Aims, Hypotheses & Sampling

Aims and Hypotheses

Each research study specifies aims and hypotheses. An aim is what it is trying to achieve, while a hypothesis is a specific prediction of what it will find.

Illustrative background for Aim ?? "content

Aim

A researcher usually states the aim of their study.
This involves saying what they are trying to achieve, or what the point of their study is.
Usually the aim is linked to a real-world purpose, i.e. a reason why it is important to find something out.
- For example, a researcher may state that they aim to find out the effect of caffeine on sleep.

Hypotheses

A hypothesis is different from an aim.
It involves making a specific prediction of what will be found, expressed in terms of a change in variables.
Usually the hypothesis is based on theories and on past research findings, i.e. there is a theoretical rationale for the hypothesis.
- For example, a researcher may state a hypothesis that consuming 200mg of caffeine will increase the length of time it takes people to fall asleep compared to having no caffeine.

Experimental vs alternative

In an experiment, the researcher’s main hypothesis is known as an experimental hypothesis. It is also referred to as H1.
In a non-experimental study, it is typically called an alternative hypothesis.

Null hypothesis

Most studies also clearly state a null hypothesis (sometimes referred to as H0).
This is a statement of what will be found if the experimental/alternative hypothesis is not supported by the results.

Directional hypothesis

A directional or one-tailed hypothesis predicts the direction in which change is expected to occur.
It is used when previous research has suggested the direction of change.
It is precise and uses words such as: faster/slower, bigger/smaller, more/less etc.
- e.g.Alcohol increases reaction times.

Non-directional hypothesis

A non-directional or two-tailed hypothesis simply predicts change and does not specify direction.
It is used when there is no previous research. It is non-specific and uses words like: effect, change, difference etc.
- e.g. Alcohol will affect reaction times.
NB. All variables must be fully operationalised e.g. alcohol measured in units; reaction times measured in seconds.

Populations and Samples

Any research study needs a group of participants. These are called the sample, and they are drawn from a wider group called the target population.

Sampling

Sampling means selecting a group of participants who will take part in the study.

Populations

A sample always comes from a broader population.
This does not necessarily mean the whole population of a country, but could be a specific group.
This is known as the target population.
- For example, all sixth-form school pupils in the country is an example of a target population, and a selection of 50 sixth-form school pupils is an example of a sample.

Representation

A key aspect of sampling is that the sample should be representative of the target population.
This means that they should have similar characteristics.
Studying a representative sample allows the researcher to generalise the findings to the target population. This is a key aim of any research.

Sampling Techniques

There are multiple ways of obtaining a sample for a research study. Four major sampling techniques are opportunity sampling, systematic sampling, volunteer sampling and stratified sampling.

Opportunity sampling

Opportunity sampling is the most common sampling technique. It involves accessing participants on the basis of their convenient availability to the researcher:
- Examples of opportunity sampling include conducting research on the researcher’s own friends, classmates or students.
- Opportunity sampling is very prone to bias because the most easily available participants may not be representative of the target population.

Systematic sampling

Systematic sampling involves applying a regular system or rule when selecting participants:
- Examples of systematic sampling include picking every 50th person that walks along a corridor, or every 100th name in the phone book, or posting a questionnaire to every 10th house in a village.
- Systematic sampling reduces researcher bias, but some potential participants may be excluded e.g. because they are not in the phone book or do not live in a house. This leads to bias.

Volunteer sampling

Volunteer sampling allows participants to select themselves, such as by responding to an advert or email call for participants:
- Eg. posting an advert on a school noticeboard, asking people to complete your online survey.
- One source of bias with volunteer sampling is that certain personalities are more likely than others to come forward and help the research. This may have affected classic research studies such as Milgram’s obedience research and Zimbardo’s Stanford Prison experiment.

Stratified sampling

Stratified sampling involves selecting participants in such a way as to recreate the same proportions of groups that exist in the population:
- An example of stratified sampling would involve selecting people from different ethnic groups to create a sample with the same proportions as exist in the target population.
- This reduces bias by making the sample more representative, but before stratification can occur, participants must already have been selected using another sampling technique.

Random sampling

In random sampling like the National Lottery, all members of the target population must stand an equal chance of being selected.
Random sampling does not guarantee a representative sample, but the laws of probability predict that the chances of selecting a biased sample are minimal.
- E.g. putting the names of every member of the target population into a hat and pulling a sample out (without looking!).

Evaluation of random sampling

Strengths:
- If the sample is large enough, the rules of probability suggest that it should be representative.
Limitations:
- Participants may not be willing or able to take part in the research.
- Sample could still be biased in terms of variables such as gender, age, ethnicity etc.

