Psychology - Experiments, Ethics, Sampling, Aims and Hypotheses

RESEARCH METHODS

a range of ways to carry out scientific investigations

RELIABILITY

This refers to how consistent a study or measuring device is. A measurement is said to be reliable or consistent if it can produce similar results if used again in similar circumstances. As a psychologist you have to ask yourself ‘Did every participant experience my study in the same way?’ If they can say yes to that question, they have high reliability.

VALIDITY

As a psychologist you have to ask yourself ‘Is my study testing what I want it to test?’ Having high validity can also be thought of as collecting data that truly reflects how a participant would behave. A psychologist must ensure that their participants aren’t effected by anything else, other than what they are testing. They may ask ‘Are my participants lying? Are they changing their behaviour due to my presence?’ If the answer is no to these questions, they have high validity

External Validity

Whether the findings will generalise to other populations, locations, contexts and times and still hold true.

External Validity: Ecological validity AKA Mundane realism

Refers to the extent to which the findings of a research study are able to be generalised to real-life settings.

External Validity: Population Validity

How representative the sample used is to other populations.

External Validity: Historical/Temporal Validity

Will the findings still be valid as society changes over the years e.g. will a study conducted about female behaviour in 1965, generalise to females today?

Internal Validity

Within your measure, the IV is the only variable effecting the DV.

Internal Validity: Face Validity

The degree to which a procedure, especially a psychological test or assessment, appears effective in terms of its stated aims.

Internal Validity: Concurrent Validity

Whether a measure produces similar results for a participant as another test that claims to measure the same thing e.g. a participant completes a brand-new test for autism and gained very similar results in a previously well-established test of autism.

Experiments

Experiments are the only research method that manipulates variables. We manipulate one variable (IV) and see if it could have an effect on another variable (DV) (cause and effect)

Experiment using a Self-Report

Experiments can be used alongside other research methods; . For example a self-report can be used as your dependent variable. A self-report is when you ask people how they think and behave. This can be done through interviews questionnaires. Psychologists then make conclusions about how people think and behave from their answers.

example of experiment using a self report:

I want to know whether the temperature of a room has an effect on people’s ability to concentrate.

For example: Ask people to rate from 1-10 how hard they find it to concentrate (using a questionnaire as the dependent variable) in a warm or a cold room (this would the independent variable, as it is the thing that changes).

Experiment using an Observation

Experiments can also use an observation as the dependent variable. An observation is where you watch how people behave. Then psychologists make conclusions based only on what you can observe

example of experiment using an observation:

I want to know whether the temperature of a room affects people’s ability to concentrate.

For example: Go to a library and observe how many books they read/how distracted they get/how long they stay for, when the temperature is cold compared to warm

ethics:

a moral code that psychologists follow in order to protect both the participants and researchers.

explanation of ethics:

Psychologists are obliged to consider the psychological well-being, health, values and dignity of their participants. If they do not do this properly, their research is described as unethical. This would put psychology is an unfavourable light and would hinder the ability to replicate the research. Researchers should strive to ensure that their research is as ethical as possible.

how is ethics guided?

Guidelines are issued by the British Psychological Society (BPS). These clarify what is ethically acceptable in psychological research.

mnemonic for ethics:

Can Do, Can’t Do With Participants In Psychology

CAN:

Confidentiality – Participants results and personal information should be kept safely and not released to anyone outside of the study.

DO:

Deception – Participants should not be deliberately lied to about the aim of the study and procedure. If participants are not told the true aim of the study, every step should be taken to ensure that there are no harmful effects to the participant. For example, a thorough debrief, counselling sessions, ethics committee there at all times to stop experiment if they feel that it is harming participants etc.

CANT:

Competence – having the knowledge and skills, and attitudes, values, and judgment needed to perform the work of a psychologist

DO:

Debrief – Full explanation of the aims and potential consequences of a study are given to the participants straight after the study has finished. The debrief is extremely important because it fulfills many other ethics in the process. For example, in the debrief will advise participants that their data is to be kept confidential. They will also be given another opportunity to withdraw their data after the event even if they consented to the survey and were aware of the aim at the start. The psychologist will ensure that no one has been harmed and if so, will be offered additional support.

WITH:

Withdrawal – Participants should be made aware that they can leave at anytime and can remove their data from the study at anytime.

PARTICIPANTS:

Protection from psychological and physical harm – avoid harming participants mentally/physically or psychologically – Participants should leave in the same positive state when they finish the study, as when they arrived.

IN:

Informed consent – Having sufficient knowledge about the study to be able to make an informed decision to participate. After being informed about the study, participants must agree to take part before the study.

PSYCHOLOGY:

Privacy – Ensuring that participants are aware that they do not have to answer anything that may make them feel uncomfortable, thus protecting their privacy. In addition, you cannot observe people in private environments i.e. peeping through someones window, without their knowledge.

