceptable so they don't feel embarrassed.

If we want to conduct a correlational study through surveys, here's what we would do. First, we would find a topic, ask some questions, and read the existing research available. Then we would write a hypothesis. For example, we might propose that students who take a psychology course in high school have more satisfying relationships. Then we would develop some questions asking people if they have taken a psych course and how they feel in their relationships.

Who is going to answer our surveys? First we need to identify the population we want to understand (in this case it would be high school students), and then we need to choose a random sample of those people to take the survey. We can choose every 15^th person who walks by us at the mall, every 100^th student on the alphabetical list of high school students, or use some other method, as long as we get a random sample. We can't just ask for volunteers or pick the first three kids to walk by, because then our study would not represent the population.

Psychologists can also use naturalistic observation to determine correlation. We could do our study on psychology classes and satisfying relationships through naturalistic observation. We would do some research to find people who had taken a psychology course and then observe them in their natural environment to find out about their relationships, making notes as we follow them around.

Both of these methods (surveys and naturalistic observation) can show a relationship between variables, known as correlation. The correlation is the relationship between two variables, and it is measured using a correlation coefficient. The correlation coefficient is a number expressing the strength of a relationship between two variables. A correlation coefficient always falls between -1.00 and +1.00. Numbers closer to 1 indicate a stronger positive relationship and numbers closer to -1 show a stronger negative relationship.

A scatterplot is used to illustrate correlation. A positive correlation tells us that two factors are increasing together and move in the same direction. A negative correlation tells us that two factors move in opposite directions. (The terms positive and negative describe the direction of the relationship, not whether or not something is good or bad!) For example, time spent brushing and flossing leads to a decrease in cavities. This is a good thing, and it would illustrate a negative correlation (as flossing increases, cavities decrease).

The image illustrates what a perfect positive correlation, a perfect negative correlation, and no correlation would look like on a scatterplot. Perfect positives or perfect negatives are rare, but the direction of the correlation will be the same. An example of uncorrelated variables or no correlation would be the relationship between your shoe size and your IQ.

Experimental Method

While correlational studies are useful for proving the relationship between variables, only one method can show a cause and effect relationship. That's what the experimental method is for!

The experimental method is also known as causational research because it shows the cause of a phenomenon. An experiment can prove causation because it involves carefully manipulating situations so that only one variable changes. The independent variable(IV) is the one the researcher changes between the two groups. The experimental group gets the treatment (the special version of the independent variable) and the control group gets the placebo or no treatment at all. Everything else should be exactly the same in the two groups to ensure that any differences result from the independent variable. The dependent variable(DV) is the one the researcher measures to see if the independent variable affected it.

Complete the activity below:

When conducting an experiment, random assignment is vital. Researchers must randomly assign participants to either the control or experimental group. We wouldn't want to let participants choose their groups because then the groups might be biased in some way. Each participant should have a 50/50% chance of being chosen to participate in one of the groups.

Sometimes events or factors that are out of our control can affect the DV. These are called confounding or extraneous variables.

Researchers consider the possibility that other variables might alter the outcome of their study. The placebo effect is an example of one of the possible confounding variables. Experimenter bias can also occur. This is when the experimenter unconsciously sways the outcome of the experiment or control group by their actions. Using a double-blind procedure reduces experimenter bias and the placebo effect.

Ethics

Psychologists must always follow the ethical guidelines that have been established by the American Psychology Association. These include:

Ethical Standards for Working with Animals

Psychologists must have a clear scientific purpose when using animals. The animals must be acquired legally and treated humanely to minimize their suffering. You might wonder why psychologists choose to work with animals. Some important experiments are too dangerous or take too long for humans. Animals are also easier to work with because they are less complex, easier to control, and have shorter life spans.

 

Ethical Standards for Working with Humans

Psychologists must take care to ensure participation is voluntary in research that involves humans. This means the participant should not be forced to be part of the study. The purpose of the study must also be clearly stated. These factors may influence the willingness of the participant to want to participate in the study. All personal information about the participant must be kept confidential. The experiment cannot put the participant at risk for any significant mental or physical danger. Finally, the participant must be debriefed afterward to correct any misconceptions about the study.

 

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