Part 2: Thinking Critically with Psychological Science

Correlation coefficient

A correlation coefficient is a numerical indicator of the strength of the relationship between two factors. A correlation coefficient always falls in the range from -1.00 to +1.00. The correlation coefficient has two parts—the number and the sign. The number indicates the strength of the relationship, and the sign indicates the direction of the relationship between the two variables.More specifically, the closer a correlation coefficient is to 1.00, whether it is positive or negative, the stronger the correlation or association is between the two factors. Hence, a correlation coefficient of +.90 or -.90 represents a very strong association, meaning that the two factors almost always occur together. A correlation coefficient of +.10 or -.10 represents a very weak correlation, meaning that the two factors seldom occur together. Notice that correlation coefficients do not function like the algebraic number line. A correlation of -.80 represents a stronger relationship than does a correlation of +.10. The plus or minus sign in a correlation coefficient simply tells you the direction of the relationship between the two variables.

Negative correlation

A finding that two factors vary systematically in opposite directions, one increasing as the other decreases. Example: In a study investigating the relationship between multitasking and GPA, Reynol Junco and Shelia Cotten (2012) found that there was a negative correlation between time spent sending text messages while studying and GPA: As time spent texting while studying increased, GPA decreased.

Positive correlation

A finding that two factors vary systematically in the same direction, increasing or decreasing together. Example: Hartwig and Dunlosky (2012) found that there was a strong positive correlation between GPA and use of self-testing as a study strategy. That is, as the use of self-testing increased, so did GPA. Other study strategies, such as using flashcards, rereading, or highlighting, were not associated with an increase in GPA.

Theory vs. Hypothesis

A hypothesis is a specific question or prediction to be tested. In contrast, a theory integrates and summarizes numerous research findings and observations on a particular topic

Correlational research

A research strategy that allows the calculation of how strongly related two factors are to each other. Correlations can be used to analyze the data gathered by any type of descriptive method, and are also used to analyze the results of experiments.

Scientific method

A set of assumptions, attitudes, and procedures that guide researchers in creating questions to investigate, in generating evidence, and in drawing conclusions

Theory

A tentative explanation that tries to integrate and account for the relationship of various findings and observations (book). Explanation using an integrated set of principles that organizes observations and predicts behaviors or events (teacher). Characteristics of a good theory: Effectively organizes a range of self-reports and observations, leads to clear predictions that anyone can use to check the theory, often stimulates research that leads to a revised theory which better organizes and predicts what we know, may be replicated and supported by similar findings

Hypothesis

A tentative statement about the relationship between two or more variables; a testable prediction or question (book). Testable prediction, often implied by a theory (teacher)

Surveys (descriptive research)

Book- A questionnaire or interview designed to investigate the opinions, behaviors, or characteristics of a particular group. One key advantage offered by survey research is that information can be gathered from a much larger group of people than is possible with other research methods.Typically, surveys involve carefully constructed questionnaires. Questionnaires may be paper, Internet-based, computer-based, or administered in person or over the telephone by a trained interviewer. Researchers usually select a sample rather than everyone within the particular group or population. Selecting a sample that is representative of the larger group is the key to getting accurate survey results. A representative sample very closely parallels, or matches, the larger group on relevant characteristics, such as age, sex, race, marital status, and educational level. Researchers select participants through random selection so that their sample is representative of the larger group. Random selection means that every member of the larger group has an equal chance of being selected for inclusion in the sample. One potential problem with surveys and questionnaires is that people do not always answer honestly, especially when they are asked questions about sexual activity, drug or alcohol use, or illegal activities. The tendency to respond in socially desirable ways can be addressed in a carefully designed survey. One strategy is to rephrase the question and ask for the same information in a different way at different points during the survey. Researchers can then compare the responses to make sure that the participant is responding honestly and consistently. There is some evidence that participants are more likely to respond honestly to Internet or computer-administered surveys than to surveys that are administered in person. Teacher- Descriptive technique for obtaining the self-reported attitudes or behaviors of a group, usually by questioning a representative, random sample of that group.

Case studies (descriptive research)

Book- An intensive study of a single individual or small group of individuals. Involve compiling a great deal of information from numerous sources to construct a detailed picture of the person. The individual may be extensively interviewed, and his or her friends, family, and co-workers may be interviewed as well. Psychological and biographical records, neurological and medical records, and even school or work records may be examined. Other sources of information can include psychological testing and observations of the person's behavior. Clinical psychologists and other mental health specialists routinely use case studies to develop a complete profile of a psychotherapy client. Case studies are also used in psychological research investigating rare, unusual, or extreme conditions. These kinds of case studies often provide psychologists with information that can be used to help understand normal behavior. The most important limitation is that the findings on people with rare or unusual conditions might not apply to people in the broader population. Teacher- Descriptive technique in which one person or group is studied in depth in the hope of revealing universal principles

