Practical Investigation (Edexcel A-Level Psychology): Revision Notes

Guide to the Practical Investigation

Introduction to the practical investigation

The practical investigation is a compulsory component of A-Level Criminological Psychology. You must design and conduct an investigation using a questionnaire, interview or case study related to topics covered in criminological psychology. The investigation allows you to apply research methodology knowledge to a real psychological study.

Before beginning your practical investigation, review relevant methodology sections covering questionnaires, interviews and case studies. Familiarity with key terms and concepts is essential for successful completion.

Conducting criminological psychology research

Following research guidelines is essential for any psychological investigation. The planning stage ensures your investigation adheres to ethical and methodological standards required of psychologists.

This guide presents an example investigation examining whether people recall events more accurately from video footage compared to witnessing real-life events. While you can gather qualitative or quantitative data, you must be able to convert data into quantitative form for analysis. This example gathers quantitative data, though you may choose qualitative data that can be quantified using content analysis.

Research background

Numerous laboratory and field experiments have investigated recall accuracy. Laboratory experiments examining recall have been criticised for lacking validity because participants tend to be passive observers of staged footage, emotionally disengaged from events and less concerned with recall quality. In contrast, field experiments provide findings with greater ecological validity, though often at the expense of adequate control. Research evidence suggests participants demonstrate more accurate recall under laboratory conditions compared to naturalistic settings.

Laboratory experiments have generated controversy regarding whether they over-inflate memory accuracy. The practical investigation will compare recall of video footage and a live staged event. Participants' memory of the event (live or video) will be recorded using a questionnaire the following day. The questionnaire contains closed questions (yes/no responses) concerning event details; the greater the number of correct answers, the more accurate the recall.

Research design

Aim

To investigate whether recall is more accurate when recalling a real-life event or video footage of the same event.

Variables

Identifying variables clearly ensures your procedure and data collection methods are objective and reliable. Information about what participants remember can be gathered via interview or questionnaire techniques. Interviews require transcription and quantification using techniques such as content analysis for accuracy or amount remembered. This can be done by carefully reading transcripts and tallying the number of details or accuracy of details remembered.

In this investigation, the context of the witnessed event affects recall accuracy.

Hypotheses

Experimental hypothesis

Participants will give more correct answers on a recall questionnaire after watching video footage of a staged event than participants watching a live staged event.

The hypothesis is directional because substantial research indicates the likely direction of difference to be found: that memory of video footage is more accurate than live events.

Null hypothesis

There will be no difference in the accuracy of recall of video footage or live staged event.

Planning the practical investigation

Careful consideration must be given to the staged event's nature and questionnaire construction. The staged event should be practical and ethical, allowing you to video-record and produce as a live event with actors. Setting up a live event requires careful planning as participants cannot be distressed and it should be fairly naturalistic, allowing all participants to see what is occurring.

Consider how the questionnaire will be constructed, as different question types produce different data types allowing different analysis levels. Remember that you can gather qualitative and quantitative data, but analysis must be quantitative, meaning data must be put into tables and graphs and subjected to statistical testing.

Types of interview questions

Interview questions can take various forms:

1. Did you see a teacher in the classroom? Yes/No
2. Was there a pen on the desk? Yes/No
3. Did you see a student enter the classroom? Yes/No
4. Did the student say anything? Yes/No
5. Did the student take anything from the classroom? Yes/No

These closed-ended questions allow for straightforward quantification and comparison between conditions.

Experimental design

When selecting an experimental design, consider the strengths and weaknesses of each design for your particular study aim. This investigation tests whether a live or video footage of an event affects recall, so an independent groups design may be more appropriate than a repeated measures design because participants will not view the staged event twice or have different events set up. This avoids demand characteristics and order effects, where participants alter their behaviour because they guess the research aim, become more or less accurate through practise or fatigue at remembering and recalling events they have witnessed, or different event characteristics affecting recall.

If you choose a repeated measures design for your experiment, consider using counterbalancing or randomisation of conditions. You must also consider using different types of staged events or leaving a time gap between watching video footage and witnessing the live event.

Sampling

You need to gather a sample of participants for your study. If you use a repeated measures design, approximately ten participants will provide enough data. If you use an independent groups design, you need to double your sample size.

Because this investigation's aim concerns anyone who is a potential witness to an event, the target population is the general population. Gathering a representative sample of the general population can be problematic and would require access to all members of the public, such as an electoral roll, from which to select participants. Different witness factors known to affect recall accuracy, such as age and experience, make producing a truly representative sample using random or stratified sampling methods difficult.

For this investigation, 20 participants will be selected by opportunity sample from students attending a geography club at school. Participants will be asked by the geography teacher if they would like to take part in a psychology experiment, and their names will be forwarded to the researcher so formal consent can be gained.

Controls

When planning the experiment, remember that validity and reliability of findings can be limited by decisions made at planning, particularly whether other factors may influence the outcome. You need to consider any extraneous variables that may occur and how they may affect results if they were to occur. To counteract some extraneous variables, it may be possible to control or eliminate them.

Participant variables

Participants will be tested in one of two groups; each geography club member who agrees to participate will be randomly assigned to either the live or video footage condition. The live event group will attend the first half of lunchtime geography club in the geography classroom and the video footage group will attend the second half of the club.

