IB Psychology HL: Lessons 1.1 and 1.2

1.1: Research in Psychology, 1.2: Quantitative Research

1.1 Psychology

The study of how mental processes influence behaviour.

Conditions for Experimental Study

1. Must be falsifiable

2. Must be replicable

3. Must be backed-up by empirical evidence

Study: Clever Hans

Horse was able to perform arithmetic problems.

It was later revealed that he was responding to cues from his trainer rather than performing actual calculations.

Behaviour

What can be registered by an observer empirically.

Mental Processes

The causes behaviour.

Nomothetic Approach

A method used in a study to conclude general principles or laws from collected data.

Construct

Theoretically defined variables that CANNOT be observed. E.g. anger.

Operationalisation

Methods employed to make constructs observable.

Experimental Studies

A study used to define a cause-and-effect relationship.

Includes 1 IV, DV, and Operationalisation method.]

Example: Effects of Psychotherapy on Depression (IV: Psychotherapy, DV: Depression levels (construct), OM: Tests)

Correlational Studies

A study that aims to establish a relationship between 2 variables without their manipulation.

Example: Relationship between study time and exam scores. (OM: A survey to check study time, and score received on test)

Descriptive Studies

A study where relationships are not made, rather variables are investigated; informative.

Example: Case studies or surveys.

Ways to Measure Quality of Research

1. Sampling: Obtain specific sampling method for study

2. Credibility

3. Generalisability: Applicability of study in other samples

1.2 Confounding Variables

Experiment 1 - IV: A, DV: B, CV: C

Changing A unintentionally changes C, which affects B.

We infer that the change is caused by A, when it is actually caused by C.

Random Sampling

Every member is randomly selected

Example: US jury representation

Stratified Sampling

Sample is chosen based on characteristics of study

Example: How phones affect 10th graders school performance in Australia - Sample would be 10th graders in Australia.

Convenience Sampling

Recruit based on how easy it is to get a participant

Self-Selected Sampling

Advertising experiment and having people sign up.

Independent Measures Design

Results tested in Experiment Group and Control Group

No confounding variables

Random Group Allocations

Match Pairs Design

Participants are matched based on characteristics (e.g., age, gender, etc), and then one is assigned to a different condition.

Repeated Measures Design

This form of design is used to compare conditions in an experiments.

Construct Validitiy

How well the operationalisation reflects the construct,

Internal Validity

To what extent the IV change the DV

External Validity

To what extent the study can be used in other samples.