Extra info about correlational research

Even if two factors are very strongly correlated, correlation does not necessarily indicate causality. A correlation tells you only that two factors seem to be related or that they co-vary in a systematic way. Although two factors may be very strongly correlated, correlational studies cannot be used to demonstrate a true cause-and-effect relationship

Experimental research

Experimental research is used to demonstrate a cause-and-effect relationship between changes in one variable and the effect that is produced on another variable. Conducting an experiment involves deliberately varying one factor, called the independent variable. The researcher then measures the changes, if any, that are produced in a second factor, called the dependent variable, also called the outcome variable. In every experiment, there are at least two conditions of the independent variable, a control condition and a treatment condition. The treatment condition is the particular condition, substance, or situation that the researchers wish to test to see whether it will affect the dependent variable. The experimental group is the group of participants that is exposed to the treatment condition. It's important that experiments also include a control group, which is exposed to the control condition of the independent variable. The control group serves as a baseline against which changes in the experimental group can be compared. In a typical experiment, the participants in the control group go through all the experimental phases but are not exposed to the specific treatment that the experimental group experiences. To the greatest degree possible, all other conditions in the experiment are kept exactly the same for all participants. Thus, when the data are analyzed, any changes that are measured in the dependent variable can be attributed to the deliberate manipulation of the independent variable. In this way, an experiment can provide evidence of a cause-and-effect relationship between the independent and dependent variables. In designing experiments, psychologists try to anticipate and control for confounding variables. Also called extraneous variables, these factors are not the focus of the experiment. However, confounding variables might produce inaccurate experimental results by influencing changes in the dependent variable. Confounding variables in a psychology experiment could include unwanted variability in such factors as age, gender, ethnic background, race, health, occupation, personal habits, education, and so on. A well-designed and carefully executed experiment can provide convincing evidence of a cause-and-effect relationship between the independent and dependent variables. But experiments do have limitations. Because experiments are often conducted in highly controlled laboratory situations, they are sometimes criticized for having little to do with actual behavior. That is, the results may not generalize well, meaning that the results cannot be applied to real-world situations or to more general populations beyond the participants in the study. To minimize this, experiments are sometimes carried out in natural settings, rather than in a laboratory. A second potential limitation is that the phenomena the researchers want to study may be impossible or unethical to control experimentally. But researchers are sometimes able to take advantage of naturally occurring events or conditions. In a natural experiment, researchers carefully observe and measure the impact of a naturally occurring event or condition on their study participants. Although these are not true experiments, psychologists can use natural experiments to study the effects of disasters, epidemics, or other events

Example of case studies

Much of our early knowledge about the brain came from case studies of people who experienced brain injuries or damage, such as Phineas Gage. Case studies are also an excellent tool to learn about unique conditions, such as psychological disorders

Descriptive research

Scientific procedures that involve systematically observing behavior in order to describe the relationship among behaviors and events

Scientific method steps (short-version)

Step 1. Formulate a Testable Hypothesis Step 2. Design the Study and Collect the Data Step 3. Analyze the Data and Draw Conclusions Step 4. Report the Findings

Scientific method steps (long-version)

Step 1. Observe an interesting behavior Step 2. Form initial theory Step 3. Construct hypothesis from the theory Step 4. Test hypothesis by manipulating independent variable(s) and measuring dependent variable(s) Step 5. If results don't support hypothesis→ revise theory→ construct hypothesis, etc. Step 6. If results support hypothesis→ try to replicate results Step 7. If results can be replicated→ theory is established Step 8. If results cannot be replicated→ theory is rejected Step 9. Form new theory→ construct hypothesis, etc.

Naturalistic observation (descriptive research)

The systematic observation and recording of behaviors as they occur in their natural setting. Usually, researchers engaged in naturalistic observation try to avoid being detected by their subjects, whether people or nonhuman animals. Psychologists very carefully define the behaviors that they will observe and measure before they begin their research. Often, to increase the accuracy of the observations, two or more observers are used. In some studies, observations are recorded so that the researchers can carefully analyze the details of the behaviors being studied. One advantage of naturalistic observation is that it allows researchers to study human behaviors that cannot ethically be manipulated in an experiment. Because the observations occur in the natural setting, the results of naturalistic observation studies can be generalized to real-life situations with more confidence than can the results of studies using artificially manipulated or staged situations. Teacher- Descriptive technique of observing and recording behavior in naturally occurring situations without trying to change or control the situation

Example of naturalistic observation

This method has been used to develop theories related to parent-child attachment, and describe such things as social media use and social interactions. For instance, this research design found that we tend to laugh 30 times more in a social situation in comparison to when we are alone.

Example of surveys

This method has been used to gather information regarding political preference, drug use histories, sexual practices and so on. Using this design has shown that Saturdays and Sundays are the days when people are the happiest.