Experimental Method in Psychology: Experimental Designs ch 7 PDF

12/7/24, 7:48 PM Summary | Raena AI Experimental Method in Psychology: Experimental Designs ch 7 Learning Objectives This material is designed to equip students with the following skills and knowledge:...

12/7/24, 7:48 PM Summary | Raena AI Experimental Method in Psychology: Experimental Designs ch 7 Learning Objectives This material is designed to equip students with the following skills and knowledge: The ability to differentiate between experimental and non- experimental research methods. Identifying key concepts associated with the experimental method. Discussing the three conditions necessary for making a causal inference. Understanding various techniques to eliminate alternative explanations. Identifying the concepts of internal and external validity in experimental designs. Explaining various experimental designs and techniques to address factors threatening internal validity. Why Psychologists Conduct Experiments Psychologists conduct experiments to achieve several objectives: https://app.raena.ai/summary/pgd34uqh0p 1/9 12/7/24, 7:48 PM Summary | Raena AI Testing hypotheses derived from existing theories. Evaluating the effectiveness of treatments or interventions. Experiments facilitate the examination of the causes of behavior, setting them apart from other research designs like observational studies or surveys, and allowing researchers to achieve the explanatory goal of psychological research (Shaughnessy, Zechmeister, & Zechmeister, 2012, p. 185). Experimental and Non-Experimental Methods Experimental Method The experimental method involves the manipulation of an independent variable (IV) by the researcher. For example, a study examining the effect of positive reinforcement on students’ classroom participation demonstrates this method. Here, researchers can control the presence or absence of positive reinforcement, influencing the teaching methods employed. Non-Experimental Method In contrast, the non-experimental method does not allow for manipulation of independent variables. For instance, studying the relationship between self-concept and GPA scores among UAEU students exemplifies a non- experimental approach; here, the researcher can observe the correlation but not control the variables directly. Examples of Experimental vs Non-Experimental Designs Experimental: The effect of varying classroom lighting levels on students’ attention. https://app.raena.ai/summary/pgd34uqh0p 2/9 12/7/24, 7:48 PM Summary | Raena AI Non-Experimental: Investigating the correlation between third graders' attitudes toward school and their academic achievement. Non-Experimental: Exploring the relationship between UAEU students’ happiness levels and variables such as gender, majors, and academic standing. Class Activity: Differentiating Between Methods In small groups, students will: Objective Differentiate between experimental and non-experimental methods. Task Provide an example of a psychological experimental method and justify its classification. Provide an example of a psychological non-experimental method and justify its classification. Identify the dependent variable in both examples. Experimental Research Framework Key Components Every experiment must comprise: An Independent Variable (IV) that the researcher manipulates, with at least two conditions (i.e., treatment vs. control). https://app.raena.ai/summary/pgd34uqh0p 3/9 12/7/24, 7:48 PM Summary | Raena AI Dependent Variables (DVs) which are measured to assess the effects of the IV. Example of Experimental Research Pennebaker and Francis (1996) explored whether writing about emotional experiences improves outcomes. Their study manipulated the IV—a type of writing—with two conditions: Emotional Writing: Defined operationally as writing “about your deepest thoughts and feelings about coming to college.” Superficial Writing: Defined as describing “any particular object or event as objectively as you can.” Measuring Outcomes Pennebaker and Francis measured several DVs including: Health Outcome: Number of physician visits. Academic Outcome: Students’ Grade Point Average (GPA). Cognitive Change: Measured by frequency counts of “insight” and “understand” keywords in the writings. Formulating Hypotheses The hypotheses posited that students engaging in emotional writing would exhibit better health and academic outcomes than those in the superficial writing condition, and they would also demonstrate greater cognitive change. Internal Validity and Experimental Control https://app.raena.ai/summary/pgd34uqh0p 4/9 12/7/24, 7:48 PM Summary | Raena AI Understanding Internal Validity An experiment achieves internal validity when the researcher can confidently assert that the IV caused any observed differences between groups concerning the DV. Achieving this requires ruling out alternative explanations for the findings. ““Internal validity refers to the extent that we can be confident that a causal relationship exists between the independent and dependent variables.”” Conditions for Causal Inferences According to Shaughnessy et al. (2012), three conditions must be met for causal inferences: 1. Covariation: A relationship must be observed between the IV and DV. 2. Example: Emotional and superficial writing yield different health and academic outcomes. 