Experimental Design & Research Methodology - Key Terms (Question & Answer)

A set of QUESTION_AND_ANSWER flashcards covering the key terms and concepts from the notes.

What is an experiment?

An investigation that looks for a causal relationship; the independent variable is manipulated and is expected to cause changes in the dependent variable.

What is the dependent variable (DV)?

The factor in an experiment that is measured and is expected to change under the influence of the independent variable.

What is the independent variable (IV)?

The factor under investigation in an experiment that is manipulated to create two or more conditions (levels) and is expected to cause changes in the dependent variable.

What is an uncontrolled variable?

A variable that either acts randomly (affecting the DV at all levels of the IV) or systematically (a confounding variable) so it can obscure the effect of the IV, making results hard to interpret.

What is an experimental condition?

One or more of the situations in an experiment that represent different levels of the IV and are compared (or compared to a control condition).

What is a control condition?

A level of the IV where the IV itself is absent; it is compared to one or more experimental conditions.

What is experimental design?

The way in which participants are allocated to levels of the IV.

What is an independent measures design?

An experimental design in which a different group of participants is used for each level of the IV (condition).

What are demand characteristics?

Features of the experimental situation that reveal aims and can cause participants to change their behavior to fit expectations, reducing validity.

What is random allocation?

A method to reduce the effect of confounding variables by giving each person an equal chance of being in any condition.

What is a repeated measures design?

An experimental design in which each participant performs in every level of the IV.

What are participant variables?

Individual differences between participants (such as age, personality and intelligence) that could affect behavior and obscure differences between IV levels.

What is a confounding variable?

An uncontrolled variable that acts systematically on one level of the IV and could hide or exaggerate differences between IV levels, confounding the results.

What are order effects?

Practice and fatigue effects from participating more than once in a study, which can change performance between conditions independently of the IV.

What is a practice effect?

A situation where participants' performance improves because they experience the task more than once.

What is a fatigue effect?

A situation where participants' performance declines because they experience the task more than once.

What is randomization?

A way to overcome order effects in a repeated measures design by ensuring equal chances of participating in different levels in any order.

What is counterbalancing?

A method to overcome order effects where all possible orders of IV levels are used by different subgroups (e.g., ABBA design).

What is a matched pairs design?

An experimental design in which participants are paired on relevant similarities, and one member of each pair experiences a different level of the IV.

What is a laboratory experiment?

A research method with an IV, a DV and strict controls, aiming to determine causality, conducted in a setting distant from the participants' typical environment.

What are controls?

Ways to keep potential confounding variables constant to ensure differences in the DV are due to the IV, increasing validity.

What is standardization?

Keeping the procedure for each participant exactly the same to ensure differences are due to the variables rather than how they were treated.

What is reliability?

The extent to which a procedure, task or measure is consistent across occasions.

What is validity?

The extent to which the study tests what it claims to be testing.

What is a pilot study?

A small-scale test of the procedure to ensure the study's procedure and materials are valid and reliable and can be adjusted if needed.

What is replication?

Keeping the procedure and materials the same between studies to verify results or enable others to reuse the methods.

What is operational definition?

A clear description of a variable so it can be manipulated, measured or quantified, enabling replication; describes how IV and DV (and co-variables) are defined.

What is a placebo?

A pill or procedure given to a participant who believes it is a real treatment but has no active ingredient or therapeutic value.

What is a field experiment?

An investigation looking for a causal relationship in the participants' normal environment, with some control of variables.

What does generalize mean?

To apply the findings of a study to other settings and populations.

What is ecological validity?

The extent to which findings generalize to real-world settings, influenced by how well the situation (e.g., lab) represents real life and the task's relevance.

What is a hypothesis (plural hypotheses)?

A testable statement based on the aims of an investigation.

What is an alternative hypothesis?

The testable statement predicting a difference or relationship between variables.

What is a non-directional (two-tailed) hypothesis?

A hypothesis that predicts a relationship or difference but does not specify the direction of the effect.

What is a directional (one-tailed) hypothesis?

A hypothesis that predicts the direction of the relationship or effect (increase or decrease).

What is the null hypothesis?

A testable statement that any difference or correlation is due to chance, implying no real pattern due to the studied variables.

What is informed consent?

Knowing enough about a study to decide whether to participate.

What is the right to withdraw?

A participant should be free to withdraw from the study and have their data removed at any time.

What is protection from harm?

Participants should not be exposed to greater risk than they would encounter in daily life.

What is deception?

Deliberate misinformation about the aims or procedures should be avoided; if unavoidable, minimize distress and debrief; deception may be used to reduce demand characteristics but should be avoided.

What is privacy?

Participants' emotions and physical space should not be invaded; they should not be observed where they would not expect to be seen.

What is confidentiality?

Participants' results and personal information should be kept safe and not released outside the study.

Is the hypothesis ‘intelligence affects obedience’ directional or non-directional? Justify.

Non-directional, because the statement does not specify the direction of the relationship; it only predicts a relationship between intelligence and obedience.

Describe what an independent variable is and give an example.

An independent variable is the factor deliberately manipulated to create different levels; example: the amount of caffeine given to participants.

Describe what a dependent variable is and give an example.

A dependent variable is the measured outcome that changes due to the IV; example: score on a memory test.

Inma is observing one student at a time in the playground. Which uncontrolled variable is a participant variable?

A headache a student may have is a participant variable (an internal state of the participant).

Inma's two uncontrolled variables: which is a participant variable?

A student having a headache is a participant variable.

Inma's two uncontrolled variables: which is a situational variable?

A student being observed when few other students are present is a situational variable.