Experimental Exam 1

Science

Relies on systematic observation and publicly verifiable evidence

Theories

Organize findings, explain them, and generate predictions (productive, falsifiable, parsimonious)

Which of the following is NOT a feature of a good scientific theory?

a. Productivity

b. Falsifiability

c. Parsimony

d. Truth

D. Truth

Hypothesis

specific, testable prediction derived from an idea or theory

Operational definition

specifies how a construct is measured or manipulated

Operational defintion example

anxiety measured with a rating scale, avoidance, or physiological arousal

Independent Variable

Manipulated or selected factor

Dependent Variable

measured outcome

Control variable

Held constant

Confound

Varies systematically with the IV, offers alternative explanation

Participants have either 3 or 10 seconds to respond on a memory task. Accuracy is scored as percent correct. What is the dependent variable?

a. Time pressure

b. Response deadline

c. Percent correct

d. Memory task

C. Percent correct

Nominal scale

Categories

Ordinal

ordered categories

Interval

equal units, no true zero

Ratio

Equal units, true zero

A participant’s reaction time in milliseconds is recorded on each trial. What is the highest appropriate level of measurement?

a. Nominal

b. Ordinal

c. Interval

d. Ratio

D. Ratio

Construct validity

concerns whether the measure captures the intended construct

Temporal precedence

cause comes before the effect

covariation

changes in the cause accompany changes in the effect

internal validity

plausible alternative explanations are ruled out

manipulation and control

help support causal inference

Random sampling

determines who enters the study and supports population generalization

Random assignment

determines who recieves each condition, helps makes groups comparable

A researcher randomly selects people from a city directory, then randomly assigns them to stress or control. Which statement is correct?

a. Random selection concerns condition assignment only

b. Random assignment concerns who enters the study

c. Random sampling concerns who enters the study; random assignment concerns condition

d. Neither step is random

C. Random sampling concerns who enters the study; random assignment concerns condition

Between subjects

different people complete differnet conditions

within subjects

same people complete all conditions

matched groups

people are matched on relevant characteristics

mixed

at least one between-subjects factor and one within-subjects factor

Practice

performance improves with experience

Carryover

one condition changes responses in a later condition

Contrast

a condition feels different because of what came before it

Complete counterbalancing

uses every possible order

Everyone completes a task after placebo first and after caffeine second. Which problem is most obvious?

a. The caffeine condition is confounded with order

b. The DV is nominal

c. Random sampling guarantees causality

d. The study has no manipulation

A. The caffeine condition is confounded with order

Self-report measure

what people report about thoughs, feelings, behavior

Behavioral measure

RT, errors, choices, or accuracy

Physiological measures

bodily or brain signals (EEG, blood oxygenation)

EEG/ERP

measures electrical activity with excellent temporal resolution. Localization is difficult

fMRI and fNIRS

measure slower, indirect blood-oxygenation responses. It can locate where activity is changing

TMS

changes cortical activity and tests its contribution to behavior

Ceiling effect

scores cluster near the top

Floor effect

scores cluster near the bottom

A task is so difficult that nearly all participants score close to zero, regardless of condition. What problem is this?

a. Ceiling effect

b. Floor effect

c. Demand characteristic

d. Random assignment

B. Floor effect

A survey includes the item: “I usually feel relaxed and get enough sleep before exams.” What is the main problem?

a. It is double-barreled

b. It is a ratio measure

c. It is a factorial design

d. It is a Latin square

A. it is double-barreled

Reliability

consistency of measurement

construct validity

how well the operational definition captures the construct

Cronbach’s Alpha

summarizes internal consistency among a set of items

Reverse Scoring

items point in the opposite direction from the intended scale

On a 1–5 scale, a reverse-worded item receives a response of 4. After reverse scoring, what is the score?

a. 1

b. 2

c. 3

d. 4

2

Factorial Designs

factors are the IVs, levels are their values. Every level of each factor combines with every level of the other factors

Main effect

the effect of ane factor, averaged across the other factors

Simple effect

the effect of one factor at a particular level of another factor

Interaction

a simple effect changes across levels of another factor

A study manipulates noise level (quiet, moderate, loud) and lighting (dim, bright). How many conditions are in this factorial design?

a. 2

b. 3

c. 5

d. 6

D. 6

Which result best describes an interaction?

a. Participants perform better in bright lighting than dim lighting

b. Participants perform worse as noise increases

c. Noise hurts performance in dim lighting but not in bright lighting

d. Performance is the dependent variable

c. Noise hurts performance in dim lighting but not in bright lighting