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Psychology Research Methods

Psychology Research Methods

• The general investigative purpose of a psychology study (why the researcher has decided to conduct an investigation) is called its aim.

• A hypothesis is a precise and testable statement of what the researcher predicts will be the outcome of the study. In an experiment this is called the experimental hypothesis.

• In a correlational study the hypothesis is called a research hypothesis, and it will predict a relationship between two variables.

• A research hypothesis is called an alternative hypothesis.

An alternative hypothesis is either:

• Directional (one-tailed): predicts the direction of the effect expected (e.g. ‘using visual imagery will improve how well words are recalled’), or

• Non-Directional (two-tailed): predicts an effect but does not specify its direction (e.g. ‘using visual imagery will affect how well words are recalled’).

• Every hypothesis also has a null hypothesis. This predicts that there will not be a difference; any difference is due to chance.

Designing experimental research

Independent groups design

Each participant (P) is involved in only one condition of the experiment; the P is selected randomly for either the experiment or the control condition.

Advantages: Can be used in wide range of situations, fairly easy to run, no order effects from P’s becoming skilled, bored or fatigued.

Disadvantages: Individual differences between groups may distort findings (random allocation to conditions helps reduce this risk); require fairly large sample size because each P is used only once.

Repeated measures design

Each P is involved in all conditions, the same Ps are used in experimental and control groups.

Advantages: Economical in use of Ps, no risk of participant variables confounding the findings as same Ps used in each condition,

Disadvantages: Demand characteristics- Ps have more opportunity to guess the purpose of the study, order effects- performance could...