¶ … psychological experiment. The experiment in question studied the effect of maternal stress reduction, during pregnancy, on the health of their children, at one year of age. In this paper, I will apply my understanding of some fundamental principles of proper psychological research and the principles of critical thinking. First, I will discuss the independent variable, and possible ways the researchers' treatment of this variable may have invalidated their claimed outcome. Further, I will discuss construct and internal validity. Finally, I will investigate possible extraneous variables that may invalidate the researchers' claimed outcome of the research study. I conclude that the researchers claimed outcome results from flawed research practices and design, and that their claimed outcome is therefore, highly questionable.

The experiment analysed in a research study about preparing for parenthood. The research study focuses on the effect of maternal meditation and stress reduction on the health of their children. The hypothesis of the study was that weekly, four-hour training in stress reduction techniques during pregnancy would increase the health and happiness of their babies.

Specifically, a group of 15 pregnant women participated in a program at a local hospital. The program consisted of weekly four-hour training sessions in meditation and other stress reduction techniques. The babies were tested one year after delivery, and it was discovered that the babies of mothers who had participated in the program were healthier and happier than babies whose mothers did not sign up for the program. The researchers concluded that expectant mothers who do not take the time to learn stress reduction techniques are putting the future health and happiness of their babies at risk.

First, before undergoing a thorough analysis of the experiment in question, it is in order to define a psychological experiment, and then briefly discuss some of the fundamental principles of sound scientific research.

Christensen defines a psychological experiment as, "Objective observation of phenomena that are made to occur in a strictly controlled situation in which one or more factors are varied and the others are kept constant" (117). An experiment is designed to try to bring out cause and effect relationships.

The first steps in developing a sound experiment are to identify the research problem and hypothesis. After these are complete, a good psychological experiment allows us to systematically change one or more variables under controlled conditions, allowing the experimenter to identify causal relationships. Variables are defined as "Any characteristic or phenomenon that can vary across organisms, situations or environments" (157).

There are two main types of variables in psychological experiments. I will define these briefly, because a good understanding of the role(s) of these variables plays a key role in my critical analysis of the research study in question. Firstly, the independent variable is a variable that is changed; this is the variable that causes the effect that the researcher is interested in studying. In the study in question, the independent variable is the weekly four-hour training sessions in meditation and other stress reduction techniques.

The dependent variable is the variable that "measures the influence of the independent variable" (157). The dependent variable is tied to the dependent variable, and measures the effectiveness of the independent variable. In the research study in question, the dependent variable is the health and happiness of the babies. Theoretically, the dependent variable of the babies' health and happiness is tied to the independent variable of the weekly four-hour training sessions in meditation and other stress reduction techniques. In layman's language, the researchers believed that the babies' health and happiness would be improved by reducing the mother's stress during pregnancy, using stress reduction techniques.

One of the most obvious criticisms of the research study in question is the researcher's failure to control the variation of the independent variable, of the weekly four-hour training sessions in meditation and other stress reduction techniques. Christiansen argues that for a variable to qualify as an independent variable, it must meet...

They compared two groups, one that did not receive the stress reduction techniques, and the other group, which did receive stress reduction sessions. In this sense, then, the researchers studied both the presence and absence of the independent variable.
Certainly, the researchers in this study did not control amount of the independent variable, the stress reduction techniques. To accomplish this, the researchers could have increased or decreased the number or time of the training sessions on stress reduction techniques. For example, they could have included groups of women who received the training for four hours twice a week, or only once a week for one hour. If this condition was met, the researchers may have been able to study the effects of different amounts of stress reduction.

For example, they may have determined that the optimal effect on the babies' health and happiness occurred when the mothers' received stress reduction training for one hour, once a week. There may have been no increase in the babies' health or happiness for mothers who received more stress reduction. This is an important distinction, with real-life implications for busy women with a minimal amount of time to give to stress reduction.

Further, the experimenters could have varied the type of independent variable under examination. Specifically, the experimenters could have varied the type of stress reduction technique. For example, they could have used experimental groups who received instruction in yoga, meditation, or flower arranging exclusively.

One major concern with the study is the construct validity of the independent variable. Construct validity is the extent that the independent variable accurately represents the construct it is meant to define. In this study, the independent variable of the weekly four-hour training sessions in stress reduction techniques should match the construct of stress reduction.

Put more simply, are the stress reduction classes truly effective in reducing stress. In order to confirm the validity of their independent variable, it may have been useful for the researchers to measure if the classes did truly reduce the mothers' stress. They could measure heart rate or cortisol levels, potential indicators of stress.

Certainly, if the independent variable did not actually reduce stress, the final outcome of the study would be in question. Given that there is no indication that the classes truly reduced stress, I would argue that the final outcome claimed by the researchers is questionable.

Interestingly, it may have been useful to include a control group that received a different type of class. In this case, the independent variable may have consisted of a class that did not necessarily have stress reduction benefits, including classes on money management, or horticulture.

My discussion now moves to the dependent variable in this study, the babies' health and happiness. Certainly, the measurement of the dependent variable is in question here. Health and happiness are very vague constructs, and I am curious as to how the researchers would have measured these variables. Given the scant information at hand, I will assume that their measurements of the babies' health and happiness were reliable and valid. Instead, I will focus on other aspects of the experiment for my analysis.

Certainly, one of the most important aspects of any experiment is internal validity. Internal validity refers to the "extent to which we can accurately state that the independent variable produced the desired effect." One of the greatest dangers in psychological experiments (or other types of experiments for that matter) is that variables other than the independent variable could affect the dependent variable.

Specifically, an extraneous variable could easily confuse and confound the result of the experiment in question. An extraneous variable is "any variable other than the independent variable that influences the dependent variable" (193).

In this experiment, there are a large number of possible extraneous variables. Firstly, there is the possibility that it was social interaction with other women in the…