Methods (Edexcel A-Level Psychology): Revision Notes
Criminological Psychology Research
Introduction to criminological psychology research
When conducting research in criminological psychology, researchers must apply the same fundamental principles that guide all psychological research. However, there are additional ethical considerations when studying vulnerable populations, such as offenders or witnesses who have experienced potentially traumatic events.
Research design, sample selection and analysis must prioritise reliability (consistency of findings), validity (measuring what is intended), objectivity (remaining value-free), and credibility (trustworthiness of the research). These standards ensure psychology operates as a rigorous science.
When working with vulnerable populations in criminological research, ethical considerations extend beyond standard research guidelines. Researchers must be particularly sensitive to the potential psychological impact on participants who may have experienced trauma or criminal victimisation.
Research methods
Criminological psychology research primarily employs three methodological approaches: laboratory experiments, field experiments, and case studies. Each method offers distinct advantages and limitations when investigating questions about eyewitness testimony, offender behaviour, and crime-related phenomena.
Laboratory experiments
Laboratory experiments are conducted in artificial environments constructed by the researcher in controlled settings. The researcher manipulates the independent variable (IV) and measures the dependent variable (DV) to establish cause-and-effect relationships.
In criminological psychology, the IV might involve factors such as weapon presence or the type of leading questions used, whilst the DV typically measures testimony accuracy or witness recall. These studies are often conducted by showing participants film clips in controlled laboratory settings.
Testing actual witnesses is prohibited as it could compromise their evidence, so researchers must use simulated scenarios instead. This ethical constraint is fundamental to criminological psychology research.
Example: Loftus Eyewitness Testimony Studies
Elizabeth Loftus and colleagues examined eyewitness testimony through the following procedure:
- Gathering participants to take part in a study
- Showing them a film or photographs of an incident or a potential suspect
- Asking them to recall what they saw as a test of memory
The study may vary participant characteristics (e.g., age or gender) or manipulate what participants witness (different films, offences or suspects). Researchers may also investigate the influence of post-event information by delaying recall or altering how information is presented.
Evaluation of laboratory experiments
Strengths:
- Laboratory experiments use standardised procedures, making them easier to replicate. This allows researchers to verify findings and establish consistent results.
- Precise control of extraneous and independent variables prevents other factors from affecting the findings. For example, researchers can ensure all participants view the same film clip or can control which age group is tested.
- These controls enable researchers to establish cause-and-effect relationships with greater certainty about which factors influence eyewitness accuracy. This would not be possible in real-life witnessed events where multiple variables affect the witness.
Weaknesses:
- The artificial nature of laboratory settings may produce unnatural behaviour that does not reflect real life, resulting in low ecological validity. In Loftus' studies from the 1970s, participants watched a film clip of a car accident and were then questioned about it. Participants expected to see something on the clip and paid more attention than an individual might in the street before an unexpected accident occurs. This means findings cannot be generalised to real-life settings as the results from the laboratory may not reflect what would occur if the research involved a real accident.
- Validity is also reduced because participants are less likely to experience stress by watching a film clip than witnessing a real accident. They will not be interviewed by police and are unlikely to discuss their experience with others, thereby minimising additional influencing variables.
- Laboratory experiments often involve showing participants clips of crimes that would be unethical for them to experience in real life. Watching a film clip of a car accident is less distressing than witnessing an actual one, but may still cause upset if a participant has previous experience of a similar accident. Participants are given the right to withdraw in such cases.
Field experiments
Field experiments share the basic structure of laboratory experiments (manipulating an IV and measuring a DV) but are conducted in more natural settings. The experiment itself remains artificially constructed but takes place in an environment where the phenomenon being studied would naturally occur.
A researcher conducting a field experiment attempts to realistically recreate an environment in which a particular situation is likely to happen. For example, a staged car accident in a street. Field experiments follow similar steps to laboratory experiments, but at step 2 participants witness a real crime or a real suspect rather than viewing a film.
The 2009 Valentine and Mesout experiment involving real visitors to the London Dungeon exemplifies this approach. It occurred within the dungeon's natural setting, but visitors would not normally be asked to complete questionnaires about their experience or identify individuals they encountered within the dungeons.
