Experimental-Paradigm-24042021-075346am.pptx

psychological

1. Experimental Paradigm Sidra Shoaib Institute of Professional Psychology, Bahria University, Karachi

2. Scientific Experiments

3. Contrast Generally contrast is observed commonly b/w Several Levels of IVs on Group of Subjects Experimental Group: receives the treatment (levels of IVs) Control Group: do not receive the treatment

4. Scientific Inferences Scientific theories are based on inferences Human behaviors and thoughts changes under a variety of conditions Experimental Psychologist observe the behavior caused by some variable Develop models – generalization – development of the laws

5. Basis of the validity of the observation Influence of the Independent Variables Characteristics of the subjects Importance of Experimental and Control Groups are similar as possible Lack of control – results may be meaningless or miss leading Techniques have evolved to safeguard the errors due to lack of control

6. Types of Control Independent Variable Control IV to see effects on DV Determine the kind and quantity of the variable Hold conditions Constant Only IV should be manipulated rest of the variables to be held constant Various treatment groups and control groups must be treated alike (except for the manipulation of IV)

7. So the change in DV will be only b/c of IV The variables other than IV effects the DV are Extraneous and Confounding Variables The experimenter is not sure either the change is due to IV or due to Extraneous variable or due to both Inclusive results Repeat the research and eliminate them

8. What makes a variable extraneous??? Depends on DV Varies from experiment to experiment One variable might be extraneous for one experiment but might not be for other Control only those variables which could effect the DV Sound judgment and Knowledge can improve experimental design

9. Controlling Extraneous Variables Manipulate IV in different treatment groups Hold Conditions Constant (control and experimental groups)

10. Holding Conditions Constant Lorge (1930) experiment; massed vs distributed practice IV= length of time b/w practice session (interval) Constant Variables Same task Same amount of practice Task related abilities

11. By ensuring that these variables were the same for all treatment groups- eliminated them as explanation of the results Basic logic behind keeping the variables constant

12. Subject Variables Good Experimental Design – Holding Conditions Constant Some times violation may occur Not possible to construct the checklist of all the extraneous variables Problematic areas IV is a subject variable – hence all the other subject variables may also effect

13. Experimental results may be due to other subject variables – Subject Variable or Subject Variable Confound Potentially erroneous results which may be attributing to secondary causes based on confounding or joining subject variables Example????? Authoritarian people – would have difficulty in learning complex material than non-authoritarian people High-Authoritarian People think in a simplistic manner- difficulty in learning

14. Low-authoritarian people recalled better than High-authoritarian people Criticism- inverse relationship b/w authoritarianism and intelligence Learning is effected b/c of intelligence Subject variable is not being manipulated- subject variable confound to little danger

15. Experimental Paradigm A paradigm in experimental psychology is a model or pattern an investigator uses to organize research Independent Subject Design Matched Subject Design Repeated Measure Design Repeated measure Design with Sequence Counterbalance Factorial Design

16. Wine-Testing Experiment Effect of color on the enjoyment of the person IV= Color DV= Rating ( Lickert Scale 1-5) 1 2 3 4 5 Absolutely Not Enjoyable Not Enjoyable Moderately Enjoyable Enjoyable Absolutely Enjoyable

17. Potential Consequence Problems Temperature Lighting Sequence Subject Experience Ambience and peer Influence

18. Independent Subject Design Independent Subject Design or B/W-Group Design- Group I - artificially colored wine (called???) Group II – natural colored wine (called ???) Subject in one group are independent from other group Sample: 16 uni students (ages 21-30) 8 participants per group

19. Minimum for this kind of sample 8 each Randomized Subject Design Model 1. Independent Subject Design Experimental Group (Artificial Colored Vine ) Control Group (Natural Colored Vine ) S1 1 S9 5 S2 2 S10 4 S3 2 S11 3 S4 1 S12 5 S5 2 S13 5 S6 1 S14 4 S7 1 S15 4 S8 4 S16 5

20. Analyze the means (average) through t -test- mathematical precision Statistical Significance Highly unlikely chances of huge differences Draw inferences Paradigm is common in Psychological Experiments Subject variables distributed among the groups on the basis of random distribution

21. Matched Subjects Designs Some variable may be critical to effect the DV So the participants should be matched on that variable Wine-testing Experience –better sensory discrimination Sex, age, intelligence, running ability or training

22. Model 2. Matched Subject Design Experimental Group (Artificial Colored Vine ) Control Group (Natural Colored Vine ) S1 a 3 S9a 5 S2b 2 S10b 4 S3c 2 S11c 4 S4d 3 S12d 5 S5e 2 S13e 5 S6f 3 S14f 4 S7g 3 S15g 4 S8h 4 S16h 5

23. Powerful Design: matched variable is related to DV Also relate to IV on which the matching variables are made Invalid test or measure for the characteristics spoils the basic assumption Correlated t- test or Dependent t- test

24. Repeated Measure Design With-in Subject Design Subjects being exposed to two or more conditions Taste both kinds of Wine Each subject will be his or her own control Gathers more data Limited subjects can be a limitation

25. Model 3. Repeated Measure Design Experimental Condition (Artificial Colored Vine ) Control Condition (Natural Colored Vine ) S1 S1 S2 S2 S3 S3 S4 S4 S5 S5 S6 S6 S7 S7 S8 S8 S9 S9 S10 S10 S11 S11 S12 S12 S13 S13 S14 S14 S15 S15 S16 S16

26. Repeated Measure Design Counter Balance the Sequence Sequence is important Half of the participants will balance the colored wine first and half will natural colored wine first Multiple repeated designs Specialized statistical analysis

27. Model 4. Repeated Measure Design Experimental Group (Artificial Colored Vine ) Control Group (Natural Colored Vine ) S1 S9 S2 S10 S3 S11 S4 S12 S5 S13 S6 S14 S7 S15 S8 S16 Experimental Group (Artificial Colored Vine ) Control Group (Natural Colored Vine ) S9 S1 S10 S2 S11 S3 S12 S4 S13 S5 S14 S6 S15 S7 S16 S8

28. Factorial Designs Effect of Multiple IVs on a DV Not specifically constructed subject variable Possible Method for within subject design Modify the example: IV 1: Color of Wine (natural or burgundy) IV 2: Type of Grapes (Zinfandel, Pinot Noir or Chardonnay) Factorial Design?????

29. Factorial Design: With-in Subject/ Repeated Measure IV 1 Color of Wine Natural Burgundy IV 2 Type of Grapes Pinot Noir S1, S2, S3, S4 S1, S2, S3, S4 Zinfandel S1, S2, S3, S4 S1, S2, S3, S4 Pinot Noir S1, S2, S3, S4 S1, S2, S3, S4

30. Factorial Design: B/W Group Design/Independent Subject Design IV 1 Color of Wine Natural Burgundy IV 2 Type of Grapes Pinot Noir S1, S2, S3, S4 S13, S14, S15, S16 Zinfandel S5, S6, S7, S8 S17, S18, S19, S20 Pinot Noir S9, S10, S11, S12 S21, S22, S23, S24

31. Use of Treatment and Control Group What is Control Group???? A group of subjects similar to exp group i.e. exposed to all the conditions of an investigation except for the exp variable (IV) Selection of Sample: Random from the population for generalization (in majority of the cases)