Psy Research Methods Exam 3

define: carry over effect- fatigue

Earlier treatments may affect performance in later treatments because participants will get tired

match the solution that would best prevent within-group variability from obscuring group differences: situation noise

Experimental control Carefully controlling the experimental setting reduces situation noise.

T/F: A between-subjects design with three independent variables results in three main effects.

True (There will always be one main effect for each independent variable in a design regardless of how many variables there are.)

T/F: Every experiment requires a comparison group.

True: Without comparison, one cannot be sure the independent variable is truly affecting the dependent variable, which hinders internal validity.

A _______ is an additional dependent variable that can determine how effective the manipulation of the independent variable is. Another way to determine this, is through a ______, which is a small, simple experiment that can assist the researcher in seeing how effective a manipulation is prior to usage in the primary experiment. Both of these can help improve a study's _____ validity.

manipulation check, pilot study, construct

Define: counterbalancing

when researchers present the levels of the IV to participants in different orders.

Tia is creating a factorial experiment in which she is testing three different types of light (red, blue, and green) on three different types of mobile devices (phone, tablet, and gaming console) to see which combination results in the least amount of eye strain for the user. In this design, how many total cells will there be?

9 (The number of cells in factorial design is a function of each level of each independent variable multiplied by the number of levels in the other independent variable.)

Define Instrumentation Threat:

A measure changes over the course of an experiment.

Yoshi is testing how being exposed to pictures of different types of foods affects sleepiness. Yoshi is showing each of his participants ten pictures of dessert, ten pictures of entrees, and ten pictures of salads, and he measures sleepiness after each group of ten pictures. To eliminate order effects, Yoshi is presenting all three types of food as well as all ten pictures in each group in a random order to each participant. What technique has Yoshi used to prevent order effects?

All three conditions are represented in some way to each participant, making this a full counterbalance.

Advantages of using Matched Groups

Because each member of a matched group is randomly assigned, the technique prevents selection effects. This method also ensures that groups are are equal on some important variable.

how to control for testing threats?

Control group that takes pretest and posttest w/o treatment in between Use different way of measuring the DV in pretest and posttest (like different items on the depression scale) No pretest at all...

In all studies, experimenters keep certain factors constant in order to be sure the independent variable is what is affecting the dependent variable. Though these factors are not true variables, they are often referred to as what type of variables?

Controls

define: carry over effect- sensitization

Exposure to a stimulus may make a subject respond more strongly to another

Why is it difficult to simultaneously have strong internal AND external validity?

In an experiment, researchers often prioritize experimental control-internal validity. to get a clean manipulation, they may have to conduct their study in an artificial environment, such as a University laboratory Many scientists choose to sacrifice representatives for internal validity

define: carry over effect- learning

Learning a task in the first treatment may affect performance in the second (irrespective of IV)

Define: regression threat

Originates with statistical concept called regression toward the mean Extremely low scorers improve or extremely high scorers fall on a second administration of a test due solely to statistical reasons

Define Maturation Threat:

Participant behavior changes spontaneously over time.

Define Testing Threat:

Participants change because of interaction with a measure

Define: mixed factorial design

Participants experience multiple levels of an independent variable but not all possible combinations. (A combination of between-groups and within-groups, this design can maintain an effective manipulation while being efficient with participants)

Define: Attrition Threat:

Participants leave an experiment in a systematic way.

define: carry over effect- adaptation

Physiological changes over time based on experimental setting

define: carry over effect- habituation

Repeated exposure to a stimulus may lead to unresponsiveness to that stimulus

Disadvantages of using Matched Groups

The matching process requires and extra step. Matching, therefore, requires many more resources than random assignment.

T/F: A mixed factorial design can have more than two independent variables.

True (A mixed factorial design can combine numerous different types of within-groups or between-groups independent variables.)

Define: instrumentation threat

When the equipment or human measuring the DV changes the measuring criterion over time. (For comparison, the testing threat occurred b/c of change in participant over time; instrumentation can deal w/ change in experimenter over time What if experimenter is affected by behavior he/ she observes and begins to change measuring/scoring criteria?)

Define: Latin Square

a form of counterbalancing that ensures that each condition appears in each position at least once.

Match the threat: The three healthiest participants withdraw from a study on metabolic syndrome.

attrition threat Because the participants who withdrew were not random, this presents a threat to validity.

When an experiment tests all possible combinations of more than one independent variable, it is often referred to as a _____ design. These designs can show that the effect of one independent variable depends on the level of another independent variable, also known as a(n) ______. These effects typically have two types. If you were to display the data in a line graph, one type would show the data from one independent variable intersect with the data from the other, or a(n) ______. The second type graphed in the same way would show the data moving away from each other as the dependent variable increased, or a(n) ______.

factorial, interaction effect, crossover interaction, spreading interaction Interactions are an important aspect of psychology—often more important than effects from a single independent variable.

