PSY403 Experimental Research Strategy Revision Final Exam (2023) PDF

The Experimental Research Strategy Gravetter | Forzano, Research Methods Behavioral Sciences, 6th Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Experimental Research Strategy • What is the g...

The Experimental Research Strategy Gravetter | Forzano, Research Methods Behavioral Sciences, 6th Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Experimental Research Strategy • What is the goal of the experimental research strategy? – To establish the existence of a cause-and-effect relationship between two variables A Variable causes a change to Another Variable Gravetter | Forzano, Research Methods Behavioral Sciences, 6th Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Experimental Research Strategy • What is the goal of the experimental research strategy? – To establish the existence of a cause-and-effect relationship between two variables • Experiment (true experiment) – Must demonstrate that changes in one variable are directly responsible for causing changes in the second variable Gravetter | Forzano, Research Methods Behavioral Sciences, 6th Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Experimental Research Strategy • What is the goal of the experimental research strategy? – To establish the existence of a cause-and-effect relationship between two variables • Experiment (true experiment) – Must demonstrate that changes in one variable are directly responsible for causing changes in the second variable How is this goal accomplished? Gravetter | Forzano, Research Methods Behavioral Sciences, 6th Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. To accomplish this goal, the experimental study must contain the following 4 elements: 1. Manipulation – Researcher manipulates one variable by changing its value to create a set of two or more treatment conditions. 2. Measurement – A second variable is measured for a group of participants resulting in a set of scores in each treatment condition. 3. Comparison – The scores in one treatment condition are compared with the scores in another treatment condition. 4. Control – All other variables are controlled to be sure that they do not influence the two variables being examined. Gravetter | Forzano, Research Methods Behavioral Sciences, 6th Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Manipulation • Manipulation involves the creation of two or more conditions that differ in terms of levels of the independent variable (IV). • The levels of the IV can differ in terms of quantity or type. • The manipulation can also be in terms of whether the IV is present in one condition and absent in another condition. Gravetter | Forzano, Research Methods Behavioral Sciences, 6th Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Example of when the levels of the IV differ in terms of quantity • The experimenter is looking at the effect of reward in children’s math performance. • She gave one group of children 2 candies for each correct answer and another group 1 candy for each correct answer. Gravetter | Forzano, Research Methods Behavioral Sciences, 6th Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Example of when the levels of the IV differ in terms of type • The experimenter is looking at how positive and negative encouragement affect children’s performance in a memory test. • One group of children receives positive encouragement. • Another group of children receives negative encouragement. Gravetter | Forzano, Research Methods Behavioral Sciences, 6th Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Example of when the levels of the IV differ in terms of type • The experimenter is looking at how positive and negative encouragement affect children’s performance in a memory test. • One group of children receives positive encouragement. • Another group of children receives negative encouragement. Gravetter | Forzano, Research Methods Behavioral Sciences, 6th Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. An example of a manipulation where the IV is present in one condition and absent in another condition • A researcher is testing the effect of a new medication on headache. • One group receives the new medication, and the other group receives a placebo (a pill without the active ingredient) Gravetter | Forzano, Research Methods Behavioral Sciences, 6th Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Measurement and Comparison • Measurement: Once the two or more conditions were created, we can then measure the second variable of the study, which is the dependent variable. • We measure the second variable for every single condition in the experiment. • Comparison: We then compare the scores of participants from one condition with the scores of participants from the other condition. Gravetter | Forzano, Research Methods Behavioral Sciences, 6th Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Terminology for the Experimental Research Strategy: Independent Variable • In an experiment, the independent variable is the variable manipulated by the researcher. • The independent variable usually consists of two or more treatment conditions to which participants are exposed. Gravetter | Forzano, Research Methods Behavioral Sciences, 6th Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Terminology for the Experimental Research Strategy: Independent and Dependent Variables • The dependent variable is the variable that is observed for changes to assess the effects of manipulating the independent variable. • The dependent variable is typically a behavior or a response measured in each treatment condition. Gravetter | Forzano, Research Methods Behavioral Sciences, 6th Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Terminology for the Experimental Research Strategy • In an experiment, a treatment condition is a situation or environment characterized by one specific value of the Independent variable. • Each treatment/experimental condition is a level of the independent variable. • Number of levels of the IV is the number of treatment/experimental conditions. Gravetter | Forzano, Research Methods Behavioral Sciences, 6th Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Example of an Experiment For example, let’s say we want to test the effect of a new medication on the intensity of migraine. What would be the manipulation in this experiment? In this study, the researcher can manipulate the medication by creating two conditions, one in which participants receive the new medication and another that they receive a placebo. Gravetter | Forzano, Research Methods Behavioral Sciences, 6th Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. In other words, we give the medication with active ingredient to one group and give a placebo to another group. (randomly assign) Participants (randomly assign) A group received the medication Variable measured A group who receives a placebo Variable measured Gravetter | Forzano, Research Methods Behavioral Sciences, 6th Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. • Subsequently, we measure the intensity of the headache for both experimental and control conditions. • Then, we compare the intensity of the headache as reported by the experimental group with that by the control group. • During the study, the researcher controlled other variables and