Notas

Research Methods

Kieya Mistry Psychology GCSE Inglês 8 páginas

Conteúdo das notas (8)

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Definitions

Key term definitions for the Research Methods topic

Hypothesis

A prediction about the outcome of a study based on the theory being tested

Independent Variable (IV)

The variable being directly manipulated by the researcher in order to examine its effects

Dependent Variable (DV)

The variable being measured in a study - the outcome of the study

Operationalisation

Making the variables in an investigation detailed and specific so they can be measured

Alternative Hypothesis

A testable statement of the difference between the conditions in an experiment. It describes how the IV will affect the DV

Null Hypothesis

A statement which states that the difference suggested in the alternative hypothesis will not happen

Non-Directional Hypothesis

When a hypothesis does not state a direction but simply says that one factor affects another or that there will be a difference between two sets of scores

Directional Hypothesis

When a hypothesis predicts the direction of the results

Individual Differences

The variation or deviations among individuals in regard to a single characteristic or number of characteristics

Order Effects

When the positioning of tasks in an experiment influences the outcome

Demand Characteristics

When participants change their behaviour based on their perceived outcomes of a study

Investigator Effects

When a researcher unintentionally gives a participant clues, changing their behaviour

Extraneous Variable

Factors other than the IV that may affect the DV

Situational Variable

Variables that are present in the environment of the investigation/study - if they vary between conditions, they can affect the results of a study

Participant Variables

Variables that are associated with the individual participants of a study that could affect the results of the study

Confounding Variable

An extraneous variable that is not controlled and thus has an effect on the outcome of a study

Target Population

The group of people being investigated in a study

Sample

A selection of the target population that is directly studied in an investigation

Sampling Method

A technique used to gather a representative group of people as a sample from the target population

Random Sampling Method

A technique used to father a random sample of participants from the target population

Stratified Sampling Method

A technique that ensures subgroups of the target population are proportionately represented in a sample

Volunteer Sampling Method

A technique that asks for participants by placing an advert for volunteers

Opportunity Sampling Method

A technique that recruits participants who are readily available at the time

Generalisability

The extent to which the results of a study represent the whole population, not just the sample used

Biased Sample

When the sample recruited is made up of a particular type of person, which may not reflect the target population

Sample Error

When a sample differs in qualities from the target population it intends to represent

Ethical Issues

Researchers must follow codes of conduct when carrying out research to protect participants from harm

Informed Consent

Agreement of participants to take part once they are fully aware of the aims, nature, and intended outcome of a study

Deception

Misleading or lying to participants

Confidentiality

Not disclosing the identity of participants

Debriefing

After an investigation, participants are given full disclosure of the study

Right To Withdraw

Participants should be aware that they have the right to withdraw from the study at any point, including for an agreed time after the study is complete

Protection Of Participants from Physical and Psychological Harm

Safeguarding participants from physical and psychological harm

Respect

Researchers have a moral duty to respect participant's individual and cultural differences. They should inform participants of the nature of the study, offer them the right to withdraw at any time, protect them from harm, take care not to intrude on their privacy, and safeguard their details.

Integrity

Psychologists are duty bound to conduct well-designed research and not claim any misleading findings

Responsibility

Psychologists must produce beneficial findings that can be used by communities and offer value to organisations

Cost-Benefit Analysis

Participants shouldn't be placed in any situation that they wouldn't ordinarily encounter. However, if the benefit of the research outweighs the cost to participants, psychologists should safeguard participants and minimise risk of harm as much as possible.

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Operationalising Variables

It is very important to operationalise the variables to be studied, otherwise the researcher will not know what they are looking for and this can reduce the validity and reliability of their data.

Operationalising Different Variables

Speed

Miles Per Hour - use a speedometer

Time taken to travel a specific distance - Stopwatch

Speed Trap

Speed Camera

Memory

Words recalled in a specific amount of time (word recall test)

Digit span test

Aggression

Survey

Carry out an observation

Questionnaire

Rating scale

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Hypotheses

Every research study has a null hypothesis and an alternative/experimental hypothesis. These are statements of predicted outcomes based on the theory being tested. If the study is an experiment, then we would have a null hypothesis and an experimental hypothesis. If the study uses a non-experimental method then we would have a null hypothesis and an alternative hypothesis.

Examples of How to Write Hypotheses in a Standardised Format

Null

There will be no significant difference in the number of digits recalled by participants who listened to classical music and participants who listened to jazz music.

Non-Directional (Two-tailed) Experimental

There will be a significant difference in the number of digits recalled by participants who listened to classical music and participants who listened to jazz music.

Directional (One-Tailed) Experimental

Participants who listened to classical music will recall significantly more digits than participants who listened to jazz music.

Non-Directional (Two-Tailed) Alternative

There will be a significant correlation between time spent revising and percentage score on a test.

Directional (One-Tailed) Alternative

There will be a significant positive correlation between time spent revising and percentage score on a test.

Null (For a Correlation Study)

There will be no significant correlation between the time spent revising and percentage score on a test.