1Social Influence

1.1Social Influence

1.1.1Conformity

1.1.2Asch (1951)

1.1.3Sherif (1935)

1.1.4Conformity to Social Roles

1.1.5BBC Prison Study

1.1.6End of Topic Test - Conformity

1.1.7Obedience

1.1.8Analysing Milgram's Experiment

1.1.9Agentic State & Legitimate Authority

1.1.10Variables of Obedience

1.1.11Resistance to Social Influence

1.1.12Minority Influence & Social Change

1.1.13Minority Influence & Social Impact Theory

1.1.14End of Topic Test - Social Influences

1.1.15Exam-Style Question - Conformity

1.1.16Top Grade AO2/AO3 - Social Influence

2Memory

3Attachment

3.1Attachment

3.1.1Caregiver-Infant Interaction

3.1.2Condon & Sander (1974)

3.1.3Schaffer & Emerson (1964)

3.1.4Multiple Attachments

3.1.5Studies on the Role of the Father

3.1.6Animal Studies of Attachment

3.1.7Explanations of Attachment

3.1.8Attachment Types - Strange Situation

3.1.9Cultural Differences in Attachment

3.1.10Disruption of Attachment

3.1.11Disruption of Attachment - Privation

3.1.12Overcoming the Effects of Disruption

3.1.13The Effects of Institutionalisation

3.1.14Early Attachment

3.1.15Critical Period of Attachment

3.1.16End of Topic Test - Attachment

3.1.17Exam-Style Question - Attachment

3.1.18Top Grade AO2/AO3 - Attachment

4Psychopathology

4.1Psychopathology

4.1.1Definitions of Abnormality

4.1.2Definitions of Abnormality 2

4.1.3Phobias, Depression & OCD

4.1.4Phobias: Behavioural Approach

4.1.5Evaluation of Behavioural Explanations of Phobias

4.1.6Depression: Cognitive Approach

4.1.7OCD: Biological Approach

4.1.8Evidence for the Biological Approach

4.1.9End of Topic Test - Psychopathy

4.1.10Exam-Style Question - Phobias

4.1.11Top Grade AO2/AO3 - Psychopathology

5Approaches in Psychology

5.1Approaches in Psychology

5.2Comparison of Approaches (A2 only)

5.2.1Psychodynamic Approach

5.2.2Cognitive Approach

5.2.3Biological Approach

5.2.4Behavioural Approach

5.2.5End of Topic Test - Comparison of Approaches

6Biopsychology

6.1Biopsychology

6.1.1Nervous System Divisions

6.1.2Neuron Structure & Function

6.1.3Neurotransmitters

6.1.4Endocrine System Function

6.1.5Fight or Flight Response

6.1.6The Brain (A2 only)

6.1.7Localisation of Brain Function (A2 only)

6.1.8Studying the Brain (A2 only)

6.1.9CIMT (A2 Only) & Postmortem Examinations

6.1.10Biological Rhythms (A2 only)

6.1.11Studies on Biological Rhythms (A2 Only)

6.1.12End of Topic Test - Biopsychology

6.1.13Top Grade AO2/AO3 - Biopsychology

7Research Methods

7.1Research Methods

7.1.1Experimental Method

7.1.2Observational Techniques

7.1.3Covert, Overt & Controlled Observation

7.1.4Self-Report Techniques

7.1.5Correlations

7.1.6Exam-Style Question - Research Methods

7.1.7End of Topic Test - Research Methods

7.2Scientific Processes

7.2.1Aims, Hypotheses & Sampling

7.2.2Pilot Studies & Design

7.2.3Questionnaires

7.2.4Variables & Control

7.2.5Demand Characteristics & Investigator Effects

7.2.6Ethics

7.2.7Limitations of Ethical Guidelines

7.2.8Consent & Protection from Harm Studies

7.2.9Peer Review & The Economy

7.2.10Validity (A2 only)

7.2.11Reliability (A2 only)

7.2.12Features of Science (A2 only)

7.2.13Paradigms & Falsifiability (A2 only)

7.2.14Scientific Report (A2 only)

7.2.15Scientific Report 2 (A2 only)

7.2.16End of Topic Test - Scientific Processes

7.3Data Handling & Analysis

7.3.1Types of Data

7.3.2Descriptive Statistics

7.3.3Correlation

7.3.4Evaluation of Descriptive Statistics

7.3.5Presentation & Display of Data

7.3.6Levels of Measurement (A2 only)

7.3.7Content Analysis (A2 only)

7.3.8Case Studies (A2 only)

7.3.9Thematic Analysis (A2 only)