used random assignment to ensure that other variables were balanced across conditions. Gravetter | Forzano, Research Methods Behavioral Sciences, 6th Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Experimental Research Strategy Independent Variable causes a change to Dependent Variable randomly assign Participants randomly assign Experimental condition (Medication with active ingredient) DV: Intensity of headache Control Condition (Medication without active ingredient/placebo) DV: Intensity of headache Gravetter | Forzano, Research Methods Behavioral Sciences, 6th Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Extraneous variables • Extraneous variables are all variables in the study other than the independent and dependent variables. • Other variables, such as the participants’ personality, height, and weight, as well as environmental variables, such as the season and the weather conditions, are extraneous variables. Gravetter | Forzano, Research Methods Behavioral Sciences, 6th Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Confounding Variables • A confounding variable is a variable that changes systematically along with the independent variable and has the potential to influence the dependent variable. Gravetter | Forzano, Research Methods Behavioral Sciences, 6th Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Confounding Variables A confounding variable must vary systematically with the IV. – A variable that changes randomly, with no relation to the IV, is not a threat. Gravetter | Forzano, Research Methods Behavioral Sciences, 6th Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Confounding Variables For example: A researcher designs a study to determine whether preschool children prefer sweetened or unsweetened cereal. For one group, the researcher uses a box of colorful sweetened cereal and for the other group, a box of tan-colored unsweetened cereal. The results showed that the preschoolers ate more of the sweetened colorful cereal and therefore prefer the sweetened cereal. What is the confounding variable? Gravetter | Forzano, Research Methods Behavioral Sciences, 6th Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Confounding Variables Gravetter | Forzano, Research Methods Behavioral Sciences, 6th Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Confounding Variables What is the confounding variable? The color of the cereal box because it varies systematically with the IV Gravetter | Forzano, Research Methods Behavioral Sciences, 6th Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Confounding Variables What is the confounding variable? The color of the cereal box because it varies systematically with the IV. Therefore, in this experiment, it is impossible to tell whether the preference for the colorful sweetened cereal is caused by the color or the sweetness. Gravetter | Forzano, Research Methods Behavioral Sciences, 6th Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Control • Control of other variables (other than the IV and DV) – Observed relationship must not be contaminated by the influence of other variables. Gravetter | Forzano, Research Methods Behavioral Sciences, 6th Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Random Assignment One important component of the experimental strategy is: – Random assignment: randomly allocating participants to groups so that each participant has an equal chance of being placed in any group Gravetter | Forzano, Research Methods Behavioral Sciences, 6th Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Random Assignment • The goal of randomization is to disrupt any systematic relation between extraneous variables and the independent variable, thereby preventing the extraneous variables from becoming confounding variables. • Randomization involves using an unpredictable and unbiased procedure (such as a coin toss) to for example assign participants to different conditions. Gravetter | Forzano, Research Methods Behavioral Sciences, 6th Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Question • Considering the example reviewed earlier: a researchers wants to test the effect of a new medication on the frequency of headaches. • How do you call the condition or group that received the medication with active ingredient? __________________ Condition Gravetter | Forzano, Research Methods Behavioral Sciences, 6th Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Experimental Condition • Experimental Condition: it is also referred as the treatment condition. • Experimental/treatment condition is the condition that the treatment is administered (or that a level of the independent variable is present) Gravetter | Forzano, Research Methods Behavioral Sciences, 6th Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Experimental Design (randomly assign) Participants (randomly assign) Experimental Condition DV:Variable measured Received the medicine Control Condition Received the placebo DV:Variable measured Question • In the example reviewed, how do you call the condition in which the medication with active ingredient was not present? • Hint: the condition that serves as baseline comparison Gravetter | Forzano, Research Methods Behavioral Sciences, 6th Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Control Condition The control condition is the condition in which the treatment is not administered. Control Condition • The control groups serves as a comparison group. • The purpose of the no-treatment control is to provide a standard of normal behavior, or baseline, against which the treatment condition can be compared. Gravetter | Forzano, Research Methods Behavioral Sciences, 6th Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Two Types of Control Conditions Two types of control conditions: • No-treatment control condition • Placebo control condition Gravetter | Forzano, Research Methods Behavioral Sciences, 6th Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Control Conditions • No-treatment control condition – A condition in an experiment in which the participants do not receive the treatment being evaluated • Placebo control condition – An ineffective treatment that has no medicinal effect Gravetter | Forzano, Research Methods Behavioral Sciences, 6th Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. • Placebo control condition – An ineffective treatment that has no medicinal effect – The placebo effect occurs simply because the individual thinks the medication is effective. – The term nonspecific is often used in place of placebo to refer to the elements of therapy that are not specifically therapeutic. Gravetter | Forzano, Research Methods Behavioral Sciences, 6th Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Sample and Population • A population is the entire set of individuals of interest to a researcher. Although the entire population does not participate in a research study, the results from the study are generalized to the entire population. • A sample is a set of individuals selected from a population and usually is intended to represent the population in a research study. Gravetter | Forzano, Research Methods Behavioral Sciences, 6th Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Thank you! Gravetter | Forzano, Research Methods Behavioral Sciences, 6th Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.