Evaluation of field experiments
Strengths:
- Behaviour displayed by participants in field experiments more accurately reflects real life as participants essentially experience the conditions of an actual witness. They are more likely to experience stress or anxiety at what they have seen and discuss it with other witnesses, and are less likely to anticipate recalling a situation than in a laboratory experiment. This increases the ecological validity of the study and allows findings to be considered representative of real situations.
- Participants may be unaware they are participating in a psychological study conducted in the field, which minimises demand characteristics. This increases the likelihood that responses or reactions within the study are genuine and indicative of real life, allowing findings from such studies to be relied upon more confidently than if there were concerns about response bias from participants.
- Field experiments in criminological psychology possess greater validity as they are less likely to experience the problems outlined above because participants essentially experience what a real witness would. The exception is that they are unlikely to be interviewed by police.
- Case studies investigate real situations, so the information obtained reflects actual situations, making it a valid research method.
Weaknesses:
- Field experiments are more difficult to control than laboratory experiments because many situational variables may occur in a natural setting, such as distractions from other witnesses at an event. This makes it unlikely that field experiments can be replicated exactly as the extraneous variables may affect the findings, leading to inconsistent results and lower reliability.
- In case studies, controlling all participant and situational variables is very difficult. Finding two individuals who have experienced the exact same situation for comparison is challenging. Consequently, case studies also have low reliability.
Within field experiments, protecting participants as they experience potentially real-life incidents is crucial. They are more likely to experience distress than in a laboratory experiment. Researchers must carefully weigh the nature of the incident they intend to stage to ensure it does not create excessive distress, maintaining ethical principles.
Case studies
Case studies are in-depth investigations of a single person, group or event. In criminological psychology, a case study typically involves conducting interviews with an individual, such as an offender. Yuille and Cutshall's (1986) weapon focus study was a case study in which they focused on witnesses to a specific crime.
Case studies are particularly useful in understanding why a particular person committed an offence, from which a clinician may develop a clinical formulation to explore the factors relevant to their offending. Further clinical evaluations of case studies may determine if treatment of an offender, or group of offenders, is working.
Case studies employ IVs and DVs as with other methodologies. The only difference is that at step 1 there would only be one or a small number of people participating. The information gathered at step 3 is likely to be in much more detail, typically of a qualitative nature.
Evaluation of case studies
Strengths:
- Case studies provide information that is rich in detail. Information about an offender's response to treatment captures data from a variety of sources: asking the offender during an interview, using self-report questionnaires, observations by prison staff and often a review of prison documents related to the individual.
- A case study can therefore provide greater insight into a real situation than can be gained by other methods, identifying motives, beliefs and decisions of the offender and not just their behaviour.
- The information obtained has greater reliability, as it has come from the offender themselves, providing depth to the data that can be used to draw conclusions about treatment effectiveness.
Weaknesses:
- However, as case studies only involve a small number of people, findings cannot be generalised to the wider population. The reason why an offender decided to attack an ex-partner, for example, may not be representative of the motives of all stalkers. Their beliefs and subsequent case formulation is very specific to them, and it cannot be assumed that the same applies to all who commit the same offence.
- Similarly, there may be specific participant variables that influence whether an offender will respond positively to an anger management programme, not just that they committed an offence whilst angry. This is why caution should be applied when assuming that all offenders who commit offences whilst angry will have the same treatment response.
- A full understanding of the decisions surrounding the offence is necessary to consider if the treatment may also have an effect on someone with a similar formulation.
Sampling methods
Sampling methods are an important part of the research process when undertaking research in criminological psychology. Often students are selected by opportunity or randomly from a pool of research candidates for laboratory research. This poses an issue with the generalisability of the research findings to other populations as students represent a rather homogeneous group of individuals who do not have the variation of possible characteristics that typical witnesses might have.
Generalisability Challenge:
Students represent a homogeneous group that lacks the diversity of characteristics found in actual witness populations. This significantly limits the ability to generalise research findings from student samples to real-world eyewitness situations.
In field experiments, such as Valentine and Mesout (2009), participants are selected by opportunity as they are available at the time of the study being conducted.
Research issues
Reliability
Reliability refers to the consistency of research findings. A research design with many experimental controls results in high reliability, allowing for the research to be replicated.
