TYPES OF EXPERIMENT:

LABORATORY, FIELD EXPERIMENTS, NATURAL AND QUASI-EXPERIMENTS

 Laboratory, field, natural and quasi-experiments all investigate relationships between variables by comparing groups of scores. Still, there are also significant differences between different types of experiments, such as how respected they are.

• Laboratory experiments fulfil all the criteria of an actual experiment but have problems with external validity.

• Field experiments are true but don't occur in a controlled environment or have random allocation of participants.

• Natural and quasi-experiments cannot prove or disprove causation with the same confidence as a lab experiment.

• Natural experiments don't manipulate the IV; they observe changes in a naturally occurring IV.

• Quasi-experiments don't randomly allocate participants to conditions.

FIELD EXPERIMENTS

As the name suggests, a field study is an experiment performed in the real world. Unlike case studies and observational studies, a field experiment still follows all of the steps of the scientific process; basically, the same rules apply: an independent variable is manipulated to see how it affects a dependent variable. 
Students often become confused about the distinction between lab and field experiments, mistakenly believing that lab experiments must be conducted in a laboratory setting and field experiments must occur outside in real-life settings. However, this isn't entirely accurate. Lab experiments can be conducted outdoors or in real-world environments, while field experiments can be conducted in laboratory settings.

The key difference lies in the behaviour being studied. In lab experiments, participants know they are part of an experiment, creating an artificial setting. On the other hand, in field experiments, participants are unaware that they are being observed and are simply going about their normal activities.

To illustrate the difference between lab and field experiments using the Solomon Asch study on conformity and the weapon focus study by Johnson and Scott (1976), we can contrast the settings and participant awareness in each study.

In the Solomon Asch study on conformity, participants were explicitly informed that they were taking part in a perception study. This awareness of being part of an experiment could have influenced their behaviour as they were asked to identify the correct line lengths. The fact that participants knew they were in an experiment might have made them more conscious of how they were expected to behave, potentially leading to demand characteristics and other biases that could affect the study's validity. Therefore, the Solomon Asch study can be classified as a lab experiment due to the controlled setting and participants' awareness of being part of an experiment.

On the other hand, in the weapon focus study by Johnson and Scott (1976), participants were unaware that they were part of an experiment during the critical moment. Although they knew they were involved in a study, the experiment occurred unexpectedly while they believed they were waiting for the experiment to start. This lack of awareness minimized the likelihood of demand characteristics or other biases influencing their behaviour. Thus, the weapon focus study can be considered a field study as the behaviour under investigation occurred naturally without participants' conscious awareness of being observed.

• Settings could include the workplace, school, the street, laboratory, etc. 

• Participants don’t know they are in an experiment.

• Social scientists and psychologists often use field experiments to perform blind studies, where the participants are unaware they are under scrutiny. A good example of this is the Piliavin and Piliavin experiment, where the propensity of strangers to help blood-covered 'victims' was meat. This is now frowned upon under the policy of informed consent and is only used in rare and highly regulated circumstances.

ADVANTAGES OF FIELD EXPERIMENTS

Field experiments usually offer higher mundane realism and ecological validity than lab experiments. Participants are more likely to behave naturally, reducing the risk of demand characteristics, the Hawthorne effect, social desirability bias and investigator effects. For example, Sherif's Robbers Cave study observes boys forming teams and competing in a summer camp where such activities normally occur. Remember that a field experiment is still an experiment. The researchers will be manipulating an IV, measuring a DV, and trying to control as many extraneous variables as possible.

If there's no IV, it isn't a field experiment but a naturalistic observation.

DISADVANTAGES OF FIELD EXPERIMENTS

LESS CONTROL OF VARIABLES: the experimenter has less control over the environment, so extraneous variables may affect the outcome.  For example, in the Subway Samaritan experiment, researchers could not have controlled who got on the subway that day. As a result, we cannot be certain that the IV has caused the change in DV.  Cause and effect relationships are, therefore, difficult to establish. 