Define: Partial counter balancing

in which only some of the possible condition orders are represented. One way to do this is to present the conditions in a randomized order for each subject.

Match the threat: Observers code social behavior as less friendly over time.

instrumentation threat With this threat, the instrumentation changes rather than the dependent variable.

disadvantages of full counter balancing

minimum number of subjects can get large fast (Ex. 5 conditions: 5x4x3x2x1=120 subjects needed)

How do we control for instrumentation?

Calibrate instruments along the way, especially before pretest and posttest Train coders multiple times throughout course of experiment

T/F: Manipulating the independent variable establishes temporal precedence.

False: The manipulated variable must come before the dependent variable is measured in order to establish temporal precedence.

Single Independent Variable Designs include...

independent variable, main effect, within-groups (Many non-factorial designs have an independent variable.) (A main effect is not necessarily factorial and would still exist with just one independent variable.) (An experiment with a single independent variable can use a within-groups design.)

What are the 6 types of carry over effects?

learning, fatigue, habituation, sensitization, contrast, and adaptation.

Define: Confounds

potential threats to internal validity (in an experiment you are confused about what is causing the change in the dependent variable)

Define: null effect

when the IV manipulated by the experimenters did not result in a change in the DV.

Define independent variable:

A variable, whose variation does not depend on that of another. It stands alone and isn't changed by the other variables you are trying to measure. Doesn't change.

Define: maturation threat

Changes in participants that occur over time during an experiment. These changes could include actual physical maturation or tiredness, boredom, hunger, and so on. (more or less spontaneously over time)

Define: within-groups factorial design

Each participant experiences all combinations of the independent variables. (This design capitalizes on being able to use fewer participants to find complex effects)

T/F: A within-groups factorial design typically requires the most participants.

False (A within-groups design is typically the most efficient, as separate groups are not needed for different levels of the independent variable.)

T/F: A mixed factorial design is only used as a last resort.

False (Mixed factorial designs can be extremely useful and have no specific drawbacks to restrict their use.)

T/F: Every experiment requires a control group.

False: Often a clear control group does not exist or is not possible.

advantages of partial counterbalancing

Likelihood of treatment effects being the result of carryover effects small (but possible)

Define: attrition threat

Mortality can occur if experimental participants from different groups drop out of the experiment at different rates. This only becomes a problem for internal validity when it is systematic; that is, only when a certain type of drops out.

advantages of latin square

controls for ordinal position of each treatment Each condition precedes or follows each other condition once.

Define/advantages of: Full counterbalancing

in which all possible orders (treatments) are represented

A team of researchers is conducting a study to see if videogame experts respond differently to various types of pictures compared to non-experts. They show each group of participants violent and nonviolent images and compare the skin conductance response to each category of picture. Which design best describes the example study?

mixed factorial (This example combines a within-groups independent variable and a between-groups independent variable.)

disadvantages of within-group designs

repeated-measures designs have the potential for order effects, which can threaten internal validity. These groups may not be possible of practicle in certain situations. When people see all levels of the IV then they may change the way they would naturally act.

A research study has a 2 × 2 × 3 within-subjects factorial design. In this example, there are a total of ____ cell(s). Researchers will need to investigate ____ main effect(s), ___ two-way interaction(s), and ___ three-way interaction(s).

twelve, three, two, one (An addition of a third independent variable drastically increases the number of effects that need to be investigated.)

match the solution that would best prevent within-group variability from obscuring group differences: measurement error

validated scales and increase measurements Measurements that have been previously tested and validated reduce measurement error. Increasing the number of measurements reduces the effect that error can have on data.

Define: within-group design

there is only one group of participants, and each person is presented with all levels of the IV

Match each variability type to the error associated with it: systematic variability

type I error Systematic variability can often make a manipulation appear to have an effect where there is actually none.

Match each variability type to the error associated with it: Unsystematic variability

type II error Unsystematic variability can obscure the experiment's effects, but is not considered a confound.

Define: Matched groups

used when assigning small numbers of participants to a group. Researchers measure participants on a particular variable that might matter to the dependent variable and then they would match participants by sets.

Define History Threat:

Participants' responses to the independent variable are altered by an event other than the independent variable.