3. Time-order Relationship: The cause must precede the effect. For instance, emotional writing occurs before improvements in health and academic performance. 4. Elimination of Plausible Alternative Causes: Researchers must use control techniques to rule out other potential causes for the outcome. Causal Inferences: Understanding Confounding Variables Confounding occurs when an IV of interest covaries with another potential independent variable, creating ambiguity about causation. An experiment possesses internal validity when it is free of confoundings. https://app.raena.ai/summary/pgd34uqh0p 5/9 12/7/24, 7:48 PM Summary | Raena AI Example of a Confounding Variable In a situation where emotional writing participants receive counselor interviews while the superficial writing group does not, confounding emerges. The distinction clouds whether observed health and academic benefits stem from writing type or the additional support provided by the counselor. Class Activity: Identifying Confounding Variables Students in small groups will review a study involving the effect of video games on problem-solving skills among third graders. They will identify potential confounding variables affecting the study. Control Techniques in Experiments Main Techniques To reduce alternative explanations, two primary control techniques are used: Holding Conditions Constant: Ensures that all conditions apart from the IV remain consistent across groups. Balancing: Addresses participant characteristics that could confound results by equitably distributing them across conditions. Example of Holding Conditions Constant If emotional writing participants are tested differently than superficial writing participants, validity may be compromised. Such differences must https://app.raena.ai/summary/pgd34uqh0p 6/9 12/7/24, 7:48 PM Summary | Raena AI be controlled to ascertain that the IV is the sole variable influencing outcomes. Balancing Participants' Characteristics Balancing ensures that groups are equivalent regarding characteristics like health, intelligence, etc., before any manipulation of the IV. Random assignment is the most effective strategy for achieving this equivalence. Class Activities on Control Techniques Identifying Control Techniques Students will work in small groups to identify appropriate techniques to control extraneous variables related to gender, age, and intelligence. Independent Groups Designs In independent groups designs, different individuals participate in each condition. Types include: Random Groups Designs Matched Groups Designs Natural Groups Designs Random Groups Designs Participants are randomly assigned to different conditions of the IV. For instance, Pennebaker and Francis used random assignment in their experiment, allowing for the isolation of the IV’s effects. https://app.raena.ai/summary/pgd34uqh0p 7/9 12/7/24, 7:48 PM Summary | Raena AI Advantages of Randomized Block Design This design helps maintain equal group sizes and controls for time-related variables that might impact results. Threats to Internal Validity Internal validity can be threatened by: Using intact groups for experiments. Failing to control extraneous variables. Selective subject loss throughout the experimental process. Not managing demand characteristics and experimenter effects. Extraneous Variables These may create confounding issues, particularly when different individuals administer conditions, leading to variability in outcomes due to factors unrelated to the IV. Placebo Controls and Demand Characteristics Placebo control groups provide a means to assess whether participant expectations influence outcomes. In double-blind studies, both participants and experimenters remain unaware of condition assignments, reducing bias and improving the credibility of results. Conclusion In psychological research, careful consideration of experimental design, control of variables, and validity remains essential for understanding the https://app.raena.ai/summary/pgd34uqh0p 8/9 12/7/24, 7:48 PM Summary | Raena AI causal relationships between behaviors and treatments. Familiarity with these principles is crucial for both conducting research and critically evaluating existing studies. https://app.raena.ai/summary/pgd34uqh0p 9/9