Research methods psychology

what is an independant groups design

Different participants take part in each condition. Example: one group uses mental images and another group memorises words.

What is a strength and limitation of independent groups?

Strength: no order effects because participants do only one condition. Limitation: participant differences, such as memory ability, may affect results. Random allocation helps reduce this.

What is a repeated measures design?

The same participants take part in every condition. Example: everyone tries both learning methods using different word lists.

What is a strength and limitation of repeated measures?

Strength: controls participant differences because the same people do both conditions. Limitation: order effects, such as practice or fatigue. Counterbalancing helps control these.

What is a matched pairs design?

Participants are paired on a relevant characteristic, such as memory ability, then one person from each pair takes part in each condition.

What is a strength and limitation of matched pairs?

Strength: reduces relevant participant differences without order effects. Limitation: matching participants takes time and cannot account for every difference.

How can you tell independent groups from matched pairs?

Both use different people in each condition. Only matched pairs explicitly matches people on relevant characteristics before splitting pairs between conditions.

What is a laboratory experiment?

The researcher manipulates the IV in a controlled setting and measures the DV. Example: changing the learning method in a laboratory memory task.

What is a strength and limitation of laboratory experiments?

Strength: control over extraneous variables increases internal validity. Limitation: artificial tasks or settings may reduce ecological validity.

What is a field experiment?

The researcher manipulates the IV in a natural, everyday setting and measures the DV. Example: changing whether a shop assistant smiles and measuring customer spending.

What is a strength and limitation of field experiments?

Strength: behaviour may be more natural, increasing ecological validity. Limitation: less control over extraneous variables makes cause and effect harder to establish.

What is a natural experiment?

The IV varies naturally; the researcher does not manipulate it. Example: comparing recall in schools affected and unaffected by an unexpected closure.

What is a strength and limitation of natural experiments?

Strength: allows study of variables that would be unethical or impractical to manipulate. Limitation: no random allocation, so differences between groups may affect results

What is a quasi experiment?

The IV is an existing participant characteristic, such as age or a diagnosis. The researcher compares DV scores between groups.

What is a strength and limitation of quasi experiments?

Strength: allows study of characteristics that cannot be manipulated. Limitation: no random allocation, so other participant differences may explain results.

How do experimental designs differ from types of experiment?

Design describes who takes part in each condition. Type describes the setting or how the IV arises. A laboratory experiment can use independent groups, repeated measures or matched pairs.