Laboratory experiments have high reliability as the controlled nature of the design prevents other factors from affecting what is being studied. This can include controlling participant and situational variables. For example, the same film clip may be shown or a researcher can ensure only a specific age group is being researched if this is what they wanted. These high controls allow for the research to be replicated many times and provide consistency.
Field experiments are more difficult to control as there is more chance of situational variables occurring in a natural setting. This makes it difficult to replicate the exact same conditions in future research due to these extraneous variables. As a result, findings may be inconsistent and this lowers the reliability of the findings.
Similarly, in case studies, it can be very difficult to control all the participant and situational variables. It is difficult to find two identical people who have experienced the exact same situation to compare findings. As such, case studies also have low reliability.
Validity
Validity refers to how well a study measures what it is supposed to measure.
Concerns have been raised about the validity of findings from laboratory experiments in relation to eyewitness testimony. Participants may be more or less cautious about their testimony compared to a real witness as it is known to be an experiment. Wagstaff et al. (2003) found little evidence for factors such as weapon focus, age or level of violence having any effect on witness testimony among real witnesses, despite laboratory (and field) experiments suggesting these to be influential variables.
Similarly, Yuille and Cutshall's (1986) study showed limited effect of leading questions on real witnesses to a robbery, despite this having been demonstrated within a laboratory setting. Ihlebaek et al. (2003) compared memory for a live staged robbery (field setting) and film footage of the same robbery (laboratory setting). They found those who watched the film footage recalled more details with greater accuracy than the staged robbery. The number of errors in recall was the same for both conditions.
Laboratory Experiments and Validity:
Laboratory experiments may overestimate witness recall compared to real-world situations. This is likely due to the level of attention participants pay to film clips compared to unexpected real-life incidents. Therefore, reliance on findings of laboratory experiments, as valid indications of the accuracy of eyewitness testimony, should be viewed with caution.
Field experiments in criminological psychology are more valid as they are less likely to suffer from these problems because essentially the participants are experiencing what a real witness would experience. The only exception is they are unlikely to be interviewed by the police.
As case studies investigate real situations, the information obtained is that of a real situation. It is therefore a valid research method.
Demand characteristics can also reduce the validity of an artificial experiment such as a laboratory experiment. As people may alter their behaviour in response to the situation, this does not reflect a true-life situation and therefore lowers the validity. For example, a participant may guess that the aim of the study is to test how stress affects witness recall, so they may recall less to meet the expectations of the researcher.
Demand characteristics may also occur in case studies. The person being interviewed may have an understanding of the aims of the interview and provide information that would support the research. For example, an offender may guess that a researcher is looking to investigate if completion of the anger management programme has a positive effect on their ability to manage trigger situations for anger. They may therefore state that they have not experienced high levels of anger in such situations.
Case studies also have the added difficulty of researcher bias as the information being gathered is qualitative data and so requires subjective analysis; in addition to this there is a high level of researcher involvement, which can potentially reduce objectivity. This can also lower the validity.
Objectivity
Objectivity requires researchers to remain totally value free when investigating a topic. Whilst they might have a hypothesis about the factors that may influence the accuracy of eyewitnesses, they should try to remain totally unbiased in their investigations and simply gather facts that may prove or disprove their hypothesis. This can be achieved in laboratory and field experiments, which typically gather quantitative data that requires no interpretation by the researcher and minimises the potential for bias.
Undertaking a case study of an offender can involve the researcher spending considerable time with the individual, and time speaking about them with others, for example, prison staff. Over time, it is possible that the researcher feels that they know the person very well, and that they have a full understanding of the reasons for their offending.
Risk of Researcher Bias in Case Studies:
The researcher may become invested in the aims of the research, for example to show that an individual has succeeded in reducing anger via treatment, and seek only evidence that supports this finding or may place greater interpretative emphasis on evidence that supports this aim.
Achieving objectivity makes the research more scientific. Quantitative data requires little interpretation and therefore is more objective. Such data is obtained in field and laboratory experiments. Case studies however, due to the depth of detail, gather qualitative data. Analysis of such data can lead to subjectivity and researcher bias.
Credibility
Credibility refers to how seriously research is taken by psychologists. They want the research they undertake to be considered seriously and aim to contribute to the field of psychological research and influence its future. For this to happen, the research should have credibility. All three research methods can achieve credibility by striving to undertake research that is reliable, valid and objective.