Participants will be asked if they have any visual impairment that might affect their ability, and asked to wear glasses if they normally do so.

Situational variables

Situational variables are any environmental factors that might potentially affect study results. This is particularly important if factors affect one experimental condition but not the other. In any experiment, controlling the surroundings and any potential disturbance from noise or distraction is important.

Developing a procedure

The procedure should clearly outline what you are planning to do and at what stage, in what order you are going to do each step. Areas to consider include:

• The standardised instructions that you will give to participants
• The timing and location of the experiment
• Whether you will test individuals or groups of participants
• Where and when you are going to conduct the questionnaire
• How participants are going to be debriefed

Ethical considerations

Consideration must be given to the event you ask individuals to recall. It cannot be distressing or embarrassing in any way, and does not need to contain acts of aggression or violence to establish whether recall is accurate.

Consent form

The aim of the study is to investigate whether people recall more about video footage than witnessing live events. You will be asked to take part in a memory experiment in your geography club at lunchtime. The club members will be divided into two groups (video or live event) and required to attend the first or second half of the club. You will be informed which half of the club to attend. During the experiment you will witness an event and then you will answer a questionnaire about what you saw in tutorial the following day. The purpose of the study is to compare real life and simulated laboratory experiments to see which is a better measure of memory.

You will not be named or identified in the research and the event that you witness will not cause any distress or embarrassment. You will be asked to not discuss any of the events during the experiment with family, friends or other students and staff until after you have completed the questionnaire and spoken to the researchers involved. You can decline to take part in the experiment at any point and without consequence. The data gathered from your responses will be destroyed at the end of the year.

I can be contacted if you have any further questions and my supervising teacher will also be available throughout the experiment and afterwards.

I have understood these instructions and the implications of taking part in this experiment.

• Signature of participant: ______ Date: ______
• Signature of researcher: ______ Date: ______
• Signature of supervising teacher: ______ Date: ______

Design decisions summary

Analysing results

Data gathered from the questionnaire must be collated and a comparison between the two experimental conditions compared. This establishes whether there is a difference in recall accuracy between the live and video footage staged events. Each participant will receive a score for recall accuracy, so the data is at least ordinal level. This type of data should be presented in a histogram or bar chart of the modal scores and analysed using a Mann-Whitney U test of significance.

Quantitative analysis

Table 6.5: Raw data from the experiment

Participant	Accuracy score of recall of live event (out of 20)	Participant	Accuracy score of recall of video footage (out of 20)
1	6	11	13
2	9	12	12
3	13	13	14
4	11	14	15
5	15	15	16
6	9	16	14
7	7	17	12
8	14	18	11
9	8	19	14
10	-	20	16

Table 6.6: Results showing the mode and range of correct responses given to questions concerning a live and staged event

	Live event	Video footage
Mode of correct responses	9	14
Range of correct responses	9	5

Inferential test of significance

To determine whether the practical investigation findings are statistically significant, or just due to chance, you will have to run what is known as an inferential test. For your practical investigation you will need to gather quantitative data and conduct a chi-squared, Mann-Whitney U or Wilcoxon non-parametric test of difference.

The investigation here produced frequencies, so is at least ordinal level and an independent groups design was used to look for a difference between the two conditions. This means that a Mann-Whitney U test will be used to establish whether there is a difference between the accuracy of recall of a live staged event and video footage. Any difference found using the test will indicate that the context of the witnessed event has an impact on the accuracy of recall.

Drawing conclusions

The conclusions you draw from the analysis should be logical, based on the findings you have presented. Conclusions can be discussed briefly to avoid repeating findings in detail. Returning the reader back to the original hypothesis and research aims and then discussing if the results support or disprove the hypothesis is a systematic way of referring back to the original purpose of the study.

Understanding significance levels

Evaluating the practical investigation

When evaluating your practical, it is necessary to consider both its strengths and weaknesses. As with evaluation of any research study, a range of possible considerations can be made, including validity, reliability, generalisability, application, scientific value and credibility of the research. You should also consider possible improvements that could have been made to the practical investigation if it was to be replicated in the future.

General questions to ask include:

• Is the study ethical?
• Can you generalise the findings to others/different cultures/different eras?
• Is the study reliable?
• Is the study carried out in a natural or artificial environment?
• Is the task ordinary?
• Are the findings useful in real life?
• Is the research valid?
• Is there any conflicting evidence from other research?

Is the study valid and reliable?

A number of issues need to be addressed to ensure a study is valid. One of these is how you went about operationalising memory recall. In this practical investigation, accuracy of recall was measured using a questionnaire based on the events that were staged. We know that the questions are an accurate reflection of the event, because they were based on the video footage, so can be verified.

Can we generalise the findings?

Generalisability is the aim of any scientific research; it should be possible to widely apply findings to other people in other places and times. We know that witnesses vary considerably and it is unlikely that a small sample of geography club attendees represent all potential witnesses. This means that we cannot generalise the findings to everyone and limits the usefulness of such research, particularly if it was to be used to inform police practice. It also means that the research lacks scientific credibility because it only applies to a specific group of people.

Remember!