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Psychology's Scientific Methods


The Big Picture: Chapter Overview

Psychology is a science; therefore, it relies upon scientific research to study behaviors and mental processes. In comparison to personal observations and experiences, scientific research is systematic and usually requires collaboration among researchers. The scientific approach is characterized by four ideals: curiosity, skepticism, objectivity, and critical thinking. Embracing these attitudes or ideals increases the likelihood that psychological research will result in reliable and objective scientific findings.

Research in psychology is based on the scientific method and involves:

    1. Conceptualizing a problem. This step involves taking an issue that the researcher is curious or skeptical about and expressing it in terms of operational definitions and hypotheses.
    2. Collecting data. Based on the conceptualization of the problem, the researcher selects a research method that will be appropriate to explore the issue or test the proposed hypothesis or hypotheses. An important aspect of collecting data is selecting an appropriate sample that is representative of the population of interest. One of the options researchers have is to use a random sample, to increase the ability to generalize the results from the sample to the population. In psychology, generalizations often result from similar findings across a number of studies.
    3. Analyzing the data. Based on what data was collected and how it was collected, the researcher will then proceed to analyze the data. Most research in psychology is analyzed using statistical procedures.
    4. Drawing conclusions. Based on the results of the analysis of the data, the researcher develops explanations for the findings. These explanations involve the extent to which the findings confirm the theories and hypotheses that the study was addressing.

In the process of conceptualizing the problem, the researcher chooses the research method that will better address the research topic.Psychologists rely on three basic types of research methods to perform their studies of behaviors and mental processes: descriptive, correlational, and experimental. Descriptive methods involve systematic observations and recording of behaviors. The four types of descriptive methods discussed in Chapter Two are observations, surveys and interviews, standardized tests, and case studies. Observations can take placed in natural settings or in laboratories. In naturalistic observation, the psychologist observes behavior in real-world settings and makes no attempt to manipulate or control the situation. However, many of the observations that take place in psychology occur in the laboratory, which gives the psychologist control over factors; for this reason, there are several drawbacks to this method, such as the unnatural behaviors that result from people knowing that they are being observed. An interview involves asking people questions to find out about their experiences and attitudes. One problem of interviewing people is the concern of participants to tell the interviewer what they think is socially acceptable or desirable. Surveys or questionnaires require subjects to read questions and mark their answers. Some psychologists observe behavior and mental processes by administering standardized tests. Standardized tests allow the researcher to measure some aspect of the participant's behaviors and/or mental processes, and compare each individual's outcome to others that have also performed the same test. The last descriptive method discussed in Chapter Two is the case study, which provides an in-depth examination of a single individual, from which the results may not be easily generalized to other people.

The correlational method is basically a statistical procedure that allows the researcher to describe how strongly two or more events or characteristics are related. The correlation coefficient is a measure of the strength and direction of the relationship between the two factors. It is important to note that correlation does not equal causation, but can allow us to make predictions.

Unlike the correlational method, the experimental method allows psychologists to determine the causes of behaviors and mental processes. In an experiment, one or more factors are manipulated and all other factors held constant. The factor that is manipulated is called the independent variable. The behavior or mental process that is observed and measured in the experiment is called the dependent variable. In general terms, the goal of an experiment is to determine the extent to which the independent variable influences and causes the dependent variable. In experiments, researchers usually expose a number of participants to one level of the independent variable and others to another level. The group of participants whose experience is being manipulated is the known as the experimental group, while the comparison group is called the control group. In experimental research, participants are randomly assigned to experimental and control groups. One concern involves the experimenter's own bias influencing the outcome of the research; this is called experimenter bias. On the other hand, research may also be influenced by participant bias, where the research participants have beliefs about how they are expected to behave and behave according to their expectations. The research participant bias is also referred to as the placebo effect. To control for these expectations, an experiment may be designed as a double-blind experiment, where neither the participant nor the experimenter know in which condition is the participant.

In order to analyze the data collected in systematic research, psychologists rely on statistics, which are mathematical methods. There are two basic categories of statistics: descriptive and inferential. Descriptive statistics are used to summarize the information acquired in the study. Two types of descriptive statistics are discussed in Chapter Two: (1) measures of central tendency, which are used to assess the general tendencies or the "average" behavior or mental process that was observed in the study, and (2) measures of variability, which inform us as to the differences in behaviors and mental processes inside the sample that was studied. Once you understand the three most common types of measures of central tendency, you will understand the importance of measures of variability. The first measure of central tendency is the mean. This is what we commonly associate with an "average" response.The mean is calculated by adding all the scores and then dividing that total by the number of scores or participants. The median is the score that stands right in the middle of the series of scores. The third measure of central tendency is the mode, which is the most typical score in the series of scores; . in other words, the most typical behavior observed in the study. While these three measures of central tendency do give us a summary or idea of the behaviors and mental processes observed in the participants of the study, they do not include information about the individuals in the study and the differences between the participants. Here is where the measures of variability play a very important role in psychological research. The range and the standard deviation give information about the differences between the people that participated in the study. The range is the distance between the highest and the lowest score. The standard deviation is a measure of, on average, how different individuals are from the mean or average behavior. The higher the standard deviation, the more difference was there between the mean score and the scores of individuals. In other words, the higher the standard deviation, the less descriptive or representative is the mean of the behaviors and mental processes of the individual participants. Inferential statistics are used to analyze the data collected in the study to test the hypotheses that guided the study. A hypothesis explains the expected relationship between the manipulated independent variable and the dependent variable. Inferential statistics inform the researcher regarding the extent to which the relationship between the independent variable and the dependent variable is real and significant or is due to chance. Psychologists only report an effect as significant if the inferential statistics indicate that the odds of the results being due to chance is equal or less than 5 out 100 or .05 statistical significance.

Ethics and values are of great concern to psychologists. Values influence the types of questions psychological research poses. The American Psychological Association has developed a code of ethics for researchers that calls for researchers to provide subjects with informed consent, confidentiality, debriefing, the careful use of deception, and protection from physical and mental harm. Current controversies surround the values of psychology and use of animals in research. In recent years, psychologists have shown increasing interest in and sensitivity toward gender, cultural, and ethnic bias in psychological research.

Learning to read journals can be of benefit regardless of one's career choice. Journal articles are often written with technical language and specialized terms since they are usually intended to be read by professionals in the field. Learning to be a wise consumer of information about psychology is very important. When reading information presented in the media, one needs to pay attention to overgeneralization based on a small sample and acknowledging that one study should not be taken as the final answer on a problem.











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