The Experiment

Question 0

Quasi-Experiment

Answer 0

Cannot randomly assign people to the levels of the IV.
•Cannot control something of interest.
Ex: Drug exposure on a fetus.

Question 1

True Experiments

Answer 1

Can randomly assign individuals to levels of the IV. (Random Assignment: every participant has an equal chance for being in the levels of the experiment.)
•Control everything
Ex: Alcohol and reaction time.

Question 2

Independent Variable

Answer 2

The one we believe is causing the change. (The group your in)

Question 3

Levels of the Independent Varaible

Answer 3

The different values of an independent variable.

Question 4

Types of Experiments

Answer 4

• Between Subjects Design

* Within Subjects Design

Question 5

Between Subjects Design

Answer 5

Groups of participants only receive one level of the IV.
•Different groups receive the different levels of the IV.
EX: Group 1: Alcohol
EX: Group 2: No Alcohol

Question 6

Within Subjects Design

Answer 6

(aka: Pretest-Posttest or Repeated Measures Design)
Subjects receive all the levels of the IV.
EX: Alcohol and reaction time
EX: No Alcohol and reaction time

Question 7

Goal of the Experiment

Answer 7

Internal Validity

Question 8

Internal Validity

Answer 8

The point of a true experiment.
•Ability to say that the manipulation of the IV caused the changes in the DV.
•Rule out extraneous (confounding) variables: something else that could be causing the changes noted.

Question 9

Threats to Internal Validity in Between Subjects Designs (aka: Pretest-Posttest or Repeat Measures Design)

Answer 9

1. Selection
2. Selection by Maturation
3. Mortality

Question 10

Threats to Internal Validity in Between Subject Designs due to Selection

Answer 10

Where the groups are equivalent before the study began. Self-selection threat.
Ex: Age and Political Views: How people feel about a topic comparing older and younger people.

Question 11

Threats to Internal Validity in Between Subjects Design due to Selection by Maturation

Answer 11

(Maturation: the individual is developing and changing.)
Asking whether your two groups would have naturally grown apart even without the treatment.
•Weren’t equal to begin with and they would have grown apart anyway.

Question 12

Threats to Internal Validity in Between Subjects Designs due to Mortality

Answer 12

Dropout rates or death.

More people dropout of one group than another.

Question 13

Controlling Threats to Internal Validity in Between Subjects Designs

Answer 13

• Random assignment

* Matching

Question 14

Random Assignment

Answer 14

every person has an equal chance.

Question 15

Matching

Answer 15

Make samples equivalent in some way on important variables.

EX: Income or Age

Question 16

Threats to Internal Validity in Within Subjects Designs

Answer 16

1. Maturation
2. History
3. Instrumentation
4. Mortality
5. Regression to the Mean

Question 17

Threats to Internal Validity in Within Subjects Designs due to Maturation

Answer 17

Growing up or changing.

Question 18

Threats to Internal Validity in Within Subjects Designs due to History

Answer 18

Could other events in the participants lives have caused the pretest-posttest difference.

Question 19

Threats to Internal Validity in Within Subjects Designs due to Instrumentation

Answer 19

Was the same instrument used in the pretest as in the posttest.

Question 20

Threats to Internal Validity in Within Subjects Designs due to Mortality

Answer 20

Die or Dropout. Start and end with the same amount of participants.

Question 21

Threats to Internal Validity in Within Subjects Designs due to Regression to the Mean

Answer 21

Statistical phenomenon that extreme scores are unlikely to occur repeatedly.

Question 22

Additional Threats to Internal Validity in Within Subjects Design due to Carryover Effects

Answer 22

The effect of one treatment persists to influence the participants response to the next treatment.

Question 23

Additional Threats to Internal Validity in Within Subjects Design due to Practice Effects

Answer 23

Similar to Maturation = Growing up or changing.

Question 24

Additional Threats to Internal Validity in Within Subjects Design due to Order Effects

Answer 24

The position of a treatment in a series determines in part the participants response. EX: Brush teeth then drink orange juice versus drinking orange juice then brushing teeth.

Question 25

Counterbalancing in Repeated Measures/Within Subjects Design

Answer 25

Presenting different treatment sequences.

Question 26

Within Subject Counterbalancing (Participants)

Answer 26

The presentation of different treatment sequences to the same participant (subject). Ex: Coke before Pepsi than Pepsi before Coke: Do you like Coke or Pepsi better?

Question 27

Within Subject Counterbalancing

Answer 27

1. Obtrusive Observation 2. Resentful Demoralization 3. Compensatory Rivalry 4. Treatment Contamination

Question 28

Within-Subject Counterbalancing: | Obtrusive Observation

Answer 28

(Observable, reactance) | Participants react differently because of the presence of the researcher.

Question 29

Within-Subjects Counterbalancing: | Resentful Demoralization

Answer 29

If control groups are given boring experiences they may perform extremely low. Ex: Gate classes versus regular classes.

Question 30

Within-Subjects Counterbalancing: | Compensatory Rivalry

Answer 30

Sometimes control groups work extra hard to compensate for weaker treatment. Underdog Ex: Bell shaped curve, there are few extremes.

Question 31

Within-Subjects Counterbalancing: | Treatment Contamination

Answer 31

Participants in different groups talk to each other and mess up the manipulation of the IV.

