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Research Design & Analysis 2: Class 14

Research Design & Analysis 2: Class 14. Small n-designs (continued) Review of and more on: External and Ecological Validity Using animals in research. 2-Way ANOVA Output From Lab . Note: F -ratios are the Mean square terms for the effect being tested divided by the mean square error.

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Research Design & Analysis 2: Class 14

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  1. Research Design & Analysis 2: Class 14 • Small n-designs (continued) • Review of and more on: External and Ecological Validity • Using animals in research

  2. 2-Way ANOVA Output From Lab Note: F-ratios are the Mean square terms for the effect being tested divided by the mean square error. Psyc2023 Class#14 (c) Peter McLeod

  3. Characteristics of single-subject baseline (from table 10-1 of text) • Individuals are observed under each of several phases with multiple records under each phase • Extensive baseline observations are made • Each subject is observed under all phases with each treatment repeated at least twice (intrasubject replication) • A stability criterion is often used • Multiple subjects may be used (intersubject replication) Psyc2023 Class#14 (c) Peter McLeod

  4. Functions of the Baseline 1) establishes level of the DV prior to intervention 2) allows assessment of variability in DV • May involve a stability criterion to minimize error variance so that any effect of the intervention will be more apparent Psyc2023 Class#14 (c) Peter McLeod

  5. Assessing Generalizabiliy • Intersubject Replication • Present data from each subject individually Psyc2023 Class#14 (c) Peter McLeod

  6. Fig 10-1: Psyc2023 Class#13 (c) Peter McLeod

  7. Fig 10-3 Psyc2023 Class#14 (c) Peter McLeod

  8. Assessing Reliability With single-subject designs, reliability is assessed through intrasubjectreplication • (e.g., ABAB design) in contrast with: Group designs in which inferential statistics are used to assess reliability after a fairly complex chain of logical inferences Note that in both cases, the key is degree of overlap of distributions Psyc2023 Class#14 (c) Peter McLeod

  9. Dealing with Error Variance Philosophical difference between single-subject approach and group approach in dealing with error variance. With group approach, error variance is controlled somewhat, either experimentally (through randomization) OR statistically - if effects are significant (can reject the null) little further effort is made to determine the sources of error variance. With Small-n designs, control as much as possible experimentally Psyc2023 Class#14 (c) Peter McLeod

  10. Time-Series (Small-N) Designs • Don’t involve random assignment • control and manipulate variables sequentially (not simultaneously as in analytic experiments) • anything else that occurred in this time is therefore a potential confound. • Remember: with experimentation we look after these things with simultaneous manipulations (between groups designs) or by counterbalancing (within groups designs) Psyc2023 Class#14 (c) Peter McLeod

  11. Types of Replication Intrasubject - to assess reliability (given time confound) Intersubject - to assess generalizability also: Distinction between systematic replication (introduces some extension or variation on the original research - often to assess generalizability of the phenomenon) and direct replication Psyc2023 Class#14 (c) Peter McLeod

  12. Variation in baseline Variability can be due to: 1) chance variation 2) carryover effects Psyc2023 Class#14 (c) Peter McLeod

  13. Problematic Baselines • Drifting baselines • Unrecoverable baselines (due to carryover effects) • Unequal baselines between subjects • Inappropriate baselines -- floor and ceiling effects Psyc2023 Class#14 (c) Peter McLeod

  14. Drifting Baseline Psyc2023 Class#14 (c) Peter McLeod

  15. Small-n Design: Terminology Not standardized but: • Single-factor • e.g., AB, ABA, ABAB (reversal design), multilevel (ABACA..) • Multi-factor designs (> 1 IV) • Multiple baseline design (>1 DV) Psyc2023 Class#14 (c) Peter McLeod

  16. Multivalent Single-Factor Small-n Designs A-baseline B-Placebo cookie C- artificially coloured cookie Psyc2023 Class#14 (c) Peter McLeod

  17. AB (ABA) Type Non-Experimental Studies Example: Drunk driving in Michigan • legal age 21  18 in 1972, then 18  21 in 1978 • % alcohol related traffic accidents: 15%  22% in ‘72, decreased again in ‘78 • Does a lower drinking age cause alcohol related traffic deaths? Confounds? • Wider alcohol availability in ‘72 • oil crisis in ‘78 -- 55 mph limit imposed in 1973/74 Psyc2023 Class#14 (c) Peter McLeod

  18. Other Examples of AB Studies TV effects on children: Tannis MacBeth-Williams David Phillips Research: • Motor vehicle accidents after publicized suicides • Airplane accidents after publicized murder-suicides (non-equivalent control groups) • Homicides after heavyweight prize fights Psyc2023 Class#14 (c) Peter McLeod

  19. Berkowitz ‘70 Psyc2023 Class#14 (c) Peter McLeod

  20. Phillips:Car suicides? Psyc2023 Class#14 (c) Peter McLeod

  21. Phillips:Noncommercial Plane suicides? A: all plane crash fatalities B: multifatality crashes C: Single fatality crashes Psyc2023 Class#14 (c) Peter McLeod

  22. Phillips:Converging evidence? Psyc2023 Class#14 (c) Peter McLeod

  23. Phillips;prizefights Highest peak in homicides on day 3 Psyc2023 Class#14 (c) Peter McLeod

  24. Multiple baselines Psyc2023 Class#14 (c) Peter McLeod

  25. Liberman & Smith 1972 Psyc2023 Class#13 (c) Peter McLeod

  26. Non-Equivalent Control Groups Different than AB type non-experimental studies in that a comparison “individual” is also studied e.g., Mining Safety study: Lucky Star mine… (Overhead) Psyc2023 Class#14 (c) Peter McLeod