Target Population

The set of people researchers want to find out about

Sample

A small set of people taken from the target population

Representative

How well a sample reflects the target population

Sampling Bias

Samples can be biased; they do not reflect the target population and this affects the conclusions we can draw from these samples.

Androcentric

a sample that contains a large proportion of males.

Gynocentric

a sample that contains a large proportion of females.

Cultural bias

a sample that is too focused on one culture, isn’t representative of all cultures

Ethnocentric

This is when research is generalised (trying to apply) to other cultures without considering how cultures are different

Population validity

Being able to generalise results from our sample to the target population and still hold true.

Sampling Methods/Techniques:

1. opportunity sampling

2. volunteer/self selected sampling

3. random sampling

4. stratified sampling

5. systematic sampling

Opportunity Sampling:

Anyone who is available at the time of your research e.g. I want to research into the eating habits of men. I walk around the college and survey the first 20 males I find

Strengths:

1. Quick and easy to carry out. This is because it relies on people who are around at the time and is therefore more time efficient than other sampling methods.

2. Can help to collect participants with similar characteristics as people who share characteristics tend to segregate in the same areas. This is a strength because it can help to generalise (apply) findings to a target population.

Weaknesses:

1. May not always be representative, as the kinds of people available are likely to be limited, and therefore similar, so although they may apply to the target population, it may be difficult to generalise to the wider population.

2. Increased chance of researcher bias as they may only approach people who they feel will give them the results they want.

Volunteer/Self-selected Sampling:

Participants choose themselves to take part in the study. They could be recruited through; using online email surveys, signing up or applying to take part, or responding to adverts or posters.

Strengths:

1. This method is relatively easy as the participants come to you. This is a strength because they are likely to remain committed to the study and less likely to drop out, preventing the chance of a small, unrepresentative sample.

2. Can reach a wider variety of participants through emails, posters, advertisements compared to opportunity sample, which will only cover a small area.

Weaknesses:

1. This method may have an issue with sample bias. This is because certain individuals tend to volunteer for studies and therefore may not be representative of all people. For example if I wanted to investigate the effect of exercise on mood, people who are good at exercise are likely to come forward. Therefore, the results would not be valid when generalising to people who do not exercise.

2. Sometimes there will not be enough interest in your studies advert which can lead to a small sample. This is a weakness as it could lead to an unrepresentative sample.

Random sampling:

Every member of the population has a fair and equal chance of taking part. e.g. Everybody puts their name into a hat, draw first 25 names out of the hat for the sample.

Strengths:

1. This is the most representative sampling technique to use as all types of people in the population have an equal chance of being chosen. If you have a wide variety of differences in your sample, it is more likely to be generalisable to the wider population (i.e. other people outside of the target population)

2. It can provide an unbiased sample as the researcher has no part in deciding who is selected, therefore reduces the chance of researcher bias, increasing validity.

Weaknesses:

1. Time consuming and hard to ensure that everyone is equally chosen e.g. due to lack of information or access.

2. Sample could still be biased e.g. if only girls happen to be selected, this would create a gynocentric sample that lacks generalisability.

3. It can be impractical (or not possible) to use a completely random technique, e.g. the target group may be too large to assign numbers to. Therefore there tends to be some choice from the researcher in terms of narrowing the sample down.

Stratified Sampling:

Here the sampler divides or ‘stratifies’ the target group into sections, each showing a key characteristic which should be present in the final sample. Then each of those sections is sampled individually. All types of members of the population are represented by deliberately selecting participants from all strata e.g. elderly, middle-age, young adults, teenagers, children. The sample thus created should contain members from each key characteristic in a proportion representative of the target population. For example, if there were strata’s of the class system – upper, middle and lower class, there would need to be a much larger sample for the lower class sample compared to the upper class, as there are a lot more people in the lower class population compared to upper class.

Strengths:

1. This sample is likely to be more generalisable and this is because it tries to gain a wide variety of people. The more diverse a sample is, the more generalisable it is to the wider population.

2. Assuming the list order has been randomised, this method offers an unbiased chance of gaining a representative sample

Weakness:

1. Difficult, as all the subgroups in the population must be known and accessible, this is often difficult to achieve.

2. It takes more time and resources to plan.

Systematic sampling:

A systematic method is chosen for selecting from a target group, e.g. every fourth person in a list could be used in the sample. It differs from random sampling in that it does not give an equal chance of selection to each individual in the target group.

Strengths:

1. It can provide an unbiased sample as the researcher has no part in deciding who is selected, therefore reduces the chance of researcher bias, increasing validity.

2. Higher chance of gaining a representative sample as it is likely to gain a varied sample from the systematic formula. It would be quite unlucky to only pick females for example.

Weaknesses:

1. If the list has been assembled in any other way it could unintentionally create a biased sample. For example if every fourth person in the list was male, you would have only males in your sample.