Question 32

Participant as Extraneous Variable

Answer 32

1. Characteristics of the Experimenter 2. Good Subject Effect 3. Screw-You Effect 4. Evaluation Apprehension (Social Desirability) 5. Test Sophistication 6. Research Sophistication

Question 33

Participant as Extraneous Variable: | Characteristics of the Experimenter

Answer 33

Sometimes participants react differently due to the way people look or act. Ex: Wearing a Uniform

Question 34

Participants as Extraneous Variable: | Good Subject Effect

Answer 34

Participants try to figure out what they think they are suppose to do and then do it.

Question 35

Participants as Extraneous Varaible: | Screw-You Effect

Answer 35

Subjects deliberately undermine the study. | EX: Sex: Male or Female? __A lot!

Question 36

``` Participants as Extraneous Variable: Evaluation Apprehension (Social Desirability) ```

Answer 36

Participants are uncomfortable answering certain questions so they use social desirability response set.

Question 37

Participants as Extraneous Variable: | Test Sophistication

Answer 37

Some people learn to be good test takers.

Question 38

Participants as Extraneous Variable: | Research Socphistication

Answer 38

When participants guess the nature of deception or guess at the hypotheses.

Question 39

Participants as Extraneous Variable: | How Do I Fix It?

Answer 39

Demand Characteristics | Obtrusive Observation

Question 40

Demand Characteristics

Answer 40

Blind or double-blind or placebo: where the researchers, or the participants, or both don't know what level of the IV they are experiencing.

Question 41

Participant as Extraneous Variable: | Obtrusive Observation

Answer 41

Unobtrusive observation: If we are changing peoples' behavior because they know they are being watched. The others? You do your best.

Question 42

Experimenter as an Extraneous Variable

Answer 42

1. Observer Differences Effect 2. Interpreter Effects 3. Intentional Effects 4. Biosocial Effect 5. Psychosocial Effect 6. Situational Effect 7. Modeling Effect

Question 43

Experimenter as an Extraneous Variable: | Observer Differences Effect

Answer 43

Systematic observation errors. Experimenter themselves become a confounding error. Ex: One experimenter starts the stop watch.

Question 44

Experimenter as an Extraneous Variable: | Interpreter Effect

Answer 44

Systematic interpretive errors. | Ex: Aggression in apes: one experimenter calls things aggressive.

Question 45

Experimenter as an Extraneous Variable: | Intentional Effect

Answer 45

Deliberate dishonesty or sloppiness in data collectors.

Question 46

Experimenter as an Extraneous Variable: | Biosocial Effect

Answer 46

Demographic or biological characteristics of the data collectors (researchers) the effect the participants responses or vice versa.

Question 47

Experimenter as an Extraneous Variable: | Psychosocial Effect

Answer 47

Data collector's interpersonal styles affect participant responses. Ex: Anxiety study: by highly anxious collector.

Question 48

Experimenter as an Extraneous Variable: | Situational Effect

Answer 48

Results are unique to the situation under which the data are collected.

Question 49

Experimenter as an Extraneous Variable: | Modeling Effect

Answer 49

Researchers offer sample answers or demonstrate a procedure and are then repeated by the participants.

Question 50

Counterbalancing in Repeated Measures (Within Subjects) Design: Within-Group Counterbalancing

Answer 50

•Split up the sequences across the participants in our groups. Different because: Not everyone sees all the treatments. •Randomly assign half to have Coke-Pepsi. •Half to have Pepsi-Coke.

Question 52

Complete Counterbalancing (Best Way) Controls for All

Answer 52

* n! (n factorial) * 3 levels * (3)(2)(1) = 6 need at least 6 participants or more in sixes.

Question 53

Incomplete Counterbalancing

Answer 53

Some but not all sequences | •Randomly chose the first sequence and then rotate.

Question 54

Requirements for Complete Counterbalancing

Answer 54

•Each Treatment must be: •Presented to each participant an equal # of times. •Occur an equal # of times at each testing or practice 1 time. •Precede and follow each of the other treatments an equal # of times. Ex: # of times Coke before Pepsi after Select, etc.

Question 55

Internal Validity - Experimenters and Participants

Answer 55

* Demand Characteristics | * Experimenter Drift

Question 56

Participant as Extraneous Variable: | Demand Characteristics

Answer 56

Participants themselves become extraneous, overt or subtle cues to participants on how they should behave. Ex: Predictive Horse

Question 57

Participant as Extraneous Variable: | Experimenter Drift

Answer 57

There's a gradual change in how the subjects are treated over the course of the study.

Question 58

Participant as Extraneous Variable: | How do I fix it?

Answer 58

* Observer and Interpreter Effect | * The others

Question 59

Participant as Extraneous Variable: How do I fix it? | Observer and Interpreter Effect

Answer 59

Inter-Rater Reliability

Question 60

Participant as Extraneous Variable: How do I fix it? | The Others

Answer 60

Blinding, standardization of instructions and procedures, and training.

Question 61

Experimenter as an Extraneous Variable

Answer 61

Rosenthal Effect •Maze "Bright" vs. Maze "dull" •Intellectual Bloomers

Question 62

Rosenthal Effects

Answer 62

The experimenter's preconceived idea of appropriate responding influences the treatment of participants and their behavior (experimenter expectancies)

Question 63

Rosenthal Effect: | Maze vs Maze

Answer 63

Maze "Bright" vs. Maze "Dull": | Heterogeneous rats, randomly assign to two boxes.

Question 64

Rosenthal Effects: | Intellectual Bloomers

Answer 64

•Intellectual Bloomers: Go into public school and randomly select 7 students, lie to teachers that they will have an intellectual growth spurt. End of year they bloom.