What is the structure of an experiment?
The general structure of an experiment (but not its specific content). A treatment condition in which the researcher applies a particular value of an independent variable to subjects and then measures the dependent variable; in an experimental group-control group design, the group that receives some value of the independent variable.
What is a treatment condition in research?
A treatment condition in which the researcher applies a particular value of an independent variable to subjects and then measures the dependent variable; in an experimental group-control group design, the group that receives some value of the independent variable.
How do you determine whether a treatment has an effect?
The most reliable way to determine whether a treatment has an effect is to compare the outcome for the treatment group with the outcome for a control group, using a random mechanism to allocate individuals between the treatment group and control group. This is called a controlled randomized experiment .
What is an example of an unethical psychological experiment?
For example, it had only a single subject and no control subjects. Furthermore, such an experiment could be hard to conduct in compliance with current law and regulations, it is now generally considered to be one of the more unethical psychological experiments conducted throughout the years. View More Replies...
What are the 4 types of experiments?
Four major design types with relevance to user research are experimental, quasi-experimental, correlational and single subject. These research designs proceed from a level of high validity and generalizability to ones with lower validity and generalizability. First, a note on validity.
What is the treatment in an experiment called?
The treatment group (also called the experimental group) receives the treatment whose effect the researcher is interested in. The control group receives either no treatment, a standard treatment whose effect is already known, or a placebo (a fake treatment).
What is an example of quasi-experimental design?
This is the most common type of quasi-experimental design. Example: Nonequivalent groups design You hypothesize that a new after-school program will lead to higher grades. You choose two similar groups of children who attend different schools, one of which implements the new program while the other does not.
When a subject fails to finish an experiment before it is completed it is called?
Participants frequently drop out of experiments whilst they are taking place/before they finish; something that is known as experimental mortality (or experimental attrition).
What is a treatment group in an experiment?
An experimental group (sometimes called a treatment group) is a group that receives a treatment in an experiment. The “group” is made up of test subjects (people, animals, plants, cells etc.) and the “treatment” is the variable you are studying.
What is a completely randomized experimental design?
A completely randomized design is a type of experimental design where the experimental units are randomly assigned to the different treatments. It is used when the experimental units are believed to be “uniform;” that is, when there is no uncontrolled factor in the experiment.
What is treatment in quasi-experiment?
Quasi-experimental methods are research designs that that aim to identify the impact of a particular intervention, program or event (a "treatment") by comparing treated units (households, groups, villages, schools, firms, etc.) to control units.
What's the difference between experimental and quasi-experimental?
A true experiment uses random assignment of the participants while quasi-experiments does not. This allows its wide use in ethical problems. Quasi-experiments allots the participants based on a study, unlike true experiments where they have an equal chance of getting into any of the groups.
What is meant by a quasi-experiment?
A quasi-experiment is a type of research design that attempts to establish a cause-and-effect relationship. The main difference between this and a true experiment is that the groups are not randomly assigned.
What is subject attrition?
Attrition occurs when participants leave during a study. It almost always happens to some extent.
What is subject mortality?
Subject Index In educational research, mortality (also referred to as experimental mortality or attrition) is a metaphorical term that is used to describe the loss of participants from a study prior to completion. Mortality is among one of eight common threats to internal validity.
What is intervening in research?
Intervening variables An intervening variable, sometimes called a mediator variable, is a theoretical variable the researcher uses to explain a cause or connection between other study variables—usually dependent and independent ones. They are associations instead of observations.
Why did Jews undergo experiments?
Jews were subjected to experiments intended to benefit the military, including hypothermia studies where prisoners were immersed in ice water in an effort to ascertain how long a downed pilot could survive in similar conditions.
How many prisoners were in the Stateville prison experiment?
Beginning in 1944 and spanning over the course of two years, more than 400 prisoners at the Stateville Penitentiary in Illinois were subjects in an experiment aimed at finding an effective drug against malaria.
What did Unit 731 do?
In addition to working with pathogens, Unit 731 conducted experiments on people, including — but certainly not limited to — dissections and vivisections on living humans, all without anesthesia (the experimenters believed using it would skew the results of the research). Advertisement.
What was the treatment for war wounds?
Effectively treating war injuries was also a concern for the Nazis, and pharmaceutical testing went on in these camps. Sulfanilamide was tested as a new treatment for war wounds. Victims were inflicted with wounds that were then intentionally infected. Infections and poisonings were also studied on human subjects.
Why was TB injected into prisoners?
Tuberculosis (TB) was injected into prisoners in an effort to better understand how to immunize against the infection. Experiments with poison, to determine how fast subjects would die, were also on the agenda.
Why were the men in the Tuskegee study not told they were recruited?
