Experimental Designs, Chapter 6, 3

Question 1

What are experimental designs?

Answer 1

The different ways in which participants can be organised in relation to the experimental conditions

Question 2

What is independent groups design?

Answer 2

Participants are allocated to different groups where each group represents one experimental condition

Question 3

What are repeated measures?

Answer 3

All participants take part in all conditions of the experiment

Question 4

What is matched pairs design?

Answer 4

Pairs of participants are first matched on some variables that may affect the dependent variable. Then one member of the pair is assigned to Condition A and the other to Condition B

Question 5

What is random allocation?

Answer 5

An attempt to control for participant variables in an independent groups design which ensures that each participant has the same chance of being in one condition as any other

Question 6

What is counterbalancing?

Answer 6

An attempt to control for the effects of order in a repeated measures design: half the participants experience the conditions in one order and the other half in the opposite order

Question 7

How would independent groups be incorporated in the energy drink investigation?

Answer 7

One group of participants (Group 1) drinking the energy drink (Condition A, the experimental condition)

A different group of participants (Group 2) drinking water (Condition A ) the control experiment

Question 8

How would we compare the performance of the two groups in the energy drink investigation?

Answer 8

Compare the difference in the mean number of words spoken in the five-minute period after drinking for each group/ condition

Question 9

How would repeated measures be incorporated in the energy drink investigation?

Answer 9

Each participant would first experience Condition A (the energy drink condition, the experimental condition)

Each participant would then later be tested again in Condition B (the glass of water condition, the control condition)

Question 10

What would be completed in the energy drink investigation to see if there was a difference between the repeated measures in both conditions?

Answer 10

The two mean scores from both conditions would be compared to see if there was a difference

Question 11

What is an example of a matched pairs design?

Answer 11

In a memory study, participants might be matched on their IQ, as this is a good indicator on their ability to recall information

Question 12

How would a memory study in a matched pairs design play out?

Answer 12

The two participants with the first and second highest IQ would be paired together as would the participants with the third and fourth highest, etc.

One participant from each pair would be allocated to a different condition of the experiment

Question 13

What is the matched pairs design in a memory study an attempt to control?

Answer 13

An attempt to control for the confounding variable of participant variables and often necessitates the use of a pre-test if matching is to be effective

Question 14

What is the biggest issue with an independent groups design?

Answer 14

The participants who occupy the different groups are not the same in terms of participant variables

Question 14

What is an example of the matched pairs design in the energy drink investigation?

Answer 14

We might observe participants interacting in a room before the experiment begins and select the two people that appear to be the chattiest.

One of the pair would be placed in condition A and the other in condition B.

We would then do the same with the third and fourth most talkative participants, etc.

The experiment would then be run in the same way as an independent groups design

Question 15

What may be more to do with participant variables than the effects of the IV?

Answer 15

If a researcher finds a mean difference between the groups on the dependent variable

Question 16

What may the mean difference between the groups on the dependent variable act as?

Answer 16

A confounding variable, reducing the validity of the findings

Question 17

To deal with this problem of a confounding variable in the mean difference between the groups on the dependent variable, what do researcher’s use?

Answer 17

Random allocation

Question 18

What are independent groups less of ?

Answer 18

Independent groups are less economical than repeated measures as each participant contributes a single result only

Question 19

How many participants would be needed in an independent groups designs compared to a repeated measures design?

Answer 19

Twice as many participants would be needed to produce equivalent data to that collected in a repeated measures design?

Question 20

What is wrong with independent groups designs needed twice as many participants?

Answer 20

This increases the the time/ money spent on recruiting participants

Question 21

What are the strengths of using independent groups?

Answer 21

Order effects are not a problem whereas they are a problem for repeated measures designs. Participants are also less likely to guess the aims

Question 22

What is the biggest issue for repeated measures?

Answer 22

Each participant has to do at least 2 tasks and the order of these tasks may be significant (i.e. there are order effects)

Question 23

Why may having an energy drink first be an order effect?

Answer 23

They may have a continuing effect when a participant drinks water afterwards. To deal with this researchers use counterbalancing

Question 24

How do researches deal with order effects?

Answer 24

By using counterbalancing

Question 24

What can order effects also arise from?

Answer 24

Because repeating two tasks could create boredom or fatigue that might cause deterioration in performance on the second task, so it matters what orders tasks are in

Question 25

Alternatively, how might the participants’ performance improve?

Answer 25

Through effects of practice, especially on a skill-based task- in this case of the energy drinks, participants would perform better on the second task

Question 26

What does order act as in the energy drink experiment?

Answer 26

As a confounding variable

Question 27

What is also more likely when participants experience all conditions of the experiment?

Answer 27

It is more likely that participants will work out the aim of the study

Question 28

What tend to be more of a feature of repeated measures designs than independent groups?

Answer 28

Demand characteristics due to participants being able to work out the aim of the study when experiencing all conditions

Question 29

What are the strengths of using repeated measures?

Answer 29

Participants variables are controlled, therefore higher validity and fewer participants are needed therefore less time spent recruiting time

Question 30

What are less of a problem in matched pairs?

Answer 30

Order effects and demand characteristics

Question 31

What can never happen with participants in matched pairs designs?

Answer 31

Although there is some attempt to reduce participant variables in this design, participants can never be matched exactly

Even when identical twins are used as matched pairs, there will still be important differences between them that may affect the DV

Question 32

What are the struggles with matching?

Answer 32

Matching may be time-consuming and expensive, particularly if a pre-test is required, so this is less economical than other designs