  27. Non-Equivalent Control Groups Psyc2023 Class#14 (c) Peter McLeod

  28. External and Ecological ValidityUsing Animals in Research Psyc2023 Class#14 (c) Peter McLeod

  29. Stress and Cancer 93 lab rats randomly assigned from a defined population Yoked control Psyc2023 Class#14 (c) Peter McLeod Based on Visintainer, Volpicelli, & Seligman, 1982

  30. Results Psyc2023 Class#14 (c) Peter McLeod

  31. Factors Influencing External Validity Issue of generalizability beyond the specific experimental conditions • Population sampled • Operational definitions • Parameter values • Demand characteristics Ecological validity? Psyc2023 Class#14 (c) Peter McLeod

  32. Factors Influencing External Validity Population sampled • be careful generalizing beyond population studied • look for converging evidence that there is nothing importantly unique • External validity not crucial for basic research • Sample - to - population generalizations • Sometimes unusual populations are sought out • HIV resistant individuals, spotted hyenas Psyc2023 Class#14 (c) Peter McLeod

  33. Spotted Hyena Psyc2023 Class#14 (c) Peter McLeod

  34. Factors Influencing External Validity Operational definitions • construct validity Unavoidable shock-- unnatural but are effects unique? • Look for converging evidence Psyc2023 Class#14 (c) Peter McLeod

  35. Operational Definitions of Stress Phenomena associated with stress Operational definition of stress Overcrowding Gastric ulcers Inescapable shock Depression Sensory deprivation High blood pressure Sleep deprivation Psyc2023 Class#14 (c) Peter McLeod

  36. Factors Influencing External Validity Parameter values Values selected for each variable • both independent and controlled Psyc2023 Class#14 (c) Peter McLeod

  37. Factors Influencing External Validity Demand characteristics subtle cues in a research procedure that influence the participants serious problem in social sciences • characteristics of volunteers can influence both internal and external validity Students holding “poisonous” snakes, throwing “acid” in another’s face Psyc2023 Class#14 (c) Peter McLeod

  38. Factors Influencing External Validity Ecological validity How generalizable are the experimental results to the specific set of conditions -- those of the natural context in which the phenomena usually occurs Psyc2023 Class#14 (c) Peter McLeod

  39. Research Examples: Alcohol consumption • Alcohol consumption extremely stable in adults (r>.85) • Substantial individual variability • Four patterns of drinking Abusive binge drinking Heavy steady drinking Moderate drinking Avoidance of drinking Psyc2023 Class#14 (c) Peter McLeod

  40. Research Examples: Alcohol consumption • Abusive drinkers also prefer stronger drinks • Can be distinguished pharmacologically • lower 5-HIAA levels (serotonin metabolite) Psyc2023 Class#14 (c) Peter McLeod

  41. Abusive drinking ... Psyc2023 Class#14 (c) Peter McLeod

  42. Research Examples: Alcohol consumption • Females > Males to be moderate drinkers • Females prefer sweetened mix • Subjects Psyc2023 Class#14 (c) Peter McLeod

  43. Fruit flies & alcoholism • Dr. Vanessa Auld: Dept. of Zoology at the University of British Columbia studies alcoholism in fruit flies Drosophola spp. (with alcohol vapor) • Researchers have been studying fruit flies to see if they can understand alcoholism in humans. • Increased activity and courting, then poor coordination etc. then pass out. Quirk & quarks Jan 15th approx 19:00 in Real Audio Psyc2023 Class#14 (c) Peter McLeod

  44. Fruit flies & alcoholism • “Inebriometer”: DV: time to fall Norm approx 20min, mutant, 12 min (sensitive to alcohol) • Isolated “cheap-date” gene • had already been studied in learning and memory (“amnesiac” gene) • First evidence for a defect in the brain associated with alcohol susceptibility • Looking at the mechanism of alcohol’s long term effects on the brain Quirks & quarks Jan 15th @ approximately 19:00 in Real Audio Psyc2023 Class#14 (c) Peter McLeod

  45. Using animals in psychological research • Much of what we know in psychology comes from animal research • Models of human psychopathologies • Basic research on how the brain works, perception, learning, memory, motivation • Which animal to use, depends on: • research question, previous literature, facilities, availability/cost Psyc2023 Class#14 (c) Peter McLeod

  46. Using Animals in Psychological Research • Why? • Ethical reasons; e.g., effects of brain lesions, extreme levels of some IVs that can be studied in humans • Greater control and internal validity • Convenient • Ethical considerations and guidelines (CCAC) • Cost-benefit ratio • Generality (external validity question) Psyc2023 Class#14 (c) Peter McLeod

  47. Thalidomide Psyc2023 Class#14 (c) Peter McLeod

  48. Prenatal stress & feminized behaviour • Environmentally stressed females give birth to male rats/mice whose behaviour is feminized and demasculinized • Prenatally stressed males display less sexual behaviour • If castrated and given female hormones, more likely to show lordosis • Show more paternal behaviour • Less masculine anatomy and SDN-POA Psyc2023 Class#14 (c) Peter McLeod

  49. Using animals in psychological research • Animal rights movement • Alternatives to using animals • in vitro studies • computer simulations • …”there are no viable alternatives to using animals in behavioral research” Psyc2023 Class#14 (c) Peter McLeod

  50. Psyc2023 Class#14 (c) Peter McLeod

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