The men in the study weren't told that they were recruited for the program because they were actually suffering from the sexually transmitted disease syphilis, nor were they told they were taking part in a government experiment studying untreated syphilis, the "Tuskegee Study of Untreated Syphilis in the Negro Male.".
Where was aversion therapy used?
In particular, aversion therapy techniques were used on prisoners and on South Africans who were forced to join the military under the conscription laws of the time. At Ward 22 at 1 Military hospital in Voortrekkerhoogte, Pretoria, between 1969 and 1987 attempts were made to "cure" perceived deviants.
How to evaluate whether a treatment has an effect?
To evaluate whether a treatment has an effect, it is crucial to compare the outcome when treatment is applied (the outcome for the treatment group) with the outcome when treatment is withheld (the outcome for the control group ), in situations that are as alike as possible but for the treatment. This is called the method of comparison .
What is the problem of determining whether a treatment has an effect?
Treatment is meant generically: It could be a magnetic field, a metallic coating, welfare, decreasing the marginal income tax rate, a drug, a fertilizer, or an advertising campaign.
How many dowsers participated in the water test?
One of the 20 who showed said the environment had too much radiation, so he could not possibly work under the circumstances. Thus 19 dowsers participated in the water test.
Why is it important to use a placebo in an experiment?
This is important because the mere belief that one is being treated has an effect, called the placebo effect .
How to prevent confounding in treatment and control groups?
To prevent confounding, the treatment and control groups should be alike in every regard that can affect the outcome, except the treatment. Then, differences between the outcomes for the treatment group and for the control group can be ascribed to the effect of the treatment, rather than to other variables that differ for the two groups. As a practical matter, it can be hard to ensure that the two groups are alike: Often nature, history, or the individuals themselves divide the treatment group from the control group. Moreover, sets of subjects usually do not come in matched pairs, one to assign to treatment and one to control—although identical twins are very popular medical subjects!
What is a double blind experiment?
An experiment in which the subjects do not know whether they are in the treatment or control group, and in which the assessors do not know which subjects are in the treatment group and which are in the control group, is called a double-blind experiment . The best method for determining whether a treatment has an effect on human subjects is ...
How many women applied to graduate school at UCB in 1973?
In 1973, 8,442 men and 4,321 women applied to graduate programs at UCB. About 44% of the men and 35% of the women were admitted. This looks like women might have been discriminated against, if applicants of both genders were equally qualified.
What was the Stanford Prison Experiment?
The Stanford prison experiment was an attempt to investigate the psychological effects of perceived power, focusing on the struggle between prisoners and prison officers. It was conducted at Stanford University in 1971, by a research group led by psychology professor Philip Zimbardo and using college students as subjects.
What was the class divide experiment?
A Class Divided Experiment. In 1968, following the murder of civil rights leader Martin Luther King , teacher Jane Elliott tried discussing issues of discrimination, racism, and prejudice with her third grade class in Riceville, Iowa. Not feeling that the discussion was getting through to her class, who did not normally interact with minorities in ...
How many children stutter after therapy?
Of the six ‘normal’ children in the stuttering group, five began stuttering after the negative therapy. Of the five children who had stuttered before their ‘therapy’, three became worse. In comparison, only one of the children in the group labelled ‘normal’ had greater speech problems after the study.
What did the 1974 car crash experiment prove?
The 1974 Car Crash Experiment by Loftus and Palmer aimed to prove that wording questions a certain way could influence a participant’s recall, by twisting their memories of a specific event. They asked people to estimate the speed of motor vehicles using different forms of questions.
What is experimental psychology?
Encompassing a range of areas, from anthropological studies to social behavior and the complex biological processes occurring in the brain, the carefully controlled studies carried out in the name of experimental psychology have taught us so much about the human condition and given us a deeper understanding of why we act the way that we do.
When did Fantz do his experiment?
In 1961, when Fantz carried out his simple yet genius experiment, there wasn’t much you could do to find out what was going on in a baby’s head – other than watch. And watching the baby is what he did.
Who was the scientist who discovered that stuttering was genetic?
This experiment was conducted by Dr. Wendell Johnson, a speech pathologist who wanted to show that the prevailing theories about the causes of stuttering were wrong. During the 1930s it was thought that stuttering had an organic or genetic cause. This meant you were born a stutterer (or not) and little could be done.
The Method of Comparison
Confounding
Historical Controls
Longitudinal and Cross-Sectional Comparisons
Simpson's Paradox
Experiments and Observational Studies
The Placebo Effect
John Snow's Study of The Mode of Communication of Cholera: A Natural Experiment
- That is, nature essentially performed a controlled randomized experiment, in which the control and treatment groups differed in their water supply, but not in other factors that might have affected the outcome. The assignment to treatment and control was not exactly random, but was effectively random, depending on accidents of history. This is call...
Summary
Key Terms