7.3.10End of Topic Test - Data Handling & Analysis

7.4Inferential Testing

7.4.1Introduction to Inferential Testing

7.4.2Sign Test

7.4.3Piaget Conservation Experiment

7.4.4Non-Parametric Tests

8Issues & Debates in Psychology (A2 only)

8.1Issues & Debates in Psychology (A2 only)

8.1.1Culture Bias

8.1.2Sub-Culture Bias

8.1.3Gender Bias

8.1.4Ethnocentrism

8.1.5Cross Cultural Research

8.1.6Free Will & Determinism

8.1.7Comparison of Free Will & Determinism

8.1.8Reductionism & Holism

8.1.9Reductionist & Holistic Approaches

8.1.10Nature-Nurture Debate

8.1.11Interactionist Approach

8.1.12Nature-Nurture Methods

8.1.13Nature-Nurture Approaches

8.1.14Idiographic & Nomothetic Approaches

8.1.15Socially Sensitive Research

8.1.16End of Topic Test - Issues and Debates

9Option 1: Relationships (A2 only)

9.1Relationships: Sexual Relationships (A2 only)

9.1.1Sexual Selection & Human Reproductive Behaviour

9.1.2Intersexual & Intrasexual Selection

9.1.3Evaluation of Sexual Selection Behaviour

9.1.4Factors Affecting Attraction: Self-Disclosure

9.1.5Evaluation of Self-Disclosure Theory

9.1.6Self Disclosure in Computer Communication

9.1.7Factors Affecting Attraction: Physical Attributes

9.1.8Matching Hypothesis Studies

9.1.9Factors Affecting Physical Attraction

9.1.10Factors Affecting Attraction: Filter Theory 1

9.1.11Factors Affecting Attraction: Filter Theory 2

9.1.12Evaluation of Filter Theory

9.1.13End of Topic Test - Sexual Relationships

9.2Relationships: Romantic Relationships (A2 only)

9.2.1Social Exchange Theory

9.2.2Evaluation of Social Exchange Theory

9.2.3Equity Theory

9.2.4Evaluation of Equity Theory

9.2.5Rusbult’s Investment Model

9.2.6Evaluation of Rusbult's Investment Model

9.2.7Relationship Breakdown

9.2.8Studies on Relationship Breakdown

9.2.9Evaluation of Relationship Breakdown

9.2.10End of Topic Test - Romantic relationships

9.3Relationships: Virtual & Parasocial (A2 only)

9.3.1Virtual Relationships in Social Media

9.3.2Evaluation of Reduced Cues & Hyperpersonal

9.3.3Parasocial Relationships

9.3.4Attachment Theory & Parasocial Relationships

9.3.5Evaluation of Parasocial Relationship Theories

9.3.6End of Topic Test - Virtual & Parasocial Realtions

10Option 1: Gender (A2 only)

10.1Gender (A2 only)

10.1.1Sex, Gender & Androgyny

10.1.2Gender Identity Disorder

10.1.3Biological & Social Explanations of GID

10.1.4Biological Influences on Gender

10.1.5Effects of Hormones on Gender

10.1.6End of Topic Test - Gender 1

10.1.7Kohlberg’s Theory of Gender Constancy

10.1.8Evaluation of Kohlberg's Theory

10.1.9Gender Schema Theory

10.1.10Psychodynamic Approach to Gender Development 1

10.1.11Psychodynamic Approach to Gender Development 2

10.1.12Social Approach to Gender Development

10.1.13Criticisms of Social Theory

10.1.14End of Topic Test - Gender 2

10.1.15Media Influence on Gender Development

10.1.16Cross Cultural Research

10.1.17Childcare & Gender Roles

10.1.18End of Topic Test - Gender 3

11Option 1: Cognition & Development (A2 only)

11.1Cognition & Development (A2 only)

11.1.1Piaget’s Theory of Cognitive Development 1

11.1.2Piaget's Theory of Cognitive Development 2

11.1.3Schema Accommodation Assimilation & Equilibration

11.1.4Piaget & Inhelder’s Three Mountains Task (1956)

11.1.5Conservation & Class Inclusion

11.1.6Evaluation of Piaget

11.1.7End of Topic Test - Cognition & Development 1

11.1.8Vygotsky

11.1.9Evaluation of Vygotsky

11.1.10Baillargeon

11.1.11Baillargeon's studies

11.1.12Evaluation of Baillargeon

11.1.13End of Topic Test - Cognition & Development 2

11.1.14Sense of Self & Theory of Mind

11.1.15Baron-Cohen Studies

11.1.16Selman’s Five Levels of Perspective Taking

11.1.17Biological Basis of Social Cognition

11.1.18Evaluation of Biological Basis of Social Cognition

11.1.19Important Issues in Social Neuroscience

11.1.20End of Topic Test - Cognition & Development 3

11.1.21Top Grade AO2/AO3 - Cognition & Development

12Option 2: Schizophrenia (A2 only)

