Reactive arrangements are considered a threat to validity within a research design. Elements within an experimental setting could cause subjects to react differentially to the experimental arrangements rather than to the experimental variable alone. In defining threats to validity, Thomas D. Cook and Donald T. Campbell, as well as other colleagues, attribute these reactions to the use of measures in a study and/or other reactions due to the fact that participants are aware that they are in a study. Reactive arrangements are present when these participant reactions become a functional part of the treatment or independent variable in the study. For example, research participants that receive a pretest might be more or less responsive to the experimental variable as a reactive response. This human reaction impacts the study treatment and may produce reactive results. Reactive arrangements relate to changes in individuals’ responses that can occur as a direct result of participants being aware of their involvement in a research study. For example, the mere presence of observers in a classroom may cause students to behave differently than if the observer was not present, thereby altering the observation findings. Additionally, reactions to the study procedures may occur and cause reactivity. For example, reactivity may be present if participants …show more content…
In this situation, it would also be important for the pretest measures to mask the expected outcomes. Oftentimes a no-treatment approach is utilized through a “business as usual” (BAU) group, whereas the BAU treatment would be considered to be weaker or ineffective to the intervention being studied. Assessing outcomes on a delayed basis would also be a less obvious method to protect against the threat of reactive
Within the target site of the experiment, researchers wanted to answer their hypothesis; hypothesis was that increased police
If a study is confounded, the researcher is not absolutely certain that changes in the dependent variable were caused by the manipulation of the independent variable, or some other uncontrolled variable. In a non-equivalent control group post-test only design, any differences observed between the two classes may be due to the non-equivalence of the groups and not to the injection of quizzes. No pre-test measures were given to establish equivalence.
Evaluation Models with Follow-Up Strategies for Investigators, Second Edition (2). London, GB: CRC Press, 2014. Web.
West, S. L., & O'Neal, K. K. (2004). Project D.A.R.E. outcome effectiveness revisited. American Journal of Public Health. doi:10.2105/AJPH.94.6.1027
The teachers would initiate a “shock” to the student every time they got an answer wrong, but the teachers were unaware that the shock was fake. As the experiment continued, the shocks became more severe, and the students would plead for the teacher to stop since they were in pain. Despite the fact, that the participants continuously asked the authoritative experimenter if they could stop, “...relatively few people [had] the resources needed to resist authority” (Cherry 5). The participants feared questioning the effectiveness of the experiment, or restraining from continuing in fear of losing their job, going to jail, or getting reprimanded by Yale. A majority of the participants were intimidated by the experimenter, hence why they continued to shock the students, even though they knew morally, it was incorrect what they were doing. This experiment concluded, “...situational variables have a stronger sway than personality factors in determining obedience...” (5). One's decisions are based on the situation they are facing. If someone is under pressure, they will resort to illogical decision making. There thoughts could potentially be altered due to fear, or hostility. In conclusion, the rash, incohesive state of mind, provoked by fear will eventually lead to the rise of
Randomized Controlled Trials can be used to in several types of evaluations, including new therapies (i.e. Cognitive behavioral therapy versus emotionally focused therapy when treating couples), community interventions, and diagnostic techniques (O'Brien, 2013). The RCT study design randomly assigns participants into an experimental group or a control group. As the study is conducted, the only expected difference between the control and experimental groups is the outcome variable being studied (O'Brien, 2013).
...though the researchers weren’t looking for it, he results represent ideas that can help the bystander effect in a situation. Smaller numbers increase the percentage of realization when it comes down to an emergency. The victim, if cohesive, actually plays a big role in causing the bystander effect as well. When a victim is unable to verbally communicate with bystanders, it lessens the chance of help. If a victim is capable of communicating, the help given could be more efficient. This is because it can help break the diffusion of responsibility. A victim looking a bystander directly in the eyes can even spark a quicker reaction in them. These are all ideas that psychologists still study today, and many even consider learning about this phenomenon a requirement.