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Experimental Design

Once the researcher has chosen the experimental method which best suits the nature of the study, they then have to choose what type of design will have.

Repeated Measures - Using the same participants in all conditions of a study

Strengths

Fewer participants needed, making it more economical

No individual differences between conditions of the study

Weaknesses

Demand characteristics are more likely as participants are more likely to guess the aim

Order effects may affect results

Independent Groups - Participants are split into groups and are tested in only one condition

Strengths

No order effects as participants only take part in one condition of the study

Weaknesses

More participants needed than repeated measures

May be individual differences between the groups

Matched Pairs - Using different participants in each condition of the study, but matching them for likeness on important characteristics for the study

Strengths

Fair comparisons can be made between the groups as they are equally matched

Weaknesses

Time consuming to match participants

Not all characteristics can be equally matched

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Extraneous Variables

Once a psychologist has decided on an experimental design, they must then consider factors which may affect the participants in these designs and in the experiment method in general. These factors are known as extraneous variables. There are two types of extraneous variable.

Situational Variables - Variables that are present in the environment of the investigation/study; if they vary between conditions, they can affect the results of a study

Examples

Noise

Light Levels

Distractions

Temperature

Participant Variables - Variables that are associated with the individual participants of a study that could affect the results of a study

Examples

Personality Type

Physical Ability

Memory Ability

Substance Tolerance

What is the difference between extraneous and confounding variables?

Extraneous variables are extra variables that are not the IV, but may still have an effect on the outcome of a study, and so must be controlled. If an extraneous is not controlled, and thus has an effect on the outcome of a study, it becomes a confounding variable - this is because it confounds (damages) the results.

Controlling Extraneous Variables

There are three ways to control extraneous variables:

Random Allocation - Might involve picking names out of a hat to ensure that everyone has an equal chance of being put in each group

Could be used to control extraneous variables such as age

Standardised Procedure - Ensuring that everyone takes part in the same situation

Could be used to control extraneous variables such as time of day

Counterbalancing - Having one half of the participants take part in Condition A first, and the other half taking part in Condition B first, then swapping them over

Used to control order effects

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Demand Characteristics & Investigator Effects

There are other types of extraneous variables that are known as demand characteristics and investigator effects.

Demand Characteristics - When a participant alters their behaviour to meet the perceived aims of the investigation

Example

For example, if participants were told a study was aimed at measuring their aggressive behaviour then they could change their behaviour to be more or less aggressive than usual

How To Control

Single Blind Technique - Information about the study is withheld from the participants

Investigator Effects - When a researcher unintentionally gives a participant clues, changing their behaviour

Example

For example, in an experiment where some participants are given a placebo and others a real drug, a researcher might treat the participants differently if they knew who was in each group

How To Control

Double Blind Technique - The aims of the study are withheld from both the participants and the researchers

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Sampling

When we carry out research, we need people to take part. These are called participants.

The target population is the group of people from whom the sample is drawn.

It is not usually possible to test everyone in the target population so therefore psychologists use sampling techniques to choose people who are representative of the population as a whole.

If your sample is representative then you can generalise the results of your study to the wider population.

Random Sampling - A sample in which every member of the target population has an equal chance of being chosen. This involves identifying everyone in the target population and then selecting the number of participants you need in a way that gives everyone in the population an equal chance of being picked.

Strengths

Everyone has an equal chance of being chosen

Helps control extraneous participant variables

Weaknesses

Most likely won't be representative

People could refuse to take part which would lead to a less representative sample

Stratified Sampling - Classifying the target population into categories and then choosing a random sample which consists of participants from each category in the same proportions as they are in the population.

Strengths

Useful if a small population of the target population may be missed out by random sampling

Ensures that the sample is completely representative

Weaknesses

Time consuming

People may still refuse to take part, leading to a sample error which can lead to invalid conclusions being drawn about the target population

Volunteer Sampling - Participants become part of a study because they volunteer in response to an advert in a newspaper or on a noticeboard

Strengths

Researcher doesn't need to do much

Possible to recruit from a target population by placing the advert in a specific location

Most ethical method as it avoids placing pressure on people to participate

Weaknesses

Less representative than random/stratified as not everyone will see the advert or want to respond

Could be a biased sample as volunteers tend to have a particular type of personality

May mean that the findings are unreliable

Opportunity Sampling - Taking the sample from people who are available at the time that the study is carried out and fit the criteria being looked for

Strengths

Quickest and simplest sampling method

Weaknesses

Can lead to a biased sample as not every member of the target population may be around at the time of the study

Findings most likely won't be generalisable to the whole target population

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Ethics

The Code of Ethics and Conduct of the British Psychological Society underpins the activities of all practising psychologists. Whenever any research is carried out it must be ethical.

Ethical Issues - Researchers follow codes of conduct when carrying out research to protect participants form harm

Informed Consent - Agreement of participants to take part once they are fully aware of the aims, nature, and intended outcome of a study

Why is it an issue? Why is it a problem for participants?

Sometimes research has to be conducted without consent (i.e. observing the everyday behaviour of people in public places)

Participants should be aware of what they are doing