Chapter 10: Introduction to Simple Experiments

Question 1

condition

Answer 1

The level of manipulation used for the independent variable.

Question 2

control variable

Answer 2

A variable that the experimenter holds constant on purpose.

Question 3

comparison group

Answer 3

A group of participants that do not receive the experimental treatment.

Question 4

confound

Answer 4

A possible alternative explanation for a research question.

Question 5

design confound

Answer 5

A mistake in the design of the IV; occurs when a second variable happens to vary systematically along with the intended IV.

Question 6

systematic variability

Answer 6

A consistent difference between subject groups -> e.g. during baby study, one group of adults smiled and one group didn’t BUT “smiling” wasn’t the IV; creates confounds.

Question 7

unsystematic variability

Answer 7

A random(ized) difference between participants in both subject groups -> e.g. during baby study, both groups had a few adults who smiled and who didn’t smile; IS NOT a design confound.

Question 8

selection effects

Answer 8

A bias that could occur if the experimenters assign one type of person to one condition, and another type of person to another condition AKA participants/researchers get a choice to which group a subject gets assigned.

Question 9

Random assignment

Answer 9

Participants are randomly assigned to different levels of the IV.

Question 10

matched groups

Answer 10

Participants are sorted from lowest to highest on some key control variable and grouped into sets of two. Individuals within each set are then assigned at random to the two experimental groups; prevents selection effects.

Question 11

independent-groups design (AKA between-subjects design)

Answer 11

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

Question 12

within-groups design (AKA within-subjects design)

Answer 12

Each participant is presented with ALL levels of the IV.

Question 13

posttest-only design

Answer 13

An independent-groups design in which participants are randomly assigned to IV groups and are tested on the DV once.

Question 14

pretest/posttest design

Answer 14

An independent-groups design in which participants are randomly assigned to at least two groups and are tested on the key DV twice – once before and once after exposure to the IV; used to exclude selection effects and track subjects’ performance over time.

Question 15

repeated-measures design

Answer 15

A within-groups design in which participants are measured on a DV more than once, after exposure to each level of the IV.

Question 16

concurrent-measures design

Answer 16

A within-groups design in which participants are exposed to all levels of an IV at roughly the same time, and a single attitudinal or behavioral preference is the DV.

Question 17

order effects

Answer 17

Due to being exposed to one condition first, participants change their reaction to the later condition; happens when exposure to one level of the IV influences responses in the next level and is a confound.

Question 18

practice effects

Answer 18

A long sequence might lead participants to get better at a task or to get tired or bored toward the end; it is an order effect.

Question 19

carryover effects

Answer 19

Some form of contamination carries over on the participants from one condition to the next; it is an order effect -> e.g. sipping orange juice right after brushing your teeth.

Question 20

counterbalancing

Answer 20

Researchers present the levels of the IV to participants (in within-groups designs) in different sequences; is used to avoid order effects.

Question 21

full counterbalancing

Answer 21

All possible orders of presenting the levels of the IV in a within-groups design are represented.

Question 22

partial counterbalancing

Answer 22

Only some of the possible orders of presenting the levels of the IV in a within-groups design are represented; can be randomized or done with a ‘Latin square’.

Question 23

Latin square

Answer 23

A formal system to ensure that every condition appears in each position at least once.

Question 24

demand characterisitic

Answer 24

A cue in an experiment that can lead participants to guess an experimenter’s hypothesis.

Question 25

manipulation check

Answer 25

An extra DV that researchers can insert into an experiment to convince them that their experimental manipulation worked; mostly used when participants are made to think or feel certain ways.

Question 26

pilot study

Answer 26

A simple study, using a separate group of participants, that is completed before the study of interest to confirm the effectiveness of the manipulations.

Question 27

confidence intervals (CI)

Answer 27

A range designed to include the true population value for 95% of the time.

Question 28

extraneous variable

Answer 28

During an experiment, any variable that is not investigated that can potentially affect the outcomes.