Longitudinal design validity is also dependent upon using set time intervals that make sense with the research being performed. This study does not say explicitly express how intervals for MI instruction were chosen. Furthermore, the study does not explain why or how intervals for pre and post assessments were decided. This is important because past research may have told how long it takes for MI to be successful and at what intervals it needs to be performed in order to yield the best outcomes for participants. This data may have changed the length of the study or the time intervals and potentially changed results.
The study that I will be reviewing for this assignment is the Bystander Effect. This particular experiment struck my interest a lot more than the other options presented to us and I definitely wanted to look more into it. According to psychologist the bystander effect is a social psychological phenomenon that refers to cases in which individuals do not offer any means of help to a victim when other people are present. The probability of help is inversely related to the number of bystanders. This experiment took me back to the Asch Conformity experiment and showed very similar characteristics.
The first method to be discussed and analysed are experimental methods. There is a variety of experimental methods including; laboratory, field and natural experiments. These methods are the most scientific method due to them being highly objective and systematic. In addition, this method is regarded as the most powerful research method used in psychology because of the potential to investigate the causes of events and therefore, identifying the cause and effect relationship. When carrying out an experiment the researcher intervenes directly in the situation being investigated. The researcher manipulates an independent variable (IV) in order to investigate whether there is a change in the dependent variable (DV). Any other variables that could have an
A researcher uses an experiment to scientifically test out a hypothesis. In an experiment there are many different factors that are involved. There is the independent variable, which is the cause, it is the one that is being manipulated, and the dependent variable, which is the effect, is the response. When conducting a experiment it is important to make sure that the only thing than can affect the dependent variable is the independent variable. This is known as internal validity. Using random assignment to separate the participants into groups helps eliminate any outside factors, and creates an equal chance for all participants to be apart of the experimental conditions. There are many pros and cons to this type of method. The experimental method creates a strong control of the variables involved in the experiment, which allows an easier determination on cause and effect. If needed, it is fairly easy to replicate an experiment and is less time consuming than other research methods. However there are many downfalls as well. When conducting an experiment the setting of where the experiment is taking place is more artificial which may cause certain behaviors that wouldn’t occur in real life. This is known as external validity, which is the measure of how much the results of a study can be generalized and used in different situations, and people. To improve external validity cover stories are created when conducting experiments so the participants are not aware of what is really going on, or experiments are done in a natural setting as opposed to in a laboratory. However, this creates less control over confounding variables that can affect the experiment, which can create bias results (Aronson,
Observation is essential for psychologists to get to know their clients. Examination consists of learning and understanding the way the client acts and thinks. While observing it is important to take mental notes and be aware of body language to see how the client reacts to certain questions and situations. There are many ways to do this, including case studies, surveys, and naturalistic observation. The case study examines an individual in depth, but often is in need for further study. “We must ask questions and look for answers within several different research methods.” (Plante, 2005) The survey looks at cases in less depth, but is used to estimate outcomes from a group of people. Naturalistic observation notes behavior in a natural environment, yet it does not explain behavior, it describes it. While observing, it is helpful to look for patterns and sequences because as Heffner stated “Order can be found in even the most random data.” (2001) Nevertheless, observation is important because before psychologists can explain what people do, they must first observe what it is that they do.
Researchers work hard to eliminate bias from outcomes through approaches that diminish subjectivity and modification from unknown sources. Randomization, use of well-matched controls, and blinding of analysts and researchers are some ways to try to a...
An important part of an experiment is random assignment. If the participants for the study are randomly assigned to create two groups, and the researcher has enough participants in the study to have the desired “probabilistic equivalence” (Trochim & Donnelly, 2008, p. 187) then the researcher will feel a sense of confidence that the study will have internal validity in order to assess whether or not the treatment caused the outcome hypothesized. Well-c...
The first experiment that DeVoe and House (2012) conducted was to directly test their hypothesis. The procedure of this experiment was to take 53 undergraduate students (32 femal...