REPLICATION: Replication poses challenges in field experiments due to the inability to control various variables, as demonstrated by the Subway Samaritan study. Repeating the study's procedures exactly as before is complicated because external factors, such as the composition of passengers, cannot be controlled. For instance, if researchers attempted to replicate the study, they could not ensure that the same types of passengers would be in the subway during subsequent weeks. This variability introduces uncertainty regarding the consistency of results across different study instances, highlighting the difficulty of achieving precise replication in field settings.

SAMPLE BIAS: Field studies face challenges related to the lack of random allocation to conditions, which can impact the validity and interpretability of results. Unlike controlled experiments conducted in laboratory settings, field studies often rely on the non-randomised assignment of participants to different conditions due to practical or ethical constraints. This non-random allocation introduces potential biases and confounding variables that may affect the study's outcomes. As a result, researchers must carefully consider and account for these limitations when designing and interpreting field studies to ensure the validity and reliability of their findings..

ETHICS: In field experiments, ethical considerations encompass standard practices like obtaining informed consent from participants and ensuring that interventions avoid causing harm or discomfort to individuals or communities. What sets field experiments apart is that participants are unaware they are part of an experiment, making it challenging to obtain informed consent until after the study. Deception is also a factor in field experiments, as participants do not know they are being researched. It is imperative in field experiments that participants are debriefed and given a chance to withdraw any personal data that has been collected.

Some psychologists argue that if participants in field experiments encounter situations typical of everyday life, the study may inadvertently deceive them. For instance, witnessing a drunk person falling over is a relatively common occurrence. Additionally, in the "Subway Samaritan" study, researchers tallied the number of passengers offering help without collecting personal details, a practice often considered ethical. However, despite these precautions, some critics maintain that studies like the Subway Samaritan still raise ethical concerns. They suggest that participants may experience psychological distress from witnessing such behaviour, highlighting potential ethical dilemmas inherent in field experiments.

Ethical complexities arise in field experiments where personal details are collected, as exemplified by the "Tearoom Trade" study conducted by sociologist Laud Humphreys in the early 1970s. Although this study was not a field experiment, the ethical concerns are similar. In this study, Humphreys investigated male homosexual behaviour in public restrooms, conducting covert observations and obtaining participants' license plate numbers without their consent. Later, he tracked them down and interviewed them under the guise of a public health researcher. This study sparked significant ethical debate due to the invasion of privacy and lack of informed consent. In such cases, ensuring participant confidentiality and minimising potential harm become essential, underscoring the importance of meticulous ethical considerations in field research.

EXAMPLES:

1. "Broken Windows" Study: In this field experiment conducted by Wilson and Kelling, researchers manipulated environmental cues such as littering and vandalism in urban neighbourhoods to observe their effects on crime rates. The study aimed to test the "broken windows" theory, which suggests that visible signs of the disorder can encourage further criminal behaviour. This field experiment was conducted in a real-world setting (urban neighbourhoods), where the researchers manipulated variables to observe their impact on crime rates.

2. "Door-in-the-Face" Compliance Technique Study: This classic field experiment, conducted by Cialdini et al., aimed to investigate the effectiveness of the door-in-the-face compliance technique in increasing compliance with a request. Researchers approached individuals in a public setting (shopping mall) and made an initial large request (e.g., to chaperone delinquent juveniles for two hours a week). After the participant refused, researchers made a smaller request (e.g., to chaperone for one hour). This study is a field experiment conducted in a natural (shopping mall) environment, allowing for observations of real-life behaviours.

3. "Stand on the Right" Campaign Study: In this field experiment, researchers aimed to assess the effectiveness of a campaign encouraging individuals to stand on the right side of escalators to allow others to walk on the left. The experiment involved implementing the campaign in various subway stations and observing the behaviour of commuters. This study is a field experiment because it took place in a real-world setting (subway stations), where researchers manipulated environmental cues (campaign signage) to observe changes in behaviour.

4. The "Subway Samaritan" study conducted by Darley and Batson is another notable example of a field experiment. In this study, researchers staged an emergency scenario in which a person in distress (an actor) appeared to be having a seizure on the subway. The experiment investigated whether bystanders would offer assistance to the person in need. This study is considered a field experiment because it was conducted in a real-world setting (the subway), allowing researchers to observe spontaneous reactions and behaviours of participants in response to the emergency.