ABC/123 Version X 1 Experimental Designs Worksheet PSY/335 V

ABC/123 Version X 1 Experimental Designs Worksheet PSY/335 Version

Fill in the Blank Using the terms listed below, complete the following: 1. ___________ group receives treatment in an experimental design. 2. ___________ group does not receive treatment in an experimental design. 3. A ___________ design has many observations on a single case or a few subjects. 4. When separate groups of subjects receive different levels of the independent variable, this is referred to as _____________ design. 5. When all subjects receive all levels of the independent variable, this is referred to as ____________ design. 6. When the researcher measures a behavior that needs to be changed and then applies therapy and measures the behavior again, this is referred to as _____________ design. 7. When the researcher measures a behavior that needs to be changed, applies therapy and measures the behavior again, and then removes the treatment and measures the behavior again, this is referred to as ______________ design. 8. When the criterion outcome changes over time this is referred to as _______________ design. 9. When measuring several behaviors or several people with baseline periods of varying lengths and an independent variable occurs, this is referred to as a ______________ design. 10. When subjects are not randomly assigned and not all variables are under the control of the presenter, this is referred to as ______________ design. A. Multiple Baseline B. Small n C. AB D. Control E. Experimental F. ABA G. Between Subject H. Quasi-Experimental I. Changing Criterion J. Within Subject Matching.

Read the following scenarios and match each scenario with the correct type of experimental design.

1. _____ Two classes of children are studied regarding the effects of a new teaching method in science. One group received the new method of instruction, while the other group uses the standard, traditional method of instruction. Both classes are measures for achievement before and after the teaching methods.
2. _____ Divide your subjects in half. One group receives one treatment of the independent variable and the other group receives a different treatment of the independent variable. Subjects were all told they would see a video of a therapist's session after which they would rate the quality of the session. The groups differed in that the subjects in one group were told that prior evaluations indicated that the therapist was effective whereas subjects in the other group were told that the evaluations indicated that the therapist was not effective. These different subjects were used for the two levels of the independent variable: subjects were in either the "effective therapist" or the "ineffective therapist" condition.
3. _____ All subjects perform at all levels of the independent variable. Subjects diagnosed as having attention deficit disorder were each tested on a concentration task after receiving medication. All subjects were tested four times, once after receiving one of the four doses. Each subject was tested under each of the four levels of the independent variable—dose of medication.
4. _____ A small group is measured for the amount of anxiety they experience in math class (baseline). They are taught a relaxation method and measured again to measure anxiety in math class.
5. _____ To study verbal commands in canines, during week 1 the baseline is recorded for how many times a dog chased a cat. During week 2, the dog was verbally scolded (treatment) when the dog chased the cat, and the chasing behavior was recorded. During week 3, the chasing behavior was recorded without the verbal scolding (treatment).

Paper For Above instruction

Experimental research in psychology employs various design strategies to determine causal relationships, understand behaviors, and evaluate interventions effectively. The methodological approach selected hinges on the research question, the nature of the independent and dependent variables, and practical considerations like resources and ethical constraints. This paper explicates the fundamental types of experimental designs, elucidates their characteristics through examples, and discusses their significance in psychological research.

Types of Experimental Designs

In experimental designs, participants are typically divided into groups that receive different treatments or interventions, allowing researchers to compare outcomes and infer causality. The design choice profoundly impacts the internal validity and generalizability of findings. The primary types include control, experimental, quasi-experimental, and specific variations like within-subjects and between-subjects designs.

The most basic form is the control group design, where one group receives the treatment (manipulation of the independent variable), and another group does not. The treatment group, often called the experimental group, is exposed to the intervention to observe its effect. Conversely, the control group helps to account for placebo effects, natural progression, or external influences that would independently affect outcomes (Cook & Campbell, 1979).

Within-subject designs involve the same participants experiencing all conditions of the independent variable, allowing for control over individual differences — a technique advantageous for small sample studies and longitudinal assessments (Barlow, Nock, & Hersen, 2009). In contrast, between-subject designs assign different participants to each condition, emphasizing randomization to reduce selection bias and confounding variables (Leary, 2004).

Specific Experimental Designs and Their Applications

• AB Design: This simple single-subject or small-n design involves baseline (A) and treatment (B) phases, enabling researchers to observe behavioral changes corresponding with intervention onset (Kazdin, 2011). For example, measuring anxiety levels before and after relaxation training.
• ABA Design: An extension of AB, where the treatment is withdrawn to verify whether observed behavior changes are attributable to the intervention (Vollmer et al., 2008). This design enhances internal validity but can be ethically challenging if treatment withdrawal causes harm.
• Multiple Baseline Design: This involves staggering the introduction of treatment across different subjects, settings, or behaviors, providing evidence of experimental control while minimizing ethical concerns of withdrawing treatment (Barlow et al., 2009). For example, implementing relaxation techniques sequentially across different individuals to ascertain effectiveness.
• Within-Subjects and Between-Subjects Designs: The within-subjects approach assesses individuals across all conditions, increasing statistical power and controlling for individual variability. The between-subjects approach involves comparison across different groups, emphasizing randomization and group equivalence (Leary, 2004).

Application Examples Demonstrating Design Choice

Consider a study examining a new teaching method's effectiveness in science education. Two classes are assigned different instructional approaches, with pre- and post-assessment scores measured. This resembles a between-subjects design, enabling comparison across groups and attributing differences to the treatment if randomization and controls are properly implemented. Alternatively, testing the same participants under different medication doses in a repeated-measures setup exemplifies a within-subjects design, reducing variability and increasing sensitivity to observed effects (Kazdin, 2011).

In behavioral research, the ABA or multiple baseline designs are crucial for demonstrating causality while ethically managing the withdrawal or staggered introduction of interventions. For instance, in the canine verbal command study, the baseline phase establishes initial behavior, the treatment phase introduces verbal reprimands, and the subsequent phase assesses behavior without reprimands, fitting an ABA pattern (Vollmer et al., 2008).

Importance of Experimental Design in Psychological Research

Robust experimental designs underpin valid scientific findings and facilitate the development of evidence-based interventions. They enable researchers to isolate variables, test hypotheses rigorously, and generalize results to broader populations. Understanding the nuances and appropriate application of various designs ensures the integrity of conclusions drawn from psychological studies (Shadish, Cook, & Campbell, 2002).

Conclusion

Choosing an appropriate experimental design is fundamental to scientific inquiry in psychology. Whether employing between- or within-subjects methods, or opting for more complex arrangements like multiple baseline or ABA designs, researchers must consider the research question, ethical concerns, and practical constraints. Proper design not only bolsters internal validity but also enhances the reproducibility and applicability of findings, ultimately advancing psychological science.

References

• Barlow, D. H., Nock, M. K., & Hersen, M. (2009). Single Case Experimental Designs: Strategies for Studying Behavior Change. Pearson.
• Cook, T. D., & Campbell, D. T. (1979). Quasi-Experimentation: Design & Analysis Issues for Field Settings. Houghton Mifflin.
• Kazdin, A. E. (2011). Single-Case Research Designs: Methods for Clinical and Applied Settings. Oxford University Press.
• Leary, M. R. (2004). Introduction to Behavioral Research Methods. Pearson.
• Shadish, W. R., Cook, T. D., & Campbell, D. T. (2002). Experimental and Quasi-Experimental Designs for Generalized Causal Inference. Houghton Mifflin.
• Vollmer, T. R., Iwata, B. A., & Zarcone, J. R. (2008). Behavioral Interventions: Characterizing and Analyzing Behavior Patterns. Springer.