Research within the field of criminal psychology needs to be credible as the application of the research findings is important for the courts and police. Findings may influence legal decisions and police procedures, making credibility absolutely essential.
Data analysis
Once data has been gathered, it is subject to analysis to determine if the data is meaningful to the research question. The analysis may look at determining relationships between variables or whether the findings from research are statistically significant.
In experiments such as those undertaken by Loftus and Palmer (1974), the analysis seeks to explore if there is a relationship between leading questions and the accuracy of recall.
Ethics
The British Psychological Society (BPS) has produced guidance for those wanting to undertake psychological research or engage in clinical practice such as psychological formulations or treatment interventions. This is known as the Code of Ethics and Conduct (BPS, 2009). It provides guidance about the general conduct of a psychologist to ensure any psychological roles they undertake fulfil a minimum standard, to protect all involved.
Psychologists who practise in the field of psychology (known as practitioner psychologists, for example, 'Forensic' Psychologists and others with protected titles: 'Clinical' Psychologists, 'Health' Psychologists, etc.) also have to follow additional guidance from their legal governing body: the Health and Care Professions Council (HCPC).
Consequences of Ethical Violations:
Practitioner psychologists who do not follow the guidelines can be 'struck off' from the Council and are no longer allowed to practise as psychologists. Psychologists registered with the BPS can also be removed from the Register if they act in an unethical manner.
The ethical guidance must therefore be taken very seriously. As many practitioner psychologists are often registered with both the BPS and the HCPC, it is best practice to follow both guidelines when conducting psychological research.
Ethical guidelines
Criminological studies should follow strict ethical guidelines. These include the following principles.
Protection of the participant
Eyewitnesses who see real-life crimes can become distressed and it would be unethical to expose someone to this for an experiment. Watching a crime in a film clip would be less distressing than seeing it in reality. However, it is possible that watching a film clip can remind them of any past similar experience that may have occurred, for example, if someone had been victim to a similar crime.
Participants should be allowed to withdraw from the experiment in this case or in any other situations in which they start to feel distressed. Laboratory experiments have greater protection for participants than field experiments or case studies, as the event is artificial. When conducting research with real situations, careful consideration is required to minimise any possible distress.
Deception and consent
Deception may be used to minimise demand characteristics. This can increase the validity of the findings. As such, a researcher may not tell participants the true aim of the study. If deception is used, there is a lack of informed consent. As the participants do not know what the study is about, they cannot be fully aware of the nature and consequences of the research.
Laboratory experiments and case studies are more likely to require consent than field experiments as the person will know they are involved in an experiment or study. Field experiments may have less need for consent if it stages an incident that someone is likely to experience in their everyday lives. This possibility is more limited in criminological psychology.
Deception can still be an issue for all three methodologies. For example, in field studies, participants may not be fully aware that they are in a staged situation in which they are about to witness a specific crime. If deception and consent are issues, guidance suggests the need to debrief participants once the research is complete.
Right to withdraw
This may be less of an issue in field experiments if, as with consent, they are likely to experience the situation in their everyday lives. However, laboratory experiments and case studies should always offer the right to withdraw, to comply with guidance regarding protection of participants. As with deception, participants should be debriefed if there are issues relating to their right to withdraw.
In addition to ethical guidance, the BPS has also issued documentation to support the clinical practice of psychologists, which forms guidelines to be adhered to when undertaking certain tasks such as psychological formulations or treatment interventions. These guidelines not only support the ethical principles outlined above, but specifically in relation to such tasks, they provide a framework of best practice to ensure the maintenance of high-quality psychological input.
Key Points to Remember:
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Laboratory experiments offer high control and reliability but low ecological validity. They use artificial settings where participants watch films rather than witnessing real events.
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Field experiments provide higher ecological validity as participants experience realistic situations, but they are more difficult to control and replicate, resulting in lower reliability.
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Case studies yield rich, detailed qualitative data about individual offenders or specific incidents, but findings cannot be generalised to wider populations.
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Reliability, validity, objectivity and credibility are the four key issues to consider when evaluating criminological psychology research. Each research method has different strengths and weaknesses across these dimensions.
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Ethical guidelines from the BPS must be followed, particularly regarding protection of participants, informed consent, deception, and the right to withdraw. Criminological research requires additional ethical considerations due to potentially distressing content.