In an experiment, when the dependent variable does not vary because of the independent variable, it is known as a(n) _____. Sometimes this can occur due to design flaws in the experiment. A(n) _____ can occur when the change in the independent variable is not strong enough to affect the dependent variable. An experiment could also have a(n) ______, which is a dependent variable that is not responsive enough to detect change from the independent variable. Scores from the dependent variable can also inadvertently cluster near the top of possible scores, known as the ______, or bottom, known as the ______, which can make covariance undetectable.

null effect, weak manipulation, insensitive measure, ceiling effect, floor effect

Define: internal Validity

Did your IV actually cause the change you observe in your DV? If you use adequate control techniques, your experiment should be free from confounding variables and you can, indeed, conclude that your IV caused the change in your DV.

Define: independent-groups factorial design

Each cell of each of the independent variables has unique subjects. (Though this design requires the most participants, it is sometimes essential for the manipulation to be effective)

Define: history threat

Events that occur between the DV measurements in a repeated measures design (pretest-posttest). (external events that affects most members of the treatment group at the same time as the treatment, making it unclear whether the change in the experimental group is caused by the treatment received or the historical factor)

Define Regression Threat:

Extreme scores return to average during an experiment.

What are the 3 rules recognize if an experiment meets criteria for establishing causation?

Covariance. Is the causal variable related to the effect variable? Are distinct levels of the IV associated with different levels of the DV? Temporal Precedence. Does the causal variable come before the effect variable in time? Internal Validity. Are there alternative explanations for the results?

Define dependent variable:

A variable, whose value depends on that of another. It is something that depends on other factors. Changes.

T/F: Manipulating the independent variable establishes covariance.

True: Without manipulation, causality cannot be established.

Match the threat: Students in a study on grade performance naturally improve during the study.

maturation threat Participant behavior is not static and can often change throughout a study, regardless of the manipulation.

what are the 6 threats to internal validity?

maturation threats, history threats, regression threats, attrition threats, testing threats and instrumentation threats.

Amir is conducting a study in which he shows participants one of three television commercials (charity, political, or control) in order to see which causes the most helping behavior. In this study, Amir is also interested in seeing how sex (male versus female) may interact with the type of commercial watched and affect helping behavior. Identify the number of main effects and interactions Amir is likely to find in his study. how many main effects and interactions?

two, one (In this example, there could potentially be a main effect for type of video and a main effect for sex.) (In this example, there could potentially be an interaction between sex and type of video shown.)

Define: testing threat

Because measuring the DV causes a change in the DV. Campbell (1957) noted that if you take the same test more than once, scores on the second test may vary systematically from the first scores simply because you took the test a second time-the practice effect.

Antonio is studying how different pamphlets promoting local charities may increase volunteer behavior in high school students. He creates one pamphlet that shows students having fun and being social while volunteering, and another that discusses the benefits volunteering has for college and future careers. Antonio has participants read one pamphlet or the other and then fill out a measure about volunteering intentions for the future. Antonio's measure asks how likely participants are to volunteer in the future from 1 ("I will not volunteer at all") to 5 ("I will likely volunteer in the future"). When looking at his results, Antonio finds that both groups scored very high on his measure and there is no difference between the two groups. What problem is most likely causing a null effect in the study?

Ceiling Effect: Most people will say they plan to volunteer in the future regardless of the manipulation, so it is likely scores in this study would be high regardless.

What are the different ways you can interpret a null effect?

Not enough between-group differences (weak manipulations, insensitive measures, and reverse design confounds might prevent an experiment from detecting a true difference that exists between two or more experimental groups). Too much unsystematic variability within each group, which creates noise (the more unsystematic variability there is within each group, the more the scores in the two groups overlap with each other. the greater the overlap, the less apparent the average difference). Or perhaps there really was no difference (the IV truly doe not affect the DV).

define: carry over effect- contrast

Participants will compare the current treatment to treatments that came before

If a study lacks the ability to truly show the effect of the independent variable even when all other parts of the experiment go correctly, it is said to lack what?

Power: Power is typically related to the number of participants collected and unsystematic variability or extraneous differences.

Imagine you are reading the following example from a popular press article. Researchers tested a series of different newspaper articles and found that articles containing abstract language and an African American perpetrator increased racial bias in those who watched the news on a regular basis. Which of the following best describes this design?

Three-way interaction (In this example, three independent variables (race, type of language, and news watching) are all described on how they affect racial bias.)

Factorial design includes...

difference in differences, interaction, mixed design. (This is a key term for identifying any type of factorial design. This would be impossible to show in a design with a single independent variable.) (Any design that has an interaction is a factorial design.) (In order for there to be a mixed design, more than two independent variables must be present.)

Define: Between-group design (also independent-group design)

different groups of participants are placed into different levels of the IV.