12.1Schizophrenia: Diagnosis (A2 only)

12.1.1Classification & Diagnosis

12.1.2Reliability & Validity of Diagnosis

12.1.3Gender & Cultural Bias

12.1.4Pinto (2017) & Copeland (1971)

12.1.5End of Topic Test - Scizophrenia Diagnosis

12.2Schizophrenia: Treatment (A2 only)

12.2.1Family-Based Psychological Explanations

12.2.2Evaluation of Family-Based Explanations

12.2.3Cognitive Explanations

12.2.4Drug Therapies

12.2.5Evaluation of Drug Therapies

12.2.6Biological Explanations for Schizophrenia

12.2.7Dopamine Hypothesis

12.2.8End of Topic Test - Schizoprenia Treatment 1

12.2.9Psychological Therapies 1

12.2.10Psychological Therapies 2

12.2.11Evaluation of Psychological Therapies

12.2.12Interactionist Approach - Diathesis-Stress Model

12.2.13Interactionist Approach - Triggers & Treatment

12.2.14Evaluation of the Interactionist Approach

12.2.15End of Topic Test - Scizophrenia Treatments 2

13Option 2: Eating Behaviour (A2 only)

13.1Eating Behaviour (A2 only)

13.1.1Explanations for Food Preferences

13.1.2Birch et al (1987) & Lowe et al (2004)

13.1.3Control of Eating Behaviours

13.1.4Control of Eating Behaviour: Leptin

13.1.5Biological Explanations for Anorexia Nervosa

13.1.6Psychological Explanations: Family Systems Theory

13.1.7Psychological Explanations: Social Learning Theory

13.1.8Psychological Explanations: Cognitive Theory

13.1.9Biological Explanations for Obesity

13.1.10Biological Explanations: Studies

13.1.11Psychological Explanations for Obesity

13.1.12Psychological Explanations: Studies

13.1.13End of Topic Test - Eating Behaviour

14Option 2: Stress (A2 only)

14.1Stress (A2 only)

14.1.1Physiology of Stress

14.1.2Role of Stress in Illness

14.1.3Role of Stress in Illness: Studies

14.1.4Social Readjustment Rating Scales

14.1.5Hassles & Uplifts Scales

14.1.6Stress, Workload & Control

14.1.7Stress Level Studies

14.1.8End of Topic Test - Stress 1

14.1.9Physiological Measures of Stress

14.1.10Individual Differences

14.1.11Stress & Gender

14.1.12Drug Therapy & Biofeedback for Stress

14.1.13Stress Inoculation Therapy

14.1.14Social Support & Stress

14.1.15End of Topic Test - Stress 2

15Option 3: Aggression (A2 only)

15.1Aggression: Physiological (A2 only)

15.1.1Neural Mechanisms

15.1.2Serotonin

15.1.3Hormonal Mechanisms

15.1.4Genetic Factors

15.1.5Genetic Factors 2

15.1.6End of Topic Test - Aggression: Physiological 1

15.1.7Ethological Explanation

15.1.8Innate Releasing Mechanisms & Fixed Action Pattern

15.1.9Evolutionary Explanations

15.1.10Buss et al (1992) - Sex Differences in Jealousy

15.1.11Evaluation of Evolutionary Explanations

15.1.12End of Topic Test - Aggression: Physiological 2

15.2Aggression: Social Psychological (A2 only)

15.2.1Social Psychological Explanation

15.2.2Buss (1963) - Frustration/Aggression

15.2.3Social Psychological Explanation 2

15.2.4Social Learning Theory (SLT) 1

15.2.5Social Learning Theory (SLT) 2

15.2.6Limitations of Social Learning Theory (SLT)

15.2.7Deindividuation

15.2.8Deindividuation 2

15.2.9Deindividuation - Diener et al (1976)

15.2.10End of Topic Test - Aggression: Social Psychology

15.2.11Institutional Aggression: Prisons

15.2.12Evaluation of Dispositional & Situational

15.2.13Influence of Computer Games

15.2.14Influence of Television

15.2.15Evaluation of Studies on Media

15.2.16Desensitisation & Disinhibition

15.2.17Cognitive Priming

15.2.18End of Topic Test - Aggression: Social Psychology

16Option 3: Forensic Psychology (A2 only)

17Option 3: Addiction (A2 only)

Jump to other topics