When researchers manipulate a variable in a study, they are carrying out a(n) ____. The manipulated variable is often called the _____ variable. A manipulated variable always has more than one level or ____ and is altered to see if it will result in a change in the _____ variable, which is typically measured.

experiment, independent, condition, dependent (An experiment is the only way to conclude a causal relationship.)

what are the 3 different methods of counterbalancing?

full counterbalancing, partial counterbalancing, and latin square.

Match the threat: A large clearance sale takes place during a study on shopping behavior.

history threat The occurrence of the clearance sale likely influenced shopping behavior of the participants outside of what would have been typical.

Define: Carryover effect

in which some form of contamination carries over from one condition to the next. (Exposure to a pervious treatmenet affects performance in a subsequent treatment (also called order effects).

match the solution that would best prevent within-group variability from obscuring group differences: individual differences

increased number of participants and within group design Increasing the number of participants reduces the chance that individual differences will affect the results. A within-groups design helps control for individual differences.

A(n) ________ design happens when different participants are placed in the various levels of the independent variable. There are two basic forms of this design. The first is the _____ design where participants are tested on the dependent variable only once following the manipulation. The second is the _______ design where participants are tested on the dependent variable before and after the manipulation.

independent-groups, posttest-only, pretest/posttest

In a factorial design with two independent variables, researchers will need to review one _____ and two _____. This design will also yield four _____, which are the averages of each level of the independent variable collapsed across the levels of the other independent variable.

interaction effect(s), main effect(s), marginal mean(s) (Marginal means are critical in understanding main effects in a factorial design.)

Advantages of within-group designs

it ensures the participants in the two groups will be equivalent (they are the same participants). Provides the ability to use each participant as his or her own control. These groups also give researchers more power to notice differences between conditions. It also generally requires fewer participants overall. They potentially also establish covariance, ensure temporal precedence, and when experiments control for order effects, they can establish internal validity too.

Rebecca is interested in how solving different types of puzzles influences creativity. She will have participants try four different puzzles (word, 3-D, 2-D, and number) and measure creativity after each puzzle. To prevent order effects, Rebecca will sort participants into groups and have each group do the puzzles in a different sequence. The first sequence will be word, 3-D, 2-D, number; while the second will be 3-D, 2-D, number, word; and so forth, until each possible condition falls in each position in the experiment. What technique has Rebecca used to prevent order effects?

latin square: In this example, the puzzles were ordered so that each level of the independent variable appears in each position at least once.

In a within-groups design, exposing participants to one level of the independent variable can change how they respond to the other levels of the independent variable. This problem is generally referred to as ____ effects, of which there are various types. One specific type is known as a _____ effect. This occurs when exposure to one level of the independent variable contaminates how other levels of the independent variable are perceived. Another type is a _____ effect, which occurs when participants change their responses based on repetition of the independent variable rather than on the influence of the variable itself. It is also possible that repeated exposure to the independent variable may cause participants to guess the hypothesis of the experiment, also known as ______.

order, carryover, practice, demand characteristics Within-groups designs have their own set of issues that can occur and that need to be addressed.

Mariah is testing whether or not loud music causes people to drive more recklessly. For each participant, Mariah flips a coin and places all the heads in one group and all the tails in the other. All participants complete a driving simulator course that measures their speeds and number of mistakes. Mariah then has one group listen to a rock song at a very loud volume, and the other at a lower volume. After listening to the song, participants once again complete the driving simulator course. (3 things apply)

pretest/posttest design, random assignment, independent-groups design Mariah pretested participants' driving ability to look for change in response to the level of music. Using the results of a coin toss to place participants in a group is a form of random assignment. Different participants were placed in each level of the independent variable.

Match the threat: Participants showed very high stress scores at pretest and returned to average at posttest.

regression threat Because the original scores were extreme, it was likely they would return to average regardless of the manipulations.

When a researcher inadvertently creates a condition with a fundamentally different type of participant than another condition, this can create a ______. You can combat this by arbitrarily assigning participants to each level, known as ________. In some cases, especially with smaller sample sizes, researchers will assign participants to groups so that each group has a similar makeup for a particular attribute they may be concerned about. This is known as creating _______.

selection effect, random assignment, matched groups

Match the threat: Participants change their answers on a racism scale after seeing it a second time.

testing threat In this example, the instrument is changing how the participants behave.

Imagine you are reading the following example from a popular press article. Researchers tested different forms of textbooks and found that interactive classrooms were more effective only for students who had high levels of previous technology experience. Which of the following best describes this design?

two-way interaction (In this example, two independent variables (type of classroom and technology experience) are described, indicating a likely two-way interaction.)

What are potential ways to deal with carryover effects?

using counterbalancing (full, partial, and latin square) trying to minimize carryover effects and treatment order as an IV